Gravel pack fluid composition and emulsion therefor

摘要

A gravel pack fluid comprising
i) a water-in-oil emulsion comprising:
a) an organic continuous phase comprising 0.1 to 5 vol% of the emulsion of non-ionic or cationic surfactant and 0.25 to 3 vol% of the emulsion of sorbitan ester;
b) a dispersed aqueous phase comprising 0.05 to 3 vol% of the emulsion of a partial ester of a polyol with C6-C22 fatty acids and at least one of an acid or precursor therefor and a chelating compound; and
c) a density control agent; and
ii) gravel. The fluid can display a delayed break of up to about 48 hours to enable clean-up of mud cake.