Abstract: Causes of and preventive measures for cave-in of wells in the Dagang oil field is discussed through analysis of the mineral composition of mudstone samples. An introduction is made of the use of polyacrylonitrile nitrated-sulfonated potassium humic acids and potassium chloride as additive in mud for prevention of cave-in.

摘要： 本文分析了大港地区泥岩矿物组份变化规律,对该地区井塌原因及防止井塌措施进行了探讨,并介绍了腐钾、氯化钾泥浆防塌作用机理及现场使用情况。

关键词: 大港油田, 泥岩水化, 沙河街组, 井塌, 井下复杂情况, 蒙脱石, 伊利石, 回收率, 井径扩大率, 氯化钾泥浆