An interference well test method for the identification of high-consumption water zone

In order to accurately identify the high-consumption water zone which is formed in the reservoir in the middle and late development stages of water-drive oil reservoir, the reservoir with high-consumption water zone was treated as a double-layer oil reservoir from the point of reservoir percolation characteristics. According to the percolation mechanics theory and the superposition principle, a mathematical model for the interference well test after the formation of high-consumption water zone in the reservoir was established. In this model, the effect of high-consumption water zone on the pressure response of the observation well was analyzed, and sensitivity analysis was also carried out. Then, based on the optimization theory, a mathematical model for the quantitative characterization of high-consumption water zone was established by taking the minimum sum of squares of the difference between the measured value and the predicted value as the objective function. This model was solved by means of the genetic algorithm, and accordingly the parameters of high-consumption water zone were obtained, including permeability and volume. Finally, the steps for quantitatively interpreting the parameters of high-consumption water zone by means of the interference well test method were put forward. This method was applied on site in the Shengli Oilfield. It is indicated that this method is accurate and effective. The interpretation result is in better accordance with the interwell tracer test result, and the test period is shortened from several months to 1-2 weeks. The research results can provide the theoretical reference for the on-site identification of high-consumption water zone and the adjustment of development scheme.