密闭取心技术在塔中4油田的应用

APPLICATION OF PRESSURE CORING TECHNOLOGY IN THE FOURTH OILFIELD OF TAZHONG

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。

The paper presents the field application and technology of MQX194 - 115 pressure coring tool in well 4 ?7 - 19 in Tazhong oilfield. Water cut of Tazhong 4 oilfield is over 40ml/kg due to waterflooding operation for long time, the polarity of core surface is strengthened, thus avidity of closed fluid is reduced to core surface. The closed effect is in fluenced Through controlling bottom - hole pressure drawdown, optimized design coring bit and selecting performance stable closed coring uool, 88. 8m cores have been obtained from Carboniferous sandstone by means of pressure coring technology in Well 4 - 7 - 19 of Tazhong, recovery ratio and sealing ratio are 98. 4% and 88% respectively. It created good achievements in the fourth oilfield of Tazhong in terms of coring in high water - bearing formation.