Fluid-loss control pills comprising breakers that comprise orthoesters and/or poly(orthoesters) and methods of use

Abstract

Provided herein are methods and compositions for generating acids for use downhole, for example, to break fluid-loss control pills. The delayed-release acid breakers of the present invention comprise orthoesters and / or poly(orthoesters).

Description

BACKGROUND OF THE INVENTION [0001] The present invention relates to methods and compositions for treating subterranean formations, and more specifically, to self-destructing fluid-loss control pills for fluid-loss control in drilling, completion, and stimulation applications and their associated methods. “Fluid loss” refers to the undesirable migration or loss of fluids (such as the fluid portion of a drilling mud or cement slurry) into a subterranean formation. [0002] Providing effective fluid-loss control for well treatment fluids is highly desirable. A “well treatment fluid” is a fluid used in a subterranean application. The term “treatment” herein does not imply any particular action by the fluid or any component thereof. Fluid-loss control materials are additives specifically designed to lower the volume of a filtrate that passes through a filter medium. Most attain their fluid-loss control from the presence of solvent-specific solids, or from hydrated linear polymers that rely...

AI Technical Summary

Benefits of technology

[0008] The present invention relates to methods and compositions for treating subterranean formations, and more specifically, to self-destructing fluid-loss control pills for fluid-loss control in drilling, completion, and stimulation applications, and their associated methods.

[0009] One embodiment of the present invention provides a method comprising: providing a fluid-loss control pill that comprises an aqueous base fluid and a gelling agent, and a delayed-release acid breaker that

Problems solved by technology

Further, crosslinked fluid-loss control pills have demonstrated that they require relatively limited invasion of the formation face to be fully effective.

After their application, fluid-loss control pills can cause severe damage to near-well bore areas due to polymer filtration or filter-cake formation.

Polymer-based fluid-loss control pills often require long cleanup periods.

Such fluid circulation may not be feasible.

), it is often difficult to find an internal breaker for the fluid-loss control pills that will work effectively.

Although conventional breakers (both internal and external) tend to work very quickly, usually within hours, they often do not provide predictable breaks, and thus there is little control over the break.

As a result, secondary precipitation materials may result that may be damaging to the formation.

Another conventional method of cleaning up a fluid-loss control pill is to add a spot of a strong acid (e.g., 10% to 15% hydrochloric acid) with coiled tubing, which is expensive and can result in hazardous conditions.