地应力对页岩储层开发的影响与对策

Impact of in-situ stresses on shale reservoir development and its countermeasures

张金才 亓原昌

Jincai Zhang Yuanchang Qi

油气富集程度和页岩脆性在北美页岩油气开发中是地质条件方面成功与效益的关注重点，但对于中国四川盆地海相页岩储层，除上述因素外，复杂地质构造下高地应力条件成为阻碍效益开发的主要因素之一。重点阐述了复杂地应力下水力压裂裂缝扩展机理，展示了复杂构造下不利地应力条件对钻井压裂效果的重要影响；四川盆地页岩气储层的最小水平主应力较高，因此具有较高的破裂压力。通过理论分析和案例应用，提出钻井和完井的优化设计，包括水平井钻井方向、井筒轨迹以及完井压裂层段的选取。根据四川盆地不同地区地应力状况，提出涪陵、威荣和威远页岩气田的钻完井建议。

The degree of shale oil and gas enrichment and rock brittleness are key to the successful development of shale oil and gas in North America; however, in addition to the above factors, the high in-situ stresses in a complex geological structure also serve as a main factor hindering the effective development of marine shale gas in the Sichuan Basin.This study focuses on explaining the mechanism of hydraulic fracture propagation under complex and high in-situ stresses and demonstrating the impact of unfavorable in-situ stress conditions on fracturing effectiveness.The results show that shale reservoirs in the Sichuan Basin have higher minimum principal stresses, causing very high formation breakdown pressures.Through theoretical analysis and case study, the optimized design of drilling and completion is proposed, including horizontal well drilling direction, wellbore trajectory, and selection of hydraulic fracturing intervals.Recommendations for drilling and completion of the Fuling, Weirong, and Weiyuan shale gas fields are proposed based on the various in-situ stresses in different areas of the Sichuan Basin.

10.11743/ogg20200411