Dynamic Induced Fractures in Waterfloods and EOR

Abstract It is well established within the Industry that water injection mostly takes place under induced fracturing conditions. Particularly in low-mobility reservoirs or when injecting contaminated water (e.g. PWRI), large fractures may be induced during the field life. This paper presents a new modeling strategy that combines fluid-flow and fracture-growth (fully coupled) within the framework of an existing ‘standard’ reservoir simulator. We demonstrate the coupled simulator by applications to a model five-spot pattern flood model, and to a number of actual field cases (waterfloods, produced water disposal) worldwide. In these field cases, validity checks were carried out comparing our results with available surveillance data. These applications address various aspects that often play an important role in waterfloods, such as shortcut of injector and producer, vertical fracture containment, and reservoir sweep. We also demonstrate that induced fracture dimensions can be very sensitive to typical reservoir engineering parameters, such as fluid mobility, mobility ratio, 3D saturation distribution (in particular, shockfront position), positions of wells (producers, injectors), and geological details (e.g. flow baffles, faults). The results presented in this paper are expected to also apply to (part of) EOR operations (e.g. polymer flooding).