川东北气液转换井壁稳定技术研究与应用

Reseach and Application of Wellbore Stability Technique with Gas-fluid Conversion in the Northeast Sichuan

针对川东北地区在空气钻井后转化为钻井液钻井过程中因井壁掉块和坍塌,造成长时间大段划眼、测井遇阻、卡钻等复杂情况,研制了空气钻井后的转换钻井液。其耐温大于150℃,抗盐达饱和,抗石膏污染达2%,相对回收率96.0%。并开发了空气钻井后气液转化工艺,使转换钻井液的井壁稳定能力提高。空气钻井后转换钻井液技术在川东北地区P103-4和P102-1等井的应用结果表明,空气钻井后转换钻井液钻井顺利,转换过程中未出现井壁坍塌等复杂情况,井眼质量提高。

According to the complicated conditions of long -interval reaming, obstruction in logging, drill pipe sticking caused by wellbore sloughing and collapse in the conversion process of drilling fluid after air drilling in the Northeast Sichuan, the drilling fluid for the conversion process was prepared. It has heat - resistance of more than 150 ~C, salt -tolerance of up to saturation salt solution, CaSO4 -tolerance of 2%, and the relative recovery rate of 96%. The technique of gas - fluid conversion was developed which made to improve the wellbore steady ability of the converting drilling fluid. The technique was applied in P103 -4 and P102 - 1 well in the Northeast Sichuan, and the results showed that the conversion processes fi＇om air drilling into fluid drilling were all right and complicated conditions such as slough and collapse of borehole wall did not happened. The borehole quality was improved.