Pressure transient analysis of non-planar asymmetric fractures connected to vertical wellbores in hydrocarbon reservoirs

Abstract

The paper developed a new constant-rate solution for non-planar asymmetric fracture connected to a vertical wellbore in hydrocarbon reservoirs. The non-planar asymmetric fracture has been modeled by combination of two unequal length wings with varied intersection angles. The type curves were drawn in the case of varied fracture conductivities, non-planar angles, and asymmetric factors. The results indicated that fracture conductivity, non-planar angle, and asymmetric factor have coefficient effects on the pressure response, which makes the dimensionless wellbore pressure and pressure derivative curves deviate from the conventional type curves of vertical fractured wells. The dimensionless wellbore pressure and pressure derivative curves are divided into five flow periods. The non-planar angle and asymmetry factor have their unique influences on the shape of type curves during different periods under the different fracture conductivities. The termination of bilinear flow and formation linear flow happened increasingly early with the decrease of non-planar angle or the increase of asymmetry factor. As the fracture conductivity increases, the effect of non-planar angle on the curves moves from the early flow period to the late flow period while the trend of effect of asymmetric factor is quite opposite. The new method lays the foundation of the pressure analysis of the complicated fracture system in developing hydrocarbon reservoirs.