U.S. patent application number 17/383058 was filed with the patent office on 2021-11-11 for methods and means for simultaneous casing integrity evaluation and cement inspection in a multiple-casing wellbore environment.
This patent application is currently assigned to Visuray Intech Ltd (BVI). The applicant listed for this patent is Visuray Intech Ltd (BVI). Invention is credited to Alex Stewart, Philip Teague.
Application Number | 20210349235 17/383058 |
Document ID | / |
Family ID | 1000005728400 |
Filed Date | 2021-11-11 |
United States Patent
Application |
20210349235 |
Kind Code |
A1 |
Teague; Philip ; et
al. |
November 11, 2021 |
Methods and Means for Simultaneous Casing Integrity Evaluation and
Cement Inspection in a Multiple-Casing Wellbore Environment
Abstract
An x-ray based cement evaluation tool for measurement of the
density of material volumes within single, dual and multiple-casing
wellbore environments is provided, wherein the tool uses x-rays to
illuminate the formation surrounding a borehole, and a plurality of
detectors are used to directly measure the density of the cement
annuli and any variations in density within The tool uses x-rays to
illuminate the casing surrounding a borehole and a plurality of
multi-pixel imaging detectors directly measure the thickness of the
casing The tool includes an internal length having a sonde section,
wherein the sonde section further includes an x-ray source; a
radiation shield for radiation measuring detectors; sonde-dependent
electronics; and a plurality of tool logic electronics and PSUs.
Other systems and subsystems appropriate for carrying out the
foregoing are also disclosed, as are a plurality of example methods
of use therefor.
Inventors: |
Teague; Philip; (Houston,
TX) ; Stewart; Alex; (San Francisco, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Visuray Intech Ltd (BVI) |
Road Town |
|
VG |
|
|
Assignee: |
Visuray Intech Ltd (BVI)
Road Town
VG
|
Family ID: |
1000005728400 |
Appl. No.: |
17/383058 |
Filed: |
July 22, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16162824 |
Oct 17, 2018 |
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17383058 |
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62573401 |
Oct 17, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01V 5/104 20130101;
G01V 5/12 20130101; E21B 47/01 20130101; E21B 47/005 20200501 |
International
Class: |
G01V 5/12 20060101
G01V005/12; G01V 5/10 20060101 G01V005/10; E21B 47/01 20060101
E21B047/01; E21B 47/005 20060101 E21B047/005 |
Claims
1. An x-ray based cement evaluation tool for measurement of the
density of material volumes, wherein the tool uses x-rays to
illuminate a formation surrounding a borehole and a plurality of
detectors are used to measure the density of the cement annuli and
variations in density within, said tool further comprising: an
internal length comprising a sonde section, wherein said sonde
section further comprises an x-ray source; a radiation shield for
radiation measuring detectors; sonde-dependent electronics; and a
plurality of tool logic electronics and PSUs.
2. The tool of claim 1, further comprising a detector that is used
to measure casing standoff such that other detector responses are
compensated for tool stand-off and centralization.
3. The tool of claim 1, wherein said shield further comprises
tungsten.
4. The tool of claim 1, wherein the tool is configured so as to
permit through-wiring.
5. The tool of claim 1, wherein a plurality of reference detectors
is used to monitor the azimuthal output of the x-ray source.
6. The tool of claim 1, wherein the shortest-axial offset imaging
detector array is configured to distribute incoming photons into
energy classifications such that photoelectric measurements may be
made.
7. The tool of claim 1, wherein the x-ray source energy is capable
of being modulated to modify the optimum-detector axial offset in
order to assist with the creation of response sensitivity
functions.
8. The tool of claim 1, wherein the tool is combinable with other
measurement tools comprising one or more of neutron-porosity,
natural gamma and array induction tools.
9. The tool of claim 1, wherein an azimuthally segmented acoustic
measurement is integrated into the tool.
10. The tool of claim 1, wherein the tool determines the position,
distribution and volume of fractures, either natural or artificial,
within the formation surrounding the cased wellbore.
11. The tool of claim 1, wherein the tool is integrated into a
logging-while-drilling assembly.
12. The tool of claim 1, wherein the tool is powered by mud-turbine
generators.
