钾铵基悬浮乳液钻井液体系在大牛地气田的应用

APPLICATION OF POTASSIUM- AMMONIUM SUSPENDED-EMULSION DRILLING-FLUID SYSTEM TO DANIUDI GASFIELD

针对大牛地气田水平井钻井中常规钻井液存在的问题,根据气田的储层特征,优选出钾铵基悬浮乳液钻井液体系。室内实验表明,该钻井液体系具有良好的抗温、抗盐性,较强的抑制性,优异的防塌性,可有效抑制黏土矿物的膨胀、分散、运移,极大地预防了井壁失稳;钻井液滤失量低,侵入储层深度浅,滤饼易于消除,具有良好的储层保护效果。现场应用表明,钾铵基悬浮乳液钻井液体系可有效解决大牛地气田水平井钻井中存在的井壁稳定和储层保护的难点,取得良好的经济效益。

For some problems existing in conventional drilling fluid used for horizontal-well drilling in Daniudi gasfield, a potassium-ammonium suspended-emulsion drilling-fluid system was developed according to the reservoir characteristics. Its experiment shows that, with good resistance to heat and salt, strong capability of rejection,and excellent collapse prevention, this system can effectively control the inflation, dispersal and migration of clay min-erals in order to prevent borehole instability. With lower filtrate loss, shallower invasion depth, the easy-to-remove filter cake, it shows a better capability of reservoir protection. Field application indicates that this system can solve the problems of borehole instability and reservoir protection existing in the horizontal-well drilling, and obtained good e-conomic benefits.