Numercal Analysis For Solid-liquid Two-phase Flow Field Of Jet Pumps Used In Draining-sand Of Petroleum Well

When the oil flows into the petroleum well, some fine sand with the oil enters into the petroleum well at the same time. Then the fine sand is deposited on the bottom of the petroleum well. The production capacity would be reduce or all disappeared with the fine sand deposited. The fraying effect would be generated as the fine sand that enters into the interior of the oil extraction equipment. The oil extraction equipment would be badly frayed by the fine sand. So it is necessary to wash wells for cleaning out the fine sand. For the fraying effect, the mechanical pump used for washing well and cleaning out the fine sand has been strictly limited. For the jet pump has not any moving mechanical parts, the fraying effect could be furthest decreased. So the jet pump is the most effective equipment to wash oil well for cleaning out the fine sand.As the development of project, jet pump has been put forward higher requirements in all aspects of performance. Although the jet pump used in oil production has been very mature, the single-phase flow theory isn't applied to jet pump for draining sand, while the solid-liquid theory should be used. For the performance research was little in the solid-liquid two-phase flow of jet pumps, it is very necessary to research the performance of draining sand jet pump. As the complex flow field of jet pump and the low efficiency of energy transfer, which are caused by mixd loss in washing well, the application of the jet pumps has been restricted. Therefore, the numerical analysis for the solid-liquid two-phase flow field of the draining-sand jet pump is in order to improve the efficiency of washing wells and optimizing structural parameters of jet pumps.This paper is relied on the cooperative project "The Optimization of Structural and Process Parameters for Jet Pumps Used in Petroleum well" between Jilin university and Liaohe Oilfield, mainly studies the structural parameters of jet pumps and the ability of draining sand. The main contents are as follows: (1) Combined with the project, the working system of draining sand jet pump is illustrated and the structure and working principle of draining sand jet pumps is introduced. Then the basic technical parameters of draining wells are enumerated, and the theoretical foundation for numerical analysis of jet pumps is laid.(2) Based on the characteristics research of draining sand jet pump, the basic characteristics equation of jet pump is established, the optimal area ratio and the maximum pressure ratio, which is accord with the actual operating conditions, are obtained, and the structural parameters of nozzle and throat optimized are obtained. Theoretical results show that when the area ratio is 0.719, while the diameter of nozzle is 6.268mm, the diameter of throat is 7.392mm, draining sand jet pump has high pressure ratio.(3) The calculation for flow field has been determined by CFD; the three-dimensional model of jet pump has been established, while the calculation mesh and boundary conditions have been set; then the numerical analysis for solid-liquid two-phase flow field of draining-sand jet pump has been calculated.(4) The performance of draining sand jet pump is analyzed for each diameter combination of nozzle and throat by simulation results, in order to find out optimal diameter combination; then the angle of the diffuser and the flow fields of diffuser outlet have been analyzed in order to optimize the outlet structure.(5) Based on the simulation, the internal flow field flow mechanism of jet pump is studied in detail. The numerical analysis results show that inlet pressures, solid phase ratio, velocity distribution, pressure distribution, are contrasted with each other. To reduce or eliminate the contrary velocity vector of the solid-liquid two-phase flow and to increase the range of the vacuum are the key techniques for improving the comprehensive properties of the draining-sand jet pump by optimizing the diameter fitting of the nozzle and the throat.(6) Based on the simulation, the performance experiments and production experiments had been executed. The results show the feasibility of experimental methods. It was improved that the theory design methods and CFD can be used for the design and research of the draining-sand jet pump.Based on the analysis and numerical solution for solid-liquid two-phase flow field of jet pump used in the draining-sand of petroleum well by CFD, the key factors which affect the performance of jet pumps are analyzed. Then, the structure of jet pumps is optimized according to the numerical analysis results. It shows that the numerical analysis method and theoretical design method are significantly for the structural design and research of draining-sand jet pumps...