U.S. patent application number 14/246218 was filed with the patent office on 2014-08-07 for 3-d well log invention.
The applicant listed for this patent is Mark C. Robinson. Invention is credited to Mark C. Robinson.
Application Number | 20140222342 14/246218 |
Document ID | / |
Family ID | 50391904 |
Filed Date | 2014-08-07 |
United States Patent
Application |
20140222342 |
Kind Code |
A1 |
Robinson; Mark C. |
August 7, 2014 |
3-D Well Log Invention
Abstract
In an embodiment, creation of a continuous three dimensional
array of data from digital information obtained from a wellbore,
and representation in a seismic data formatted dataset. In an
embodiment, providing the capability to export stratigraphic
interpretations made while working within the 3D-log data volume
back to any wellbore that is encompassed within the areal extent of
the 3D-log data volume. In one embodiment, a 2D well grid creation
process comprises the steps of (a) selecting an initial grid
spacing, (b) assigning wells from a dataset of well data to closest
nodes in the grid, (c) if a plurality of wells are assigned to a
single node after completing step (b), narrowing the grid spacing
and repeating step (b) until no more than one well is assigned to
any node. In an embodiment the non-well nodes are populated by
extrapolating from adjacent single well nodes.
Inventors: |
Robinson; Mark C.; (Spring,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Robinson; Mark C. |
Spring |
TX |
US |
|
|
Family ID: |
50391904 |
Appl. No.: |
14/246218 |
Filed: |
April 7, 2014 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
12911272 |
Oct 25, 2010 |
8694261 |
|
|
14246218 |
|
|
|
|
61313211 |
Mar 12, 2010 |
|
|
|
Current U.S.
Class: |
702/6 ;
703/10 |
Current CPC
Class: |
G01V 2210/665 20130101;
G01V 1/282 20130101; G01V 11/00 20130101; E21B 47/00 20130101 |
Class at
Publication: |
702/6 ;
703/10 |
International
Class: |
G01V 1/28 20060101
G01V001/28; E21B 47/00 20060101 E21B047/00 |
Claims
1. A process to create a 2D well grid comprising the steps of: a.
selecting an initial 2D grid spacing, b. assigning wells from a
dataset of well data to closest nodes in the grid, and c. if a
plurality of wells are assigned to a single node after completing
step b, narrowing the grid spacing and repeating step b until no
more than one well is assigned to any node.
2. A process to create a 3D well log grid, comprising the step of
associating tabulated well log data with a matrix of grid nodes
wherein single wells are assigned to single nodes to generate a 3D
well log grid.
3. The process of claim 2 comprising generating the matrix of grid
nodes by the steps of: a. selecting an initial 2D grid spacing, b.
assigning wells from a dataset of well data to closest nodes in the
grid, and c. if a plurality of wells are assigned to a single node
after completing step b, narrowing the grid spacing and repeating
step b until no more than one well is assigned to any node.
4. The process of claim 3 wherein the tabulated well log data
comprise stratigraphic correlations by well, whereby the 3D well
log grid comprises a matrix of grid nodes with stratigraphic
correlations assigned to the single-well nodes.
5. The process of claim 1, further comprising populating non-well
nodes with stratigraphic correlation data.
6. The process of claim 3, further comprising populating non-well
nodes with stratigraphic correlation data.
7. The process of claim 1, further comprising populating non-well
nodes with well log data extrapolated from single-well nodes.
8. The process of claim 3, further comprising populating non-well
nodes with well log data extrapolated from single-well nodes.
9. The process of claim 5 wherein stratigraphic tops are used to
control the non-well node population.
10. The process of claim 6 wherein stratigraphic tops are used to
control the non-well node population.
11. The process of claim 2 further comprising converting the
all-node-populated 3D matrix of well log data to a seismic data
format.
12. The process of claim 3 further comprising converting the
all-node-populated 3D matrix of well log data to a seismic data
format.
13. The process of claim 11 wherein the seismic data format
comprises SEG-Y or SEG P1.
14. The process of claim 11 further comprising interpreting the
seismic data formatted 3D matrix.
15. The process of claim 12 further comprising interpreting the
seismic data formatted 3D matrix.
16. The process of claim 14, wherein the interpretation is selected
from petrophysical, log facies, structural and combinations
thereof.