13. The tool of claim 1, wherein the tool is powered by
batteries.
14. The tool of claim 1, wherein the tool is configured so as to
permit through-wiring.
15. The tool of claim 1, wherein a plurality of reference detectors
is used to monitor the output of the x-ray source.
16. The tool of claim 1, wherein the shortest-axial offset detector
is configured to distribute incoming photons into energy
classifications such that photoelectric measurements may be
made.
17. The tool of claim 1, wherein the x-ray source energies are
modulated to modify the optimum-detector axial offset in order to
assist with the creation of response sensitivity functions.
18. The tool of claim 1, wherein the tool is combinable with other
measurement tools comprising one or more of neutron-porosity,
natural gamma and array induction tools.
19. The tool of claim 1, wherein azimuthally segmented acoustic
measurements are integrated into the tool.
20. The tool of claim 1, wherein the tool determines the position,
distribution and volume of fractures, either natural or artificial,
within the formation surrounding the cased wellbore.
21. The method of x-ray based cement evaluation for measuring the
density of material volumes within single, dual and multiple-casing
wellbore environment, wherein said method comprises: illuminating
the formation surrounding a borehole using x-rays; using a
plurality of detectors to measure the density of the cement annuli
and any variations in density within; and illuminating the casing
surrounding a borehole using x-rays and then using a plurality of
multi-pixel imaging detectors to measure the thickness of the
casing.
22. The method of claim 21, further comprising: measuring casing
standoff such that other detector responses can be compensated for
tool stand-off and centralization.
23. The method of claim 21, further comprising using a plurality of
reference detectors to monitor the azimuthal output of the x-ray
source.
24. The method of claim 21, further comprising: configuring the
shortest-axial offset imaging detector array to distribute incoming
photons into energy classifications such that photoelectric
measurements may be made.
25. The method of claim 21, further comprising modulating the x-ray
source energy source to modify the optimum-detector axial offset to
aid the creation of response sensitivity functions.
26. The method of claim 21, further comprising combining the tool
with other measurement tools comprising one or more of
neutron-porosity, natural gamma and array induction tools.
27. The method of claim 21, further comprising integrating an
azimuthally segmented acoustic measurement into the tool.
28. The method of claim 21, further comprising determining the
position, distribution and volume of fractures, either natural or
artificial, within the formation surrounding the cased
wellbore.
29. The method of claim 21, further comprising using a plurality of
reference detectors to monitor the output of the x-ray source.
30. The method of claim 21, further comprising configuring the
shortest-axial offset detector to distribute incoming photons into
energy classifications such that photoelectric measurements may be
made.
31. The method of claim 21, further comprising modulating the x-ray
source energies so as to modify the optimum-detector axial offset
in order to aid the creation of response sensitivity functions.
32. The method of claim 21, further comprising determining the
position, distribution and volume of fractures, either natural or
artificial, within the formation surrounding the cased wellbore.
Description
TECHNICAL FIELD
[0001] The present invention relates generally to methods and means
for detecting anomalies in annular materials, and in a particular
though non-limiting embodiment to methods and means for detecting
anomalies in the annular materials of single and dual casing string
environments and measuring the integrity of the casing immediately
surrounding the tool.
BACKGROUND
[0002] Within the oil and gas industry, it is important to be able
to gauge the quality of cement through multiple casings, as is the
ability to determine the status of the annuli. The industry
currently employs various methods for the verification of the
hydraulic seal behind a single casing string. Typically, ultrasonic
tools are run within the well in order to determine whether cement
is bonded to the outside of the casing, thereby indicating the
presence of cement in the annulus between the casing and formation,
or between the casing and an outer casing. Ultimately, a pressure
test is required to ensure that zonal isolation has been achieved
as ultrasonic tools are highly dependent upon quality of the
casing, the bond between the casing and the material in the
annulus, and the mechanical properties of the material in the
annulus to be able to work correctly. In addition, since ultrasonic
tools treat the material in the annulus as a single isotropic and
homogenous volume, any actual deviation away from this ideal leads
to inaccuracies in the measurement.
