Modeling Multi-Stage Twisted Hydraulic Fracture Propagation in Shale Reservoirs Considering Geomechanical Factors

Abstract

To model hydraulic fracture propagation in naturally fractured reservoirs, fracture propagation is generally assumed to be a single planar fracture propagated only in the vertical direction from a horizontal well, regardless of the presence of natural fractures. In this paper, we developed a multi-stage hydraulic fracture propagation model using a twisted multiple planar fracture that is able to describe the propagation of hydraulic fractures more realistically. In propagating hydraulic fractures, we used two criteria: maximum tangential stress, to determine the fracture initiation angle, and whether a hydraulic fracture passes through a natural fracture. The developed model was used with a commercial reservoir simulator through grid mapping in the form of a discrete fracture network using microseismic data. The results of the verification matched the experimental results well for various intersection angles and maximum horizontal stress directions. In the investigation of the direction of maximum horizontal stress, the frictional coefficient of the fracture interface, and fracture orientation, hydraulic fracture propagation modeling results showed that the hydraulic fracture passed through a natural fracture, and thereafter propagated in a manner suitably consistent with the theoretical results, based on a fracture interaction criterion. After confirming the twisted multiple planar fracture model suggested in this work, discrepancies were found in the fracture connectivity and the stimulated reservoir volume. This indicates that the twisted multiple planar fracture approach, which is more realistic in terms of fracture propagation, is extremely important in evaluating the initial gas in place, calculated according to the stimulated reservoir volume.

Hydraulic Fracturing Design Considerations and Optimal Usage of Water Resources for Middle Eastern Tight Gas Reservoirs

“…As shown in Figure , Wiremesh, Planar3D, Pseudo 3D, and the unconventional fracture model (UFM) are a few of the extensively implemented approaches within the industry, with each having its own advantages and constraints. It is evident that interaction of natural fractures with hydraulic fractures can lead to fracture growth and propagation. , Parameters such as the stress distribution, reservoir heterogeneity, and natural fracture distribution/orientation are reported to play a significant role in the same. UFM, a model recently developed, incorporates the stress fields, natural fracture orientation, and rock deformation that are critical to analyzing the hydraulic fracture propagation behavior in an unstructured grid .…”

“…However, since the geometry of the discrete fractures is not explicitly modeled along with the solution or flow pathway, they result in erroneous flow calculations in reservoir portions where well control is restricted . In contrast, the DFN model solves some of these shortcomings as it involves analysis and modeling, which explicitly incorporates the geometry and properties of discrete features as a central component controlling flow and transport . DFNs can lead to a more realistic description of the network, as they are stochastic models that incorporate statistical scaling rules derived from the analysis of fracture length, height, spacing, orientation, and aperture…”

“…21 In contrast, the DFN model solves some of these shortcomings as it involves analysis and modeling, which explicitly incorporates the geometry and properties of discrete features as a central component controlling flow and transport. 18 DFNs can lead to a more realistic description of the network, as they are stochastic models that incorporate statistical scaling rules derived from the analysis of fracture length, height, spacing, orientation, and aperture. 22 This investigation began with the creation of a rudimentary simulation case to analyze the fundamentals of hydraulic fracture propagation.…”

Analysis of Hydraulic Fracture Propagation Using a Mixed Mode and a Uniaxial Strain Model considering Geomechanical Properties in a Naturally Fractured Shale Reservoir

“…Hydraulic fracturing using a horizontal well is an essential production technique in shale gas formations [1][2][3][4][5]. Various approaches have been developed to model hydraulic fracturing phenomena to obtain an accurate estimation of shale gas production-for example, extended and generalized finite elements methods (XFEM and GFEM, respectively) [6][7][8][9], displacement discontinuity methods (DDM) [10][11][12], boundary element methods (BEM) [13][14][15], phase-field formulations [16][17][18][19][20][21][22], and discrete fracture network (DFN) [23][24][25].…”