致密储层地层参数对体积压裂缝网的影响研究

The Effect of Geological Parameters on Volume Fracturing in Tight Reservoir

针对致密储层的关键地层参数如何影响水平井体积压裂缝网效果这一问题,应用岩石力学参数计算方法和储层压裂裂缝启裂和延伸基本原理,建立了岩石脆性系数、水平应力差异系数、天然裂缝密度3个地层参数对缝网影响的模拟模型,计算和评价了页岩储层的缝网效果,分析了3个地层参数不同情况下对缝网的有效压裂体积、增产储层体积、增产储层体积百分比等参数的影响变化规律,算例分析认识到:岩石脆性系数越大或者水平应力差异系数越小,分支缝密度会越大,缝网区域半长相反越小,早期生产优于后期;天然裂缝密度越大,近井缝网沟通越密集,缝网区域外仍可参与渗流,由此可弱化缝网半长。模型的建立和参数影响分析可以为现场提供参考依据。

In allusion to the issue of how the crack network of the volume fracturing being affected by the key geological parameters in the tight reservoirs,models of brittleness coefficient,horizontal stress differential coefficient and natural fracture density were established for simulating the effect of the crack network by using the method of rock dynamic parameter calculation and principles of crack initiation and its expansion.The effect of crack network in the shale reservoir was calculated and evaluated.The rules of the effective fractured volume,stimulation reservoir volume(SRV),stimulation reservoir volume percentage(SFR)influenced from three different geological parameters were analyzed.The results show that the more rock brittleness coefficient is,the less the horizontal stress differential coefficient is,the bigger the branched crack density is,the less the half-length is in crack network,the production in early period is better than that in the late period.The bigger the nature fracture is,the dense the communication network is in the adjacent wells,it can take part in seepage even outside the crack network,by which the half-length of the network is weakened.T it can provide the reference for the establishment of models and parameter analyses.