大型穿越钻进工程防冒浆钻井液技术

Technology preventing oozing slurry drilling fluid in large crossing drilling engineering

在大型穿越钻进铺管工程中,地面冒浆是很突出又很难解决的问题。冒浆的主要原因是钻井液配方选择不当,钻屑无法从钻孔顺利排出,导致钻孔环空泥浆压力过大并压裂上覆地层,从而使地面发生冒浆。经过大量室内外实验,得出以高剪切稀释(降低流阻)为主要性能指标,同时兼有降滤失、抑制孔壁失稳等性能的防冒浆钻井液体系。工程应用证明,该钻井液技术能有效减少钻孔环空泥浆压力。

The problem of oozing slurry is salient and difficult to solve in the large crossing drilling engineering. The main reason of oozing slurry is improper drilling fluid, the drilling cuttings can be not discharged from bore hole. It results in annulus overpressure and breaking down overlying stratum, and then oozing slurry in the ground. During indoor or outdoor experiments, we founded the mud system of preventing oozing slurry with main performances of dilution sheafing （flow resistance reducing）, filtration control, against sloughing and so on. Field application proves that the mud system can reduce annular mud pressure effectively, and solves the problem of oozing slurry radically.