Adjustable coring assembly and method of using same

Patent metadata

Field	Value
Publication number	US-9494004-B2
Application number	US-201314136856-A
Country	US
Kind code	B2
Filing date	Dec 20, 2013
Priority date	Dec 20, 2013
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

A coring extender for a coring tool is provided. The coring tool is deployable by a downhole tool into a wellbore. The coring extender includes a housing operatively connectable to the downhole tool, a mandrel, and seals. The housing has fluid chambers therein. The mandrel is positionable in the housing, and includes a locking tube operatively connectable to the housing and a coupling tube operatively connectable to the coring tool. The coupling tube is adjustably positionable relative to the locking tube such that a length of the mandrel is adjustably defined therebetween. The coupling tube has an outer surface slidably positionable along an inner surface of the housing. Seals are positionable between the mandrel and the housing to define a fluid pocket to isolate the fluid therebetween as the coupling tube moves along the housing whereby the fluid permitted to flow about the fluid pocket to balance between the fluid chambers.

First claim

What is claimed is:

1. A coring extender for a coring tool for obtaining a core sample of a subterranean formation, the coring extender comprising:
a housing having a longitudinal axis and including a first fluid chamber and a second fluid chamber axially spaced from the first fluid chamber;
a mandrel disposed in the housing, the mandrel comprising a locking tube operatively connectable to the housing and a coupling tube configured to be coupled to the coring tool, the locking tube operatively connectable to the coupling tube and adjustably positionable relative thereto such that a length of the mandrel is adjustably defined therebetween, the coupling tube having an outer surface slidably positionable along an inner surface of the housing; and
a first seal positioned between the mandrel and the housing and a second seal positioned between the mandrel an the housing, wherein the second seal is axially spaced from the first seal, wherein the first fluid chamber and the second fluid chamber are axially positioned between the first seal and the second seal;
wherein the first seal and the second seal define a fluid pocket between the housing and the mandrel to isolate a lubricating fluid therebetween as the coupling tube moves along the housing, wherein the fluid pocket is configured to permit the lubricating fluid to flow between the first fluid chamber and the second fluid chamber to lubricate engaged mating threads axially positioned between the first chamber and the second chamber.

2. The coring extender of claim 1 , wherein the coupling tube comprises a coupling portion configured to be coupled to the coring tool and a fluid portion movably engageable with the locking tube.

3. The coring extender of claim 1 , wherein the locking tube comprises a lock engageable with the housing, the lock defining a stop to terminate travel of the coupling tube.

4. The coring extender of claim 1 , wherein the coupling tube has a channel extending along the outer surface thereof, wherein the channel extends between the first fluid chamber and the second fluid chamber to permit flow of the lubricating fluid therebetween.

5. The coring extender of claim 1 , further comprising a wear ring positionable between the mandrel and the housing.

6. The coring extender of claim 1 , wherein the housing has a first port in fluid communication with the first fluid chamber and a second port in fluid communication with the second fluid chamber.

7. The coring extender of claim 6 , further comprising a first plug disposed in the first port and a second plug disposed in the second port.

8. The coring extender of claim 1 , wherein the mandrel has ports and a passage therein for the passage of a fluid therethrough and a seat for receiving a ball.

9. The coring extender of claim 1 , wherein the engaged mating threads axially positioned between the first chamber and the second chamber comprise threads on the outer surface of the coupling tube that threadedly engage mating threads on the inner surface of the housing.

10. The coring extender of claim 9 , wherein the engaged mating threads on the outer surface of the coupling tube and on the inner surface of the housing are configured to allow the coupling tube to move axially relative to the locking tube and the housing.

11. The coring extender of claim 1 , wherein the first seal sealingly engages the coupling tube and the mandrel, and wherein the second seal sealingly engages the coupling tube and the mandrel.

12. A coring assembly for obtaining a core sample of a subterranean formation, the coring assembly deployable into a wellbore penetrating the subterranean formation, the coring assembly comprising:
a coring extender comprising:
a housing having a plurality of fluid chambers therein;
a mandrel positionable in the housing, the mandrel comprising a locking tube operatively connectable to the housing and a coupling tube configured to couple to a coring tool, the locking tube operatively connectable to the coupling tube and adjustably positionable relative thereto such that a length of the mandrel is adjustably defined therebetween, the coupling tube having an outer surface slidably positionable along an inner surface of the housing;
a first seal positioned between and sealingly engaging the coupling tube and the housing; and
a second seal positioned between and sealingly engaging the coupling tube and the housing, wherein the first seal and the second seal define a fluid pocket to isolate the fluid therebetween as the coupling tube moves along the housing whereby the fluid permitted to flow about the fluid pocket to balance between the fluid chambers.

13. The coring assembly of claim 12 , further comprising a ball deployable into a passage of the mandrel and seatable therein.

14. The coring assembly of claim 13 , wherein the mandrel has ports therein for the passage of fluid therethrough.

15. The coring assembly of claim 12 , wherein the coupling tube has threads on the outer surface of the coupling tube that threadedly engage and mate with threads on the inner surface of the housing, wherein threads of the coupling tube and the threads of the housing engage between the first seal and the second seal.

16. The coring assembly of claim 15 , wherein the fluid in the fluid pocket is configured to lubricate the threads of the coupling tube and the threads of the housing.

17. A method of obtaining a core sample of a subterranean formation, the method comprising:
deploying a coring assembly into the wellbore via a downhole tool, the coring assembly comprising a coring tool having a coring cavity to receive the core sample and a coring extender operatively connectable to the coring tool, the coring extender comprising a housing and a mandrel, the mandrel comprising a locking tube and a coupling tube, the housing having a plurality of fluid chambers therein;
adjusting a length of the mandrel in the housing by slidably positioning the coupling tube along the locking tube;
sealing a lubricating fluid in a pocket between the coupling tube and the housing;
permitting the lubricating fluid to flow in the pocket between the plurality of fluid chambers as the coupling tube moves along the housing to lubricate engaged mating threads between the coupling tube and the housing; and
receiving a coring sample into the core cavity.

18. The method of claim 17 , wherein the adjusting comprises moving the coupling tube along the housing via threads therebetween.

19. The method of claim 17 , further comprising passing fluid into and out of the fluid chambers via ports in the housing.

20. The method of claim 17 , wherein the adjusting is performed repeatedly without requiring removal of the fluid.

21. The method of claim 17 , further comprising selectively diverting fluid flow about the coring assembly.

22. The method of claim 17 , wherein the deploying comprises deploying the coring assembly via a downhole drilling tool, the method further comprising drilling the wellbore with the downhole drilling tool.

23. The method of claim 17 , wherein the coring assembly includes a first seal that sealingly engages the coupling tube and the housing and a second seal that sealingly engages the coupling tube and the housing, wherein the pocket is axially positioned between the first seal and the second seal.

Assignees

• Nat Oilwell Varco Lp

Inventors

• Trinh Khoi
• Ozah Folarin
• Mecham Rick N

Classifications

• E21B25/10 Primary

  Formed core retaining or severing means (E21B25/06, E21B25/08 take precedence) · CPC title

• E21B25/00 Primary

  Apparatus for obtaining or removing undisturbed cores, e.g. core barrels or core extractors (core bits E21B10/02) · CPC title