Advances in Geomechanics and Wellbore Integrity of Unconventional Reservoirs

With the increasing consumption of oil and gas resources, conventional resources cannot meet the rapid energy demand due to the depletion and exploitation challenges. Therefore, unconventional reservoirs such as shale gas with ultra-low permeability have progressively drawn industry attention for exploration and production activities over the last decade. These reservoirs generally do not possess natural productivity, and conventional stimulation techniques cannot easily turn these reservoirs into highly productive ones. Hence, extensive multistage hydraulic fracturing stimulations have been a renewed technique to address these limitations by developing complex fracture networks in the rock to accelerate fluid production. There have been some efforts to improve ultimate recovery by enhancing fracture network complexity, while extensive stimulations have redistributed in-situ stresses, dramatically. In such cases, wellbore integrity issues like sustained casing pressure and casing deformation are more likely than ever to occur.

Wellbore integrity problem while fracturing treatment has been a big threat to the development of unconventional reservoirs. Wellbore integrity issues during production especially in shale gas reservoirs have already been highlighted in the petroleum engineering literature. However, the driving mechanisms behind the casing failure have remained unknown. Therefore, it is of vital importance to understand rock mechanics and stresses induced by fracturing treatments and analyze their impacts on wellbore integrity. We would like to invite researchers and engineers working in relevant fields to contribute papers that aim to address wellbore integrity issues from the perspective of geomechanics. This research topic aims to fill the gaps among fundamental theories, applied technologies, and field practices, reporting recent innovations and advances related to wellbore integrity control while fracturing treatment in unconventional reservoirs.

This Research Topic covers themes such as rock mechanics in unconventional reservoirs, in-situ stress assessment, fracture network growth, and casing deformation mechanism. We seek comprehensive reviews, experimental studies, numerical simulations, and field applications related to geomechanics and wellbore integrity in unconventional reservoirs. Specific topics of interest include, but are not limited to the following:
• Machine learning for geomechanics
• Novel hydraulic fracturing technologies and simulation methods
• In-situ stress measurement technologies
• New theories and simulations on mechanisms of casing deformation and sustain casing pressure while fracturing
• New methods and equipment for evaluation of wellbore integrity issues and their control in lab and field
• New tools, software, and technologies for addressing wellbore integrity issues