关键词: 水平井, 非稳态, 压降, 裂缝

Abstract: An unsteady model of fractured horizontal wellbore coupling with a box-shaped reservoir is constructed with consideration of anisotropy in a low permeability reservoir. Solution of the model is shown. Pressure drops of friction and acceleration are considered under different types of constraints. Flow condition in fractured horizontal well is divided into early transient period and pseudo-steady period. In transient period, the output from each fracture differs little, and total production rate increases linearly with fracture number. In pseudo-steady phase, production rate of fractures at the toe and heel is higher than that in the middle. Fractures in symmetrical position have different yield due to frictional and accelerational pressure drops. Pressure loss along the wellbore results in decrease of production in horizontal well and non-uniform distribution of pressure in wellbore. Under constant flow rate followed by constant bottom-hole pressure constraints, production plateau stays longer with increase of fracture number.

Key words: horizontal well, non-steady state, pressure drop, fracture