U.S. patent application number 11/209732 was filed with the patent office on 2007-03-15 for digital core workflow method using digital core image.
Invention is credited to Yuanxian Greg Hu.
Application Number | 20070061079 11/209732 |
Document ID | / |
Family ID | 37770747 |
Filed Date | 2007-03-15 |
United States Patent
Application |
20070061079 |
Kind Code |
A1 |
Hu; Yuanxian Greg |
March 15, 2007 |
Digital core workflow method using digital core image
Abstract
A method for registration and correction of downhole core depth
information using digital core images. Digital core images are
employed during depth registration, with top and base depths for a
selected interval being determined by field data and a digital
ruler which calculates an actual interval length based on the
digital core image. Correction of the top and base depths is
enabled by side-by-side display of the digital core image interval
and corresponding well logging data, which displayed information
can be manipulated by a user to provide more accurate depth
information. The method further allows for shale volume
calculations and facies interpretation, again employing the digital
core images.
Inventors: |
Hu; Yuanxian Greg; (Calgary,
CA) |
Correspondence
Address: |
GOWLING LAFLEUR HENDERSON LLP
SUITE 1400, 700 2ND ST. SW
CALGARY
AB
T2P 4V5
CA
|
Family ID: |
37770747 |
Appl. No.: |
11/209732 |
Filed: |
August 24, 2005 |
Current U.S.
Class: |
702/6 |
Current CPC
Class: |
E21B 25/00 20130101;
E21B 47/04 20130101 |
Class at
Publication: |
702/006 |
International
Class: |
E21B 47/00 20060101
E21B047/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 23, 2005 |
CA |
2,516,872 |
Claims
1. A method for registration of downhole core depth information
comprising the steps of: a. providing at least one digital image of
a core sample from a well; b. displaying the at least one digital
image on a display device; c. selecting a displayed interval from
the displayed at least one digital image, the displayed interval
being defined by a first depth and a second depth spaced from the
first depth; d. establishing an approximate actual depth value for
the first depth of the displayed interval; and e. measuring the
length of the displayed interval to determine an approximate actual
depth value for the second depth of the displayed interval.
2. A method for registration and correction of downhole core depth
information comprising the steps of: a. providing at least one
digital image of a core sample from a well; b. providing well
logging data corresponding to the core sample; c. displaying the at
least one digital image on a display device; d. selecting a
displayed interval from the displayed at least one digital image,
the displayed interval being defined by a first depth and a second
depth spaced from the first depth; e. establishing an approximate
actual depth value for the first depth of the displayed interval;
f. measuring the length of the displayed interval to determine an
approximate actual depth value for the second depth of the
displayed interval; g. displaying the well logging data adjacent
the displayed interval; h. allowing for comparison of the well
logging data and the displayed interval; and i. allowing for
correction of the first depth and the second depth.
3. A method for on-line registration and correction of downhole
core depth information comprising the steps of: a. providing a web
portal for accessing digital images and well logging data and a
server for storing the digital images and the well logging data; b.
allowing for uploading of at least one digital image of a core
sample from a well to the server; c. allowing for uploading of well
logging data from the well to the server; d. downloading and
displaying the at least one digital image on a display device; e.
selecting a displayed interval from the displayed at least one
digital image, the displayed interval being defined by a first
depth and a second depth spaced from the first depth; f.
establishing an approximate actual depth value for the first depth
of the displayed interval; g. measuring the length of the displayed
interval to determine an approximate actual depth value for the
second depth of the displayed interval; h. downloading and
displaying the well logging data adjacent the displayed interval;
i. allowing for comparison of the well logging data and the
displayed interval; and j. allowing for correction of the first
depth and the second depth.
4. The method of claim 1 or 2 wherein the providing of the at least
one digital image of a core sample from a well is achieved by
obtaining the at least one digital image from an oil company.
5. The method of any one of claims 1 to 3 wherein the display
device is a computer monitor receiving signals from a user computer
workstation.
6. The method of any one of claims 1 to 3 wherein the displayed
interval is selected by means of: positioning a mouse cursor over a
first location on the displayed at least one digital image
representing the first depth; clicking a mouse button to select the
first location; positioning the mouse cursor over a second location
on the displayed at least one digital image representing the second
depth; and clicking the mouse button to select the second
location.
7. The method of any one of claims 1 to 3 wherein the first depth
represents the top depth of the displayed interval, and the second
depth represents the base depth of the displayed interval.
8. The method of any one of claims 1 to 3 wherein the first depth
represents the base depth of the displayed interval, and the second
depth represents the top depth of the displayed interval.
9. The method of any one of claims 1 to 3 wherein the approximate
actual depth value for the first depth is established based on
field data.
10. The method of any one of claims 1 to 3 wherein the length of
the displayed interval is measured by means of a predetermined
digital ruler that equates pixel numbers with a set length
value.
11. The method of claim 2 or 3 wherein the providing of the well
logging data is achieved by obtaining the well logging data from an
oil company.
12. The method of claim 2 or 3 wherein the allowing for comparison
of the well logging data and the displayed interval is achieved by
means of displaying the well logging data and the displayed
interval in parallel, adjacent orientation, enabling a user to
visually inspect the well logging data and the displayed interval
for correlation purposes.
13. The method of claim 2 or 3 wherein the allowing for correction
of the first depth and the second depth is achieved by means of:
allowing a user to pick corresponding markers on the well logging
data and the displayed interval, by means of mouse cursor
positioning and location selection; inserting correlation lines
connecting the corresponding markers; inspecting the digital
interval to determine if there are any lost core intervals; adding
any desired sub-intervals to the displayed interval to represent
lost core intervals; and axially shifting the displayed interval
such that the correlation lines are generally horizontal.
14. A computer readable memory having recorded thereon statements
and instructions for execution by a computer to carry out the
method of any one of claims 1 to 3.
15. A method for determining shale volume in a core sample from a
well comprising the steps of: a. selecting at least one region of a
digital image of the core sample to represent a shale type; b.
specifying colour threshold values for the shale type; c.
specifying shale volume calculation options; and d. calculating a
shale volume value.
16. The method of claim 15 wherein a plurality of shale volume
values are calculated, each at a discrete shale volume depth point,
enabling plotting of a shale volume curve which can be displayed on
a display device.
17. The method of any one of claims 1 to 3 comprising the further
steps of: a. selecting at least one region of the at least one
digital image of the core sample to represent a shale type; b.
specifying colour threshold values for the shale type; c.
specifying shale volume calculation options; and d. calculating a
shale volume value.
18. A method for enabling facies interpretation of a core sample
from a well comprising the steps of: a. displaying a digital image
of the core sample on a display device; b. defining at least one
facies by means of characteristics including facies colour and
minimum and maximum shale volume value cut-offs, the facies colour
and minimum and maximum shale volume value cut-offs being
determined by reference to the digital image of the core sample; c.
selecting a facies interval directly from the digital image by
selecting first and second locations representing top and base
depths of the facies interval; d. identifying the at least one
facies with at least a part of the facies interval based on the
characteristics; e. displaying the at least one facies on the
display device according to the top and base depths; and f.
allowing for inspection and interpretation of the displayed at
least one facies.
19. The method of any one of claims 1, 2, 3 and 15 comprising the
further steps of: a. displaying the digital image of the core
sample on the display device; b. defining at least one facies by
means of characteristics including facies colour and minimum and
maximum shale volume value cut-offs, the facies colour and minimum
and maximum shale volume value cut-offs being determined by
reference to the digital image of the core sample; c. selecting a
fades interval directly from the digital image by selecting first
and second locations representing top and base depths of the facies
interval; d. identifying the at least one facies with at least a
part of the facies interval based on the characteristics; e.
displaying the at least one facies on the display device according
to the top and base depths; and f. allowing for inspection and
interpretation of the displayed at least one facies.
20. The method of claim 2 or 3 comprising the further step of using
corrected top and base depths to annotate the at least one digital
image.
21. A digital core workflow method comprising the steps of: a.
providing at least one digital image of a core sample from a well;
b. providing well logging data corresponding to the core sample; c.
displaying the at least one digital image on a display device; d.
selecting a displayed interval from the displayed at least one
digital image, the displayed interval being defined by a first
depth and a second depth spaced from the first depth; e.
establishing an approximate actual depth value for the first depth
of the displayed interval; f. measuring the length of the displayed
interval to determine an approximate actual depth value for the
second depth of the displayed interval; g. displaying the well
logging data adjacent to the displayed interval; h. allowing for
comparison of the well logging data and the displayed interval to
enable selecting corresponding depth markers on the displayed
interval and the displayed well logging data, and to enable
adjusting lost core intervals; i. allowing for correction of the
first depth and the second depth; j. selecting at least one region
of the at least one digital image of the core sample to represent a
shale type; k. specifying colour threshold values for the shale
type; l. specifying shale volume calculation options; m.
calculating a shale volume value; n. defining at least one facies
by means of characteristics including facies colour and minimum and
maximum shale volume value cut-offs, the facies colour and minimum
and maximum shale volume value cut-offs being determined by
reference to the at least one digital image; o. selecting a facies
interval directly from the at least one digital image by selecting
first and second locations representing top and base depths of the
facies interval; p. identifying the at least one facies with at
least a part of the facies interval based on the characteristics;
q. displaying the at least one facies on the display device
according to the top and base depths; r. allowing for inspection
and interpretation of the displayed at least one facies; and s.
using corrected top and base depths to annotate the at least one
digital image.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to methods for determining
formation depths, and more particularly to core logging
methods.
