The Effect of Hydraulic Fracture Geometry on Well Productivity in Shale Oil Plays with High Pore Pressure

Abstract

We propose three idealized hydraulic fracture geometries (“fracture scenarios”) likely to occur in shale oil reservoirs characterized by high pore pressure and low differential in situ stresses. We integrate these geometries into a commercial reservoir simulator (CMG-IMEX) and examine their effect on reservoir fluids production. Our first, reference fracture scenario includes only vertical, planar hydraulic fractures. The second scenario has stimulated vertical natural fractures oriented perpendicularly to the vertical hydraulic fractures. The third fracture scenario has stimulated horizontal bedding planes intersecting the vertical hydraulic fractures. This last scenario may occur in mudrock plays characterized by high pore pressure and transitional strike-slip to reverse faulting stress regimes. We demonstrate that the vertical and planar fractures are an oversimplification of the hydraulic fracture geometry in anisotropic shale plays. They fail to represent the stimulated volume geometric complexity in the reservoir simulations and may confuse hydrocarbon production forecast. We also show that stimulating mechanically weak bedding planes harms hydrocarbon production, while stimulated natural fractures may enhance initial production. Our findings reveal that stimulated horizontal bedding planes might decrease the cumulative hydrocarbon production by as much as 20%, and the initial hydrocarbon production by about 50% compared with the reference scenario. We present unique reservoir simulations that enable practical assessment of the impact of varied hydraulic fracture configurations on hydrocarbon production and highlight the importance of constraining present-day in situ stress state and pore pressure conditions to obtain a realistic hydrocarbon production forecast.

Sensitivity Analysis of Geomechanics Influence on The Success of Hydraulic Fracturing in Shale Gas Reservoir

“…So it is necessary to pay attention to minimize the differential stress due to the greater bottom hole pressure. Then, pore pressure becomes an important part of hydraulic fracturing to control the final stimulation of the fracture geometry (Arias Ortiz et al, 2021). b) Biot Coefficient One of the parameters to determine and minimize geomechanical effects during the process fracturing job is the biot's coefficient.…”

Optimization of Financial Indicators in Shale-Gas Wells Combining Numerical Decline Curve Analysis and Economic Data Analysis

“…The proposed methodology combines numerical simulation of gas production and stochastic simulation of the gas price based on historical data. Through computational fluid dynamics, we obtain the decline curves of gas production for different combinations of porosity (ϕ), induced permeability or EPV permeability (k EPV ), and EPV geometry values (AR) [50][51][52]. Using historical gas price data and applying the bootstrapping statistical re-sampling technique [53], we obtain the drift and volatility of the stochastic process of gas price evolution over time [54].…”