Bracewell & Giuliani LLP
Plugging thief zones and fractures by in-situ and in-depth crystallization for improving water sweep efficiency of sandstone and carbonate reservoirs
The present invention relates to methods and compositions that can be used to delay crystallization of a treatment solution so that thief zones or fractures are plugged in subterranean formations at a substantial distance from a wellbore. A supersaturated sodium aluminate solution, or other solutions, are introduced into the reservoir. The solution is relatively stable in the supersaturated state. Crystallization, or de-stabilizing the solution, can be controlled, which in turn plugs the thief zone or fracture at a designed point of time. By controlling the time that crystallization starts, i.e., the induction period, thief zones that are located at a substantial distant from the wellbore can be plugged.
Saudi Arabian Oil Company
C C C E
C09K C09K C09K E21B
inventional inventional inventional inventional
Yun Xianmin Joe
Chang Zhou