Shape memory polyurethane foam for downhole sand control filtration devices
Filtration devices may include a shape-memory material having a compressed run-in position or shape and an original expanded position or shape. The shape-memory material may include an open cell porous rigid polyurethane foam material held in the compressed run-in position at the temperature below glass transition temperature (T g ). The foam material in its compressed run-in position may be covered with a fluid-dissolvable polymeric film and/or a layer of fluid-degradable plastic. Once filtration devices are in place in downhole and are contacted by the fluid for a given amount of time at temperature, the devices may expand and totally conform to the borehole to prevent the production of undesirable solids from the formation.
1. A wellbore filtration device comprising: a shape-memory porous material, the shape-memory porous material having a compressed position and an expanded position, where the shape-memory porous material is maintained in the compressed position at a temperature below its glass transition temperature, where the shape-memory porous material expands from its compressed position to its expanded position when it is heated to a temperature near or above its glass transition temperature, wherein the shape-memory porous material comprises a polyurethane foam formed by mixing a polycarbonate polyol with a polyisocyanate.
2. The filtration device of claim 1 , wherein the shape-memory porous material has an outer surface covered with a covering selected from the group consisting of a fluid-dissolvable polymeric film, a layer of thermally fluid-degradable plastic, and a combination thereof.
3. A method of installing a wellbore filtration device on a downhole tool in a formation, the method comprising:
(a) securing a downhole tool to a string of perforated tubing, the downhole tool comprising a filtration device comprising a shape-memory porous material, the shape-memory porous material having a compressed run-in position and an original expanded position, wherein the shape-memory porous material is maintained in the compressed run-in position below a glass transition temperature of the shape-memory porous material, the shape-memory porous material in its compressed run-in position having an outer surface with a covering selected from the group consisting of a fluid-dissolvable polymeric film, a layer of fluid-degradable polyurethane plastic or fluid-degradable polyester plastic, and a combination thereof;
(b) running the downhole tool in a wellbore;
(c) contacting the covering and the shape-memory porous material with a fluid;
(d) removing the covering with the fluid;
(e) expanding the shape-memory porous material from the compressed run-in position to an expanded position against the wellbore.
4. The method of claim 3 further comprising (f) producing hydrocarbons from the formation through the wellbore where the shape-memory porous material in the expanded position prevents the undesirable production of solids from the formation but allows the desirable production of hydrocarbons.
5. The method of claim 3 where the fluid is water.
6. The method of claim 3 where the fluid is oil.
7. The method of claim 3 where the shape-memory porous material comprises polyurethane formed by mixing a polycarbonate polyol with a polyisocyanate.
8. A wellbore filtration device comprising: a shape-memory porous material, the shape-memory porous material having a compressed position and an expanded position, where the shape-memory porous material is maintained in the compressed position at a temperature below its glass transition temperature, where the shape-memory porous material expands from its compressed position to its expanded position when it is heated to a temperature near or above its glass transition temperature, wherein the shape-memory porous material has an outer surface covered with a covering selected from the group consisting of a fluid-dissolvable polymeric film, a layer of thermally fluid-degradable plastic, and a combination thereof.
9. The filtration device of claim 8 , wherein the shape-memory porous material comprises a polyurethane foam.
10. The filtration device of claim 8 where the polyurethane foam material is formed by mixing a polycarbonate polyol with a polyisocyanate.