A NUMERICAL STUDY OF PARAMETER INFLUENCES ON HORIZONTAL HYDRAULIC FRACTURE
Horizontal fracture is the most common fracture configuration during hydraulic fracturing treatments in reservoirs at shallow depth.The practical exploitations in a main producing area of Daqing oilfield demonstrate that the majority of the hydraulic fractures is horizontal.The reservoir around a well in the area is simplified as a layered porous medium.The corresponding 3D finite element model is set up with the ABAQUS software and related user subroutines.The tube,cement sheath,perforation,pay zone and barrier layer are included in the model.Fluid-solid coupling solid elements are used to describe the mechanical behavior of rock and cohesive elements are employed to simulate the process of fracture initiation and propagation.The fracturing treatment of the well is simulated with the model.The formation parameters and physical property parameters in simulation are adopted from Daqing oilfield.The time history curves of the pressure at the fracture mouth from numerical simulation are in good coincidence with those obtained from the field measurements.The correctness of the proposed model is validated.The influences of major geological parameters and treatment parameters on horizontal fracturing are studied.The concerned parameters include in-situ horizontal stress contrast,permeability,elastic modulus,injection rate and viscosity.