BACKGROUND OF THE INVENTION
[0002] Although relatively expensive, coring--the taking of
subsurface rock samples with specialized drilling tools--is one of
the oldest methods of subsurface formation evaluation and the only
method (other than cuttings analysis) for providing rock samples
for laboratory analysis. Coring is used to provide geologists and
other earth scientists with physical rock samples that can provide
much-needed information on a direct rather than indirect basis.
[0003] A core bit is used to cut a generally cylindrical section of
rock that is contained within a coring tube, which section within
the tube is then brought to surface (any expected portion of the
core that does not make it back to surface is considered to be
"lost core"). The core tube is marked with a well name, core
number, and subsurface interval depths and orientation (which end
of the core was originally up-hole) by workers on the drilling rig.
The marked core tubes, which may need to be frozen in the field
(especially oil sands cores), are transported to a core handling
lab where cores (with tube) are cut or "slabbed" along the tube
length into two halves (see step 20 of FIG. 2, which Figure
summarizes the traditional physical core workflow), one side for
viewing and the other side for cutting physical samples. The
slabbed two halves are placed in two separate sets of boxes for
future handling, with the viewing side being cleaned first before
it is placed into core boxes. Core boxes of the two separate sets
are labelled in a certain way to preserve the field information of
the cores, including the well name, core number and orientation.
Additional information (e.g. physical core box number) is added to
the box label. If the cores are frozen, the sample side of the core
will be sent back to a freezer to preserve the original state, and
the viewing side of the core will be displayed in a room to be
dried at step 21, normally at room temperature and typically for 24
to 48 hours.
[0004] Various tests and analyses can then be conducted on the
cores in a laboratory setting. Traditionally, after the viewing
side of the cores are dried to a certain degree, geologists use the
physical core to engage in "core logging" at step 22 which includes
determining core depths and core order in the subsurface and
describing the cores. Geologists also need to provide guidelines
for lab technicians to select, or select by themselves, sample
intervals (at step 23) and then do physical samplings (at step 27)
with digital image shooting (at step 24) and image annotation (at
step 25) in between.
[0005] Geologists need to determine exactly where (at what depths)
the rock samples were taken from in order to understand geology
deep in the Earth and to assess the spatial occurrence of mineral
resources. As depth analysis is part of core logging, core depth
correction has also been routinely performed by geologists for many
years. During drilling, core depths are recorded by workers on a
drilling rig, but very often they are not accurate (off-depth), and
the geologist is faced with the task of attempting to determine
depth information based on rock that has already been brought to
surface.
[0006] The task of depth determination has been aided considerably
by the development and use of special tools (well logging tools)
which measure physical rock properties around the borehole. These
rock properties include rock gamma radiation, resistivity, and
porosity, among many others. Logging tools are sent downhole and
take measurements at even spacing along the borehole. All the
measurements for a given rock property, when plotted out against
depth, will produce a rock property curve (or well log). Any given
well will normally have a suite of well logs, and the depths on
well logs are believed to be generally accurate if good logging
procedures have been followed during well logging. As can be seen,
rock samples and well logs provide different kinds of information
from virtually the same object (rock), an analogy being the human
body and its X-ray image. As a result, it is expected that a suite
of well logs will match the physical cores in a certain way, which
is the basis of core depth correction with well logging data as the
depth reference.
[0007] Depth correction is used to shift initial core depths to
match the depths determined by well logging data (including well
logs and borehole imaging logs), as the latter is considered to
provide accurate depth information. In a traditional physical core
workflow, geologists bring a paper copy of the relevant well logs
to the lab and lay them out on a table side-by-side with the core
boxes, along with a copy of the field core depth sheet. They will
then locate a depth reference marker on the well logs and its
corresponding depth marker on the cores, assigning the depth of the
depth reference marker to the corresponding core marker. Based on
core length from the core depth reference marker and the depth of
the marker itself, geologists then calculate depths of any points
on the cores above and below the marker. They repeat this process
until all the cores are depth-shifted or depth-corrected and have a
good depth match with the well logs. A corrected core depth table,
which normally includes top and base depths of each core box (and
lost core intervals if any exist), is produced and provided to the
lab for calculating sample depths. They may need to adjust lost
core intervals (add or delete) and amend core orders to achieve a
good match between the cores and the well logs. A mismatch between
cores and well logs is normally caused by (1) core depths
(including lost core intervals) being incorrectly recorded in the
fields, (2) core expansion, (3) core being upside-down, (4) core
being misplaced, or (5) any combination of these four. Depth
correction alone normally takes 3 to 4 hours for a typical oil
sands well.
[0008] Following core depth correction, geologists engage in core
description by looking at physical cores (including visually
estimating volume of shale), observing and describing the cores and
recording a description on paper or in a computer file. Core
description will normally take 4 to 8 hours per oil sands well.
Core depth correction and description are normally performed by one
geologist.
[0009] After the cores are described, the geologist will provide
sampling guidelines to enable a lab technician to select the sample
intervals (or mark sample intervals by themselves). A lab
technician will select sample intervals on the viewing portion of
the cores, mark the sample intervals on the core boxes, and then
calculate the sample depths based on the corrected core depth table
provided by the geologist. The lab technician will also need to
determine the physical position on the core for every meter depth,
and these positions are marked on the core boxes for later use.
Determination of sample depths and meter depth are traditionally
achieved by using measurements of physical core lengths to enable
calculation based on core top/base depths in the corrected core
depth table. Sample selection/marking, sample depth calculation and
determination/marking of position for each meter depth normally
takes 2 to 4 hours per oil sands well. The marked sample intervals
will usually then be translated to the sampling portion of the
cores by another lab technician to guide physical sampling.
[0010] The viewing side of the core, which has been described by
the geologist and marked with sample intervals, is then transported
to a digital lab for digital imaging at step 24. Before digital
images of the cores can be taken, the photographer needs to
manually place many labels onto the physical cores, normally with
magnetic stickers. There are three key label types (in addition to
others): (1) top and base depths of cores; (2) sample intervals and
sample numbers; and (3) meter depths. The manual, hard-coded
labelling is a very time-consuming process and prone to errors; it
also makes any updating of labels extremely difficult, especially
when the geologist changes a depth. Changes in the geologist's core
depths normally require re-calculating of meter depths/sample
depths, which also requires "laying out" of the physical cores
again and probably re-shooting the digital images. Labelling and
digital imaging typically take 3 to 4 hours per oil sands well. Any
label updating or re-shooting will add extra time to this process.
This process produces raw digital images with labels.
[0011] Raw digital images with labels need to be cropped, and other
information such as well name, depth scale, and company logo will
be added to produce ready-for-print images at step 25 or 26. This
process normally takes less than one hour per oil sands well.
Ready-for-print digital core images will then be printed on
high-quality photographic paper to produce core photographs or on
paper at step 26. A paper copy is generally used by the lab
technician to translate sample intervals that are marked on
view-side cores and recorded on the digital images to the
sample-side cores to enable physical sampling. The core photograph
hard copies are normally not printed out on photographic paper
until the passage of 1 to 4 weeks, to avoid any potential waste
should any update on image annotation be needed.
[0012] As is abundantly clear from the foregoing, there are
numerous disadvantages to the traditional physical core workflow:
[0013] 1) Several people are necessarily involved. More than eight
people (one geologist and more than seven lab technicians) are
usually involved, from core slabbing to producing deliverable
results for oil companies. The more people that are involved, the
harder it is to co-ordinate and the more opportunities there are
for mistakes. There are more inherent errors as well. [0014] 2) The
traditional workflow is time-consuming (as can be seen in FIG. 2).
It typically takes 24 to 48 hours to dry oil sands cores. Seventeen
to twenty-two hours elapses from core logging (core depth
correction and description) to producing ready-for-print digital
images and getting ready for physical sampling, and another 1 to 4
weeks will usually pass while waiting for the core photographs.
[0015] 3) The reliance on a physical core workflow. Most processes
are happening on physical cores. People involved therefore need to
be physically present in a lab, working on the physical cores. The
workflow also accordingly requires usage of physical lab space.
[0016] 4) Geologists do the depth correction and core logging with
physical paper-copy well logs and physical cores. In order for them
to do core depth correction, geologists need to visually estimate
the depth of a depth marker on well logs, and then manually
translate that depth to the corresponding core depth marker, to
physically measure the core length at a given point from a core
marker with a measuring tape (and then to calculate the corrected
depth of the given point). They need to repeat the above process
for every point for which they need to calculate a corrected core
depth. The process is slow and prone to errors; in addition, any
change in the depth of a depth marker requires repetition of the
above steps. [0017] 5) The use of manual, hard-coded labelling. All
sample intervals, core depth and meter depth labels, plus all other
labels are manually placed on the physical cores before any digital
images are taken. The labelling process is time-consuming and prone
to errors, and the resultant labelling (now part of the images) is
hard-coded and makes it extremely difficult to make any required
updates and changes. [0018] 6) Due to the time-consuming nature of
the traditional workflow, sample selection and sample depth
calculation are normally carried out by a lab technician with
sampling guidelines provided by a geologist. As a result, sample
selection is not totally controlled by the geologist, and very
often more samples are taken than is needed.
