Oilfield isolation element and method
An isolation element includes a body having at least one sealing surface, an internal cavity within the body, and a chemical agent disposed within the internal cavity. The chemical agent is configured to substantially increase a rate of degradation of the body.
1. An isolation element, comprising:
a body having at least one sealing surface;
an internal cavity within the body;
a chemical agent disposed within the internal cavity; and
a degradable bladder disposed within the cavity and being adapted to degrade in the presence of a well fluid,
wherein the chemical agent is configured to substantially increase a rate of degradation of the body and the chemical agent being disposed within the bladder.
2. The isolation element of claim 1 , further comprising:
a passageway between the internal cavity and an outside of the body; and
a plug positioned within the passageway to control communication of the well fluid with the degradable bladder.
3. The isolation element of claim 2 , wherein the plug is made of a material that degrades in a well fluid.
4. The isolation element of claim 1 , wherein the chemical agent is adapted to degrade the body upon contact with the body, and the degradable bladder is adapted to isolate the chemical agent from the body and thereafter allow communication between the chemical agent and the body in response to degradation of the bladder by the well fluid.
5. The isolation element of claim 4 , wherein the chemical agent comprises an acid.
6. The isolation element of claim 5 , wherein the acid comprises at least one selected from hydrochloric acids, fluoric acids, and nitric acids.
7. The isolation element of claim 1 , wherein the chemical agent will react exothermically with a well fluid.
8. The isolation element of claim 7 , wherein the chemical agent comprises at least one selected from a metal hydroxide, a hydration agent, and an acid.
9. The isolation element of claim 8 , where in the metal hydroxide comprises at least one selected from sodium hydroxide, potassium hydroxide, lithium hydroxide, and cesium hydroxide.
10. The isolation element of claim 8 , wherein the hydration agent is selected from the group consisting of metallic nitrates and zinc nitrates.
11. The isolation element of claim 8 , wherein the acid comprises at least one selected from hydrogen bromide, hydrogen chloride, hydrogen iodide, aluminum chloride, sulfuric acid, and percholoric acid.
12. The isolation element of claim 1 , wherein the isolation element forms one selected from a dart and a ball.
13. The isolation element of claim 1 , wherein the internal cavity includes a degradation enhancement feature.
14. The isolation element of claim 13 , wherein the degradation enhancement feature comprises a projection into the body.
15. The isolation element of claim 1 , wherein the body is comprised at least partly of a material that degrades in a well fluid.
16. A method of actuating a downhole tool in a well, comprising;
positioning a tool in a wellbore using a tubing string;
introducing an isolation element into the tubing string;
as the isolation element descends in the tubing string, responding to hydrostatic pressure present in the tubing string to establish communication of a well fluid with a bladder to degrade the bladder to cause release of a material contained in the bladder for substantially increasing a rate of degradation of a body of the isolation element; and
after the isolation valve lands in a flow restriction orifice, actuating the downhole tool by increasing fluid pressure within the tubing string.
17. A method of actuating a downhole tool in a well, comprising;
positioning a tool in a wellbore using a tubing string;
introducing an isolation element into the tubing string;
degrading a plug in the isolation element;
exposing a chemical agent for substantially increasing a rate of degradation of a body of the isolation element, the exposing comprising dissolving a bladder within the isolation element at least in part by exposing the bladder to well fluid; and
after the isolation is positioned in a flow restriction orifice, actuating the downhole tool by increasing fluid pressure within the tubing string.
18. An isolation element, comprising:
a body with at least one sealing surface;
means for allowing a well fluid to penetrate into an interior of the body; and
means for dissolving a bladder comprising a chemical agent for substantially increasing a rate of degradation of the body when exposed to the well fluid.