Apparatus utilizing shape-memory and self-assembly to plug relatively wide remote fractures
Embodiments relate to a lost circulation material comprising a plurality of shape memory polymer members, each member having a temporary shape and a permanent shape. The members may be programmed to form a temporary shape that is small enough to be used with conventional drilling equipment and may further transform to corresponding permanent shapes to plug fractures. Specifically, the shape memory polymer-based lost circulation material can utilize self-assembly to plug fractures formed during drilling. Embodiments of the lost circulation material can be particularly useful for plugging large fractures. Permanent shapes present different topologies including granular, fibers, and two-dimensional networks/lattices in which can mechanically interlock and form a three-dimensional plug large enough to seal large width fractures.
1 . A lost circulation material, comprising:
a plurality of shape memory polymer members having a temporary shape and a permanent shape, wherein the plurality of shape memory polymer members are programmed to have the temporary shape through mechanical deformation,
wherein the plurality of shape memory polymer members are each configured to transform from the temporary shape to the permanent shape upon stimulation by an external trigger, and
wherein the plurality of shape memory polymer members comprise:
at least one shape memory polymer member with a granular permanent shape;
at least one shape memory polymer member with a fibrous permanent shape and a temporary shape selected from the group consisting of a spring, a zigzag-shaped spring, and a spiral-shaped spring; and
at least one shape memory polymer member with a planar permanent shape.
2 . The lost circulation material of claim 1 , wherein the external trigger is a temperature above the glass transition temperature of the plurality of shape memory polymer members.
3 . The lost circulation material of claim 1 , wherein the plurality of shape memory polymer members are one or more selected from the group consisting of an ionomer of poly (ethylene-co-methacrylic acid), a thermoset polymer, and a thermoplastic.
4 . The lost circulation material of claim 1 , wherein the temporary shape has at least one dimension that is smaller than at least one dimension of the permanent shape, and wherein the temporary shape has a dimension that is 20 mm or less.
5 . The lost circulation material of claim 1 , wherein the lost circulation material is configured to form a jamming structure when the at least one member transforms to the permanent shape, the jamming structure configured to plug a fracture having a width, wherein the width of the fracture is at least one order of magnitude larger than a dimension of the temporary shape.
6 . The lost circulation material of claim 1 , wherein at least a portion of the shape memory polymer members have a textured surface configured to increase surface friction between members.
7 . The lost circulation material of claim 1 , wherein the mechanical deformation is selected from the group consisting of rolling, spinning, folding, compressing, and providing tension.
8 . The lost circulation material of claim 1 , wherein the at least one shape memory polymer member with a fibrous permanent shape is configured to unfold and expand in multiple directions upon transformation from the temporary shape to the permanent shape.
9 . The lost circulation material of claim 1 , wherein the plurality of shape memory polymer members are configured such that upon transformation to their respective permanent shapes, the granular, fibrous, and planar members form an interlocked network capable of plugging fractures having a width of at least 12 mm.
10 . The lost circulation material of claim 1 , wherein the lost circulation material is positionable within a wellbore.
11 . The lost circulation material of claim 10 , wherein the lost circulation material is depositable on a fractured wellbore.
12 . The lost circulation material of claim 10 , wherein the lost circulation material is configured to seal a fracture within the wellbore.