辽河西部致密砂岩储层保护钻完井液技术研究

辽河坳陷西部凹陷南部沙三段属于低孔特低渗致密砂岩油气藏，油气资源分布广泛开采难度大。现有的钻完井液体系不能满足安全快速钻井和储层保护的要求，进行了该项目的研究。室内对该区块致密砂岩储层进行了储层物性、敏感性及水锁等方面的评价，确定了钻井过程中存在的主要储层损害因素。通过室内试验优选优化了KCl钻完井液体系，并根据储层孔喉大小分布对该体系进行了广谱屏蔽暂堵技术改造。室内评价表明KCl钻完井液体系均具有良好的热稳定性。体系的润滑性和抑制防塌性好，抗污染能力强，可以满足探井的需要，渗透率恢复率均在82％以上，暂堵深度〈1．1cm且易反排。可满足辽河坳陷西部凹陷南部沙三段致密砂岩储层保护的要求。

Research on Drilling and Completion Fluid Technology for Tight Sandstone Reservoir Protection in Western Liaohe

Sha 3 member in south of Liaohe western depression is super-low porosity and permeability reservoir, the oil and gas resources are widely distributed,but it is difficult to explore. The existing system of drilling and completion fluid technology cannot satisfy the requirement of safety and quickly drilling and reservoir protection. In this paper, reservoir physical parameters, sensibility, and water block of the tight sandstone reservoir were analyzed and evaluated in laboratory, the main adverse factors existing in the course of well drilling were determined. The KCL drilling and completion fluid system was optimized through the laboratory test, and the general-purpose temporary shield plugging technology was reformed on the basis of pore size and distribution. The laboratory test indicates that the KCI system of drilling and completion fluid has good thermostability, good lubricity, high collapse-prevention capacity and strong anti-pollution capacity, which can meet the demand of exploration well, the recovery rate of permeability is always above 82%, and the temporary plugging depth is less than 1. lcm and easy to discharge backward. On a whole, the system can meet the need of Sha 3 member reservoir protection in south of Liaohe western depression.