Understanding the Mechanism of Interwell Fracturing Interference With Reservoir/Geomechanics/Fracturing Modeling in Eagle Ford Shale

Abstract

Summary Tightly spaced horizontal wells are widely used in the development of unconventional resources. The effectiveness of this strategy is largely affected by interwell fracturing interference, indicated by interwell fracture geometry and fracture hits, because interwell interference affects both the parent- and infill-well production. This work proposes a reservoir/geomechanics/fracturing modeling work flow for understanding the interference mechanism and quantifying effects of parent-well fracture geometry, differential stress, and the design of infill-well completion on interwell fracturing interference. Reservoir models are constructed for the analysis of Eagle Ford scenarios. The numerical work flow involves a finite-element model that fully couples reservoir flow and geomechanics, and a complex multifracture propagation model coupling rock mechanics and fluid flow in wellbore and fractures. The work flow characterizes the temporal-spatial evolution of pressure and stress caused by legacy-parent-well production. The fracture model is used to simulate the complex fracture geometry created by infill-well completion, on the basis of an updated heterogeneous reservoir stress state. The resulting fracture geometry quality is quantified by the occurrence of fracture hits and the relative growth of fractures in longitudinal and transverse directions. Nonuniform fracture geometries lead to more-complex stress changes, induced by depletion, rather than by uniform fracture geometries along parent wells. A smaller in-situ differential stress results in stronger stress reorientation that is caused by parent-well depletion, which induces longitudinal fractures along infill wells, and greatly reduces stimulated reservoir volume (SRV) and initial well performance of infill wells. A larger in-situ differential stress induces less stress reorientation and is more likely to lead the fractures to propagate toward pre-existing fractures, generate fracture hits, and affect the production of parent wells. The quantification study in the sensitivity analysis indicates that differential stress and the infill-well completion design have the most significant influences on interwell interference. This study suggests optimal infill-well completion designs for Eagle Ford scenarios. The study also provides insights for an infill-well completion design in unconventional reservoirs developed by tightly spaced horizontal wells, in terms of how to adjust field operational schedules to avoid fracture hits, and change the complexity of the interwell fracture networks.

How will treatment parameters impact the optimization of hydraulic fracturing process in unconventional reservoirs?

“…In Manchanda et al [30], a 3D reservoir-scale poro-elastic geomechanics software (Multi-Frac) was utilized to model the production decline of the parent well and calculate its impact on the pressure, total stress and effective stress. Similarly, a fully coupled flow and geomechanics model was developed [31,32] to the identify the poro-elastic behavior of multiphase-fluid diffusivity and rock deformation of interwell fracturing interference in Eagle Ford unconventional reservoirs, using finite-element method (FEM) and multifracture propagation using the displacement discontinuity method.…”

A criterion for identifying a mixed-mode I/II hydraulic fracture crossing a natural fracture in the subsurface

“…Mixed-mode I/II hydraulic fracture A hydraulic fracture in a reservoir generally deviates from a plane because of many factors, such as stress interference during multistage fracturing (Guo et al, 2019b), discontinuities in naturally fractured reservoirs, and the use of oriented perforations in the borehole.…”

Numerical simulation on the simultaneous stress interference of parallel multiple hydraulic fractures

“…Sobhaniaragh et al shed light on the stress shadowing effect on conventional completion designs, namely simultaneous HF (Sim-HF) and Sequential HF (Seq-HF) with the help of the Texas two-step method (TTSM) (Sobhaniaragh et al, 2019). The stress interference between simultaneously grown hydraulic fracturing and how they propagate transversely and longitudinally under evolving in-situ stress conditions is thoroughly discussed (Guo et al, 2019a(Guo et al, , 2019b. Increasing fracture spacing can reduce stress interference and avoid post-fracturing fractures penetrating into fracturing hydraulic fractures (Nicolas and Mukul, 2010;Peng, 2020;Soliman et al, 2008).…”