[0003] Current tools can offer information regarding the cement
bond of the inner-most casing, yet lack the ability to discriminate
between and amongst various depths into the cement or annular
material. This limitation means that fluid migration paths may
exist at the cement-formation boundary, within the cement itself,
or between the casing and an outer casing, thereby leading to a
loss of zonal isolation. In addition, the ability to resolve the
mechanical and structural integrity of the aforementioned casing is
currently reliant upon the use of mechanical calipers that are
deployed separately to any cement evaluation techniques. The
mechanical calipers provide an operator with a geometric
measurement of the inner diameter of the innermost casing, and
assume that the outer-diameter of the casing remains unaffected by
corrosion, remaining consistent with API-standard pipe
diameters.
[0004] No viable technologies are currently available which are
able to determine the radial and azimuthal position of anomalies
within the annular region (up to the cement-formation boundary) to
ensure that no fluid paths exist that may pose a risk to zonal
isolation and well integrity, while simultaneously measuring the
integrity of the casing.
[0005] Prior art teaches a variety of techniques that use x-rays or
other radiant energy to inspect or obtain information about the
structures within or surrounding the borehole of a water, oil or
gas well, yet none teach methods or means capable of accurately
analyzing the azimuthal and radial position of anomalies in the
annular materials surrounding a wellbore in single or multi-string
cased well environments. In addition, none teach of a method of
accurately analyzing the azimuthal position of anomalies with a
means which includes a centralized (non-padded) tool that is
concentric with the well casing, rather than being a `padded` tool
that requires the source and detector assemblies to be in contact
with said casing, much as with mechanical calipers when attempting
to determine the integrity of the casing by assuming the material
remaining in the thickness of materials of the casing.
[0006] U.S. Pat. No. 7,675,029 to Teague et al. teaches an
apparatus that permits the measurement of x-ray backscattered
photons from any horizontal surface inside of a borehole that
refers to two-dimensional imaging techniques.
[0007] U.S. Pat. App No. 20180180765 by Teague et al. teaches an
x-ray based cement evaluation tool for measurement of the density
of material volumes within single, dual and multiple-casing
wellbore environments.
[0008] U.S. Pat. No. 8,481,919 to Teague teaches a method of
producing Compton-spectrum radiation in a borehole without the use
of radioactive isotopes, and further describes rotating collimators
around a fixed source installed internally to the apparatus, but
does not have solid-state detectors with collimators. It teaches of
the use of conical and radially symmetrical anode arrangements to
permit the production of panoramic x-ray radiation.
[0009] U.S. Pat. No. 3,564,251 to Youmans discloses the use of a
azimuthally scanning collimated x-ray beam that is used to produce
an attenuated signal at a detector for the purposes of producing a
spiral-formed log of the inside of a casing or borehole surface
immediately surrounding the tool, effectively embodied as an x-ray
caliper.
[0010] U.S. Pat. No. 7,634,059 to Wraight discloses an apparatus
used to measure two-dimensional x-ray images of the inner surface
inside of a borehole without the technical possibility to look
inside of the borehole in a radial direction.
[0011] US 2013/0009049 by Smaardyk discloses an apparatus that
allows measurement of backscattered x-rays from the inner layers of
a borehole.
[0012] U.S. Pat. No. 8,138,471 to Shedlock discloses a
scanning-beam apparatus based on an x-ray source, a rotatable x-ray
beam collimator and solid-state radiation detectors enabling the
imaging of only the inner surfaces of borehole casings and
pipelines.
[0013] U.S. Pat. No. 5,326,970 to Bayless discloses a concept for a
tool that aims to measure backscattered x-rays from inner surfaces
of a borehole casing with the x-ray source being based on a linear
accelerator.
[0014] U.S. Pat. No. 7,705,294 to Teague teaches an apparatus that
measures backscattered x-rays from the inner layers of a borehole
in selected radial directions with the missing segment data being
populated through movement of the apparatus through the borehole.
The apparatus permits generation of data for a two-dimensional
reconstruction of the well or borehole, but the publication does
not teach of the necessary geometry for the illuminating x-ray beam
to permit discrimination of the depth from which the backscattered
photons originated, only their direction.
[0015] U.S. Pat. No. 5,081,611 to Hornby discloses a method of back
projection to determine acoustic physical parameters of the earth
formation longitudinally along the borehole using a single
ultrasonic transducer and a number of receivers distributed along
the primary axis of the tool.
