亓倩, 岳明, 朱维耀, 马文江. 页岩储层多级压裂水平井流固耦合产能分析[J]. 工程科学学报. DOI: 10.13374/j.issn2095-9389.2024.03.26.001
引用本文: 亓倩, 岳明, 朱维耀, 马文江. 页岩储层多级压裂水平井流固耦合产能分析[J]. 工程科学学报. DOI: 10.13374/j.issn2095-9389.2024.03.26.001
QI Qian, YUE Ming, ZHU Weiyao, MA Wenjiang. Fluid–solid coupling productivity analysis of multi-stage fractured horizontal wells in shale reservoirs[J]. Chinese Journal of Engineering. DOI: 10.13374/j.issn2095-9389.2024.03.26.001
Citation: QI Qian, YUE Ming, ZHU Weiyao, MA Wenjiang. Fluid–solid coupling productivity analysis of multi-stage fractured horizontal wells in shale reservoirs[J]. Chinese Journal of Engineering. DOI: 10.13374/j.issn2095-9389.2024.03.26.001

页岩储层多级压裂水平井流固耦合产能分析

Fluid–solid coupling productivity analysis of multi-stage fractured horizontal wells in shale reservoirs

  • 摘要: 从渗流微观–宏观动力学行为出发,通过应力敏感实验研究储层流固耦合作用与流体流动规律,探究微观与宏观有效应力的相互作用关系;基于有效应力原理,考虑页岩气滑移扩散、解吸及页岩变形的多尺度流固耦合作用,分别建立页岩储层基质和裂缝网络的孔隙度、渗透率在有效应力作用下的数学模型. 基于页岩气储层多区耦合渗流物理模型,考虑储层变形对页岩基质和裂缝网络孔隙度、渗透率的流固耦合作用,建立了页岩气水平井流固耦合产能模型,揭示了多级压裂水平井流固耦合非线性渗流规律,分析了页岩气储层多级压裂水平井流固耦合页岩气井产能影响因素;对基质岩样和裂缝岩样进行了应力敏感性实验,结果表明基质岩样的应力敏感性强于裂缝岩样;模型研究表明:考虑与不考虑流固耦合作用对页岩气渗流影响的累计产气量相差14%左右,且缝网区流固耦合作用更为敏感;解吸吸附发生收缩变形量越大,弹性模量越小,泊松比、Biot系数、初始孔隙度越大,流固耦合作用越明显,产气量越低. 泊松比对流固耦合作用的影响比较小,产气量变化不大. 模型模拟结果与现场实际数据一致,产气量满足 “L型”递减规律,且符合率达70%以上,验证了模型的准确性.

     

    Abstract: Starting from the micro/macro dynamics of seepage behavior, stress-sensitive experiments are conducted to investigate the fluid–solid coupling and fluid flow law in shale gas reservoirs. These experiments elucidate the interaction between micro and macroscopic effective stress based on the dynamic behavior of seepage. By applying the principle of effective stress, a nonlinear seepage mathematical model for matrix–fracture porosity and permeability in shale reservoirs is established, considering multi-scale fluid–solid coupling effects such as slip diffusion, desorption, gas flow, and shale deformation. Based on the multi-zone coupled seepage physical model of a shale gas reservoir, a fluid–solid coupling productivity model for shale gas horizontal wells is established. This model considers the impact of reservoir deformation on shale matrix–fracture porosity and permeability. Additionally, it reveals the nonlinear seepage law of multistage fractured horizontal wells and analyzes factors influencing productivity. Stress sensitivity experiments on matrix rock samples and fracture rock samples indicate that the stress sensitivity of matrix rock samples is stronger than that of fracture rock samples. The research shows that cumulative gas production, accounting for the influence of fluid–solid coupling on shale gas seepage, differs by approximately 14% compared to when it is not considered. The difference is mainly attributed to the fluid–solid coupling in the fracture network of the reconstruction area. Analyzing fluid–solid coupling parameters reveals that larger elastic modulus results in stronger resistance to deformation, leading to a weaker fluid–solid coupling effect and decreased gas production. Shale skeleton shrinkage deformation during desorption makes the fluid–solid coupling effect more pronounced, though it slightly reduces gas production. Higher Poisson’s ratio and Biot coefficient increase the deformation sensitivity of the shale reservoir and decrease the resistance to deformation in the fracture network zone, resulting in a more significant fluid–solid coupling effect and decreased gas production. As initial porosity increases, the absolute value of the fluid–solid coupling stress sensitivity coefficient decreases gradually, significantly enhancing the fluid–solid coupling effect characterized by the permeability model. The simulation results of the model align with actual field data, showing that gas production follows an “L-shaped” decline pattern with a coincidence rate exceeding 70%, verifying the model’s accuracy.

     

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