17. The process of claim 14, further comprising associating the
interpretations with a well process at a specific well through the
use of unique well identifiers.
18. The process of claim 14, wherein the well process comprises
completion or production of oil and gas wells.
19. The process of claim 14, wherein the well process comprises the
creation of pseudo wells to evaluate exploration opportunities.
20. The process of claim 15, wherein the well process comprises the
creation of pseudo wells to evaluate exploration opportunities.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of co-pending U.S. Ser.
No. 12/911,272 filed Oct. 25, 2010, now U.S. Pat. No. 8,694,261
which is a non-provisional of U.S. Pat. No. 61/313,211, filed Mar.
22, 2010.
BACKGROUND
[0002] The term "pseudo-seismic" has been used to describe efforts
to convert any non-seismic data type into the seismic data domain.
Previous workers converted digital well-log data into SEG-Y format
and loaded those data into seismic workstations. The results were
less than acceptable because of the discontinuous nature of
wellbore data and the fact that the method destroyed the connection
between the actual wellbore location and the location of the trace
to which it has been assigned. See Carr et al., 2-D and 3-D
Pseudo-Seismic Transforms of Wireline Logs: A Seismic Approach to
Petrophysical Sequence Stratigraphy, Open-File Reports, Kansas
Geological Survey, University of Kansas (1995) (available at
http://www.kgs.ku.edu/PRS/publication/carr.html); Escaloma et al.,
Sequence Stratigraphic analysis of Eocene clastic foreland deposits
in central Lake Maracaibo using high-resolution well correlation
and 3-D seismic data., AAPG Bulletin, V. 90, No. 4, pp. 581-623
(April 2006).
[0003] For example, previous workers also calibrated seismic
attribute data with wellbore data to generate pseudo-well logs to
predict the nature of rocks at a given location. The method used
3D-seismic attribute data as input to derive expected values of
standard well log curves at a single location, which may be a
wellbore or a hypothetical wellbore location. For example, see U.S.
Pat. No. 7,706,981.
[0004] Denham and Nelson, Rock Property Data Volumes from Well
Logs, Search and Discovery Article #40268 (2007), generated rock
property data in 60 meter vertical sample intervals for wellbores
and loaded these data into a regular grid. The values of the grid
nodes were averaged based upon the proximity of the wellbores
selected within a given radius of the wellbore. They concluded that
the technique was suitable for regional analysis only.
[0005] U.S. Pat. No. 7,054,753 discloses a method of locating oil
and gas exploration prospects by data visualization and
organization by digitizing well log data, marking common geologic
time markers and visually displaying the data in various viewing
formats.
[0006] All references mentioned herein are hereby incorporated
herein by reference in their entireties for all purposes.
SUMMARY OF THE INVENTION
[0007] The present invention relates in one aspect to the creation
of a continuous three dimensional array of data derived from
digital information obtained from various depths within a wellbore,
and the representation of these data in a formatted dataset that
can be manipulated in standard 3D-seismic interpretation and
visualization software. The invention also relates in another
aspect to providing the capability to export stratigraphic
interpretations made while working within the 3D-log data volume
back to any wellbore that is encompassed within the areal extent of
the 3D-log data volume.
[0008] In one embodiment, a 2D well grid creation process comprises
the steps of (a) selecting an initial grid spacing, (b) assigning
wells from a dataset of well data to closest nodes in the grid, (c)
if a plurality of wells are assigned to a single node after
completing step (b), narrowing the grid spacing and repeating step
(b) until no more than one well is assigned to any node.
[0009] In another embodiment, a 3D well log grid creation process
comprises the step of associating tabulated well log data with a
matrix of grid nodes with single wells assigned to single nodes. In
a further embodiment, the tabulated well log data can comprise
stratigraphic correlations by well, whereby the 3D well log grid
comprises a matrix of grid nodes with stratigraphic correlations
assigned to the single-well nodes. Further still, in an embodiment
the process can include populating non-well nodes with
stratigraphic correlation data.