[0016] U.S. Pat. No. 6,725,161 to Hillis discloses a method of
placing a transmitter in a borehole, and a receiver on the surface
of the earth, or a receiver in a borehole and a transmitter on the
surface of the earth, used to determine structural information
regarding the geological materials between the transmitter and
receiver.
[0017] U.S. Pat. No. 6,876,721 to Siddiqui discloses a method of
correlating information taken from a core-sample with information
from a borehole density log. The core-sample information is derived
from a CT scan of the core-sample, whereby the x-ray source and
detectors are located on the outside of the sample, and thereby
configured as an "outside-looking-in" arrangement. Various kinds of
information from the CT scan such as its bulk density is compared
to and correlated with the log information.
[0018] U.S. Pat. No. 4,464,569 to Flaum discloses a method of
determining the elemental composition of earth formations
surrounding a well borehole by processing the detected neutron
capture gamma radiation emanating from the earth formation after
neutron irradiation of the earth formation by a neutron
spectroscopy logging tool.
[0019] U.S. Pat. No. 4,433,240 to Seeman discloses a borehole
logging tool that detects natural radiation from the rock of the
formation and logs said information so that it may be represented
in an intensity versus depth plot format.
[0020] U.S. Pat. No. 3,976,879 to Turcotte discloses a borehole
logging tool that detects and records the backscattered radiation
from the formation surrounding the borehole by means of a pulsed
electromagnetic energy or photon source, so that characteristic
information may be represented in an intensity versus depth plot
format.
[0021] U.S. Pat. No. 9,012,836 to Wilson et al. discloses a method
and means for creating azimuthal neutron porosity images in a
wireline environment. Similar to U.S. Pat. No. 8,664,587, this
reference discloses an arrangement of azimuthally static detectors
which could be implemented in a wireline tool to assist an operator
in interpreting logs post-fracking, by subdividing the neutron
detectors into a plurality of azimuthally arranged detectors which
are shielded within a moderator to infer directionality to incident
neutrons and gamma.
[0022] U.S. Pat. No. 4,883,956 to Manente et al. discloses an
apparatus and methods for investigation of subsurface earth
formations using an apparatus adapted for movement through a
borehole. Depending upon the formation characteristic or
characteristics to be measured, the apparatus may include a natural
or artificial radiation source for irradiating the formations with
penetrating radiation such as gamma rays, x-rays or neutrons. The
light produced by a scintillator in response to detected radiation
is used to generate a signal representative of at least one
characteristic of the radiation and this signal is recorded.
[0023] U.S. Pat. No. 6,078,867 to Plumb discloses a method of
generating a three-dimensional graphical representation of a
borehole, including at least the steps of receiving caliper data
relating to the borehole, generating a three-dimensional wire mesh
model of the borehole from the caliper data, and color mapping the
three-dimensional wire mesh model from the caliper data based on
either borehole form, rugosity and/or lithology.
[0024] U.S. Pat. No. 3,321,627 to Tittle discloses a system of
collimated detectors and collimated gamma-ray sources to determine
the density of a formation outside of a borehole, optimally
represented in a density versus depth plot format. However, the
reference fails to teach or suggest any method or means used to
achieve such through a steel wall of a single or multiple well
casings.
SUMMARY
[0025] An x-ray based cement evaluation tool for measurement of the
density of material volumes, wherein the tool uses x-rays to
illuminate a formation surrounding a borehole and a plurality of
detectors are used to measure the density of the cement annuli and
variations in density within is provided, the tool including at
least: an internal length comprising a sonde section, wherein said
sonde section further comprises an x-ray source; a radiation shield
for radiation measuring detectors; sonde-dependent electronics; and
a plurality of tool logic electronics and PSUs.
[0026] A method of x-ray based cement evaluation for measuring the
density of material volumes within single, dual and multiple-casing
wellbore environment is also provided, the method including at
least: illuminating the formation surrounding a borehole using
x-rays; using a plurality of detectors to measure the density of
the cement annuli and any variations in density within; and
illuminating the casing surrounding a borehole using x-rays and
then using a plurality of multi-pixel imaging detectors to measure
the thickness of the casing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 illustrates an x-ray-based tool being deployed into a
borehole via wireline conveyance. Regions of interest within the
materials surrounding the borehole are also indicated.
