Workflow for Integrating Geomechanics, Hydraulic Fracturing, and Reservoir Simulation to Determine Marcellus Shale Horizontal Well Production Potential
A workflow for data analysis and model development for accurate prediction of the gas production from a Marcellus shale horizontal well with multiple hydraulic fracture stages was developed and implemented. The available data from a Marcellus shale horizontal well were collected, analyzed, and utilized to develop a reservoir simulation model. The properties of the hydraulic fractures were determined from the fracture treatment data and the mechanical properties by employing a commercial fracturing software which accounting for the impact of the stress shadowing. The available core plugs measurements, well logs, and the image logs were analyzed to determine the shale petrophysical and geomechanical properties including natural fracture (fissure) distribution. The available laboratory measurements and published data were analyzed to determine the gas adsorption characteristics and the shale compressibility. The impact of the shale compressibility was then incorporated in the model by developing multipliers for different s components of the compressibility, i.e., fissure permeability, matrix permeability, and hydraulic fracture conductivity as function of net stress.
The model provided accurate prediction of the gas production which was confirmed by comparison against the production data. The inclusion of the compressibility multipliers (matrix, fissure, and hydraulic fracture), stress shadow-impacted hydraulic properties, and adsorbed gas were critical for achieving accurate gas production predictions. The low stress barriers between Marcellus shale and the upper zone caused the hydraulic fractures to grow in upward direction from Marcellus Shale and reduced efficiency of the hydraulic fractures. The compressibility and stress shadowing were found to negatively impact the gas production, particularly during the early stages of the production (1-5 years). The workflow developed in this study can be used to accurately predict the gas production and determine the optimal hydraulic fracture spacing for horizontal shale wells with multiple hydraulic fracture stages.
The following conclusions were reached during this study:
The impacts of the stress shadow and compaction must be considered for accurate prediction of thegas production from horizontal Marcellus shale with multiple hydraulic fracture stages.
Stress Shadow has a negative impact on gas production, particularly during the early stages of theproduction (1-5 years).
Compaction has more impact on gas production as compared to the impact of the stress shadow s dueto Marcellus shale’s low Young’s modulus and high density of natural fractures along the horizontallength.
Ignoring the impacts of the stress shadow and compaction leads to over-estimation of the gas recovery.