WO2023225248A1

WO2023225248A1 - Method and apparatus for preventing sediment disruption due to degassing in coring operations

Info

Publication number: WO2023225248A1
Application number: PCT/US2023/022824
Authority: WO
Inventors: Priyank Jaiswal
Original assignee: The Board of Regents for the Oklahoma Agricultural and Mechanical Colleges
Priority date: 2022-05-20
Filing date: 2023-05-19
Publication date: 2023-11-23

Abstract

A core sample liner has an outer liner and a perforated insert positioned in the core liner. The perforated insert has a plurality of perforations to communicate gas released from a core sample in the core sample liner to a degassing chamber in the core sample liner.

Description

METHOD AND APPARATUS FOR PREVENTING

SEDIMENT DISRUPTION DUE TO DEGASSING IN CORING OPERATIONS

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application No. 63/344,344 filed May 20, 2022, which is hereby incorporated by reference.

[0002] Coring operations during the drilling of wellbores for the exploration, evaluation and production of oil and gas reservoirs are well known, and are conducted for both onshore and offshore oil and gas wells. Cores of physical rock samples are acquired during a coring operation, and the depositional sequences of the sample can be examined, which offers insight into the presence of hydrocarbons, other compositions of interest and properties of the survey area. In a conventional coring process, once a wellbore is drilled to a zone of interest, the conventional drill bit is replaced with a coring bit which is a hollow bit attached to a barrel. The coring bit grinds away rock and leaves a cylindrical core of rock held in the barrel. Sidewall coring may also be conducted downhole. In a sidewall coring operation, a rotary coring tool extracts a core from the side wall of the wellbore. Rotary coring tools employ drill bits that will drill into the sidewall of the wellbore and the core from the sidewall is held inside the tool body.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] FIG. l is a schematic of a coring assembly lowered into a wellbore using a core liner disclosed herein.

[0004] FIG. 2 is a top view of an embodiment of a core liner disclosed herein.

[0005] FIG. 3 is a section view from line 3-3 of FIG. 5.

[0006] FIG. 4 is a section view from line 4-4 of FIG. 5.

[0007] FIG. 5 is a cross section from line 5-5 of FIG. 2.

[0008] FIG. 6 is a top view of an additional embodiment of a core liner of the current disclosure.

[0009] FIG. 7 is a section view in the direction of line 7-7 of FIG. 9.

[00010] FIG. 8 is a section view in the direction of line 8-8 of FIG. 9.

[00011] FIG. 9 is a section view of the core sample liner from line 9-9 of FIG.6 rotated so that the upper end of the core liner is at the top of the page. [00012] FIG. 10 is a section view of the core sample liner from line 10-10 of FIG. 6 rotated so that the upper end of the core sample liner is at the top of the page

DESCRIPTION OF AN EMBODIMENT

[00013] In the drawings and description that follow, like parts are typically marked throughout the specification and drawings with the same reference numerals, respectively. In addition, similar reference numerals may refer to similar components in different embodiments disclosed herein. The drawing figures are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. The present invention is susceptible to embodiments of different forms. Specific embodiments are described in detail and are shown in the drawings, with the understanding that the present disclosure is not intended to limit the invention to the embodiments illustrated and described herein. It is to be fully recognized that the different teachings of the embodiments discussed herein may be employed separately or in any suitable combination to produce desired results.

[00014] Unless otherwise specified, use of the terms "connect," "engage," "couple," "attach," or any other like term describing an interaction between elements is not meant to limit the interaction to direct interaction between the elements and may also include indirect interaction between the elements described. It should also be understood that, as used herein, “first,” “second,” and “third,” are assigned arbitrarily and are merely intended to differentiate between two or more components, flow ports, etc., as the case may be, and do not indicate any sequence. Furthermore, it is to be understood that the mere use of the word “first” does not require that there be any “second,” and the mere use of the word “second” does not require that there be any “third,” etc.

[00015] Unless otherwise specified, use of the terms "up," "upper," "upward," "up-hole," "upstream," or other like terms shall be construed as generally toward the surface; likewise, use of "down," "lower," "downward," "down-hole," "downstream," or other like terms shall be construed as generally away from the surface, regardless of the wellbore orientation. Use of any one or more of the foregoing terms shall not be construed as denoting positions along a perfectly vertical axis. A wellbore can include vertical, inclined or horizontal portions, and can be straight or curved. [00016] FTG. 1 is a schematic representation of a core sample liner 10 of the current disclosure lowered into a wellbore 5. In the embodiment described wellbore 5 has casing 7 therein. Core sample liner 10 may comprise part of a core sample collection apparatus that includes a core barrel 15, which may be referred to as an outer barrel 15. Outer barrel 15 may be connected in a drill string 20 that has a coring bit 25 connected to a lower end thereof. Coring bit 25 will be of a type that has an opening 30 therethrough so that as it drills the sediment/rock drilled through will pass upwardly therethrough. The core sample collection apparatus may also comprise a core catcher 32 positioned below core sample liner 10. Core catcher 32 may be of a type known in the art. In the described embodiment core sample liner 10 is positioned in a vertical well. In operation in a vertical well the coring bit 25 will be rotated by the drill string 20, which includes outer barrel 15. Sediment will pass into core sample liner 10 which provides for degassing during drilling and lifting to the surface as described in more detail herein. Although described with respect to a vertical wellbore with a coring bit, it is understood that the core sample liner 10 disclosed herein may be used in any coring operation such as sidewall coring. The core sample liner 10 disclosed herein is a core sample degassing apparatus that allows the release of fluid, and in particular gas from a core sample while it is downhole.