[0028] FIG. 2 illustrates one example of the azimuthal placement of
near-field imaging detector arrays, arranged so as to enable
imaging of the inner-most casing.
[0029] FIG. 3 illustrates one example of the axial placement of
near-field imaging detector arrays, arranged so as to enable
imaging of the inner-most casing while illuminated by a conical
beam of x-ray, while an array of longer offset detectors
interrogate the materials surrounding the borehole using the same
conical x-ray beam.
[0030] FIG. 4 illustrates how manipulation of an arrangement of
collimators/shields can be used to select between a fixed plurality
of x-ray beams, or a rotating set of x-ray beams, and further
illustrates how the casing imaging detectors would be arranged.
BRIEF DESCRIPTION OF SEVERAL EXAMPLE EMBODIMENTS
[0031] The methods and means described herein for simultaneous
casing integrity evaluation, through x-ray backscatter imaging
combined with x-ray-based cement inspection in a multiple-casing
wellbore environment, is deployed in a package that does not
require direct physical contact with the well casings (i.e.,
non-padded). Furthermore, the method and means employ an actuated
combination of collimators, located cylindrically around an X-ray
source within a non-padded concentrically-located borehole logging
tool, together with a single or plurality of two dimensional
per-pixel collimated imaging detector array(s) used in certain
embodiments as the primary fluid/offset compensation detectors. The
capability of actuation of the collimators permits the operator,
the opportunity between a fixed collimator mode, that provides the
output of an azimuthal array of a plurality of x-ray beams (from
said x-ray source), or to select through actuation, a mode that
produces a single or plurality of individual azimuthally arranged
x-ray beams that `scan` azimuthally, through the rotation of one of
the collimators.
[0032] In one example embodiment, an electronic-source-based
borehole logging tool [101] is deployed by wireline conveyance
[104] into a cased borehole [102], wherein the density of materials
surrounding the borehole [103] are measured by the tool. In a
further embodiment, the tool is enclosed in a pressure housing,
which ensures that well fluids are maintained outside of the
housing.
[0033] FIG. 2 further illustrates how an azimuthal plurality of
per-pixel collimated two-dimensional detectors [201] can be used to
create a plurality of two-dimensional images of the well casing
[202] as the tool [203] is logged. The output from each pixel can
be summated as a function of depth to provide tool offset
(eccentricity) data which acts as a key-input into the fluid
compensation of the detectors that possess a larger axial offset
(cement evaluation detectors), and hence, a deeper depth of
investigation into the materials surrounding the borehole.
[0034] FIG. 3 illustrates that as the x-ray beam [309] (shown as a
cone) interacts with the media surrounding the tool [307] within
the borehole [301, 302, 303, 304, 305], the counts that are
detected at each axially offset group of detectors [310, 311, 312,
313, 314] is a convolution of the various attenuation factor
summations of the detected photons as they travelled through and
back through each `layer` of the borehole surroundings [301, 302,
303, 304, 305]. The data each detector may be deconvoluted through
the use of the data collected by the 1st order detector group
[310], to compensate for fluid-thickness and casing variations
alone. As the first order detector [310] is a per-pixel collimated
imaging detector array, the detectors are also capable of creating
backscatter images of the casing [305] itself. When the tool is
actuated axially (through wireline logging) the images, collected
as a function of axial offset/depth, can be tessellated to produce
long two-dimensional x-ray backscatter images of the casing [305].
The backscatter images may also contain spectral information, such
that a photo-electric or characteristic-energy measurement may be
taken, such that the imaged material may be analyzed for
scale-build up or corrosion, etc.
[0035] In one embodiment, cylindrical collimators are used to
provide directionality to the output of an x-ray source located
within the pressure housing of a borehole logging tool. An x-ray
beam or plurality of beams, rotating azimuthally around the major
axis of the bore tool, interacts with the annular materials
surrounding the wellbore within a single or multi-string cased hole
environment to produce both single and multi-scatter responses,
depending upon the axial offset of a plurality of fixed detectors
that are employed to measure the incoming photons resulting from
said scatter. In a further embodiment, an azimuthal plurality of
per-pixel collimated two-dimensional detectors can be used to
create a plurality of two-dimensional images of the well casing as
the tool is logged.
