聚磺混油钻井液对深层裂缝性致密储层的保护能力评价

为了评价和优化塔里木盆地北部深层裂缝性致密砂岩油藏开发中使用的聚磺混油钻井液对储层的保护效果，进行了钻井液动/静态伤害、滤饼承压、流体敏感性、水相圈闭伤害和流体配伍性实验。分析了钻井液伤害的主要机理，探讨了钻井液保护效果评价方法，提出了聚磺混油钻井液优化策略。实验表明:储层钻井液动态伤害中—强，滤液静态伤害中—强，100μm及以下缝宽裂缝承压达10 MPa，流体敏感性伤害较弱，水相圈闭伤害强，滤液与地层流体配伍性差；水相圈闭、流体不配伍和固相侵入是钻井液伤害储层的主要方式；聚磺混油钻井液对储层大缝宽裂缝封堵较差、对小缝宽裂缝控滤失较差是造成储层伤害的主要原因。钻井液储层保护效果评价需综合分析钻井液伤害的主要因素，充分挖潜钻井液动态伤害实验数据，评价钻井液的固相磨蚀粒度降级率。提高钻井液屏蔽暂堵性能、改善钻井液与储层流体配伍性、加入表面活性剂将提升聚磺混油钻井液对深层裂缝性致密砂岩油藏的保护能力。

The protective ability evaluation of polysulfonate mixed drilling fluid for deep fractured tight reservoirs

In order to evaluate and optimize the reservoir protection effect of polysulfonated oil mixing drilling fluid used for deep fractured tight sandstone oil reservoir development of the northern Tarim Basin, the experiments were conducted on the dynamic and static damage of drilling fluids, the loading capacity of filter cakes, fluid sensitivity, water phase trap damage and fluid compatibility. Meanwhile, the optimization strategy of polysulfonated oil mixing drilling fluids was proposed after the analysis of the main damage mechanisms and discussion on the protective effect evaluation method of drilling fluids. The experiment shows that the dynamic damage degree of drilling fluids in the reservoir is medium strong-strong; the static damage degree of filtrate is medium strong-strong; the loading capacity of the fractures with slit width of 100 μm or less than 100 μm reaches 10 MPa; fluid sensitivity damage is weak; water phase trap damage is strong; the compatibility of filtrates and formation fluids is poor. In addition, water trap, incompatibility of fluids and solid phase invasion are the main ways by which drilling fluids damage the reservoir. Furthermore, poor sealing capacity of polysulfonated oil mixing drilling fluid for the fractures with large slit width in the reservoir and poor ability to reduce fluid loss for the fractures with small slit width are the main reasons for the reservoir damage. Comprehensive analysis of the main factors of drilling fluid damage, fully tapping the potential of the experimental data of dynamic damage, and evaluation of degradation ratio of solid phase abrasion particle size are needed for the reservoir protection effect evaluation of drilling fluids. Improvement of shielding temporary plugging property of drilling fluids and compatibility of drilling fluids and reservoir fluids, and adding surfactants will enhance the protective capacity of polysulfonated oil mixing drilling fluids for deep fractured tight sandstone oil reservoir.