A fracture upscaling method (FUM) for hydraulically fractured reservoirs: From discrete fracture modelling to finite difference simulations

Abstract

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Optimising well orientation in hydraulic fracturing of naturally fractured shale gas formations

“…Previous research has shown the significant impact of natural fractures on the propagation of hydraulic fractures and concluded that natural fractures can cause hydraulic fractures to deviate from the direction of maximum horizontal stress (Sherratt et al, 2020). In the same study, the investigators demonstrated that the angle between the plane of the natural fractures with the orientation of maximum stress can hinder hydrocarbon recovery from a single well up to 20%.…”

“…To achieve this, a method is required for modelling hydraulic fracture propagation in naturally fractured formations and the production from the resulting fracture networks. The Fracture Upscaling Method (FUM) is used to capture the complex flow behaviour of discrete fracture models in a dual-permeability finite difference-based reservoir simulator (Sherratt et al, 2020). This enables the coupling of complex finite element based hydraulic fracture simulators with conventional reservoir simulators.…”

“…FUM was developed in C++ which combines these discrete fracture objects with a dual permeability finite difference-based reservoir simulation grid. The details of this method have been presented and tested against field data in a previous study (Sherratt et al, 2020). The FUM uses a numerical method to change the properties of the grid to capture the effect of the discrete fracture network they contain.…”

“…where 𝑞 𝑗,𝑚𝑎𝑥 is the maximum number of moles of component j adsorbed per kg of rock, 𝐵 𝑖 is the Langmuir isotherm parameter. This has been fit against field data from Yu et al (2017b) to determine the values in Table 2 (Sherratt et al 2020). The initial water saturation of fractures and the fracture porosity are also detailed in Table 2.…”

“…These complexities can be incorporated by using different approaches such as Embedded Discrete Fracture Model (EDFM) methods, or grid upscaling methods e.g., Fracture Upscaling Model (FUM) developed by Sherratt et al (2020) that are computationally fast.…”