Preliminary Evaluation of Shale Gas Reservoirs: Appraisal of Different Well-Pad Designs via Performance Metrics

Shale gas production has been the focus of intense debate in recent years. Shale gas supporters claim that it could be the way to transition between fossil fuels and renewable energy sources. For instance, in the United States, power generation from coal is being replaced by power generation from natural gas, which is a cleaner fuel when compared to coal. However, shale gas critics claim that the environmental cost associated with shale gas production is high enough to negate the benefits to society. For example, high water usage as well as the potential for contamination of underground and surface water sources constitute important environmental challenges for the development of shale gas resources. This study presents a methodology for the preliminary assessment of the development of shale gas resources taking into account well-pad design as one of the most important decision variables. To perform the assessment, different performance metrics are proposed to evaluate not only the economics of developing a well-pad but also the environmental impact of its operation, including total gas production and water consumption. Finally, we illustrate through case studies that the selection of the well-pad design depends on the performance metric used