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介绍MQX194-115密闭取心工具及工艺技术在塔中4-7-19井的现场应用情况。该井位于塔里木盆地中央隆起带塔中4号构造,主要开采层位于石炭系CⅢ组。塔中4油田经过长期的注水开采,含水量大,达到40ml/kg以上,岩心表面的极性增强,从而降低了密闭液对岩心表面的亲和力,影响密闭效果。井底压差过大,CⅢ组地层压力系数为1.05,钻井液密度为1.25g/cm3,井底压差为19kg/cm2。密闭取心一般要求压差控制在低于14kg/cm2。井底压差使钻井液对地层产生先期渗透性污染,特别是渗透率好的砂岩层,从而影响岩心的密闭率。该井在石炭系砂岩中密闭取心88.8m,收获率98.4%,密闭率88%,创造了塔中4油田高含水地层密闭取心好成绩。
This paper introduces the field application of MQX194-115 closed coring tools and technology in wells 4-7-19 in Tazhong. The well is located at No.4 Tazhong in the central uplift zone of the Tarim Basin, and the main exploration layer is located in Carboniferous CⅢ Formation. After long-term water injection, the Tazhong 4 oilfield has a large water content of 40ml / kg or more, and the polarity of the core surface is enhanced. As a result, the affinity of the sealing liquid to the core surface is reduced, and the sealing effect is affected. Bottomhole pressure is too large, C Ⅲ formation pressure coefficient of 1.05, drilling fluid density of 1.25g / cm3, bottom pressure difference of 19kg / cm2. Closed coring generally require pressure control below 14kg / cm2. Bottomhole pressure difference causes the drilling fluid to cause pre-permeable pollution to the formation, especially the sandstone layer with good permeability, thus affecting the tightness of the core. The well closed coring in the Carboniferous sandstone 88.8m, the harvest rate of 98.4%, the sealing rate of 88%, creating a high water-cut formation of Taizhong 4 oil well closed coring results.