GB2597016A

GB2597016A - Wellbore plug

Info

Publication number: GB2597016A
Application number: GB2115437.2A
Authority: GB
Inventors: Peter Buckland Jonathan
Original assignee: Westfield Engineering & Tech Ltd
Current assignee: Westfield Engineering & Tech Ltd
Priority date: 2019-04-24
Filing date: 2020-04-22
Publication date: 2022-01-12
Also published as: CA3134677A1; WO2020217051A1; US20220136360A1; GB202115437D0

Abstract

A wellbore plug comprises a body received within a tubular in an oil or gas well, and engaging a seat to seal an annulus. A sealing member occludes the bore in a first configuration. A spring urges the sealing member towards one end of the body in the first configuration. A locking member locks the sealing member in the first configuration, and can be unlocked in response to pressure within the bore above a pressure threshold, which permits movement of the sealing member to a second configuration. The spring expands when pressure within the bore is reduced below the threshold to push the sealing member into a third configuration, which permits fluid passage through the bore. A method of pressure testing and a method of injecting fluid into a well is also disclosed, using the wellbore plug.

Claims

Claims

1 A wellbore plug comprising: a body having an axis and a bore adapted to transmit fluid between a first end of the body and a second end of the body, the body being adapted to be received within a tubular in an oil or gas well, and being adapted to engage a seat within the oil or gas well tubular to seal an annulus between the outer surface of the body and an inner surface of the tubular; a sealing member adapted to occlude the bore through the body to resist fluid flow through the bore of the body when the wellbore plug is in a first configuration; a resilient device adapted to urge the sealing member towards one end of the body when the wellbore plug is in the first configuration; a locking member adapted to lock the sealing member in the first configuration, and adapted to be unlocked in response to pressure within the bore above a pressure threshold; wherein unlocking of the locking member permits movement of the sealing member within the bore to shift the wellbore plug from the first configuration to a second configuration; wherein movement of the sealing member in response to expansion of the resilient device when pressure within the bore is reduced below the threshold shifts the wellbore plug from the second configuration to a third configuration; and wherein in the third configuration, the sealing member permits fluid passage through the bore between the first and second ends of the body.
2 A wellbore plug as claimed in claim 1 , wherein the locking member is adapted to break above a threshold force applied by the pressure acting on the sealing device in the bore.
3 A wellbore plug as claimed in claim 1 or claim 2, wherein the sealing member is restrained against axial movement within the bore by the locking member.
4 A wellbore plug as claimed in any one of claims 1-3, wherein the sealing member moves in one direction when the wellbore plug shifts from the first to the second configuration, and in the opposite direction when the wellbore plug shifts from the second configuration to the third configuration.
5 A wellbore plug as claimed in any one of t claims 1-4, wherein the wellbore plug comprises a dart with a tapered profile.
6 A wellbore plug as claimed in any one of claims 1-5, wherein the bore has a catching chamber having an inner diameter that is larger than the outer diameter of the sealing member.
7 A wellbore plug as claimed in claim 6, wherein the second end of the body incorporates a seal adapted to engage the seat within the oil or gas well tubular to seal the annulus between the outer surface of the body and the inner surface of the tubular, and wherein the catching chamber is disposed between the first end of the body and the sealing member when the sealing member is in the first configuration.
8 A wellbore plug as claimed in claim 6 or claim 7, wherein the catching chamber provides a clearance permitting fluid flow between the inner surface of the bore of the body and the outer surface of the sealing member when the sealing member is in the third configuration.
9 A wellbore plug as claimed in any one of claims 6-8 wherein the catching chamber retains the sealing member in the third configuration and permits fluid flow around the sealing member within the catching chamber.
10 A wellbore plug as claimed in any one of claims 1-9, wherein the bore comprises a seal housing having an inner diameter in which the sealing device is received in a sliding fit, and wherein a resilient seal is compressed between the outer surface of the sealing device and the inner surface of the seal housing.
11 A wellbore plug as claimed in claim 10, wherein the seal housing incorporates a first shoulder facing the first end of the body, and adapted to limit axial movement of the sealing member in a direction from the first end of the body to the second end within the seal housing by abutting a shoulder facing the second end of the body on the sealing member.
12 A wellbore plug as claimed in claim 10 or claim 11 , wherein the seal housing is radially stepped, with a larger diameter portion closer to the first end than to the second end, and a smaller diameter portion closer to the second end than to the first end.
13 A wellbore plug as claimed in any one of claims 1-12, wherein the sealing member prevents fluid flow within the bore in the first and second configurations.
14 A wellbore plug as claimed in any one of claims 1-13, wherein the resilient device is maintained in compression between the sealing member and a shoulder in the body in the first and second configurations, and wherein the shoulder is disposed between the second end of the body and the sealing member.
15 A wellbore plug as claimed in any one of claims 1-14, wherein the movement of the sealing member as the wellbore plug shifts from the first to the second configuration from compresses the resilient device.
16 A wellbore plug as claimed in any one of claims 1-15, wherein the resilient device is held in compression in the first and second configurations, and expands when the wellbore plug shifts from the second configuration to the third configuration.
17 A wellbore plug as claimed in any one of claims 1-16, wherein the sealing member and the body are separate.
18 A wellbore plug as claimed in any one of claims 1-17, wherein the body contains at least one port permitting fluid communication between the bore of the body and an outer surface of the body between the sealing member and the second end of the body.