[0019] What is needed, therefore, is an improved and more efficient
workflow that overcomes the above disadvantages of the traditional
physical workflow.
SUMMARY OF THE INVENTION
[0020] The present invention accordingly seeks to provide a method
for utilising digital core images in depth registration and
correction processes.
[0021] The present invention further seeks to provide a digital,
integrated workflow comprising a method for utilising digital core
images in core depth registration, core depth correction, sample
selection, digital image annotation, shale volume quantification,
facies interpretation and core description.
[0022] According to a first aspect of the present invention there
is provided a method for registration of downhole core depth
information comprising the steps of: [0023] a. providing at least
one digital image of a core sample from a well; [0024] b.
displaying the at least one digital image on a display device;
[0025] c. selecting a displayed interval from the displayed at
least one digital image, the displayed interval being defined by a
first depth and a second depth spaced from the first depth; [0026]
d. establishing an approximate actual depth value for the first
depth of the displayed interval; and [0027] e. measuring the length
of the displayed interval to determine an approximate actual depth
value for the second depth of the displayed interval.
[0028] According to a second aspect of the present invention there
is provided a method for registration and correction of downhole
core depth information comprising the steps of: [0029] a. providing
at least one digital image of a core sample from a well; [0030] b.
providing well logging data corresponding to the core sample;
[0031] c. displaying the at least one digital image on a display
device; [0032] d. selecting a displayed interval from the displayed
at least one digital image, the displayed interval being defined by
a first depth and a second depth spaced from the first depth;
[0033] e. establishing an approximate actual depth value for the
first depth of the displayed interval; [0034] f. measuring the
length of the displayed interval to determine an approximate actual
depth value for the second depth of the displayed interval; [0035]
g. displaying the well logging data adjacent the displayed
interval; [0036] h. allowing for comparison of the well logging
data and the displayed interval; and [0037] i. allowing for
correction of the first depth and the second depth.
[0038] According to a third aspect of the present invention there
is provided a method for on-line registration and correction of
downhole core depth information comprising the steps of: [0039] a.
providing a web portal for accessing digital images and well
logging data and a server for storing the digital images and the
well logging data; [0040] b. allowing for uploading of at least one
digital image of a core sample from a well to the server; [0041] c.
allowing for uploading of well logging data from the well to the
Server; [0042] d. downloading and displaying the at least one
digital image on a display device; [0043] e. selecting a displayed
interval from the displayed at least one digital image, the
displayed interval being defined by a first depth and a second
depth spaced from the first depth; [0044] f. establishing an
approximate actual depth value for the first depth of the displayed
interval; [0045] g. measuring the length of the displayed interval
to determine an approximate actual depth value for the second depth
of the displayed interval; [0046] h. downloading and displaying the
well logging data adjacent the displayed interval; [0047] i.
allowing for comparison of the well logging data and the displayed
interval; and [0048] j. allowing for correction of the first depth
and the second depth.
[0049] According to a fourth aspect of the present invention, there
is provided a method for determining shale volume in a core sample
from a well comprising the steps of: [0050] a. selecting at least
one region of a digital image of the core sample to represent a
shale type; [0051] b. specifying colour threshold values for the
shale type; [0052] c. specifying shale volume calculation options;
and [0053] d. calculating a shale volume value.
[0054] Preferably, a plurality of shale volume values are
calculated, each at a discrete shale volume depth point, enabling
plotting of a shale volume curve which can be displayed on a
display device. This fourth aspect can be combined with the methods
of the first, second and third aspects of the present
invention.
[0055] According to a fifth aspect of the present invention, there
is provided a method for enabling facies interpretation of a core
sample from a well comprising the steps of: [0056] a. displaying a
digital image of the core sample on a display device; [0057] b.
defining at least one facies by means of characteristics including
facies colour and minimum and maximum shale volume value cut-offs,
the facies colour and minimum and maximum shale volume value
cut-offs being determined by reference to the digital image of the
core sample; [0058] c. selecting a facies interval directly from
the digital image by selecting first and second locations
representing top and base depths of the facies interval; [0059] d.
identifying the at least one facies with at least a part of the
facies interval based on the characteristics; [0060] e. displaying
the at least one facies on the display device according to the top
and base depths; and [0061] f. allowing for inspection and
interpretation of the displayed at least one facies.
[0062] This fifth aspect can be combined with the methods of the
first, second, third and fourth aspects of the present
invention.
[0063] According to a sixth aspect of the present invention, there
is provided a computer readable memory having recorded thereon
statements and instructions for execution by a computer to carry
out the method of any one of the other aspects of the present
invention.
[0064] According to a seventh aspect of the present invention,
there is provided a digital core workflow method comprising the
steps of: [0065] a. providing at least one digital image of a core
sample from a well; [0066] b. providing well logging data
corresponding to the core sample; [0067] c. displaying the at least
one digital image on a display device; [0068] d. selecting a
displayed interval from the displayed at least one digital image,
the displayed interval being defined by a first depth and a second
depth spaced from the first depth; [0069] e. establishing an
approximate actual depth value for the first depth of the displayed
interval; [0070] f. measuring the length of the displayed interval
to determine an approximate actual depth value for the second depth
of the displayed interval; [0071] g. displaying the well logging
data adjacent to the displayed interval; [0072] h. allowing for
comparison of the well logging data and the displayed interval to
enable selecting corresponding depth markers on the displayed
interval and the displayed well logging data, and to enable
adjusting lost core intervals; [0073] i. allowing for correction of
the first depth and the second depth; [0074] j. selecting at least
one region of the at least one digital image of the core sample to
represent a shale type; [0075] k. specifying colour threshold
values for the shale type; [0076] i. specifying shale volume
calculation options; [0077] m. calculating a shale volume value;
[0078] n. defining at least one facies by means of characteristics
including facies colour and minimum and maximum shale volume value
cut-offs, the facies colour and minimum and maximum shale volume
value cut-offs being determined by reference to the at least one
digital image; [0079] o. selecting a facies interval directly from
the at least one digital image by selecting first and second
locations representing top and base depths of the facies interval;
[0080] p. identifying the at least one facies with at least a part
of the facies interval based on the characteristics; [0081] q.
displaying the at least one facies on the display device according
to the top and base depths; [0082] r. allowing for inspection and
interpretation of the displayed at least one facies; and [0083] s.
using corrected top and base depths to annotate the at least one
digital image.
[0084] In exemplary embodiments of the present invention, the
providing of the well logging data and the at least one digital
image of a core sample from a well is achieved by obtaining the
well logging data and the at least one digital image from an oil
company. The display device is preferably a computer monitor
receiving signals from a user computer workstation.
[0085] The displayed interval is preferably selected by means of:
positioning a mouse cursor over a first location on the displayed
at least one digital image representing the first depth; clicking a
mouse button to select the first location; positioning the mouse
cursor over a second location on the displayed at least one digital
image representing the second depth; and clicking the mouse button
to select the second location. The first depth may represent either
the top depth of the displayed interval (with the second depth then
representing the bottom depth of the displayed interval) or the
bottom depth (the second depth then representing the top depth).
The approximate actual depth value for the first depth is
preferably established based on field data, as explained below, and
the length of the displayed interval is preferably measured by
means of a predetermined digital ruler that equates pixel numbers
with a set length value.
[0086] After depth registration is accomplished, comparison and
correction processes can be conducted. Preferably, the step of
allowing for comparison of the well logging data and the displayed
interval is achieved by means of displaying the well logging data
and the displayed interval in parallel, adjacent orientation,
enabling a user to visually inspect the well logging data and the
displayed interval for correlation purposes. Allowing for
correction of the first and second depths is then preferably
achieved by means of: allowing a user to pick corresponding markers
on the well logging data and the displayed interval, by means of
mouse cursor positioning and location selection; inserting
correlation lines connecting the corresponding markers; inspecting
the digital interval to determine if there are any lost core
intervals; adding any desired sub-intervals to the displayed
interval to represent lost core intervals; and axially shifting the
displayed interval such that the correlation lines are generally
horizontal. Preferred embodiment of the present invention comprise
the further step of using corrected top and base depths to annotate
the at least one digital image.
[0087] The use of digital core images during depth registration,
rather than reliance on the presence of physical core samples,
provides tremendous advantages for geologists and the companies
they work for, particularly when this is linked to the use of the
Internet for access and dissemination of information. While digital
images have been used in the past to summarize core logging
information, and occasionally for comparison against well logging
data during depth correction processes, the advantage of using
digital core images in depth registration is a novel development in
the field.
[0088] A method according to the present invention requires fewer
personnel, with time expenditure reduced substantially when
compared with traditional methods. All information, including well
logs and cores, is provided in digital form and can therefore be
easily manipulated, analyzed, and distributed to others. The
geologist need no longer be confined to a laboratory setting to
engage in core logging, but can instead be at some remote location
anywhere in the world at a computer workstation.
