Research of Productivity and Interlayer Interference Mechanism of Multilayer Co-Production in Reservoirs With Multipressure Systems

Abstract

Due to the differences in physical and fluid properties in vertical oil layers, the interlayer contradictions are prominent and affect the reservoir utilization degree seriously. Therefore, the coordination between reasonable bottom-hole flow pressure and optimal production, as well as the reduction of interlayer interference are the primary concerns during the co-production of multilayer oil reservoirs. Based on the reservoir engineering and fluid mechanics in porous media theory, this work adopts the comprehensive pressure system and considers the interlayer interference to establish a multibranch horizontal well productivity model and interlayer interference mathematical model. By analyzing the main controlling factors and interference mechanisms, this article demonstrates a pattern of interlayer interference and improves the quantitative characterization interlayer interference theory in multilayer combined mining. The study has shown that (1) the interlayer interference is beneficial for balancing the production of different layers and improving development efficiency, and it is greatly affected by interlayer heterogeneity; (2) when the number of layers exceeds two layers, the interference coefficient increases; with the increase of the layer thickness, the thicker oil layers have higher productivity, and the thickness of the layer has a significant effect on the production of low-pressure layer; as the viscosity difference increases, the interlayer interference coefficient becomes larger, and the contribution rate of high viscosity oil layer decreases continuously. When the production pressure difference increases, the interlayer interference can be reduced; (3) the interlayer interference mathematical model constructed in this article has high prediction accuracy and strong practicality, which has theoretical guidance significance for the division of strata in the comprehensive adjustment of reservoirs.