[0010] In an embodiment, the 3D well log grid creation process can
include populating non-well nodes with well log data extrapolated
from single-well nodes. Further, in one embodiment stratigraphic
tops are used to control the non-well node population. In one
embodiment, the all-node-populated 3D matrix of well log data is
converted to a seismic data format such as, for example, SEG-Y, SEG
P1, as defined by the Society of Exploration Geophysics (SEG), and
so on. The 3D well log dataset can be interpreted using standard
seismic industry software, e.g., petrophysical, log facies,
structural and other interpretations; further the interpretations
can be associated with a well process at a specific well through
the use of unique well identifiers, e.g., completion and production
of oil and gas wells, the creation of pseudo wells to evaluate
exploration opportunities, and the like.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic overview of a 3D well log data process
according to an embodiment of the invention.
[0012] FIG. 2 is a schematic diagram of a general well data
collection process according to an embodiment of the invention.
[0013] FIG. 3 is a schematic diagram of a well log data collection
process according to an embodiment of the invention.
[0014] FIG. 4 is a schematic diagram of a 2D well grid creation
process according to an embodiment of the invention.
[0015] FIG. 5 is a schematic diagram of a 3D well grid creation
process according to an embodiment of the invention.
[0016] FIG. 6 is a schematic diagram of an alternative 3D well grid
creation process involving stratigraphic correlations according to
an embodiment of the invention.
[0017] FIG. 7 is a schematic diagram of a process to populate
non-well grid nodes according to an embodiment of the
invention.
[0018] FIG. 8 is a schematic diagram showing conversion of a 3D
well grid into a standard seismic data format according to an
embodiment of the invention.
[0019] FIG. 9 is a schematic diagram of interpretation of 3D log
dataset in standard seismic data format using standard industry
software according to an embodiment of the invention.
[0020] FIG. 10 is a schematic diagram of a process to associate the
interpretations of FIG. 9 with specific wells (or pseudo-wells)
according to an embodiment of the invention.
[0021] FIG. 11 is a plan diagram of the location of hypothetical
wells W1, W2, W3 and W4 associated with well log data according to
an embodiment of the invention as described in the examples
below.
[0022] FIG. 12 is a plan diagram of the wells of FIG. 11 with an
initial grid system applied according to an embodiment of the
invention as described in the examples below.
[0023] FIG. 13 is a plan diagram of the wells and grid of FIG. 12
showing association of the wells to the nearest grid node according
to an embodiment of the invention as described in the examples
below, wherein more than one well is associated with a grid
node.
[0024] FIG. 14 is a plan diagram of the wells of FIGS. 11 to 13
following reduction (halving) of the grid spacing from FIG. 12
showing association of the wells to the nearest grid node according
to an embodiment of the invention as described in the examples
below, wherein no more than one well is associated with any grid
node.
[0025] FIG. 15 is a plan diagram of hypothetical wells W1, W2
showing assignment to grid nodes according to an embodiment of the
invention as described in the examples below.
[0026] FIG. 16 shows a generalized well log for well W1 of FIG. 15
with stratigraphic correlations A and B according to an embodiment
of the invention as described in the examples below.
[0027] FIG. 17 shows a generalized well log for well W2 of FIG. 15
with stratigraphic correlations A and B according to an embodiment
of the invention as described in the examples below.
[0028] FIG. 18 shows a generated well log for node GN(1,1) of FIG.
15 by mathematical averaging without applying stratigraphic
correlations according to an embodiment of the invention as
described in the examples below.
[0029] FIG. 19 shows a generated well log for node GN(1,1) of FIG.
15 by applying stratigraphic correlations according to an
embodiment of the invention as described in the examples below.
[0030] FIG. 20 shows a wiggle trace display of ten well log
gamma-ray curves converted into SEG-Y format according to the
process shown in FIG. 8.
[0031] FIG. 21 shows the data shown in FIG. 20 in a commercially
available 3D seismic evaluation application.
DESCRIPTION OF THE INVENTION
[0032] With reference to FIG. 1, the 3D-log process according to
one embodiment of the invention provides a means to take depth
dependent measurements from a randomly spaced collection of
wellbores and create a continuous volume of data that can be loaded
into software designed to interpret and visualize a 3D-Seismic
dataset.
[0033] One embodiment shown in FIGS. 2 and 3 utilizes digital
wellbore data as input. Examples can include geophysical well-log
curves 210 collected from wire-line logging of wellbores, core
analyses performed on cores collected during drilling of wells, and
virtually any other data attribute that can be quantified and
associated with a depth within a wellbore.
