Abstract
With the development of Daqing oilfield, mechanical wells are confronted with more complex influencing factors. And submergence depth is one of the most important indexes to measure working condition of the mechanical wells. However, methods to determine the optimum submergence in existing researches barely focus on oil production benefit, which should be further studied.
Theoretical Models for fluid production and water cut in the downhole are established based on the reservoir seepage law and well test data for multilayer commingled production wells. And distribution of pressure and flow rate in the wellbore are determined by iterative computing of multiphase pipe flow law, thus pump intake pressure is predicted, and the relationship of surface oil production and submergence depth is achieved. Furthermore, the influence of oil production revenue and well cost are combined into the working condition evaluation function of well oil profit, which shows a more reliable and accurate optimization direction for oil wells.
Methods and specific procedures for determining the optimum submergence depth for the oil well based on the working condition evaluation function of well oil profit have been introduced. In the case of oil well Y1, the optimum submergence depth is 198m, and the optimum oil profit is 2980 RMB, and a reasonable submergence depth region ranges from 100 m to 300 m. Generally, the method has taken influencing factors such as oil production, mechanical electrical consumption and oil profit into consideration, which shows a higher accuracy.
In the paper, methods of working condition evaluation function of well oil profit have been introduced, which have taken more influencing factors into consideration, showing advantage of individual well optimization design aiming to provide a more reliable and accurate technology support for high efficient development of oil wells.