油基钻井液天然岩沥青降滤失剂的环保性能

为了解决环保油基钻井液中低成本降滤失剂环保问题，采用致癌多环芳烃含量和急性生物毒性检测对天然岩沥青降滤失剂进行环保性能评价。结果表明，天然岩沥青降滤失剂中未检出致癌多环芳烃，掺入3%天然岩沥青的白油基钻井液体系污染后的岩屑EC₅₀值为104 751 mg/L，达到环保无毒标准。沥青族组成分析结果表明，天然岩沥青中不含低分子量的饱和分和芳香分，可变形的胶质组分含量为13.83%，其余为刚性的沥青质，所有组成均可参与封堵泥饼空隙，起到降滤失效果。天然岩沥青在油基钻井液体系中150℃高温高压滤失量不大于3.7 mL，200℃高温高压滤失量不大于4.0 mL。天然岩沥青降滤失剂绿色环保、降滤失效果稳定，可用于环保油基钻井液体系。 

The Environment Protection Property of a Natural Rock Asphaltene for Oil Base Drilling Fluids

To save the operation cost, some low-cost filter loss reducers such as natural rock asphalt have been used in environmentally friendly oil base drilling fluids. The environmental protection performance of these filter loss reducer has been evaluated by examining the polycyclic aromatic hydrocarbon contents and performing acute biotoxicity test. The evaluation showed that there are no carcinogenic polycyclic aromatic hydrocarbons in the natural rock asphalt. Drilled cuttings contaminated with a white oil base drilling fluid containing 3% natural rock asphalt has an EC₅₀ of 104,751 mg/L, satisfying the environmental protection standards. Analyses of the composition of the asphalts showed that natural rock asphalts contain no low molecular weight saturates and aromatics; they contain 13.83% resins and rigid asphaltenes. All the components of the natural rock asphalt become part of the mud cakes to reduce filtrate rate. Oil base drilling fluids treated with natural rock asphalt have filtration rate that is less than 3.7 mL at 150℃ and less than 4.0 mL at 200℃. Natural rock asphalt is an environmentally friendly filter loss reducer with a stable capability of controlling the filtration rate of environment protection oil base drilling fluids.