[00017] Core sample liner 10 has first and second ends, which may be referred to as upper and lower ends 40 and 42 that are, in the disclosed embodiment, open upper and lower ends 40 and 42. Core sample liner 10 may comprise for example an outer liner 44 with a perforated insert 46 disposed therein. Perforated insert 46 is attached to outer liner 44 in any manner known in the art to prevent, or at least limit relative movement therebetween. Perforated insert 46 may be held in place for example with semi-flexible ties 47 or other known means able to withstand the linear or spiral shear caused when the core is received in the perforated insert 46. Outer liner 44 comprises a generally cylindrical outer liner. In the embodiment of FIGS. 2-5 perforated insert 46 comprises a generally cylindrical tube with open upper and lower ends 48 and 50.

[00018] Perforated insert 46 has perforations 52 through the wall thereof. In the described embodiment, insert 46 has outer diameter 54 and has a tapered portion 56 that tapers radially outwardly from diameter 54 to connect with outer liner 44 at the second, or lower end thereof. Tapered portion 56 will be made from a material sufficiently strong to maintain its shape while coring operations are being conducted Outer liner 44 and perforated insert 46 define an annular channel 58 therebetween. Annular channel 58 may be referred to as a degassing chamber 58. Degassing chamber 58 has upper opening 59. An interior 60 of insert 46 comprises a core receiving chamber 62 into which a core sample is received. Annular channel 58 provides a dedicated pathway for gas received therein from a core sample received in core receiving chamber 62, and may be referred to as a degassing chamber 58 into which fluid, including gas released from a core sample received in the core sample liner 10 may pass. The core sample liner 10 thus comprises a plurality of discrete chambers, including at least a degassing chamber and a core receiving chamber. Perforations 52 in insert 46 may extend from the upper end 48 thereof downwardly, and in the embodiment described will terminate prior to the lower end 50. Insert 46 thus has a solid portion 64 at the lower end thereof. Tapered portion 56 is solid and has no perforations therein. A diameter 66 at lower end 50 of insert 46 is larger than a diameter 68 of interior 60 above tapered portion 56. The tapering of insert 46 aids in the consolidation of the core sample received in the core receiving chamber 62. A portion of a core sample 70 is shown in FIG. 5.

[00019] An additional embodiment of a core sample liner is shown in FIGS. 6-10. Core sample liner 80 is a generally cylindrical liner with first and second ends 82 and 84. First and second ends 82 and 84 may be referred to as upper and lower ends 82 and 84 respectively. Upper and lower ends 82 and 84 are open upper and lower ends 82 and 84. Core sample liner 80 comprises an outer liner 86 with a perforated insert 88 therein. Insert 88 has upper end 90 and lower end 92 and has a plurality of perforations 94 in the wall thereof. In the embodiment of FIG. 6 upper end 90 is open and lower end 92 is a closed lower end. Perforated insert 88 may be an arcuate shaped insert which may be for example a half-tube or tube-section with a tapered portion 96 at the lower end 92 thereof. Insert 88 is positioned inside outer liner 86 and attached to the wall thereof. Tapered portion 96 creates a wedged lower end 92. Perforations 94 may extend from upper end 90 downwardly toward lower end 92. In the described embodiment tapered portion 96 does not have perforations. However, it is understood that tapered portion 96 may have perforations, and may be hollow. Insert 88 defines a volume that decreases in the tapered portion of the insert. [00020] Perforated insert 88 provides a dedicated pathway 96 for gas received from a core sample in the core sample liner 80. Dedicated pathway 96 may be referred to as a degassing chamber 98. Core sample liner 80 thus includes a plurality of chambers including at least a degassing chamber 98 and a core receiving chamber 100. In the embodiment of FIG. 6, core receiving chamber 100 is exterior to perforated insert 88. Although in the embodiment described perforated insert 88 is arcuate, any shape that will create a chamber for the receipt of gas from the core receiving chamber 100 may be used. Additional embodiments can include for example a single perforated tube-section placed on one side of the outer liner, or perforated tube-sections placed at different locations around the inner periphery of the outer liner.

