致密砂岩气藏射孔完井裂缝起裂压力研究

Fracture initiation pressure of perforation completion in tight sandstone gas reservoir

致密砂岩气藏是一种非常重要的非常规油气资源,但其储层物性差、渗透率低、开采难度大,目前开发主要依赖水平井压裂改造技术。为了准确预测裂缝起裂压力,应用岩石力学、弹性力学相关理论对致密砂岩射孔完井方式下井筒复杂的受力状态进行分析,并考虑施工注入流体压力、压裂液滤失等因素对井筒周围应力场的影响,提出了一套相对完善的储层裂缝起裂压力预测模型。现场实例验证了该模型的正确性和适用性,且对于致密砂岩气藏的现场设计与开发具有一定的指导意义。

Tight sandstone gas reservoir plays an important role in unconventional oil and gas resources.However,the reservoir has poor physical properties,low permeability and great difficulty on exploitation.At present,the development mainly depends on horizontal well fracturing technology.In order to make an accurate prediction on fracture initiation pressure,the complex stress state of the wellbore under the perforation completion mode of tight sandstone is analyzed by using the relevant theories of rock mechanics and elasticity.Considering the influence of construction injection fluid pressure,fracturing fluid filtration and other factors on the stress field around the wellbore,a prediction model of reservoir fracture initiation pressure is proposed.Field examples verify its correctness and applicability,and it provides guidance for the field design and development of tight sandstone gas reservoirs.