Methods and Means for the Measurement of Tubing, Casing, Perforation and Sand-Screen Imaging Using Backscattered X-Ray Radiation in a Wellbore Environment

Abstract

An x-ray-based cased wellbore tubing and casing imaging tool is disclosed, the tool including at least a shield to define the output form of the produced x-rays; a two-dimensional per-pixel collimated imaging detector array; a parallel hole collimator format in one direction that is formed as a pinhole in another direction; Sonde-dependent electronics; and a plurality of tool logic electronics and PSUs. A method of using an x-ray-based cased wellbore tubing and casing imaging tool is also disclosed, the method including at least: producing x-rays in a shaped output; measuring the intensity of backscatter x-rays returning from materials surrounding a wellbore; determining an inner and an outer diameter of tubing or casing from the backscatter x-rays; and converting image data from said detectors into consolidated images of the tubing or casing.

Claims

1. An x-ray-based cased wellbore tubing and casing imaging tool, said tool comprising: a shield to define the output form of the produced x-rays; a two-dimensional per-pixel collimated imaging detector array; a parallel hole collimator format in one direction that is formed as a pinhole in another direction; Sonde-dependent electronics; and a plurality of tool logic electronics and PSUs.

2. The tool of claim 1, wherein said imaging detector comprises a two-dimensional per-pixel collimated imaging detector arrays, wherein the imaging array is one pixel wide and multiple pixels long.

3. The tool of claim 1, wherein said imaging detectors comprise two sets of two-dimensional per-pixel collimated imaging detector arrays.

4. The tool of claim 1, wherein said imaging detectors comprise a plurality of two-dimensional per-pixel collimated imaging detector arrays.

5. The tool of claim 1, wherein the images contain spectral information to inform characteristics of any wellbore materials or debris.

6. The tool of claim 1, wherein said shield further comprises tungsten.

7. The tool of claim 1, wherein the tool is configured so as to permit through-wiring.

8. The tool of claim 1, wherein the tool is combinable with other measurement tools comprising one or more of acoustic or ultrasonic tools.

9. The tool of claim 1, wherein the tool is used to determine an inner diameter of a tubing or casing.

10. The tool of claim 1, wherein the tool is used to determine an outer diameter of a tubing or casing.

11. The tool of claim 1, wherein the tool is used to determine a distribution and inner diameter of a scale upon an inner diameter of a tubing or casing.

12. The tool of claim 1, wherein the tool is used to determine the position, distribution and area of perforations, within casings surrounding a cased wellbore.

13. The tool of claim 1, wherein the tool is used to determine the position and integrity of sand-screens, within casings surrounding a cased wellbore.

14. The tool of claim 1, wherein the tool is used to determine the position and integrity of gravel-packs, within casings surrounding a cased wellbore.

15. The tool of claim 1, wherein the tool is used to determine the position and integrity of side-pocket mandrels, within casings surrounding a cased wellbore.

16. The tool in claim 1, wherein 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.

17. A method of using an x-ray-based cased wellbore tubing and casing imaging tool, said method comprising: producing x-rays in a shaped output; measuring the intensity of backscatter x-rays returning from materials surrounding a wellbore; determining an inner and an outer diameter of tubing or casing from the backscatter x-rays; and converting image data from said detectors into consolidated images of the tubing or casing.

18. The method of claim 17, wherein said imaging detector comprises a two-dimensional per-pixel collimated imaging detector arrays wherein the imaging array is one pixel wide and multiple pixels long.

19. The method of claim 17, wherein said imaging detectors comprise two sets of two-dimensional per-pixel collimated imaging detector arrays.

20. The method of claim 17, wherein said imaging detectors comprise a plurality of two-dimensional per-pixel collimated imaging detector arrays.

21. The method of claim 17, wherein the images contain spectral information to inform the characteristics of any wellbore materials or debris.

22. The method of claim 17, wherein the tool is combinable with other measurement methods comprising one or more of acoustic or ultrasonic.

23. The method of claim 17, wherein the tool is used to determine an inner diameter of a tubing or casing.

24. The method of claim 17, wherein the tool is used to determine an outer diameter of a tubing or casing.

25. The method of claim 17, wherein the tool is used to determine the distribution and inner diameter of a scale upon the inner diameter of a tubing or casing.

26. The method of claim 17, wherein the tool is used to determine the position, distribution and area of perforations, within casings surrounding a cased wellbore.

27. The method of claim 17, wherein the tool is used to determine the position and integrity of sand-screens, within casings surrounding a cased wellbore.

