下扬子地区页岩气井失返性漏失堵漏技术研究--以WY-1HF井为例

Plugging technology applied for total loss in shale gas wells of Lower Yangtze Region:Taking Well-WY-1HF as an example

目前,国内页岩气钻井发生漏失情况比较普遍,适用于油基钻井液的堵漏方法不多,失返性漏失仍是业内技术人员面临的难题。以WY-1HF井现场作业为例,使用油基钻井液在该井水平段钻井时发生失返性恶性漏失,且使用常规的桥塞堵漏技术、油井水泥堵漏技术均不能有效封堵漏失层。在对该井漏失层特征分析的基础上,研究了无机凝胶的堵漏机理及桥塞堵漏材料对油基钻井液性能的影响规律,最终采用高密度(1.89 g/cm^(3))的水泥固化封堵结合低密度(1.17 g/cm^(3))无机凝胶固化封堵,配合使用油基钻井液高浓度大颗粒桥塞堵漏浆,堵漏成功,保障了后续通井、测井、下套管、固井等作业的顺利开展。该方法的成功实施对该地区页岩气堵漏技术的应用具有一定的借鉴意义。

At present,the leakage of shale gas drilling is quite common in China,and there are few plugging methods suitable for oil-based drilling fluid.The total loss of drilling fluid is still a difficult problem for technicians in the industry.Taking the field operation of Well-WY-1HF as an example,during the drilling of its horizontal well interval by using oil-based drilling fluid,the conventional plugging technology of bridge plug and cement plugging technology of oil well can not work efficiently.Based on the analysis of the characteristics of the loss zones,the effect of different plugging material of oil-base drilling fluid performance have been studied to determine the formula for successful plugging,that is high density(1.89 g/cm^(3))cement solidified plugging combined with low density(1.17 g/cm^(3))inorganic gel curing plugging,cooperating with the use of bridge plug with high concentration and large particle.It ensures the subsequent drifting,well logging,the casing and cementing operation smoothly.The successful implementation of this method provides certain reference for the application of shale gas plugging technology in the same area.