| 摘要 |
A method for releasing a stuck drill string in the borehole of an underground formation employing an non-aqueous drilling fluid, the method comprising contacting the stuck drill string with a non-emulsion based additive composition effective in reducing the annular pressure exerted by the drilling fluid or mud cake against the stuck drill string and thereby releasing the stuck drill string, the additive composition comprising a mutual solvent which is a C2 to C22 glycol ether or mixtures or combinations of these and similar compounds known to one of skill in the art and a weighting agent. Preferably, the mutual solvent may be selected from the group consisting of ethylene glycol and diethylene glycol, and the weighting agent from an organophilic clay. A further embodiment includes a solid weighting agent, preferably the solid weighting agent is selected from the group galena, hematite, magnetite, iron oxides, illmenite, barite, siderite, celestite, dolomite, calcite, and mixtures or combinations of these and similar compounds known to one of skill in the art. |