[00021] In operation, using the embodiment of FIG. 2 for exemplary purposes, as the coring bit 25 makes its way through sediments, the sediments are pushed into the perforated insert 46 through the lower end 50 thereof. The coring bit 25 will communicate sediment (a core sample) into perforated insert 46. The tapering at lower end 50 squeezes the sediments slightly which further consolidates the core sample and may build the gas pressure. The sediments mainly release gas as a result of depressurization as the core sample is brought up through the wellbore to the surface, which may be for example an ocean column in an offshore well, or the earth’s surface in an onshore well. Gas released from a core sample 70 passes through perforated insert 46 and into degassing chamber 58. Thus, in the embodiment of FIG. 2, the core sample is received in the perforated insert and gas passes outwardly therefrom into a degassing chamber. Gas received in degassing chamber 58 passes upwardly therethrough and out upper opening 59 of degassing chamber 58.

[00022] It is known that beginning at a reasonable depth below the sea floor, sediments do not flow like slurry. The sediments are fairly consolidated and have an inherent texture that comprises minute cracks and crevasses. Further, although they may be “soft,” they exhibit permeability heterogeneity with higher permeability zones such as cracks and crevasses serving as natural flow channels. Gas released from the sediments naturally finds (or creates) its way from within the core sample to the surface of the core sample. Perforated insert 46 provides a dedicated pathway for this gas to escape while holding the core sediments in place. The size of the perforations depending on the environment may vary, but will be sized to allow for a safe degassing without significantly altering the sediment texture. [00023] In some embodiments, the fluid that passes into degassing chamber 58 may be released, or may be collected for sampling and/or analysis. In addition, sensors 104 may be placed in degassing chamber 58 to measure and determine parameters of the fluid received therein and/or the nature and biological characteristics of the sediments. Sensors likewise may be placed in the core receiving portion as well. The sensors may be used to measure, for example, the amount, composition, physical and mechanical properties of the sediment, sediment fluids, produced water, etc. The sensors can gather information that may be communicated to the surface for real time measurement and analysis or may be stored for later use.

[00024] The operation of the embodiment of FIG 6 is identical except that the dedicated pathway for released gas is defined by the insert 88, and the gas is received from a core sample positioned outside the perforated liner. The material used for the outer liner and the perforated insert may be known materials typically used for core liners, and may be for example made from polycarbonate, plastics, metal alloys or composites designed to withstand the conditions in which the core liner will be used. In some embodiments, the material used for the outer liner may be different than the material used for the insert.

[00025] Embodiments include:

[00026] Embodiment 1. A core sample liner comprising an outer liner and a perforated insert positioned in the outer liner, the insert having a plurality of perforations to communicate fluid released from a core sample in the core sample liner to a degassing chamber in the core sample liner.

[00027] Embodiment 2. The core sample liner of embodiment 1, the perforated insert comprising an arcuate member fixed to an inner surface of the outer liner, the arcuate member defining the degassing chamber.

[00028] Embodiment 3. The core sample liner of embodiment 2, the arcuate member having a first open end to allow the passage of gas therethrough and a closed second end. [00029] Embodiment 4. The core sample liner of embodiment 3, the arcuate member tapering from a maximum volume to a minimum volume at the second end thereof.

[00030] Embodiment 5. The core sample liner of embodiment 1, the outer liner comprising a cylindrical liner and the perforated insert comprising a perforated tube positioned in the outer liner, the outer liner and the perforated tube defining an annular space therebetween.

[00031] Embodiment 6. The core sample liner of embodiment 5, the perforated insert being connected to the outer liner.

[00032] Embodiment 7. The core sample liner of either of embodiments 5 or 6, the perforated insert having a tapered portion at the lower end thereof.

[00033] Embodiment 8. A core sample liner for receiving a core sample from a borehole comprising an outer liner and a core sample receiving chamber in the outer liner. The core sample receiving chamber has an opening at a lower end thereof for receiving the core sample. The outer liner has a degassing chamber in the outer liner, the degassing chamber being positioned in the outer liner to receive fluid released from the core sample in the core sample receiving chamber.

[00034] Embodiment 9. The core sample liner of embodiment 8 comprising a perforated insert disposed in the body, wherein the perforated insert divides an interior of the outer liner into the core sample receiving chamber and the degassing chamber.

[00035] Embodiment 10. The core sample liner of embodiment 9, the perforated insert comprising a perforated tube disposed in the outer liner and spaced inwardly therefrom, the degassing chamber comprising an annular space defined by and between the perforated tube and the outer liner.

[00036] Embodiment 11. The core sample liner of either of embodiments 9 or 10, the perforated insert having an insert interior, the insert interior comprising the core receiving chamber. [00037] Embodiment 12. The core sample liner of embodiment 9, the core receiving chamber positioned exterior to the perforated insert.

