塔西南琼库恰克地区膏泥层井壁稳定性研究

Study on well bore stability of gypsum - shale formation in Qiongkuqiake area, southwest Tarim

琼库恰克地区位于巴楚县色力布亚乡西北,属塔里木盆地西南凹陷麦盖堤斜坡琼库恰克构造带的巴什托普背斜地带。该地区井深,地质构造十分复杂,钻井成功率低。特别是下第三系阿卡塔什组存在大段石膏和膏泥层及二叠系存在大段红层,常常引起严重的坍塌卡钻等复杂情况。本文针对石膏和膏泥层的井壁不稳定问题进行了实验研究。结果表明,石膏层特别是膏泥层的显著特点是水化强分散弱膨胀。膏泥层的稳定性在很大程度上取决于石膏的百分含量,石膏含量在20％～55％范围内的膏泥岩样易水化分散坍塌。新型的化学固壁剂和PAC141具有显著的抑制石膏和膏泥层水化分散作用,而KCl的抑制效果差。

Qiongkuqiake area is located in southwest depression of Tarim. Serious problems are encountered in the drilling of this area, such as hole collapse and pipe stuck resulted from long section of gypsum, gypsum-shale formation, and red beds. It is shown that the special points of gypsum and gypsum - shale formation are higher dispersion and lower swelling after hydration, the wellbore stability of these formations is dependent on the content of gypsum. Two polymer inhibitors are effective, and much better than potassium chloride in shale inhibition for this area.