全白油基钻井液在吉木萨尔凹陷泥岩地层中的应用

Application of whole white oil-based drilling fluid in mudstone formation of Jimsar sag

针对准噶尔盆地吉木萨尔凹陷J1井二开长裸眼段在钻井过程中极易发生因泥岩吸水膨胀引发井壁垮塌、阻卡等问题,研发了一种白油基钻井液。对白油基钻井液各项性能进行了评价:该白油基钻井液具有良好的流变性、抗污染性、抑制性和抗温性,能有效解决泥岩地层井壁易失稳的问题。J1井二开3 300 m长裸眼段钻井时根据地层压力状况及时调整钻井液组成,钻进过程中井壁稳定,二开段平均机械钻速提高一倍,钻井周期缩短一半,钻井成本大幅减少。该白油基钻井液体系完全能满足吉木萨尔凹陷泥岩地层钻井施工要求,具有良好的应用前景。

A white oil-based drilling fluid is developed to solve the problems of wellbore collapse and pipe sticking caused by water absorption expansion of mudstone in the second long open hole of J1 well in Jimusar sag, Junggar Basin. The properties of white oil-based drilling fluid are evaluated. The white oil-based drilling fluid has good rheology,pollution resistance,inhibition and temperature resistance,which can effectively solve the problem of wellbore instability in mudstone formation. The composition of drilling fluid should be adjusted in time according to the formation pressure when drilling in the second long open hole of 3 300 m in J1 well. During the drilling process, the borehole wall is stable, the average penetration rate of the second opening section is doubled, the drilling cycle is shortened by half, and the drilling cost is greatly reduced. The white oil-based drilling fluid system can fully meet the drilling requirements of mudstone formation in Jimsar sag, and has a good application prospect.