19 A wellbore plug as claimed in claim 18, wherein the port is adapted to be closed by a sleeve that slides axially within the bore.
20 A wellbore plug as claimed in any one of claims 1-19, wherein the sealing member is separate from the body, and wherein the body is adapted to be latched into the tubular, between a first section of the tubular and a second section of the tubular and installed with the tubular during deployment of the tubular, and wherein the body incorporates a seat adapted to seat the sealing member when the sealing member lands on the latched body, and wherein a pressure differential applied across the seated sealing member on the latched body is adapted to unlatch the body from the tubular to permit the body to travel axially along the second section of the tubular.
21 A wellbore plug as claimed in any one of claims 1-20, wherein the sealing member incorporates a channel permitting selective fluid communication across the sealing member when seated in the body, and wherein the channel incorporates a seal preventing fluid communication through the channel below a pressure differential above a burst pressure, and wherein the seal is adapted to be disrupted by a pressure differential above the burst pressure to permit fluid communication through the channel.
22 A method of pressure testing a well, comprising: plugging a tubular in the well by seating a wellbore plug in the tubular, the wellbore plug comprising a body having an axis and a bore adapted to transmit fluid between a first end of the body and a second end of the body, the wellbore plug having a sealing member occluding the bore through the body to resist fluid flow through the bore of the body when the wellbore plug is in a first configuration, a resilient device adapted to urge the sealing member towards one end of the body when the wellbore plug is in the first configuration, and a locking member adapted to lock the sealing member in the first configuration, and adapted to be unlocked in response to pressure within the bore above a pressure threshold; applying a pressure differential across the locked sealing member by pressurising the bore above the sealing member and unlocking the locking member; moving the unlocked sealing member within the bore to shift the wellbore plug from the first configuration to a second configuration; reducing the pressure differential across the sealing member and moving the sealing member within the bore in response to expansion of the resilient device to shift the wellbore plug from the second configuration to a third configuration; and permitting fluid passage through the bore between the first and second ends of the body when the wellbore plug is in the third configuration.
23 A method as claimed in claim 22, including urging the sealing member in a first direction from the first configuration to the second configuration by fluid pressure in the bore at the first end of the body, wherein a first force applied to the sealing member in the first direction by the fluid pressure in the bore at the first end of the body is higher than a second force urging the sealing member in a second direction towards the first end of the body as a result of the resilient device.
24 A method as claimed in claim 23 including maintaining the wellbore plug in the second configuration by keeping the first force greater than the second force during the pressure test.
25 A method as claimed in claim 23 or 24, including reducing the fluid pressure at the first end of the body when the sealing member is in the second configuration such that the first force drops below the second force, until force applied to the sealing member by the resilient member overcomes the first force and urges the sealing member from the second configuration into the third configuration after conducting the pressure test.
26 A method as claimed in any one of claims 23-25, including fixing the sealing member in the first configuration by the locking device.
27 A method as claimed in any one of claims 23-26, wherein the sealing member and the body are separate, and wherein the method includes launching the sealing member into the tubular separately from the body.
28 A method as claimed in any one of claims 23-27, including latching the sealing member onto the body when the body is seated in the tubular.
29 A method as claimed in any one of claims 23-28, including installing the body in the tubular between a first section and a second section wiping the first section of the tubular with the body and wiping the second section of the tubular with the sealing member.
30 A method as claimed in any one of claims 23-29, including injecting fluid into the well through the plug in the 3rd configuration to fracture the formation.
31 A method as claimed in any one of claims 23-30, wherein the plug is latched to the tubular by a releasable latch device adapted to release the plug from the tubular in response to a fluid pressure differential across the sealing member when the sealing member is engaged with the body.
32 A method as claimed in claim 31 , including moving the plug axially with respect to the tubular while maintaining a seal between the plug and the tubular.
33 A method of injecting fluid into a well, comprising: plugging a tubular in the well by seating a wellbore plug in the tubular, the wellbore plug comprising a body having an axis and a bore adapted to transmit fluid between a first end of the body and a second end of the body, the wellbore plug having a sealing member occluding the bore through the body to resist fluid flow through the bore of the body when the wellbore plug is in a first configuration, a resilient device adapted to urge the sealing member towards one end of the body when the wellbore plug is in the first configuration, and a locking member adapted to lock the sealing member in the first configuration, and adapted to be unlocked in response to pressure within the bore above a pressure threshold; applying a pressure differential across the locked sealing member by pressurising the bore above the sealing member and unlocking the locking member; moving the unlocked sealing member within the bore to shift the wellbore plug from the first configuration to a second configuration; reducing the pressure differential across the sealing member and moving the sealing member within the bore in response to expansion of the resilient device to shift the wellbore plug from the second configuration to a third configuration; injecting fluid through the bore between the first and second ends of the body when the wellbore plug is in the third configuration; and flowing the injected fluid through a radial port in the tubular located below the seated plug.