[0089] Further, geologists engaged in traditional workflow can only
do depth correction one box at a time, without having ready access
to the whole picture of the entire well. The present invention, by
contrast, can display both well logs and core images for the entire
well on one screen by changing depth scale, and depth correction
can be performed at the same time for the entire well. The methods
of the present invention allow a user to attempt different
correlation and matching scenarios before proceeding to the depth
correction stage, and a user can easily insert or delete lost core
or adjust core order.
[0090] In the end, the present invention can produce highly
accurate depth determinations, integrating depth
registration/correction with sample picking, image annotation,
V.sub.SH (shale volume) calculation and picking facies intervals
directly from digital core images, streamlining the entire core
workflow.
[0091] A detailed description of an exemplary embodiment of the
present invention is given in the following. It is to be
understood, however, that the invention is not to be construed as
limited to this embodiment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0092] In the accompanying drawings, which illustrate an exemplary
embodiment of the present invention:
[0093] FIG. 1 is a schematic illustration of a digital core
workflow according to the present invention;
[0094] FIG. 2 is a schematic illustration of a traditional physical
core workflow;
[0095] FIG. 3 is a schematic illustration of a system for executing
a method according to the present invention;
[0096] FIG. 4 is a schematic illustration of the modules and
information flow of the present invention;
[0097] FIG. 5 is a flowchart illustrating a method according to the
present invention;
[0098] FIG. 6 is a representation of a login window;
[0099] FIG. 7 is a representation of a project name entry
window;
[0100] FIG. 8 is a representation of a well name entry window;
[0101] FIG. 9 is a flowchart illustrating the depth registration
process;
[0102] FIG. 10 is a screen shot of a digital ruler definition
window;
[0103] FIG. 11 is a representation of a raw digital core image with
core number and box number as the only labels;
[0104] FIG. 12 is a screen shot of a Smart Depths.TM. window
illustrating how various depth registration information is
displayed on an annotated core image;
[0105] FIG. 13 is a screen shot of a well log loading window;
[0106] FIG. 14 is a flowchart illustrating the depth correction
process;
[0107] FIG. 15 is a schematic illustration of the adjacent display
of well logging data and stacked core images during the
marker-picking portion of the depth correction process;
[0108] FIG. 16 is a schematic illustration of the adjacent display
of well logging data and stacked core images during the fine-tuning
portion of the depth correction process;
[0109] FIG. 17 is a screen shot of the display during the
fine-tuning portion of the depth correction process;
[0110] FIG. 18 is a lost core deletion window;
[0111] FIG. 19 is a lost core insertion window;
[0112] FIG. 20 is a screen shot illustrating uncorrected and
corrected depths on a display;
[0113] FIG. 21 is a raw digital image with annotations;
[0114] FIG. 22 is a raw digital image provided with a frame and
associated information;
[0115] FIG. 23 is a digital core image with full annotation and
frame information;
[0116] FIG. 24 is a screen shot of a digital core image after
selection of two sample intervals;
[0117] FIG. 25 is a sample registration window;
[0118] FIG. 26 is a representation of a sand/shale calibration
window for shale volume calculations;
[0119] FIG. 27 is a shale volume calculation options window;
[0120] FIG. 28 is a screen shot of one embodiment of a display in
the Depth Correction Window;
[0121] FIG. 29 is a screen shot of a facies definition window;
and
[0122] FIG. 30 is a flowchart illustrating the facies
interpretation process.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
[0123] A preferred embodiment of the present invention will now be
described with reference to the accompanying drawings. The
preferred embodiment of the present invention will be described
below by reference to an overall digital core workflow, which
digital core workflow comprises a method and system referred to as
ADFM.TM. (an acronym for "Accurate Depths for Facies and
Modeling").
Digital Core Workflow
[0124] Referring now in detail to FIG. 1, a digital core workflow
is illustrated in accordance with the present invention. As can be
seen, after cores (which may be frozen) are slabbed into two halves
at step 1, the view-side cores are placed at step 2a into a
specialized drying room 2b for approximately 10 to 14 hours to dry
the cores, instead of simply displaying the cores in an ordinary
core-view room. The specialized drying room 2b is tightly sealed
after the doors are dosed and is separated from other ordinary view
rooms or office rooms. The temperature in the room is settable, and
is normally higher than room temperature. The humidity is settable,
as well, through dehumidifiers, at a level normally much lower than
typical office conditions. The room 2b is also provided with good
internal circulation. The composite effect of the above three
conditions is that the cores can be dried much faster, reducing
drying time from 24 to 48 hours down to 10 to 14 hours for typical
oil sands cores.
[0125] Dried cores are then transported to a digital imaging studio
for digital imaging at step 3. This workflow order is very
different from the traditional physical core workflow in which this
step 3 happens near the end of the workflow process (see step 24 in
FIG. 2). This change in workflow order allows for a prompt
acquisition of the digital format data of the cores, to enable the
depth registration process (described below) to begin. Only the
core number and physical box number are required to be placed onto
the physical cores for labelling, since any other labels can be
added digitally with the ADFM system at step 4. This simplified
labelling requirement can reduce digital core image shooting time
from 3 to 4 hours per oil sands well to less than one hour.
[0126] All processes at step 4 take place digitally in the ADFM
system, and the view-side cores can be sent at step 6 to a core
storage facility. The ADFM system, described in detail below, is a
computer-assisted system that enables the use of digital core
images in the core logging work that is normally done by geologists
and some of the work traditionally done by lab technicians. As will
be clear from the following description, this integrated digital
ADFM system overcomes the disadvantages of the traditional physical
workflow described above. The preferred embodiment of the ADFM
system comprises the following seven functionalities: [0127] 1)
Displaying digital well logging data such as digital well logs,
micro-formation imaging, etc. for use as a depth reference; [0128]
2), Registering (assigning) core depths on raw digital images;
[0129] 3) Performing core depth correction using digital well
logging data and digital core images; [0130] 4) Selecting samples
on digital core images; [0131] 5) Calculating sample depths; [0132]
6) Annotating raw digital core images with desired labels and
generating composite digital images that combine raw digital core
images with annotation for core photograph hardcopy printing
(annotations may include sample intervals and sample numbers, core
top/base depths, meter depths, well name, company name, company
logo, depth scale bar, plus other labels); [0133] 7) Calculating
volume of shale directly from digital core images; [0134] 8)
Functionalities for enabling geologists to record their core
descriptions and export the results, including facies (rock groups)
determinations; and [0135] 9) Exporting results.
[0136] The ADFM system preferably produces the following five sets
of results: [0137] 1) Corrected core depths, with lost core
interval depths, for core box labelling; [0138] 2) A sample list
with corrected core depths, NA (Not Analyzed) intervals and lost
core intervals; [0139] 3) Annotated digital core images that are
ready for hardcopy print on photographic paper (annotated images
are also provided by paper copy to the lab to assist in physical
sampling on sample-side cores, according to sample intervals
annotated on the images); [0140] 4) V.sub.SH and facies results;
and [0141] 5) Selected content of the Depth Correction Window.
[0142] One implementation of the preferred embodiment of the ADFM
system has demonstrated that the ADFM system can reduce the time
from the digital imaging stage to the physical sampling stage from
17 to 22 hours per oil sands well to approximately 3 to 5 hours. It
can also reduce the number of required personnel from five people
(as required in the traditional workflow) to two people (in the
ADFM system--one photographer for digital imaging and one geologist
for operating the ADFM system). With ADFM, more accurate core
depths and sample depths can be produced. A core photo hardcopy can
be printed out on photographic paper immediately upon completion of
the desired processing and delivered to the oil company within 1 to
2 days, since core depth correction, sample selection and image
annotation are handled by one geologist in a very efficient and
consistent way. This is in contrast to the traditional physical
core workflow where one might wait 1 to 4 weeks before digital
image printing, since information for annotation is obtained from
different sources: (1) core depths are provided by a geologist, (2)
meter depths and sample intervals are provided by a lab technician,
(3) most labels are put on by a photographer, and (4) the remaining
labels such as company name, well name, etc. are added by an image
editor.
ADFM System
[0143] Referring now in detail to FIG. 3, an ADFM system according
to the present invention is illustrated for executing a method
according to the present invention. As can be seen, an ADFM user
31, with access to the ADFM system 32, is connected through the
Internet 33 to a data server 34 to retrieve their assigned
privileges from the data server 34, as described in detail below.
The user 31 is provided with digital images and well logging data
either through the Internet connection or by means of portable
storage media 35. The clients 36 (oil companies, labs, etc.)
provide raw data to users by uploading raw data to the data server
(by browser or ftp client 37) or through portable storage media 35,
the users 31 typically being geologists or other earth science
professionals employed by the oil company 36 as fulltime or
contract workers to analyse the raw data from the clients 36 and
then upload analyzed results to the data server 34. The users 31
can also deliver results (for example, back to the oil company 36)
through portable media 35 or paper copy. Clients 36 or any
authorized users can browse or download results from the data
server 34. When raw data is provided in a digital format (digital
core images and digital well logging data) and results are
delivered in a digital format, ADFM users 31 can accordingly
remotely perform core logging work without ever looking at any
physical cores in a traditional lab, and can provide their services
to different clients globally, which is logistically extremely
difficult to achieve in the traditional physical core workflow.
