低损害环保型BLI钻井液的研究与应用

Research and Application on Low Damage and Environment Friendly BLI Drilling Fluid

针对大庆长垣外水平井地质特点,所用常规聚合物钻井液易堵塞储层孔道、降解能力差、污染环境等问题,研发了由阳离子包被剂CAL-90和生物润滑抑制剂BLI组成的低损害环保BLI钻井液。BLI钻井液密度为1.03～1.50 g/cm3时的漏斗黏度为31～55 s,滤失量小于3.4 mL,静切力适合,初切力、终切力分别为1.5～3.0 Pa、2.5～8.0 Pa,动塑比保持在0.29～0.40 Pa/mPa.s,流动性较好,携岩能力较强。该钻井液的抑制性较好,120℃滚动16 h的回收率高达89%。含5%BLI钻井液的极压润滑系数、滑块式摩擦系数分别为0.15、0.0437,润滑效果好。岩心经BLI钻井液处理后,平均渗透率恢复值可达90.66%,储层保护效果显著。BLI可生物降解,能有效减小对环境的污染。该钻井液现场维护处理工艺简单,可大范围推广应用。

Problems,such as reservoir pathway blocking,poor degradation capacity and environment pollution,were shown outside Changyuan area in Daqing oilfield with conventional polymer drilling fluid.New fluid system,named BLI drilling fluid,with characteristics of lower damage and environment friendly was developed,which was composed of cation peridium agent CAL-90 and biological lubricant inhibition agent BLI.BLI drilling fluid had the advantages of better flow-ability and sand carrying capacity with funnel viscosity 31—55 s（density 1.03—1.50 g/cm^3）,filtration volume less than 3.4 mL,initial gel 1.5—3.0 Pa and final gel 2.5—8.0 Pa.And the ratio between yield point and plastic viscosity was of 0.29—0.40 Pa/mPa·s.The inhibition of BLI drilling fluid was better and the rolling recovery reached up to 89% under 120℃ and 16 hrs.When the content of BLI was of 5% in drilling fluid,the extreme pressure lubricant coefficient and gliding block friction coefficient were of 0.15 and 0.0437,respectively,which indicated that the lubricant effect was good.The average permeability recovery of core after treated by BLI drilling fluid was of 90.66%.BLI drilling fluid could be biodegraded,which would lower environment pollution.This new system was easy to maintain and treat on site which could be widely applied.