Unlock the Residual Shale Gas In Fuling Block, China by Infill Wells’ Drilling and Completion: A Study on the Design, Execution, and Results on the Infill Well

Abstract

Abstract Fuling shale gas is the first commercialized shale gas block in China, and more than 30 billion m3 of gas has been produced. To achieve the yearly production target 7 billion m3, more and more infill wells have been drilled and completed. This raised a big concern on the balance of hydraulic fracturing job size of infill well and negative fracture interference on the parent wells, especially for the complex and very heterogenous Fuling reservoir due to multiple tectonic evolutions. A multidisciplinary team across five more domains was formed to turn the infill well completion design based on experience and field observation only to the focus on controlling factors of negative fracture interference, stress field evolution and then hydraulic fracturing design optimization leveraging a high-resolution 3D geological and geomechanical model. The successful unlocking of residual shale gas was realized by infill well drilling and completion relies on the following key work: Build the high-definition 3D model for reservoir properties and geomechanical properties, as well as natural fracture.Calibrate the 3D model by field observation data and production history of parent wells.Predict the pore pressure change and induced stress field change across the PAD.Optimize the infill well completion design with the updated pore pressure and geomechanical properties to release the residual gas without negative fracture interference.Verify the effectiveness of the optimization workflow by field data including microsiemic data, parent wellhead pressure and flow back data With the new workflow established in this multi-displinary study, the infill well completion design was optimized by a quantitative way. More importantly, there is good consistency between the model prediction and the field observation. Based on the workflow and key lessons from this study, the optimization on the future infill wells’ drilling and completion design could be done without compromising parent wells’ performance.