[0144] The preferred embodiment of a method according to the
present invention comprises a series of stages, namely Program
Initiation, Depth Registration, Depth Correction, Annotation,
Finalizing Annotated Images, Sample Selection, V.sub.SH (shale
volume) Calculation, Facies Interpretation, and Result Export
(including Depth Correction Window Export). These stages each have
their own corresponding module, as is illustrated in detail in FIG.
4, and will each be addressed in detail in the following, with
reference to the accompanying drawings.
Program Initiation
[0145] Referring now in detail to FIG. 5, Program Initiation begins
when the program is accessed by a user. As the preferred embodiment
is web-based, the user would utilise an Internet connection to log
onto the server to obtain the assigned privileges from the data
server. The user will be presented at step 50 with a window (see
FIG. 6) that enables entering a username and password, which
username and password will have been set up and stored in the data
server before the user requires access to the ADFM program. The
preferred user verification process is of a commonly employed form.
When the user enters their username and password at step 50, the
program will connect to the database server to retrieve preassigned
access privileges at step 51 using the username and password. If
the combination of the username and password exists in the data
server, the program will enable or disable certain modules (see
FIG. 4) of the ADFM system based on the retrieved access
privileges. If, for example, the retrieved value for a module is 1,
the module is enabled; if the retrieved value for a module is 0,
the module is disabled.
[0146] Once user verification is accomplished and the user has been
provided access to the full program functionality, the next step is
to create a "project" at step 52. To do this, the user enters a
project name in an input window (such as that shown in FIG. 7); the
project name then becomes the name of a folder on the hard disk.
The user is preferably given a number of options after the new
project is created: [0147] a) Open a project, which enables the
user to select a project folder and set it as a working project;
[0148] b) Save, where information is saved; [0149] c) Save as, to
save a project under a new name; and [0150] d) Exit, to quit the
program.
[0151] The next step 53 is to add the name of a well (one well at a
time) to a working project, thereby creating a placeholder. The
user can add as many wells to a project as desired. Where a number
of wells are added, a well list will be generated and saved for
access by the user in selecting a "working" well for the given
project. The user will be presented with options regarding wells:
[0152] a) Add, to add a well to the current project; a well name is
provided by the user (as shown in FIG. 8); when a well is added, a
folder with that well name is created; [0153] b) Export, to save
well information of the selected well(s) from the current project
into a file; [0154] c) Import, to import well information from a
file created in Export from another existing project; [0155] d)
Delete, where the well list is displayed for the user to select a
well to delete; and [0156] e) Select, where a well can be selected
from the well list under the current project as the working
well.
[0157] After a well is added to a project, the next stage, then, is
for the user to load digital core images at step 54, the raw
digital images being previously received from an oil company. The
raw digital core images can be loaded from portable storage media
or downloaded from the data sever (see FIG. 3), depending on how
the raw data was provided by the client. A well is usually
represented by 15 to 25 images in any image format, which images
are presented in file list form in a typical file-open window and
can be loaded one-by-one or all at once. The user will again be
presented with options: [0158] a) Load, to load images into the
current well; a "file open" window is presented to enable the user
to browse and select images to load; [0159] b) Select, to select an
image from the image list of the current well as the working image
and display it in the Depth Registration Window (discussed below);
on the list, images that have been depth-registered are separated
from the rest with a special sign or marker; and [0160] c) Delete,
to delete selected images (one or more) from the well.
[0161] In the Depth Registration Window (illustrated in FIG. 12 and
discussed in detail below), the selected image can be zoomed in,
zoomed out, or rotated 90.degree. left or right. Three special zoom
functions are also available: 1:1, Fit-all, and Fit-width, the
default being Fit-all. Four image navigation buttons are also
provided: First, Previous, Next, and Last. The Depth Registration
Window is a workspace on the screen for use in engaging in steps
related to the raw digital core images. Three modules (see FIG. 4)
are associated with the Depth Registration Window: (1) the
Depth/sample Registration Module for registering core depths and
selecting sample intervals; (2) the Facies Registration Module for
selecting facies top/base depths; and (3) the Annotation Module for
adding, displaying, and manipulating annotation.
[0162] Once the raw image has been selected at step 55, the program
will then display the core image in the Depth Registration Window
(as shown in FIG. 11), labelled only by core number and box number,
note that the core number defines a discrete section, or "run", of
core (usually 3 m in length for oil sands cores), while the box
number identifies the box where the actual physical cores are
stored. While digital image providers normally must spend a
substantial amount of time providing detailed annotation before
shooting digital images, the limited annotation requirements of the
present invention enable a relatively rapid shooting of digital
core images, cutting down considerably on their acquisition time.
Traditional core labs will normally have to manually insert
information, such as by putting magnetic stickers of sample
intervals, sample numbers, core top/base depths, core meter depths,
etc., on a metallic framing structure to label cores, before taking
any digital photographs, and hence there is a substantial time
savings in a method according to the present invention, normally
reducing the required time from 3 to 4 hours per oil sands well to
less than one hour.
Depth Registration
[0163] The next stage of the ADFM process is Depth Registration
(step 56 of FIG. 5). A flowchart illustrating the steps of the
depth registration stage is presented in FIG. 9, which steps are
explained in greater detail below.
[0164] First, the user must select an image at step 91 to display
it in the Depth Registration Window and then define a "digital
ruler" at step 92, which digital ruler will be employed by the
program to determine an exact, actual length of the interval in
question. To define the digital ruler, the user right-clicks (using
the mouse) anywhere over the displayed image to display a pop-up
menu and then selects "Define digital ruler" from the menu. The
user clicks on any two points on the displayed image and a "Define
digital ruler" window is popped up (see FIG. 10), including the
horizontal distance on the digital image in term of pixels between
the clicked two points (2389 pixels in FIG. 10), and two radio
buttons for selection (one for 0.75 m and the other for an
alternative length defined in the user-input box). When the OK
button is clicked, the window closes, which establishes a
user-defined relationship between digital image sizes in terms of
pixels and physical core lengths in terms of meter. For example, if
the 0.75 m radio button is selected, the program defines a digital
ruler in which 2389 pixels on the image are equivalent to 0.75 m of
physical core length. This relationship will be maintained and used
to calculate core length during the core depth registration process
until a new digital ruler is established.
[0165] Once the digital ruler is defined, depth registration
proceeds by means of the Smart Depths process, details of which
process follow, with reference to FIG. 12.
[0166] According to the Smart Depths process, the user will select
top and base depth points using the mouse to define a desired
interval, and there can be multiple selected intervals within the
same digital image. The user selects the top and base depth points
by clicking at two locations on the image itself at step 93. The
program then measures and crops a rectangular area (a depth
registration rectangle) between these top and base depth points for
later use and pops up a Smart Depths window at step 94 for the user
to input/confirm depth registration information for the interval
defined by the depth registration rectangle. Depth registration
information includes core identification (core number, box number
and interval number) and both top and base depths.
[0167] Core identification is then assigned in the following manner
the user will manually input a core number in the Smart Depths
window, and the program will then automatically determine the
proper box number. For example, using common digital images where a
typical core is 3 m, there are two physical core boxes
(representing 1.5 m of physical core each). The first physical core
box has the number "1" as its box number and the second physical
core box has the number "2" as its box number. Each 1.5 m core box
will result in two 0.75 m image sections, which are labelled "A"
and "B", respectively. As a result, core box identification will
have a format such as 1A, 1B, 2A, 2B, etc., where "1" and "2"
provide the physical core box sequence and "A" and "B" represent
the first and second 0.75 m core within a physical core box. The
program automatically advances the box number from 1A to 1B, 2A,
2B, 3A, etc., when one Smart Depths window is completed and the
user proceeds to define the next adjacent displayed interval (a new
Smart Depths window is employed for each subsequent selected
interval). This automatic advance in box number can be altered by
the user if desired at step 95.
[0168] For the first Smart Depths window representing the most
shallow core interval, the user will manually input the top depth,
which will normally be determined in the field by coring personnel,
and the program will then automatically determine the base depth
based on the digital ruler and the distance on the image between
the two clicks. The base depth will be remembered by the program
and used as the top depth for the next adjacent descending core
interval (the last depth from the former Smart Depths window cannot
be changed by the user within the new Smart Depths window, but the
user can amend the top depth in the new Smart Depths window at step
95).
[0169] When moving on to the next core, the user will manually
input a new core number in the Smart Depths window, otherwise the
program will assume that the user is still working with the
previous core interval and only update the box number. The program
will then automatically reset the box number to 1A and calculate
the new interval length and the base depth; the interval number is
specified by the user and remains the same until it is changed
again. After the user makes necessary changes at step 95, the user
will be presented with the option of either accepting the edit at
step 96a or cancelling the edit at step 96b. If "Accept" is chosen,
the program will crop out the rectangular portion, save it with its
core identification and top/base depths at step 97, and
automatically annotate each registered interval with the core
number, box number, interval number, and top and base depths, in a
program-defined format (as shown in FIG. 12).
