塔河油田钻井液体系优化

针对塔河油田的地层特征，研究适合塔河油田储集层的钻井液、完井液和防漏堵漏技术方案，有针对性地优选钻井液性能参数．使钻井液能有效地抑制泥页岩地层的水化膨胀和膏盐地层的污染、预防卡钻等其它井下复杂情况的发生，对提高该油田的钻井速度和储层的保护十分重要。通过对一开、二开、三开、四开井段的钻井液进行筛选试验，优选出密度小于1．20g／cm^2的低密度聚合醇防塌钻井液，密度大于1．20g／cm^3的聚合醇防塌钻井液和抗盐抗钙钻井液3套体系，以及相应的维护处理措施。一开井段，加入适量的包被剂和增粘降滤失剂，配合一定量的清洁剂，确保大井眼中携岩能力，井眼规则，提高固井质量；二开井段降低滤失量、粘度，提高絮凝能力，加强固相设备的使用；三开井段以聚合物抑制为主，加大抑制型聚合物用量，加入抗钙镁及抗温处理剂，补充防塌剂、降滤失剂、包被剂等，提高钻井液粘度，避免强紊流．减少对井壁的冲刷，控制好滤失量；四开井段防止井壁剥蚀掉块，井涌、井喷、漏失，要求钻井液有良好的抗温性能，增加抗盐处理剂。通过对塔河油田钻井液体系的优化，完善了钻井液性能，满足了钻井工程需要，减少了钻井事故，提高了钻井效率。

Optimization of the drilling fluid systems in Tahe Oilfield

Based on the geological characteristics in Tahe oilfield, some research programs on drilling fluid, completion fluid and plugging control technology were conducted. By optimization the drilling fluid performance parameters, the drilling fluid system effectively inhibited the hydration and inflation in shale for mation and the contamination of gypsum salt bed, and avoided downhole troubles such as pipe sticking. Selecting tests for the drilling fluid used in the 1st, 2nd, 3rd, and 4th section were conducted, and optimized 3 sets of drilling fluid systems, i. e. , low density polyol sloughing control drilling fluid with density lower than 1. 20 g/cm3 ; polyol sloughing control drilling fluid with density higher than 1. 20 g/cm3; and slat/calcium resistance drilling fluid; the corresponding maintenance measures were also optimized as well. In the 1st section, ensure the good cuttings transportation and regular high quality borehole in the large diameter hole, by adding suitable amount of encapsulating agent and fluid loss reducerf in the 2nd section, reduce the filtration, viscosity and flocculating capability, and strengthen the use of solids control equipment; in the 3rd section, enhance the inhibition by adding large amount of polymer inhibitors and additives for calcium and magnesium resistance; compensate certain amount of sloughing control agent, fluid loss reducer and encapsulating agent; improve drilling fluid viscosity and avoid excessive turbulent flow to minimize the washout and control filtration; in the 4th section, avoid such troubles as hole sloughing, well kick, blowout and lost circulation; high temperature tolerance is required and the use of slat resistance additive should be enhanced. The optimization of drilling fluid in Tahe oilfield improved drilling fluid performances, met the drilling engineering requirements, minimized downhole troubles and improved drilling efficiencv.