Swellable packer

• US 9,243,473 B2
• Filed: 07/10/2012
• Issued: 01/26/2016
• Est. Priority Date: 07/10/2012
• Status: Expired due to Fees

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Yang, Liuqing, Ren, Xiaohong, Werningsen, Camilla
• Primary Examiner(s): Ro, Yong-Suk (Philip)
• Application Number:
  US13/545,148
• Publication Number:
  US 20140014374A1
• Time in Patent Office: 1,295 Days
• Field of Search: 166/387, 166/179, 166/127, 166/132, 277/334, 277/340
• US Class Current: 1/1
• CPC Class Codes: E21B 33/1208 characterised by the construction of the sealing or packing means E21B33/1277 takes precedence
• CPC Class Codes: E21B 33/127 with inflatable sleeve E21B33/122, E21B33/124 take precedence
• CPC Class Codes: E21B 33/1277 characterised by the construction or fixation of the sleeve

Abstract

A packer that is usable with a well includes a tubular inner core and a swellable body that is mounted to the core and is adapted to swell in the presence of a triggering agent to form an annular seal in the well. The swellable body longitudinally extends between first and second ends of the body and includes a first region that is located between the first and second ends of the swellable body to swell at a first rate and at least a second region that is located closer to one of the first and second ends than the first region to swell at a second rate less than the first rate.

Claims

1. A packer usable with a well, comprising:

a tubular inner core; and

a swellable longitudinally segmented body mounted to the core and being adapted to swell in the presence of a triggering agent to form an annular seal at an inner surface of the well, the swellable body longitudinally extending between first and second ends of the body and comprising;

a first region forming a first segment of a first material located between the first and second ends of the swellable body having an exposed surface to swell at a first rate and into sealing engagement with the inner surface;

a second region forming a second segments of a second material, the second segments located closer to each of the first and second ends than the first region, the second segments having exposed surfaces exceeding an amount of the exposed surface of the first segment and to swell at a second rate and into sealing engagement with the inner surface and at a rate that is less than the first rate; and

a boundary between the first and second segments, the boundary tapered to tailor an increased surface exposure of one of the first and second segments to the well and triggering agent.

2. The packer of claim 1, wherein a difference between the first and second rates results in a centrally-disposed portion of the swellable body fully radially expanding before at least a portion of the body disposed near one of the first and second ends fully radially expands.

3. A method comprising:

tailoring a swellable body with a tapered boundary between first and second segments, for an increased surface exposure of one of the segments to a triggering agent in a well;

using the swellable body to form an annular seal in the well; and

preventing fluid from being trapped by the swellable body in response to the swellable body radially expanding, wherein preventing the fluid from being trapped comprises;

radially expanding a first region with an exposed surface of the swellable body disposed between ends of the body at a first speed of swelling in response to the exposure; and

radially expanding second regions of the swellable body with exposed surfaces exceeding an amount of the exposed surface of the first region and disposed closer to the ends than the first region at a second speed of swelling less than the first speed of swelling in response to the exposure.

4. The method of claim 3, wherein radially expanding the first region of the swellable body comprises providing a first material for the first region and providing a second material for the second regions, the first material having a greater swelling rate than a swelling rate of the second material.

5. The method of claim 4, wherein radially expanding the first region of the swellable body further comprises:

creating a boundary between the first and second materials, the boundary being tapered with respect to a longitudinal axis of the swellable body.

6. A system usable with a well, comprising:

a tubing string to extend downhole in the well; and

a packer to form an annular seal between the tubing string and a casing or wellbore wall, the packer comprising;

an inner core; and

a swellable longitudinally segmented body mounted to the inner core to swell to form an annular seal in the well at the casing or wellbore wall, the swellable body being mounted to and circumscribing the inner core and comprising;

a first segment disposed apart from longitudinal ends of the swellable body, the first segment comprising a first material associated with a first swelling rate for swelling an exposed surface into sealing engagement with the casing or wellbore wall;

second segments disposed near the longitudinal ends of the swellable body, each of the second segments comprising a second material associated with a second swelling rate with exposed surfaces exceeding an amount of the exposed surface of the first segment and for swelling into sealing engagement with the casing or wellbore wall; and

a boundary between the first and second segments tapered to tailor an increased surface exposure of one of the first and second segments to the well, wherein the first and second swelling rates differ to cause the first segment form a seal with the tubing string or casing before either of the second segments forms a seal with the tubing string or casing.

7. The system of claim 6, wherein the first segment is bonded to at least one of the second segments.

8. The system of claim 6, wherein the first swelling rate is greater than the second swelling rate.

9. The system of claim 6, wherein the first segment comprises a central segment that longitudinally extends between the second regions and is bonded to the second regions.

10. The system of claim 6, wherein the tubing string is selected from the group consisting of a work string and a production string.