Research On Gas-liquid Two-phase Flow Characteristics And Its Application In Downhole Separation System

Gas well fluid accumulation caused by floodout is the important problem to restrict nature gas exploitation. To solve the problem by using dewatering gas production is a availability method. Application convention gas well production with water withdrawal technics was that accumulated water is lift to ground. And the gas-liquid mixture of ground handling, water injection back formation. So there are more equipment, investment, environmental pollution and other issues. From clean, low input, high output perspective, the development of a cost-effective, simple, can be achieved downhole gas-liquid separation and water injection system.Gas-liquid separation devices are important parts of downhole gas-liquid separation system, its advantages and disadvantages of a direct impact on the performance of the system's efficiency. Combination of oil and gas production practice, according to the law of gas-liquid two-phase flow movement theory and experimental research of separation devices are carried out. Based on Euler-Euler's theory, taken into account gas-liquid two-phase inter-penetration of alternate coupling, obeyed adiabatic equation in separation process and assumed gas compressibility that the two-phase flow model of gas compressibility is established. On this basis, the application of Reynolds-averaged treatment methods, can be obtained solving the control of gas-liquid two-phase equations. According to renormalization group ideas derived through the mathematical derivation rotating gas-liquid two-phase turbulence modified equation model.Established by the use of gas-liquid two-phase turbulence model for the downhole separation equipment to carry out numerical simulation of gas-liquid separator velocity field, pressure field and the two-phase distribution of the analysis and structural changes on the flow, pressure drop and separation efficiency of affect the relationship. On this basis, we can launch a downhole gas-liquid separator design of structural optimization to determine the suitable for downhole separation of gas-liquid separator structure. The downhole gas-liquid separator performance carried out that test result of the study show that the simulation results in considering compressibility of gas with the experimental results better match.According to characteristics of flow around with gas-liquid two-phase, numerical simulation and experimental research of exhaust were carried out with single-media and gas-liquid two-phase,.respectively. The distribution of flow field characteristics and the characteristics of the ball float force were analysised under the structural parameters (ball float diameter, damping hole diameter, base diameter), operating parameters (flow rate, liquid volume percentage content) change so that the structure of optimized exhaust. Through experiments and numerical simulation analysis and comparison, both results agree that the establishment of mathematical model and numerical calculation method is feasible.Based on the above study to determine the structural form of downhole separation system presents ,proposes downhole gas-liquid separation and produced water re-injection technology, new process, and formed a hollow rotor screw pump and an improved gas-liquid separator for downhole separation of the core hole re-injection system, gas-liquid taken out for the separation and return to power is through a water booster pumps to achieve the hollow rotor, the separated gas from the casing to adopt out, down-hole separation out of the water through the hollow rotor screw pump provided by the re-injection channel re-injection, two flooded wells in the oil field has been successfully applied.