Patent attributes
Rapid setting plugging compositions comprising oil, clay, magnesium chloride, and magnesium oxide powder are provided for sealing permeable zones in subterranean formations. The permeable zones may be sealed by passing the plugging composition and water to the subterranean formation. While being exposed to downhole temperatures in a range of from about 0° F. to about 500° F., the plugging composition quickly thickens to form a sealing mass that is substantially impermeable to fluid in less than about 1 minute after contacting the water. It then usually develops an effective amount of compressive strength to prevent it from being washed away within a period ranging from about 5 minutes to about 2 hours at temperatures ranging from about 0° F. to about 500° F.
