大港油田重点区块保护油层钻井完井液体系设计与应用

大港油田部分重点产能区块属于中孔低渗油藏，非常容易发生油层损害。通过对这些区块油层基本特征、油层损害机理系统研究，优化设计了保护油层的理想充填型和广谱“油膜”暂堵型钻井完井液体系，并对2 种体系的油层保护效果进行了室内评价和现场应用效果对比。结果表明，广谱“油膜”暂堵型钻井完井液体系对油层的保护效果更佳，渗透率封堵率达到91.4%以上，渗透率恢复值高达99.3%，矿场测试的纯损害表皮系数接近0，阻止了钻井完井液中固相颗粒和滤液对油层的损害，实现了对油层的更好保护。

Design and application of drilling and completion fluid system for formation protection in the key blocks of Dagang Oilfield

Part key blocks of Dagang Oilfield belong to medium porosity, low permeability reservoir that is easily damaged.According to the systematic research on the basic characteristics of the reservoir and damage mechanism for these key blocks, this paper optimized the drilling and completion fluid system of the ideal packing type and the broad-spectrum oil-film temporary blocking type.Further more, the reservoir protection effect with two types of system was contrasted by the laboratory test and field application.The results show that the broad-spectrum oil-film temporary blocking type is preferable to the ideal packing type on the effect of protecting formation.Plugging rate of permeability was over 91.4%, permeability recovery value was up to 99.3%.The pure damaged skin factor of field test was close to zero.It proved that the formation damage resulted from the solid particles and filtrate in the drilling and completion fluid was prevented, achieving better protection to the formation.