HYDROCARBON-BASED DRILLING FLUID Russian patent published in 2003 - IPC

FIELD: oil and gas production. SUBSTANCE: invention concerns washer fluids used for exposing producing formations, killing wells in case of pullout of hole at lowered formation pressure as well as for boring appraisal wells and extraction of kern with natural oil saturation. Fluid of invention contains, wt %: hydrocarbon base 65-80, synthetic fatty acid 0.7-2.8, sodium hydroxide 0.60-2.40, atactic polypropylene (structure-former) 1.4-5.0, paraffin 0.70-3.0, and weighting agent - the balance. EFFECT: increased stability at high temperatures and improved rheological characteristics. 2 tbl