低密度条件下井眼稳定问题的探讨

DISCUSSION ON HOLE STABILIZATION UNDER THE CONDITION OF LOW DENSITY DRILLING FLUIDS

钻进中井眼的稳定一直是钻井工作者十分关注的问题 ,在引用井眼失稳研究成果的基础上 ,分析了降低钻井液密度的可行性。在某些地区某些构造上的某些井段 ,井眼失稳主要原因是泥页岩水化膨胀造成的 ,采用空气、泡沫、充气等低密度钻井液钻进不但可以防止井漏 ,而且还可以缓减地层垮塌。

A good deal of attention has been always paid to the hole stabilization in the process of drilling by drilling workers. On the basis of citing the research results of hole unsteadiness, the feasibiliiy of reducing the density of drilling fluid is discussed in the paper. At some in intervals in certain structures at sonic regions, the principal reason of causing hole unsteadiness is the swelling of mudstone and share by hydration. Not only lost circulation can be prevented but also well sloughing may be re-tarded by applying low density air, foam or aeration drilling fluid.