Study On The Characteristics Of Oil Well Inflow Performance Under Complicated Flow Condition

Well inflow performance refers to the relationship between well production rate and bottom hole flowing pressure, which reflects the fluid supply capacity of reservoir to oil wells. In this paper, on the basis of a widely investigation on related literatures, according to the permeation fluid mechanics theory, two-phase flow theory and reservoir numerical simulation method, characteristics of oil well inflow performance under complicated flow condition including commingled production in multi-layers reservoir with vertical well, horizontal well producing with single-phase or gas-liquid two-phase flowing in reservoir and wellbore were studied. Theses studies provides a theoretical foundation for reasonable choice for oil production methods, optimization of production parameters, analysis of well inflow performance, establishing stimulation measures and its effect evaluation. Applying of permeation fluid mechanics theory, commingled production inflow performance model in multi-layers reservoir with cross flow in vertical well was established, and validation and analysis of the model was done using reservoir numerical simulation method.Using conservation of energy, conservation of momentum and mass conservation law, a single-phase and gas-liquid two-phase variable mass flow pressure drop model of horizontal wellbore were is established. According to quality and pressure continuity equation, variable mass flow in horizontal wellbore and reservoir seepage were coupled under single-phase and gas-liquid two-phase conditions respectively. The variation characteristics of pressure drop in horiztontal wellbore, the distribution of influx along horizontal wellbore and the inflow performance relationship were investigated with models above. According to Petrobras's weighted average method of oil and water, a inflow performance relationship prediction model for three phase flow of oil, gas and water was established on the basis of modified dissolved gas drive reservoir inflow performance equation. And using the model, inflow performance relationship of oil, gas and water of horizontal well was studied.