Shale gas development: Opportunities and challenges for rock mechanics

Abstract

Multistage hydraulic stimulations on long-lateral horizontal wells are critical technologies for improving shale gas production in China. With deeper exploration and development in depth, however, more challenges spring up. For example, high risks in drilling and completion, low-efficient stimulation, and rapid production decline, etc. The topics are related with failure and seepage modeling in shale gas reservoirs, for which the nature of the problems is highly focused on rock mechanics. More breakthroughs are excepted in laboratory tests, fracture networks characterization and seepage modeling, multi-field coupling and poroelasticity theories. Although China has achieved initial victory in shale gas development, more challenges remains to be disposed by deepening theories of rock mechanics and industrial innovations. Meanwhile, clean and cost-effective recovery of shale gas is the key role throughout the life-cycle of development. In this paper, we review geomechanics assessments, fracture mechanics, seepage and fluid-solid coupling theories used in shale gas reservoirs. We cover the topics of laboratory tests, wellbore safety and effective development technologies, with discussing the research direction and hotspot in the future.