28. The method of claim 17, wherein the tool is used to determine the position and integrity of gravel-packs, within casings surrounding a cased wellbore.

29. The method of claim 17, wherein the tool is used to determine the position and integrity of side-pocket mandrels, within casings surrounding a cased wellbore.

30. The method of claim 17, wherein 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.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 illustrates an x-ray-based tubing, casing, perforation, or side-pocket mandrel imaging tool being deployed into a borehole via wireline conveyance. Regions of interest within the materials surrounding the borehole are also indicated.

[0027] FIG. 2 illustrates an example embodiment of an x-ray-based tubing imaging and measurement tool, arranged so as to enable imaging of the inner-most casing or tubing, and illustrating the ability to change modes to perform a geometric measurement of the thickness of the tubing.

[0028] FIG. 3 illustrates an example embodiment of an x-ray-based tubing imaging and measurement tool, arranged so as to perform a geometric measurement of the thickness of the tubing, and in particular to determine the inner diameter and the outer diameter of the tubing.

[0029] FIG. 4 illustrates how the intensity of detected x-rays can be translated directly into a geometric position within the tubing or casing, indicating the position of the inner diameter and the outer diameter.

[0030] FIG. 5 illustrates how the intensity of detected x-rays can be translated directly into a geometric position within the tubing or casing, indicating the position of the inner diameter of scale, simultaneously with the inner diameter of the tubing and the outer diameter.

BRIEF DESCRIPTION OF SEVERAL EXAMPLE EMBODIMENTS

[0031] Various methods and means for performing casing and tubing integrity evaluation are disclosed which, while simultaneously imaging equipment/features located immediately surrounding the borehole, using x-ray backscatter imaging in a cased wellbore environment, do not require direct physical contact with the well casings (i.e., non-padded). The methods and means herein further consist employing a combination of collimators, located cylindrically around an X-ray source, located within a non-padded concentrically-located borehole logging tool, together with a plurality of fixed three-dimensional hybrid collimated imaging detector array(s) to also be used as the primary imaging detector(s). The ability to control the solid angle of the collimated source permits the operator to either log the tool through the well casing while the detectors measure the inner diameter and outer diameter of tubing or casing, to produce a fully azimuthal two dimensional backscatter x-ray image, and to hold the tool stationary as the collimated detectors image azimuthally to capture a cylindrical image that can be improved upon ‘statically’ (as the detector continues to recapture casing images that can be added to the existing image set).

[0032] In one example embodiment, and, with reference now to the illustration provided in FIG. 1, an x-ray-based tubing imaging tool [101] is deployed by wireline conveyance [104] into a tubing [102] within a cased [103] borehole, wherein the well casing or tubing [102] is imaged. The tool is enclosed by a pressure housing [201] which ensures that well fluids are maintained outside of the housing.

[0033] FIG. 2 illustrates an example embodiment in which a pressure housing [201] is conveyed through a well casing or tubing [202]. The pressure housing contains an electronic x-ray source [203] that is configured to produce x-rays panoramically in a conical output [204], the shape and distribution of said x-ray output is determined by the geometry of an actuatable source collimator [205, 208] which is formed by creating a non-blocking region of the radiation shielding. The conical x-ray beam [204] illuminates a cylindrical section of the casing/tubing [204]. The radiation scattering from the casing is imaged by an azimuthally arranged plurality of two-dimensional detector arrays [206], which are collocated with three-dimensional parallel hole collimators [207a, 207b]. The detector collimators reduce the field of view of each pixel of the detector array such that each pixel images a distinct and unique section of the illuminated casing/tubing. The collimators are formed such that, in the transverse direction, they form the geometry of a typical pinhole detector [207a], however, in the axial-radial direction they form the geometry of a plurality of parallel hole collimators [207b]. In a further embodiment, the source collimator may be actuated [208], by command of the operator without removing the tool from the borehole, such that one axial component of the collimator [205] moves to reduce the solid-angle of the source-output, resulting in a very narrow conical beam [209], or plurality of individual beams that create a conical form. The tool is then arranged so that the narrow conical beam intersects the tubing or casing and can be used to measure the thickness of the tubing or casing more precisely. As the axial offset for each pixel is known, along with the angle and field-of-view of the collimator, as well as the angle and divergence of the beam, it is simple to remap each pixel to a radially positioned voxel along the beam-path, the form of which may be plotted as intensity [210] versus axial or radial offset [211] to produce a backscatter profile [212] of the tubing or casing material.