[0170] The user can repeat steps 93 through 97 until all core
intervals on the image are depth-registered. The user then moves to
the next image to do depth registration at step 98.
[0171] Although the preceding has been presented as a top-down
registration process, registration can be conducted top-to-bottom
or bottom-to-top, at the option of the user. The program
automatically determines whether registration is being conducted
top-to-bottom or bottom-to-top, based on the relative positions of
the two mouse-selected points and their order of selection. If the
user changes registration direction during the process, however,
the user will need to ensure that the depths are being accurately
determined, and the user may need to manually amend the
core/box/interval number if necessary when the first Smart Depths
window is popped up after a change of depth registration direction.
Depth consistency is also checked by the program, such that
shallower depth images cannot be overlapped with or displayed as
being deeper than any deeper images.
[0172] Having completed the initial depth registration steps, the
registration information can be modified by the user at this stage.
If the user clicks anywhere within a selected depth registration
rectangle, the depth registration window is popped-up with the
associated information, including top/base depths and core length.
The user can also change the core/box/interval number. However, any
change in one depth registration rectangle will not trigger changes
in other depth registration rectangles, so the user will need to
revise other interval information as desired. The user can also
delete registration information by entering depth deletion mode,
which enables deletion of a selected piece of information or all
depth registration information for the core image, and start
again.
[0173] Once the user has completed all depth registration for the
digital core images, the user can then close the core image window
and proceed to core Depth Correction in the Depth Correction
Window. Optionally, the user can select and register sample
intervals, as well, at step 57 of FIG. 5. Sample selection will be
described in detail below.
Depth Correction
[0174] The Depth Correction Window is the workspace on the display
wherein the user performs all actions related to stacked images
that are cropped from raw digital core images, which cropped images
were defined by depth registration rectangles during the depth
registration process in the Depth Registration Window.
[0175] After core depth registration is completed for all raw
digital core images, the user will then load corresponding well
logging data at step 58 (which provides depth reference, so the
well logs are sometimes termed "depth reference logs"), enabling
correcting of the core depths at step 59 below. The well logging
data can include GR, porosity, resistivity, dipmeter logs and/or
high-resolution borehole image logs such as formation micro-imaging
(FMI) logs. Well logging data can be provided in an oil industry
standard format such as LAS or a digital image format (such as .tif
or .jpeg) by oil companies, as was the case with the digital core
images, and the user accesses the well logging data by means of the
well logging data selection window shown in FIG. 13.
[0176] As is shown in FIG. 17 and described in greater detail
below, the program then displays in the Depth Correction Window (1)
the stacked, cropped core images (that have just been registered)
in a vertical orientation (the images possibly being highly
compressed depending on the depth scale used), (2) the
corresponding core identification, and (3) the well logging data.
All of these three pieces of information are displayed according to
depths, and the depth scales in the Depth Correction Window can be
changed by the user. In this preferred embodiment, there will be
two vertical core image stacks, one displaying the cropped images
according to their registered depths and the other displaying the
cropped images according to either their registered depths or
corrected depths at the user's option. The second stack is used in
the depth correction process detailed below (and illustrated in
FIG. 15). Any lost core intervals (depth gaps between any
neighbouring cropped images) are filled with a highlight colour,
such as red.
[0177] With depth reference well logs, stacked core images and
corresponding core identification displayed side-by-side on the
display device, the user begins the stage of core Depth Correction
(step 59 of FIG. 5). Depth correction is to recalculate the
top/base depths of each cropped image based on depth markers
selected by the user and save the results for further analysis.
[0178] The first step in the depth correction stage is to pick
depth reference markers, which is illustrated in the flowchart of
FIG. 14. Depth reference markers will usually be selected on the
basis of some visible feature of importance, such as a lithology
change; they are special contacts that can be easily identified on
both well logs and core images by geologists. The user will select
the marker-picking icon or a marker-picking menu to enter the
marker-picking mode at step 141, in a manner well known to those
skilled in the art. The user can then manually pick corresponding
markers on the well log and the digital image at step 142, said
depth markers being "picked" by clicking the mouse when the cursor
is over the desired point on the well logs and then the core
images.
[0179] As is shown in schematic form in FIG. 15, once corresponding
markers are selected, the program will insert horizontal lines 151
and 152 through each of the well logs and the core images,
respectively, and then also insert a correlation line 153
connecting those two horizontal lines. As many markers as are
desired may be selected. The user can delete markers, as well,
either a single selected marker or all markers.
[0180] Given the highly-compressed nature of the displayed images,
there may be some error where the user has been relying on their
own visual inspection of the displayed images to conduct
marker-picking. The next step 143, therefore, is for the user to
fine-tune the markers--to position a marker to an exact position at
the user's choice. The user enters the fine-tune markers mode by
selecting a fine-tune markers icon or fine-tune markers menu, which
will pop-up a floating window (which is shown in schematic form in
FIG. 16 and in a screen shot in FIG. 17). The floating window
(fine-tune marker window) displays a drop-down list 161 of all the
markers that have been picked and a zoom-in 162 of a small section
of the digital image centring around the current active marker 163.
The active marker 163 is the same one displayed in both the
floating window and the stacked core images in the Depth Correction
Window. The user can set a marker as active, in the fine-tune
markers mode, by (1) double-clicking a marker in the Depth
Correction Window or (2) selecting a marker on the drop-down marker
list under the zoom-in 162 in the fine-tune markers window. When
the position of an active marker 163 is changed, the zoom-in 162
image will be updated accordingly, and the new active marker 163 is
highlighted in the Depth Correction Window with a highlight colour
defined in the program.
[0181] In addition to the pop-up of a floating fine-tune markers
window, entering fine-tune marker mode will display the difference
164 in thickness (the thickness being between any two adjacent
markers) of a corresponding well log and stacked core section in
the Depth Correction Window. The preferred thickness difference
unit is centimetres (e.g. the thickness difference 164 is 20 cm in
FIG. 16). When the thickness difference exceeds a certain
established value (threshold value), the thickness difference is
highlighted with a highlight colour as defined in the program to
indicate a substantial thickness difference that the user may wish
to examine in detail.
[0182] With the help of a floating window, the user then has a more
magnified display of the digital image immediately surrounding the
selected marker, and the mouse is then employed to drag the marker
line 163 into a more desirable position based on the magnified
visual inspection. The active marker 163 can also be dragged in the
Depth Correction Window itself, and dragging in either window
automatically updates the marker in the other (and the thickness
difference is updated accordingly).
[0183] After all markers are fine-tuned and moved to their correct
positions on both core images and well logs, the thickness
difference between any two neighbouring markers should preferably
be zero or close to zero, since the markers for any corresponding
well log and core image are intended to refer to the same contact
in the subsurface. If the thickness is not zero, the geologist must
decide, based on their professional knowledge and experience, what
may have caused this difference and take actions accordingly to
render the thickness difference zero. There are three key potential
causes for the geologist to consider: (1) lost core intervals have
been recorded incorrectly in the field; (2) cores have been
misplaced or are upside-down; and (3) core expansion. Any one of
these, or any combination thereof, can cause a non-zero thickness
difference.
[0184] Lost core adjustment takes place at step 145. If there is a
lost core interval which is too thick (when compared by the program
to the well logging data), which can be indicated by a sign in
front of the thickness difference value (e.g. a "-" sign), the user
places the mouse over the lost core interval and right-clicks the
mouse to select the "Delete lost core" menu. A Lost Core Deletion
window is popped up (as is shown in FIG. 18), showing the maximum
lost core thickness that can be deleted and an input box for the
user to specify the lost core thickness for deletion. The maximum
thickness is the total thickness of the lost core interval at this
position. When the "OK" button is clicked, the specified lost core
thickness is deleted and all of the top/base depths of all cropped
images below the lost core interval are shifted up by the specified
(deleted) thickness.
[0185] A lost core interval can also be inserted into any join
between two neighbouring cropped images. To do this, the user will
place the mouse over a desired join and right-click the mouse to
select the Insert Lost Core menu, and a Lost Core Insertion window
is then popped up (as is shown in FIG. 19), with an input box
provided for the user to specify a lost core thickness to be
inserted at the join.
[0186] When the "OK" button is clicked, the specified lost core
interval is inserted into the join. If a lost core interval exists,
the specified (inserted) lost core interval is added to the
existing interval. The program will then shift down the depths of
all cropped images below the insertion join by the specified
(inserted) thickness.
[0187] The displayed core intervals (cropped core images) can each
be moved interactively up and down (if inaccurate vertical
positioning is determined to have occurred) at step 144 or rotated
180.degree. (if it is determined that core was accidentally placed
upside down, either in the field or during image shooting), if
there is an error clear from visual inspection of the well logging
data and digital images. When a cropped image is moved from one
place to another, a void (=lost core) is left at the old position;
a prompt is provided as to whether to delete the void or not. The
depth of all markers and cropped images below the old or new
position, whichever is shallower, may need to be adjusted.
[0188] Core expansion is handled by the program automatically by
shrinking cropped image lengths to their corresponding lengths at
the subsurface.
