Horizontal drilling and multi-stage hydraulic fracturing are the two critical enabling technologies to facilitate a rapid development of shale gas reservoirs. The process of hydraulic fracturing often creates complex fracture networks, especially in some shale reservoirs with a high brittleness and a large amount of pre-existing natural fractures. In addition, gas desorption might be a significant contributor to the total gas recovery. However, accurate modeling gas flow from the complex fracture networks is very challenging. Therefore, development of an efficient simulation approach to properly model gas flow from shale gas reservoirs with complex fracture geometry by taking into account the gas desorption is important to evaluate well performance and completion optimization.
In this work, we focus on developing an efficient semi-analytical approach to simulate gas production from shale reservoirs with the complex fracture networks by considering the gas desorption effect. A series of case studies are performed to compare simulation results with a numerical reservoir simulator. Single fracture, multiple fractures, uncertainty fracture pattern with varying fracture spacing and half-length are investigated with and without considering the gas desorption effect. Furthermore, single inclined fracture and multiple inclined fractures with different angels are studied. This work provides an effective tool to efficiently evaluate shale well performance with the complex fracture geometry, which can provide significant insights into optimization of fracture treatment design for shale gas reservoirs.