[00038] Embodiment 13. The core sample liner of any of embodiments 9-12, the perforated insert being fixed to an inner surface of the outer liner.

[00039] Embodiment 14. A method of degassing a core sample from a well comprising dividing an outer liner into a plurality of chambers including a core receiving chamber and a degassing chamber, lowering the outer liner into the well, receiving a core sample in the core receiving chamber and communicating fluid released from the core sample into the degassing chamber.

[00040] Embodiment 15. The method of embodiment 14 further comprising releasing gas in the degassing chamber through an upper end thereof.

[00041] Embodiment 16. The method of either of embodiments 14 or 15, further comprising lifting the core sample upwardly in the well and performing the communicating step during the lifting step.

[00042] Embodiment 17. The method of any of embodiments 14-16, the dividing step comprising placing a perforated insert in the outer liner and the communicating step comprising communicating fluid released from the core sample through perforations in the perforated insert into the degassing chamber.

[00043] Embodiment 18. The method of any of embodiments 14-17 further comprising placing a sensor in the degassing chamber to measure characteristics of the fluid released from the core sample.

[00044] Embodiment 19. The method of either of embodiments 17 or 18, the degassing chamber comprising an annular chamber defined between the perforated insert and the outer liner. [00045] Embodiment 20 The method of either of embodiments 17 or 18, the core sample being positioned exterior to the perforated insert.

[00046] Although various embodiments have been shown and described, the disclosure is not limited to such embodiments and will be understood to include all modifications and variations as would be apparent to one skilled in the art. Therefore, it should be understood that the disclosure is not intended to be limited to the particular forms disclosed; rather, the intention is to cover all modifications, equivalents, and alternatives failing within the spirit and scope of the disclosure as defined by the appended claims

Claims

What is claimed is:

1. A core sample liner comprising: an outer liner; and a perforated insert positioned in the outer liner, the insert having a plurality of perforations to communicate fluid released from a core sample in the core sample liner to a degassing chamber in the core sample liner.

2. The core sample liner of claim 1, the perforated insert comprising an arcuate member fixed to an inner surface of the outer liner, the arcuate member defining the degassing chamber.

3. The core sample liner of claim 2, the arcuate member having a first open end to allow the passage of gas therethrough and a closed second end.

4. The core sample liner of claim 3, the arcuate member tapering from a maximum volume to a minimum volume at the second end thereof.

5. The core sample liner of claim 1, the outer liner comprising a cylindrical liner and the perforated insert comprising a perforated tube positioned in the outer liner, the outer liner and the perforated tube defining an annular space therebetween.

6. The core sample liner of claim 5, the perforated insert being connected to the outer liner.

7. The core sample liner of claim 6, the perforated insert having a tapered portion at the lower end thereof.

8. A core sample liner for receiving a core sample from a borehole comprising: an outer liner; a core sample receiving chamber in the outer liner, the core sample receiving chamber having an opening at a lower end thereof for receiving the core sample; and a degassing chamber in the outer liner, the degassing chamber positioned in the outer liner to receive fluid released from the core sample in the core sample receiving chamber.

9. The core sample liner of claim 8 comprising a perforated insert disposed in the body, wherein the perforated insert divides an interior of the outer liner into the core sample receiving chamber and the degassing chamber.

10. The core sample liner of claim 9, the perforated insert comprising a perforated tube disposed in the outer liner and spaced inwardly therefrom, the degassing chamber comprising an annular space defined by and between the perforated tube and the outer liner.

11. The core sample liner of claim 9, the perforated insert having an insert interior, the insert interior comprising the core receiving chamber.

12. The core sample liner of claim 9, the core receiving chamber positioned exterior to the perforated insert.

13. The core sample liner of claim 9, the perforated insert being fixed to an inner surface of the outer liner.

14. A method of degassing a core sample from a well comprising: dividing an outer liner into a plurality of chambers including a core receiving chamber and a degassing chamber; lowering the outer liner into the well; receiving a core sample in the core receiving chamber; and communicating fluid released from the core sample into the degassing chamber.

15. The method of claim 14 further comprising releasing gas in the degassing chamber through an upper end thereof.

16. The method of claim 14, further comprising: lifting the core sample upwardly in the well; and performing the communicating step during the lifting step.

17. The method of claim 14, the dividing step comprising placing a perforated insert in the outer liner and the communicating step comprising communicating fluid released from the core sample through perforations in the perforated insert into the degassing chamber.

18. The method of claim 14 further comprising placing a sensor in the degassing chamber to measure characteristics of the fluid released from the core sample.

19. The method of claim 17 the degassing chamber comprising an annular chamber defined between the perforated insert and the outer liner.

20. The method of claim 17 the core sample being positioned exterior to the perforated insert.