[0189] After lost core interval adjustment 145 and core order
restoration 144, depth correction of the stacked core images on the
Depth Correction Window can be performed. The user selects a depth
correction icon or menu, whereupon the program displays a table
showing raw top/base depths and corrected raw/base depths for all
core boxes or cropped images, plus their thickness before and after
depth correction, for the user to review. The positions of all of
the markers are displayed, as well. "OK" and "Cancel" buttons are
provided on the table for the user to confirm or cancel the action
of depth correction. If the "OK" button is clicked, the program
then automatically performs depth correction at step 147, which
calculates corrected top/base depths of all cropped images and
adjusts core expansion (if any exists), resulting in a display as
shown in FIG. 20. Corrected top/base depths for all cropped images
can be "locked" and remain stable unless they are overwritten by
the user by "locking again". As can be seen in FIG. 20, two stacked
core image columns are presented, the first representing the
uncorrected depths and the second being updated so that all cropped
images are displayed according to their corrected top and base
depths. All markers picked on the core images will be aligned by
the program at the same level as their corresponding markers picked
on the depth reference logs, such that the two horizontal lines
151, 152 and the correlation line 153 connecting the two horizontal
lines 151, 152 will then appear as one horizontal line. Note that
the second column of cropped images need not provide the corrected
depth information; in other words, the first and second columns may
instead be presented in identical form (if it is desired, for
example, to have two separate users each correct the uncorrected
information for comparison purposes).
[0190] Any given top or base will have two associated depths: a Raw
Depth that was assigned during depth registration, and a Corrected
Depth that was calculated when depth correction was performed. In
addition, there is a Current Depth, which is a working copy of top
and base depths of cropped images. Before depth correction is
performed, Corrected Depth=Raw Depth. When displaying the depth
information, the program will offer the user with options as to
whether to use Raw Depths or Corrected Depths.
[0191] Once correction is completed, the corrected information can
be exported as displayed or in text/table format at step 148 (part
of step 60 of FIG. 5). Corrected cropped image top/base depths are
used to calculate core top and bottom depths, and meter depths.
Core top/bottom depths and meter depths are used for annotating raw
digital core images, as described in detail below.
[0192] The depth correction process traditionally takes three to
four hours for a typical oil sands core length, but this time is
cut to less than one hour with the ADFM method according to the
present invention.
Annotation
[0193] After correction of the registered depths, the user can
proceed to annotate the digital images at step 61. As stated above,
annotation has traditionally been conducted by placing magnetic
stickers on a metallic framing structure on the core box, before
any digital images are even taken. With the ADFM process, the use
of digital images as early as initial depth registration means that
all corrected depth information is easily accessible and can be
presented directly on the digital images themselves.
[0194] To begin, the user activates the Annotation Module in the
Depth Registration Window by clicking an annotation icon or by
selecting an annotation menu, and the program automatically
transfers the corrected core top and base depths and annotates them
on the digital images; the program will also automatically
calculate the position for every meter depth and mark the position
with a mark and display the depth value adjacent the calculated
position. This can be seen in FIG. 21. If samples are selected, as
described in detail below, the program will automatically annotate
sample labels, sample numbers, and sample start and end marks such
as arrows. If lab analysis results from any samples are available,
an option can be turned on to display lab results adjacent their
corresponding sample labels. If facies have been interpreted, as
described in detail below, facies identification indicators can be
annotated on the digital image with a corresponding facies
colour.
[0195] Annotations displayed on core images by the Annotation
Module can be moved by dick-and-drag of the mouse, to assist the
user in ensuring that the digital images are not obscured by the
labelling.
Finalizing Annotated Image
[0196] Once the raw digital core images have been annotated at step
61, the user can finalize the annotated images at step 62. To
finalize the annotated images, the program can add a frame, company
name, well name, the digital ruler, the client's company logo, etc.
Any of this information can be included or excluded at the user's
choice. FIGS. 22 and 23 illustrate the type of information that may
be included when finalizing the annotated image. A final, printable
copy of the annotated image, in the users choice of digital image
format, is then generated automatically by the program at step 63.
The user may then print off the finalized annotated image at this
stage or deliver it to the client by portable media or uploading to
the data server (for the client to download or browse through the
Internet).
Sample Selection
[0197] A large number of rock samples are routinely taken from oil
sands cores for analyzing bitumen weight percentage in order to
determine the richness of bitumen. Sample intervals are selected on
view-side cores by a lab technician and marked on the core boxes.
The digital photographer traditionally positions sample labels
according to these marks before shooting the digital core images.
The digital images with sample sticker labels are then used to
translate sample intervals to frozen sample-side cores to enable
physical sampling. This traditional sample selection/translation
approach usually involves two people, and is time-consuming and
prone to errors.
[0198] To sample according to the preferred embodiment of the
present invention at step 57, the user selects a Sample
Registration menu or clicks on a Sample Registration icon to enter
the sample selection mode. In the sample selection mode, the user
selects a sample interval by clicking on two points on the digital
core image. The two points have to be within a depth registration
rectangle so that sample depths can be calculated based on the
positions of the two points related to core depths. After the two
clicks are completed, a Sample Registration window is popped up (as
shown in FIG. 25) asking for three inputs from the user: (1) Label
(which indicates the kind of sample with a suggested value that
will remain the same unless the user makes a change to it); (2)
Number (the sequence number for the same kind of sample, which
automatically increases by one after every successful sample
registration; the value will be re-set to "1" when the Label input
box is changed by the user, and the value can be overwritten by the
user); and (3) two radio buttons for "Yes" and "No" to indicate if
the sample number is to be displayed in the sample annotation
("Yes" indicates real samples and the sample information will be
annotated on digital images; "No" is for "false" samples and is
only for text annotation where only the Label value will be
annotated on digital images). After "OK" is selected, the sample
intervals are displayed with two marks (for example, two arrows) to
show the start and end points of sample intervals, as is shown in
FIG. 24. If the two clicks cover a lost core interval, an error
message will be displayed and the sample selection attempt will
fail.
[0199] When the Annotation Module is activated and the program is
in annotation mode, the sample marks will be automatically moved
out of the depth registration rectangles and placed at some defined
distance above the top of the rectangle within which they reside in
the sample selection mode. Lab analysis results may also be
displayed or annotated on the digital core images, beside the
sample label and number, which is very useful for any lab result
quality checking.
[0200] Sample registration values can be edited or deleted in a
manner similar to core depth registration. A sample list table with
corrected top/base depths and sample length can be exported in
different text formats at step 60. NA (Not Analyzed) intervals and
lost core intervals can be included in the table so that the lab
can directly use the output in their lab report, saving the lab a
few hours in manually generating the similar output.
V.sub.SH Calculation
[0201] The use of digital core images throughout the process,
however, adds additional functionality to the ADFM process.
Geologists often need to determine the volume of shale (V.sub.SH)
in a given oil sands core in order to assess oil sands reservoir
quality, and the ADFM V.sub.SH Module provides a novel means of
achieving that goal. Bitumen-saturated oil sands are essentially
black in colour, while shales are light to dark grey. This
characteristic feature of oil sands makes calculation of V.sub.SH
directly from digital core images possible.
[0202] Regions of the digital image are selected at step 64 to
represent sand, shale, dark shale and water/gas sand. These
selected regions of the digital images are used by the program to
generate Red, Green and Blue (RGB) histogram curves for each
corresponding rock type in a sand/shale calibration window (see
FIG. 26).
[0203] Referring to FIG. 26, based on the histogram curves for
different kinds of rock types, the user specifies Red, Green and
Blue (RGB) threshold values for shale and dark shale. Threshold
values are displayed as interactively-movable (by means of the
mouse) vertical lines on the RGB histograms which essentially
divide the RGB index of 0 to 255 into four regions: sand, dark
shale, shale and gas/water sand, from which the V.sub.SH can be
determined: V.sub.SH=(shale region+dark shale region)/(all four
regions)
[0204] After the four regions are defined, the top and base of a
cropped image interval can be specified so that the raw core image
and interpreted sand/shale (in black and white) of the interval can
be displayed side by side to allow assessment of the validity of
the selected threshold values. When the threshold values are
changed, the sand/shale interpreted image is updated
accordingly.
[0205] The user specifies V.sub.SH calculation options (as can be
seen in FIG. 27), which options include Sampling window (the depth
interval of cropped images within which all pixels will be included
to calculate V.sub.SH) and Sampling step (the depth difference
between two nearby V.sub.SH value points).
[0206] Using the top depth of the shallowest cropped image as the
starting point, the program calculates V.sub.SH at the depth for
every sampling step, based on RGB threshold values for shale and
dark shale as determined in the calibration step and the V.sub.SH
calculation formula discussed above. The sampling window is the
interval of images centred around a sampling point. If the sampling
point is within a lost core interval, no value is calculated. If
the sampling window includes lost core, the lost core interval is
ignored.
[0207] With the threshold values determined, a pixel that has RGB
values within shale or dark shale RGB regions is classified as
shale; outside the ranges is classified as sand. The program then
calculates a V.sub.SH value at every V.sub.SH depth point and with
all pixels in the corresponding sampling window, and plots a
V.sub.SH curve in the V.sub.SH track in the Depth Correction Window
(see FIG. 28) at step 65. The V.sub.SH curve can be exported in the
LAS format, a commonly used industry standard for recording well
logs data, at step 66.
