【摘要】 近年来深水油气勘探发展迅速,与陆上及浅海区域的钻井相比,深水上覆岩层压力较低,容易发生漏失。另外,深水浅层泥页岩也容易发生水化坍塌。因此,深水钻井中要求提供更精确的安全密度窗口,以防止发生复杂事故。通过借鉴陆上与浅海地区钻井中的井壁稳定性分析方法,结合深水钻井自身特点,得出了深水钻井安全密度窗口计算方法,其中上覆岩层压力利用密度积分方法计算,孔隙压力可以利用测井数据根据Eaton法进行计算。针对深水浅部地层的特殊性,建立了塑性区半径评价法用于浅部地层坍塌压力计算,并且认为深水钻井中漏失压力等于水平最小主应力,钻井中将漏失压力作为允许使用钻井液密度的上限。根据上述计算方法可以得出深水钻井的安全密度窗口,为钻井工程提供参考。更多还原

【Abstract】 Oil and gas exploration in deepwater areas has developed rapidly for recent years.Compared with drilling on land or in shallow water,the overburden pressure was lower in deepwater,which would cause lost circulation easily.In addition,Shale in the shallow formation of deepwater area was easy to be collapse because of hydration.Therefore,more accurate safety density window was required to prevent the occurrence of complex problem in deepwater drilling.By using the analycal method of borehole stability on land and in shallow water,and in combination with the characteristics of deepwater drilling,a calculation method of drilling safety density window was obtained.Overburden pressure can be calculated by using density integral method,and pore pressure can be calculated by Eaton method with logging data.According to particularity of shallow formation in deepwater,plastic area radius estimated method is established to calculate collapse pressure.Furthermore,the upper limitation of allowable drilling fluid density in drilling is leakage pressure that is equal to minimum horizontal principle stress.The safety density window of deepwater drilling can be calculated by above method,which can provide reference for drilling engineering.更多还原