Multimaterial Multiphysics Modelling Coupled with Post-Fracturing Production Flow Simulations: Revamping Hydraulic Fracturing Design Strategy

Abstract

Abstract With the aid of a multiphysics simulator, we recently presented a novel utilization of a degradable fluid loss additive (DFLA) as a fracture geometry additive to reduce the pad volume while achieving the same geometry. Here we extend the advanced slurry flow modeling with production simulation to propose the optimum design strategy for fracturing, which may challenge current treatment design conventions. A novel workflow was developed with four coupled working blocks of laboratory, slurry flow modeling, production analysis, and machine learning. High-fidelity simulations were conducted with planar 3D geomechanics coupled with high-resolution material transport. Materials presence was defined in each grid cell as the mixture of proppant, polymer, and fluid loss additive (FLA) with given volume fractions. Fracture conductivity distribution was calculated using laboratory correlations for fracture damage of each material combination. The results were then transferred to a fracture productivity calculator to analyze the impact of polymer and FLA on post-fracturing productivity index (PI). First, a regression model was built with 32 multiphysics model outputs to create an equivalency for pad volume with and without FLA, which varied from 42% to 57% for different leakoff scenarios. Second, the laboratory results showed a logarithmic dependence of proppant pack conductivity on the FLA mass with almost 80% loss at an FLA/proppant ratio of 0.01. Consequently, three pump schedule categories of baseline (no FLA), FLA, and DFLA were used with multiple treatment sizes based on common field experience in each category. Pad volume design was based on the regression results, and the conductivity calculations were based on experiments. It was observed that for a smaller treatment size, lower FLA mass is required, and the loss of conductivity was negligible; hence, excess polymer caused 15% lower PI only. For larger treatments covering net pay thicknesses, the FLA and polymer damage together can decrease production up to 50%, and hence DFLA is the optimum option showing the maximum production potential. Additionally, we investigated the effect of real field ranges of reservoir permeability, reservoir pressure, and flowing bottomhole pressure for each of the above designs to present a flowchart specific to the reservoir conditions. The new digital framework proposes solutions to the limitations of current methodology. The multiphysics fracture and productivity calculator reveals the underutilized potential of degradable chemistry in fracturing treatments with minimal investment. We demonstrate that computationally coupled models enable swift, accurate, and engineered decision-making for optimum asset development.