FLUID LOSS CONTROL AND SEALING AGENT FOR DRILLING DEPLETED SAND FORMATIONS

摘要

An oil-based drilling fluid having a polymer latex capable of providing adeformable latex film on at least a portion of a subterranean sand formationhas been discovered to inhibit or control fluid loss and act as a sealingagent when used to drill in sand formations for hydrocarbon recoveryoperations. Typically, the polymer latex is an aqueous suspension of particlesformed by emulsion polymerization that is in turn emulsified into ahydrocarbon base fluid. The polymer particles of suitable size precipitateonto the pores of a subterranean sand formation to at least partial seal theformation with a deformable polymer film.