[0034] The reference elevation 130 (FIG. 2), i.e., the elevation
above mean sea level from which borehole measurements are taken, of
each wellbore to be used, in one embodiment is available to the
process.
[0035] In an embodiment, in step 310 (FIG. 4) a uniform grid with
constant spacing between nodes is superimposed over an area that
encompasses all wellbores to be used. Common grid node spacings can
be from 10 to 100 meters, but smaller or larger spacings can be
used if desired. In one embodiment, a uniform grid spacing can
include spacing that can be the same or different with respect to
the X- and Y-axes, e.g. a relatively larger spacing along one axis
than the other.
[0036] In an embodiment, each wellbore can have a unique identifier
carried as an attribute of the node nearest to its actual location.
This unique identifier can be the American Petroleum Institute
(API) identifier or any other suitable identifier.
[0037] In an embodiment, no two wellbores can be assigned to the
same grid node. The grid spacing can be reduced in an iterative
process in one embodiment, or one of the wellbores can be moved to
the next nearest available node in an alternative or additional
embodiment.
[0038] In an embodiment, utilizing an algorithm of triangulation,
each grid node that has not been assigned to an actual wellbore
will have calculated a weighting function based upon the distance
between it and all grid nodes with assigned data, which will be
kept in an array for reference within the processing according to
the following equation:
GN.sub.(O,n)=DF/f(DN)
where GN is the array of grid nodes containing the weighting
function values; DF is a weighting constant that can be allocated
prior to processing; f(DN) is a function that can be allocated
prior to processing, allowing flexibility in determining, for
example, whether a linear or exponential data relationship exists
between the grid nodes; and DN is the distance between the grid
node being evaluated and a grid node with an assigned well.
[0039] According to an embodiment, a data value can be determined
for each depth increment at each wellbore by using the gridnode
(GN) values calculated, and performing a summation of all wellbore
data at the same measured depth multiplied by the respective GN
value for wells within a defined search radius.
[0040] In an embodiment, the results can be assigned to a trace
array for each bin.
[0041] As shown in FIG. 8, SEGY files are generated for the 3D-log
survey.
[0042] After interpretation in any standard exploration workstation
according to the embodiment of FIGS. 9 and 10, the interpretations
are output and reformatted for loading into well databases and
interpretation systems.
[0043] Accordingly, the invention provides the following
embodiments: [0044] A. A process to create a 2D well grid,
comprising the steps of: [0045] a. selecting an initial 2D grid
spacing, [0046] b. assigning wells from a dataset of well data to
closest nodes in the grid, and [0047] c. if a plurality of wells
are assigned to a single node after completing step b, narrowing
the grid spacing and repeating step b until no more than one well
is assigned to any node. [0048] B. A process to create a 3D well
log grid, comprising the step of associating tabulated well log
data with a matrix of grid nodes wherein single wells are assigned
to single nodes to generate a 3D well log grid. [0049] C. The
process of Embodiment B comprising generating the matrix of grid
nodes by the steps of: [0050] a. selecting an initial 2D grid
spacing, [0051] b. assigning wells from a dataset of well data to
closest nodes in the grid, and [0052] c. if a plurality of wells
are assigned to a single node after completing step b, narrowing
the grid spacing and repeating step b until no more than one well
is assigned to any node. [0053] D. The process of Embodiments B or
C wherein the tabulated well log data comprise stratigraphic
correlations by well, whereby the 3D well log grid comprises a
matrix of grid nodes with stratigraphic correlations assigned to
the single-well nodes. [0054] E. The process of any one of
Embodiments A, B, C, or D, further comprising populating non-well
nodes with stratigraphic correlation data. [0055] F. The process of
any one of Embodiments A, B, C, D, or E, further comprising
populating non-well nodes with well log data extrapolated from
single-well nodes. [0056] G. The process of Embodiments E or F,
wherein stratigraphic tops are used to control the non-well node
population. [0057] H. The process of any one of Embodiments E, F,
or G, further comprising converting the all-node-populated 3D
matrix of well log data to a seismic data format. [0058] I. The
process of Embodiment H, wherein the seismic data format comprises
SEG-Y or SEG P1. [0059] J. The process of Embodiments H or I,
further comprising interpreting the seismic data formatted 3D
matrix. [0060] K. The process of Embodiment J, wherein the
interpretation is selected from petrophysical, log facies,
structural and combinations thereof. [0061] L. The process of
Embodiments J or K, further comprising associating the
interpretations with a well process at a specific well through the
use of unique well identifiers. [0062] M. The process of Embodiment
L, wherein the well process comprises completion or production of
oil and gas wells. [0063] N. The process of Embodiment L, wherein
the well process comprises the creation of pseudo wells to evaluate
exploration opportunities.