[0208] V.sub.SH calculation and display is handled by the V.sub.SH
Module in the ADFM System.
Facies Interpretation
[0209] Oil sands projects are capital-intensive and oil companies
spend considerable funds and effort in trying to characterize oil
sands reservoirs, including building 3D facies models.
Traditionally, 3D facies modellers spend 60 to 70% of their time
and effort in compiling data in an appropriate format to enable
them to load the data into their 3D facies modeling software. The
ADFM Facies Module is designed specifically for generating facies
results that can be imported into many 3D facies modeling software
programs.
[0210] According to the preferred embodiment, the user defines a
facies at step 67 by means of facies code (ID), facies colour,
facies name, and minimum and maximum V.sub.SH cut-offs (see FIG.
29). The facies code is unique and can be composed of a number,
letters or a combination of both. Two facies columns are preferably
provided on the Depth Correction Window, adjacent to the stacked
digital core images, displaying the user's facies determinations
(as described below). Once the various facies are defined by the
user, facies can be interpreted automatically (step 68 of FIG. 5)
or interactively (step 69 of FIG. 5). Facies can be auto-filled in
one facies column in the Depth Correction Window based on the
calculated V.sub.SH curve and facies V.sub.SH cut-offs, and the
automatically-filled facies can be modified interactively by the
user. Facies can be copied from one column to the other.
[0211] An interactive facies interpretation process is shown in the
flowchart of FIG. 30. The user enters the interactive mode at step
300 by selecting an interactive menu or by clicking an interactive
icon, whereupon a floating window showing the defined facies list
is popped up (FIG. 29). The user then selects a facies from the
floating window at step 301, places the mouse cursor over a facies
column or core image at step 302, and clicks on two points on the
facies column or core image to define the top and base depth of an
interval at step 303. If the mouse action is in Facies Column 1
(step 304a), the program sends the facies ID and top/base depths to
Facies Column 1 at step 304b. If the mouse action is alternatively
in Facies Column 2 (step 305a), the program sends the facies ID and
top/base depths to Facies Column 2 at step 305b. If the mouse
action is alternatively on a digital core image in the Depth
Registration Window (step 306a), the program sends the facies ID
and top/base depths to a facies column in the Depth Correction
Window at the user's choice at step 306b.
[0212] The selected interval is then filled with the predefined
facies colour of the selected facies in a corresponding facies
column at step 307, and the facies file is updated and saved at
step 308. Any previously-established facies within the interval is
replaced with the new facies. If facies above or below the interval
are the same as the new facies, they will merge into one facies
interval. If the new interval is inserted in the middle of an
existing facies interval, the existing facies interval is split
into two intervals divided by the new facies.
[0213] Where two geologists are engaged in facies determination and
each provides a facies interpretation of the core on the same well,
the program can provide two parallel facies columns in the Depth
Correction Window with one facies ID column or two displayed beside
the facies columns. If there is only one facies ID column, the
displayed facies ID can be associated with either facies column.
Each geologist, being a separate user, would independently access
the ADFM system and conduct their own facies analysis. If desired,
one geologist can copy the other geologist's facies column over to
his own column and then make changes to the copied facies. This is
extremely useful, for example, where a senior geologist is engaged
in quality control of a junior geologist's facies interpretation;
the senior geologist can make changes on his own facies column
without losing the junior geologist's work. It is also very useful
for an office geologist when refining an external consulting
geologist's interpretation.
[0214] A core/facies description column (or "notes") can also be
added adjacent to the facies column(s) for the user to type in a
description of the interval. Horizontal lines can be drawn in the
description column to divide different description text blocks, as
can be seen in FIG. 28.
[0215] Finally, facies information can then be exported in
text/table or LAS format at step 70 and the data uploaded to the
data server at step 71. Once the facies file has been updated and
saved at step 308, the user can exit the module at step 309.
Depth Correction Window Export
[0216] Information can be exported by the program by means of
text/table or LAS format, but the Depth Correction Window itself
can also be exported. Any column in the Depth Correction Window can
be turned on or off, and the width and orders of columns can be
changed at any time by the user. The content displayed in the Depth
Correction Window can be exported as a digital image in any format
or in a .pdf file.
[0217] Referring now in detail to FIG. 28, the columns of the Depth
Correction Window available for export are as follows: [0218] 1)
Gamma: (1)0-150 API from left to right or 150-300 API; (2)
depth/unit lattice; [0219] 2) Depth: (1) display scale and depth
values; (2) depth value display depends on scale; [0220] 3) Density
porosity (DPHI) and neutron porosity (NPHI) on the same track: (1)
fraction scale from 0 to 0.6; (2) curves in different colour;
[0221] 4) Resistivity: (1) display shallow, medium and deep
resistivity curves in different colours in log scale; (2) 0.2-2000
ohm.m; [0222] 5) Borehole imaging column: display borehole imaging
logs, such as Formation Micro-Imaging (FMI); [0223] 6) Correlation
columns which display the correlation lines that connect the
corresponding markers on the well logging data and the stacked core
images, and the correlation lines can be turned on or off; [0224]
7) Core image 1: (1) display cropped images according to their raw
depths and the depth scale; [0225] 8) Image identifier (1) display
identifier of cropped images on core image column 7 and (2) draw a
line between cropped images of column 7; [0226] 9) Core image 2:
(1) display cropped images according to their raw depths or
corrected depths and depth scale; [0227] 10) Image identifier (1)
display identifier of cropped images on core image column 9; (2)
draw a line between cropped images; [0228] 11) V.sub.SH column: (1)
display the V.sub.SH (volume of shale) curve in fraction scale of
0-1; (2) highlight selected V.sub.SH cut-offs defined in facies
definition by the user in different colours; [0229] 12) Facies
column 1: (1) Colour fill facies; [0230] 13) Facies ID column: (1)
display facies ID associated with Facies column 1 or Facies column
2 at the users choice; (2) draw a horizontal line between
neighbouring facies intervals; [0231] 14)Facies column 2: (1)
Colour fill facies; may be identical to Facies 1 or present an
alternative interpretation, at the user's choice; [0232] 15) Sample
column: (1) display sample intervals; (2) if lab results are
available, display lab results as a curve or histogram; [0233] 16)
Notes: (1) multiple comments blocks divided by horizontal lines.
Text Information Export
[0234] In addition to the ability to export the Depth Correction
Window itself, the program enables the export of information in
text form. An Export function is provided to enable the export of
information relating to corrected core depths, V.sub.SH values, and
facies. The user can choose what information combination from
designated well(s) to export from a well list, the information
including: [0235] a. Core depths: export corrected core box depths.
[0236] Format: Core No., Box No., Top_depth, Base_depth,
Core_corrected_length, Core_physical_length, Length_difference
[0237] b. Sample list with corrected sample depths and lengths.
Lost core intervals and NA (Not Analyzed) intervals can be
included, as well. [0238] Format: Sample_label, Sample_number,
Top_depth, Base_depth, Sample_thickness [0239] c. V.sub.SH and
Facies curves: export V.sub.SH and facies information in an
industry standard LAS format. [0240] Format: Depth, V.sub.SH,
Facies_code, Facies_name [0241] d. Facies only: export facies in
the interval format. For every facies interval on a facies column
in the Depth Correction Window, there will be one row of data.
[0242] Format: Top_depth, Base_depth, Facies_code, Facies_name
Annotated Digital Core Image Export
[0243] Composite images can be generated in any digital format.
Composite images can include raw core images overlaid with
different kinds of labels, such as sample labels, top/base depths
of core intervals, meter depths, and image frame with information
such as company name, well name, company logo, scale bar, etc. If
lab results for samples are available and facies have been
interpreted, sample results and facies ID can be annotated on the
images, as well. Any kind of label can be turned on or off at the
user's choice.
[0244] The foregoing method is preferably applied within a system
including the modules as set out in the schematic illustration of
FIG. 4, which schematic illustration illustrates the data flow. The
flowchart of FIG. 5 illustrates the entire preferred ADFM process
as described in detail above.
[0245] As is clear from the foregoing, there are substantial
advantages to the present invention when compared with traditional
core logging techniques. As can be seen in FIGS. 1 and 2, which
respectively illustrate the ADFM Digital Core Workflow and
Traditional Physical Core Workflow, the ADFM Digital Core Workflow
using digital images in initial depth registration and throughout
the remaining processes can result in substantial time savings and
reduce the number of people involved. The composite impact is an
efficient digital workflow with which information can be quickly
and remotely processed, and the results can be delivered promptly
to oil companies.
[0246] While a particular embodiment of the present invention has
been described in the foregoing, it is to be understood that other
embodiments are possible within the scope of the invention and are
intended to be included herein. It will be clear to any person
skilled in the art that modifications of and adjustments to this
invention, not shown, are possible without departing from the
spirit of the invention as demonstrated through the exemplary
embodiment. For example, the method could be embodied in a software
product that a user could purchase, rather than utilising a
password-protected on-line environment. The invention is therefore
to be considered limited solely by the scope of the appended
claims.
* * * * *