川东北河坝地区中浅部地层气体钻井出水随钻预测

Water exit prediction while drilling from mid-shallow formation during gas drilling in Heba area,northeast Sichuan

以川东北河坝地区中浅部砂泥岩地层为研究对象,基于随钻测井技术,分析随钻获取地层参数资料所需工具的结构及技术特点,对地层出水层位的预测方法进行研究,建立气体钻井出水量定量预测模型。结果表明:给出的地层出水层位预测方法能够较好地预测出水层位;气体钻井受地层出水的影响和制约明显,在目前常用井眼及气体装备条件下,气体钻井的最大携水量一般小于3 m3/h,泡沫钻井的最大携水量一般小于10 m3/h;河坝地区1.0 km以内的浅部地层和沙溪庙组地层采用空气钻井,而千佛崖组地层适宜采用雾化钻井或泡沫钻井,自流井组和须家河组地层适宜采用充气钻井液或常规水基钻井液等近平衡钻井。

Taking the mid-shallow of sand-shale formation in Heba area in northeast Sichuan as the main research object, the technology characteristics of the tools which were used to obtain the formation parameters information while drilling were ana- lyzed based on the logging-while-drilling technology. The methods of predicting formation water exit layer were studied. And the quantitative prediction model of water yield of air drilling was established. The results show that the formation water exit layer can be predicted well by using this proposed method. Gas drilling effect is affected and limited by formation water exit. Under the conditions of commonly well bore and gas equips, the maximum water carry-overs of gas drilling and foam drilling are less than 3 and 10 m3/h respectively. The shallow formation with depth being less than 1.0 km and Shaximiao formation adopt gas drilling. Qianfoya formation adopts atomization drilling or foam drilling, and Ziliujing formation and Xujiahe forma- tion adopt near-balance drilling with aerated drilling fluid or water base drilling fluid.