四川长宁页岩气水平井压裂套管变形实例分析

A Case Study on Casing Deformation of Horizontal Well during Hydraulic Fracturing in Sichuan Changning

选择一口典型井作套管变形实例分析。套管变形是在压裂期间发生的,压裂是套管变形的工程原因。套管变形位置接近小断层,邻井套管变形具有剪切特征,表明套管变形是由小断层滑动引起的。利用微地震监测数据和蚂蚁体追踪数据,识别小断层的倾角和倾向,根据地应力和施工压力数据分析该断层的力学活动性,结果表明应力状态满足滑动条件。分析该井固井质量数据、压裂施工曲线和微地震数据的特征,由于固井质量差,压裂时压裂液可能会突破套管和地层之间的间隙,侵入断层,最终激活断层。因此,为了避免套管变形,建议提高固井质量和避开小断层。

This paper selected a typical well as an example of casing deformation for analysis.Casing deformation occurs during fracturing,and fracturing is the engineering cause of casing deformation.The casing deformation position is close to the small fault,and the adjacent well casing deformation has shear characteristics,which indicates that the casing deformation is caused by small fault sliding.Using Microseismic monitoring data and ant body tracking data,the dip angle and inclination of small faults were identified,and the mechanical activity of the fault was analyzed based on the ground stress and construction pressure data.The results showed that the stress state satisfies the sliding conditions.The characteristics of well cementing quality data,fracturing construction curves and microseismic data were analyzed.Due to poor cementing quality,fracturing fluid may break through the gap between the casing and the formation,intrude into the fault,and finally activate the fault.Therefore,in order to avoid casing deformation,it is recommended to increase cementing quality and avoid small faults.