论文详情
目前页岩气储层压裂后产能评价主要通过储层压裂改造体积大小(SRV)进行计算,一般认为改造体积越大,页岩气产能效果越好,但往往没有考虑储层内部缝网密度对于页岩气产能的影响。如何结合储层内部缝网密度对页岩气产能进行合理评价是页岩气产能预测标准需要解决的问题。通过对页岩水力压裂储层内部缝网结构的分析,提出了基于裂缝体积密度的压裂改造效果的评价方法,首先通过滤失模型计算出裂缝体积,再结合SRV参数,使用SRV计算方法计算出储层压裂改造范围,然后依据压裂作业过程中满足的能量守恒与物质守恒定理,计算滤失体积,进而求出裂缝体积,用单位储层内裂缝体积占比,即裂缝体积密度,作为页岩气产能效果的评价标准。实验数据的分析结果表明:在SRV对于页岩气产能评价效果不明显的情况下,裂缝体积密度对于页岩气产能仍然保持很高的相关性,对页岩气储层压裂改造效果具有很好的评价指导作用。
Currently,the evaluation of shale gas productivity is mainly based on the calculation of the fractured reservoir reconstruction volume (SRV).A larger stimulation volume results in a greater improvement of shale gas productivity.Thus far,however,the internal fracture network density of stimulated reservoirs has not been considered as a factor that influences the shale gas productivity.Moreover,the proper evaluation of this productivity by accounting for the fracture density remains challenging.For analyzing the fracture networks of shale reservoirs stimulated via hydraulic fracturing,the concept of fracture volume density (FVD) has been proposed to evaluate the effect of the stimulation.First,the fracture volume was evaluated based on the filter loss model,and the SRV was calculated.Then,a standard shale gas productivity evaluation was proposed,wherein the FVD was defined as the proportion of internal fracture volume in a unit reservoir.Using a set of experimental data,it was shown that the SRV is not always effective for evaluating the shale gas productivity,whereas the FVD showed a better correlation.It was concluded that the proposed method has a good performance and can be used to guide the evaluation of the stimulation effect of fracturing in shale gas reservoirs.
基金项目：国家自然科学基金重点项目(42030805)资助。