[0034] In another example embodiment, the concentricity of the tool [101] compared to the tubing or casing [302] does not affect the geometric relation of the measurement with respect to the inner diameter and the outer diameter of the tubing or casing [302]. If the tool housing [301] standoff is reduced in the direction of the tubing or casing [302] then the conical x-ray beam [303] interacts with the tubing or casing [302] in a different position, such that the higher intensity region [304] of scattering photons being detected will appear to move toward the source anode position axially. On the opposite side of the tool (180 degrees away), the tool housing [301] standoff will be increased away from the tubing or casing [302] then the conical x-ray beam [303] will interact with the tubing or casing [302] in a different position, such that the higher intensity region [305] of scattering photons being detected will appear to move away from the source anode position axially. The result would be that the movement of the higher intensity region [304] when plotted as intensity [306] versus axial or radial offset [307] to form a profile [308] of the tubing or casing will shift but without changing the overall form of the tubing or casing profile, as the source beam angle will not have changed. Conversely, on the opposite side of the tool (180 degrees away) the result would be that the movement of the higher intensity region [305] when plotted as intensity [306] versus axial or radial offset [307] to form a profile [309] of the tubing or casing, will shift but without changing the overall form of the tubing or casing profile, as the source beam angle will not have changed. The change in position of the two profiles [308, 309] can be used to determine both the position of the tool within the tubing, and the diameter of the inner diameter of the tubing as a function of azimuth around the tool.

[0035] In a further embodiment the axial offset for each pixel is known, along with the angle and field-of-view of the collimator and the angle and divergence of the beam, it is simple to remap each pixel to a radially positioned voxel along the beam-path, the form of which may be plotted as intensity [402] versus axial or radial offset [402] to produce a backscatter profile of the tubing or casing material, the leading edge of the plot [403] is also co-located with the highest rate of change in intensity [401]. When the return falls to near zero backscatter intensity, the outer diameter [404] may also be determined.

[0036] In a further embodiment, the tool is then arranged such that the narrow conical beam intersects the tubing or casing and can be used to measure the thickness of the tubing or casing precisely, in addition to the thickness of scale deposits on the inner-diameter of the tubing/casing. As the axial offset for each pixel is known, along with the angle and field-of-view of the collimator, and the angle and divergence of the beam, it is simple to remap each pixel to a radially positioned voxel along the beam-path. A plot of intensity [501] versus radial distance, derived from the geometric remapping of intensity as a function of detector pixel position relative to the source output [502] may be used to determine the position of the inner diameter of scale deposits [503] upon the inner diameter of the tubing or casing, and the inner diameter of the tubing or casing [504], in addition to the outer diameter of the tubing or casing.

[0037] In a further embodiment, the radial inspection detector assemblies are used to create images of sand-screens, as well as to aid inspection.

[0038] In a further embodiment, the radial inspection detector assemblies are used to create images of side pocket mandrels, and to aid inspection.

[0039] In a still further embodiment, the radial inspection detector assemblies are used to create images of perforations, and to aid inspection and to map and size perforations.

[0040] In a further embodiment still, the radial inspection detector assemblies are used to create images of frac-sleeves.

[0041] In another embodiment, as the tool is logged axially, each axial ‘column’ of pixels of the detector arrays are sampled so that each column will image a similar section of the casing/tubing that had been imaged by a neighboring section during the prior sample. Upon encoding the images with the known azimuthal capture position of the image section, the separate image pixel columns associated with each imaged ‘slit’ section of the casing/tubing are summated or averaged to produce a higher quality image within a single pass.

[0042] In a further embodiment, the operator interrupts conveyance of the tool and uses the azimuthally imaging detector assembly to continually sample the same images tubing/casing illuminated cylinder section, so that the resulting data set can build/summate statistically to improve image quality.

[0043] In another embodiment, the backscatter images contain spectral information, so that a photo-electric or characteristic-energy measurement can be taken, and the imaged material analyzed for scale-build up or casing corrosion.

[0044] In a further embodiment, machine learning is employed to automatically analyze the spectral (photo electric or characteristic energy) content of the images and identify key features, such as corrosion, holes, cracks, scratches, and/or scale-buildup.

[0045] In a further embodiment, the per-pixel collimated imaging detector array is a single ‘strip’ array (i.e., one pixel wide azimuthally, and multiple pixels long axially), the imaging result would be a ‘cylindrical’ ribbon image. The tool is then moved axially (either by wireline-winch or with a stroker) and a new image set taken, so that a section of casing is imaged by stacking cylindrical ribbon images/logs.

[0046] In a further embodiment, 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.

[0047] 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.