Study on injection performance of horizontal water injection well with segmental perforation

It is very difficult but valuable to determine the injection rate and pressure drop distribution of each perforation intervalat given injection rate at surface. This paper develops a 3D steady state flow model of horizontal wells in closed reservoir. And theFourier transform, principle of potential superposition, trigonometric function transform and asymptotic analyses are used to solveits solution of pressure and rate distribution. Compared with injectivity of vertical wells, an equivalence radius model of horizontalwells with uniform flux can be obtained. By the use of multi-well superposition principle, the paper also develops a flow distributionmodel of horizontal wells with segmental perforation and infinite conductivity, and obtains flow rate distribution in each perforationinterval by Gaussian elimination. Then it analyzes the pressure drop of horizontal injection wells. Vital example demonstrated that alonger interval or length of perforation interval always has a larger pressure drop around it when the other conditions are identical.The pressure drop around the interim interval is little smaller than that in the end intervals in same condition. The near wellbore zonein horizontal wells with segmental perforation is easily to form near linear displacement system, especially with such perforationmode that interim interval has a larger length than that of end intervals. This method can quantify the injection rate of each perforationinterval, laying a foundation for the analysis of injection effect and producing degree of surrounding oil wells.