高泥质疏松砂岩防塌保护油气层钻井液技术

胜利油区王庄油田沙河街组地层为高泥质疏松砂岩,钻井过程中出现的主要问题是井壁坍塌和油气层损害严重。根据地层特点和测井的要求,优选出以非离子处理剂为主的聚醚多元醇钻井液,对该钻井液的流变性能、滤失造壁性能、防塌性能、抗污染性能和保护油层性能进行了评价。试验结果证明,该钻井液具有良好的流变性和滤失造壁性,页岩滚动回收率大于90%,岩心渗透率恢复率大于80%,电阻率大于1.5Ω·m。现场应用表明,聚醚多元醇钻井液有效地解决了王庄油田高泥质疏松砂岩钻井过程中出现的井壁失稳问题,保护了油气层,满足了测井要求,具有良好的综合性能。

Study on drilling fluid technology in unconsolidated sand with high clay content

Shahejie formation is the major oil-bearing series in Wangzhuang Oilfield of Shengli oil district.Loose sandstone and high clay content result in wellbore instability and permeability reducing.According to the formation characteristics and the requirement of logging,the new polyol drilling fluid was developed.The properties of the new drilling fluid system,including inhibition,mud filtrate control capacity,rheology,resistivity and formation protection ability were evaluated in laboraty. Cuttings roller recovery is more than 90%, return permeability is more than 80%, and resistivity is more than 1.5 Ω·m.Laboratory tests and in-situ application indicate that this kind of drilling fluid has the advantages of excellent inhibition, anti-sloughing, formation protection property, and reach the need of well logging.