Production performance analysis for composite shale gas reservoir considering multiple transport mechanisms

• Established the composite model for multi-stage fractured horizontal well in shale gas reservoirs.
• Adsorption, desorption, diffusion, and viscous flow were considered in this new model.
• Different flow regimes were divided based on pressure transient analysis.
• Validating the new model compared with some existing models.
• Effect of relevant parameters on production performance was modeled and analyzed.

To better evaluate production performance of shale gas reservoir development, it is urgent to resolve the Stimulated Reservoir Volume (SRV) enigma. However, it is very challenging to characterize the SRV considering multiple transport mechanisms. The SRV is always very complex after fracturing and refracturing. Hence, it is paramount to develop new models to describe SRV and analyze the well performance for shale gas reservoirs. In the paper, we present a dual-region composite reservoir model for multistage fractured horizontal well when developing shale gas. In this model, multiple transport mechanisms were considered including desorption, diffusion, and viscous flow. Then, the model solution and its validation against other semi-analytical model results were presented. Different flow regimes were divided according to pressure transient analysis curves. Sensitivity studies to quantify the key parameters affecting the well performance were performed finally. Seven variables, which are Langmuir volume, Langmuir pressure, diffusion coefficient, inner region radius, inner region permeability, stress sensitivity coefficient, and hydraulic fracture conductivity, were investigated. The model proposed here is more comprehensive by considering not only SRV but also the transport mechanisms of shale gas, and can be used for performance analysis in shale gas reservoir development.