EXAMPLES
[0064] As an example of establishing a single-well, single-node
two-dimensional grid, a process according to one embodiment of the
invention is applied to hypothetical wells W1, W2, W3 and W4 as
shown in FIG. 11. An initial grid is applied with grid nodes
GN(0,0) through GN(2,2) as shown in FIG. 12. Next, as shown in FIG.
13, the wells are associated with the closest node, i.e. W1 with
GN(0,0), W2 with GN(1,1), W3 with GN(1,1), and W4 with GN(1,2).
However, two wells (W2, W3) are associated with GN(1,1), so the
grid spacing is reduced, e.g., halved as shown in FIG. 14. In this
spacing, the wells are again associated with the closest node, i.e.
W1 with GN(0,0), W2 with GN(3,1), W3 with GN(2,2), and W4 with
GN(2,4). This grid spacing is suitable because no more than one
well is associated with any single node.
[0065] As an example of populating non-well nodes, a process
according to two different embodiments of the invention is applied
to GN(1,1), which is between GN(0,1) and GN(2,1) to which are
assigned wells W1 and W2, respectively, as shown in FIG. 15. The
generalized well logs for wells W1 and W2, respectively, shown in
FIGS. 16 and 17, have stratigraphic correlations A and B with the
relationship between depth, Y, and a generalized logging variable
X, as follows: over the intervals Y=0.fwdarw.A, X=2; over the
intervals Y=A.fwdarw.B, X=1; and over the intervals
Y=B.fwdarw.1000, X=3.
[0066] In one embodiment where stratigraphic correlations A and B
are not used, a mathematical average of the well logging variable
for the nearby wells is applied as shown in FIG. 18. In this
instance the generalized well log for node GN(1,1) is as follows:
over the interval Y=0.fwdarw.A1, X=2; over the interval
Y=A1.fwdarw.A2, X=1.5; over the interval Y=A2.fwdarw.B1, X=2; over
the interval Y=B1.fwdarw.B2, X=2; and over the interval
Y=B2.fwdarw.1000, X=3; where A1 and B1 represent the depth of the
stratigraphic correlations at well W1, and A2 and B2 at well W2.
This approach tends to blur the well log data for the non-well node
being populated across the stratigraphic correlations, but is still
useful in one embodiment.
[0067] The use of stratigraphic correlations for the same node is
illustrated in FIG. 19. In this instance, the height of the
correlations A and B at GN(1,1) is taken as a weighted average of
the heights of the same correlations at the nearby wells W1 and W2,
e.g., A(1,1)=(A1+A2)/2 and B(1,1)=(B1+B2)/2. This provides a more
realistic population of the well log data at the non-well nodes,
and a more crisp visualization of the data at the stratigraphic
correlations that can be expected.
[0068] As is illustrated in FIG. 20, well log data, in this case
ten well log gamma-ray curves have been converted into SEG-Y format
according to an embodiment of the instant disclosure. The data are
shown in a "wiggle trace" display as are readily known to one of
minimal skill in the art. FIG. 21 shows the data presented in FIG.
20, presented in a 3D seismic application (OpendTect V.4.0), which
is commercially available and readily known to one of skill in the
art. As FIGS. 20 and 21. demonstrate, the data produced according
to the processes disclosed herein may be interpreted, processed,
and manipulated just like seismic data generated from traditional
sources.
[0069] All documents described herein are incorporated by reference
herein, including any patent applications and/or testing procedures
to the extent that they are not inconsistent with this application
and claims. The principles, preferred embodiments, and modes of
operation of the present invention have been described in the
foregoing specification. Although the invention herein has been
described with reference to particular embodiments, it is to be
understood that these embodiments are merely illustrative of the
principles and applications of the present invention. It is
therefore to be understood that numerous modifications may be made
to the illustrative embodiments and that other arrangements may be
devised without departing from the spirit and scope of the present
invention as defined by the appended claims.
* * * * *
References