Extended length packer with timed setting
A device and method to control the rate of radial expansion of a compressible sealing element on a packer over the longitudinal length of the sealing element. By varying the rate of compression of the element, the rate of radial expansion of the corresponding portions of the element may also be controlled. Additionally, the rate of radial expansion may also be controlled by controlling the direction and amount of radial expansion along the length of the sealing by reinforcing certain portions of the sealing element while decreasing the rigidity of the reinforcement for other portions.
1. An apparatus for sealing in a wellbore, the apparatus comprising:
a compressible element disposed on the apparatus and defining a first longitudinal axis, the compressible element expanding radially to seal in the wellbore in response compression of the compressible element along the first longitudinal axis; and
a rigid member disposed in the compressible element; the rigid member defining a second longitudinal axis disposed along the first longitudinal axis of the compressible element and having inner and outer surfaces, the inner and outer surfaces being flat along the second longitudinal axis except for a plurality of notches of decreased rigidity indented in at least one of the inner and outer surfaces along the second longitudinal axis, each of the notches being adjacent to an adjacent portion of the compressible element and deforming in response to compression along the second longitudinal axis, timings of the radial expansion of the adjacent portions of the compressible element for at least the first and second ones of the notches being different from one another and wherein the plurality of notches do not longitudinally overlap with each other.
2. The apparatus of claim 1 , wherein each of the notches of decreased rigidity indented in the at least one of the inner and outer surfaces comprise a reduced thickness defined in the rigid member.
3. The apparatus of claim 1 , wherein the rigid member is embedded in the compressible element.
4. The apparatus of claim 1 , wherein the compressible element comprises an inner portion of elastomeric material disposed on the apparatus and comprises an outer portion of elastomeric material disposed external to the inner portion, the rigid member disposed between the inner and outer portions.
5. The apparatus of claim 1 , wherein the rigid member comprises at least two rigid slats disposed parallel to one another along the first longitudinal axis of the compressible element.
6. The apparatus of claim 5 , wherein the rigid member comprises a plurality of the rigid slats disposed around the compressible element and forming a cylinder disposed along the first longitudinal axis of the compressible element.
7. The apparatus of claim 1 , wherein each of the notches comprises a characteristic of the decreased rigidity, the characteristics of the notches being different from one another along a length of the rigid member.
8. The apparatus of claim 1 , wherein the notches comprise a first set of the notches defined on the inside surface of the rigid member and comprises a second set of the notches defined on the outside surface of the rigid member.
9. The apparatus of claim 7 , wherein the characteristic of the decreased rigidity comprises at least one of a depth and a width of the notches.
10. The apparatus of claim 1 , wherein the notches of decreased rigidity of the rigid member control the radial expansion of the compressible element from the apparatus when compressed thereon.
11. The apparatus of claim 1 , wherein the rigid member comprises a cage having at least two rigid slats.
12. The apparatus of claim 11 , wherein the cage comprises at least one band linking the at least two rigid slats together.
13. The apparatus of claim 1 , further comprising:
a mandrel of the apparatus on which the compressible element is disposed; and
at least one push member disposed on the mandrel adjacent the compressible element and being movable on the mandrel to compress the compressible element.
14. The apparatus of claim 1 , wherein the apparatus is selected from the group consisting of a packer, a liner hanger, a plug, a bridge plug, and a fracture plug.
15. The apparatus of claim 1 , wherein at least third and fourth of the notches share the timing of the radial expansion to seal the adjacent portions the compressible element, one of the third and fourth notches being the same as or different from one of the first and second notches.
16. A method of sealing a downhole tool in a wellbore, the method comprising:
deploying the downhole tool in the wellbore, the downhole tool having a compressible element with a first longitudinal axis, the compressible element having a rigid member disposed therein, the rigid member defining a second longitudinal axis disposed along the first longitudinal axis and having inner and outer surfaces, the inner and outer surfaces being flat along the second longitudinal axis except for a plurality of notches of decreased rigidity indented in at least one of the inner and outer surfaces along the second longitudinal axis, each of the notches being adjacent to an adjacent portion of the compressible element; sealing the compressible element in the wellbore by radially expanding the compressible element in response to longitudinal compression of the compressible element along the first longitudinal axis;
and controlling sealing of the adjacent portions of the compressible element with the rigid member by deforming the notches of reduced rigidity on the rigid member to radially expand the adjacent portions of the compressible element, timings of the radial expansion of the adjacent portions for at least the first and second ones of the notches being different from one another and wherein the plurality of notches do not longitudinally overlap with each other.
17. The method of claim 16 , wherein deforming each of the notches of reduced rigidity on the rigid member comprises sharing the timings of the radial expansion of the adjacent portions for at least third and fourth of the notches, one of the third and fourth notches being the same as or different from one of the first and second notches.