A Novel Characterization and Evaluation Method of Flow Field and its Application

Abstract

Abstract At present, most of the oil fields in eastern China have entered the stage of high water cut development, with a comprehensive water cut of over 90% and an oil recovery of less than 30%. To improve oil recovery, the flow field must be described qualitatively and quantitatively, so as to provide a basis for the formulation of measures. This paper proposes two categories of indicators: one is a guideline for developing measures, including streamline bundle properties, and the other is an indicator for evaluating the effects of measures, remaining oil dispersion (ROD) and dynamic heterogeneity included. Through numerical simulation methods, the regularity research and adaptive evaluation of each flow field characterization indicator are carried out. Finally, according to the streamline bundle properties of block E, the liquid rate of injection and production wells were optimized, and the effectiveness of the optimization was evaluated. The study found that under the condition of fixed well pattern, the streamline bundle flow (SF) between wells is relatively stable, and the change in streamline bundle potential (SP) and streamline bundle oil cut (SOC) tends to decrease with time. The typical curve of ROD generally includes four stages, and the effectiveness of measures is judged by the trend of ROD. For dynamic heterogeneity, the change curve generally includes unstable stage and stable stage. The value of the stable stage value can reflect the heterogeneity of the flow field. The larger the value, the stronger the heterogeneity of the flow field. According to the streamline bundle properties, three liquid rate optimization strategies, which are streamline bundle flow method (SFM), streamline bundle potential method (SPM), and streamline bundle oil cut method (SOM), are proposed, and the effectiveness of the measures is evaluated using ROD and dynamic heterogeneity. After liquid rate optimization, the ROD of the reservoir in Block E increased and decreased later, the Lorentz coefficient decreased, and the recovery increased by 3.76 percentage points. It provides a new technical means for the adjustment and evaluation of the flow field in the later stage of high water cut oilfield development.