[0036] FIG. 4 further illustrates the rotation of the collimator
[404], which permits an increase of the discrete resolving power of
the azimuthal location of density variations in the annular
materials surrounding the wellbore in multi-string cased-hole
environments. An axial plurality of fixed collimated detector-sets
[401] can be used to measure the multiple-scatter signal resulting
from the interaction of the beam with the casings and annular
materials. The collimator sleeves [405] may be actuated to enable
the selection of varying x-ray beam output modes [402, 403]. In one
example of such an arrangement, a non-rotating plurality of
azimuthally located x-ray beams [402] is provided, wherein each
beam is accompanied by an axially-paired two dimensional per-pixel
collimated imaging detector array [401]. In another example of such
an arrangement, the axial actuation of one sleeve [405] and the
rotation of another [404] produce a single or multi-element
azimuthally rotating beam [403] (similar to a lighthouse). The
azimuthal plurality of detectors [401] rotates with the source
collimation sleeve, such that the result is a multi-helical ribbon
image that can be re-formatted to create a complete image of the
360 degrees of the casing as a function of
depth/axial-distance.
[0037] In yet another embodiment, the collimators are used to
provide directionality to the output of an x-ray source are square,
formed tubes disposed within a shielding material. In a further
embodiment, the collimators are used to give directionality to the
output of an x-ray source are rectangular formed tubes within a
shielding material.
[0038] In one embodiment, the output from each pixel is summated as
a function of depth to provide tool offset (i.e., eccentricity)
data which acts as a key-input into the fluid compensation of the
detectors that possess a larger axial offset (cement evaluation
detectors), and hence, a deeper depth of investigation into the
materials surrounding the borehole.
[0039] In another embodiment, the backscatter images may also
contain spectral information, such that a photo-electric or
characteristic-energy measurement may be taken, such that the
imaged material can be analyzed for scale-build up or casing
corrosion, etc.
[0040] In a further embodiment, machine learning would be employed
to automatically analyze the spectral (photo electric or
characteristic energy) content of the images to identify key
features, such as corrosion, holes, cracks, scratches, and/or
scale-buildup.
[0041] In a further embodiment, the per-pixel collimated imaging
detector array would be a single `strip` array (i.e., one pixel
wide) and multiple pixels long--the imaging result is a `helical`
ribbon image, that can be re-formatted to create a complete image
of the 360 degrees of the casing as a function of
depth/axial-distance.
[0042] In a further embodiment, the tool is maintained stationary
in the well, and the source collimator would be rotated, the
per-pixel collimated imaging detector array would be a single
`strip` array (i.e., one pixel wide) and multiple pixels long--the
imaging result would be a `cylindrical` ribbon image. Further
passes of the rotating source/detector collimator could be
accumulated such that the statistical accuracy (and therefore
resolution) of the image is improved for each pass.
[0043] In a further embodiment, the tool is maintained stationary
in the well, and the source collimator would be rotated, the
per-pixel collimated imaging detector array would be a single
`strip` array i.e. one pixel wide, and multiple pixels long--the
imaging result is a `cylindrical` ribbon image. The tool could be
moved axially (for example, by either a wireline-winch or with a
stroker) and a new image set taken, such that a section of casing
could be imaged by stacking cylindrical ribbon images/logs.
[0044] In a further embodiment still, machine learning is employed
to automatically reformat (or re-tesselate) the resulting images as
a function of depth and varying logging speeds or logging steps,
such that the finalized casing and/or cement image is accurately
correlated for azimuthal direction and axial depth, by comparing
with CCL, wireline run-in measurements, and/or other pressure/depth
data.
[0045] The foregoing specification is provided only for
illustrative purposes, and is not intended to describe all possible
aspects of the present invention. While the invention has herein
been shown and described in detail with respect to several
exemplary embodiments, those of ordinary skill in the art will
appreciate that minor changes to the description, and various other
modifications, omissions and additions may also be made without
departing from the spirit or scope thereof.
* * * * *