| In the process of oil well exploitation,the sand particles in the oil layer are scoured by the fluid,and some of the sand particles will separate from it and enter the oil well with the fluid,thus forming the sand settling in the well.There are two main factors that influence the oil recovery rate:one is the accumulation of sand in the well,which will block the oil reservoir,reduce the oil production rate of the well or even not produce oil;on the other hand,with the oil flowing into the fine sand of the oil recovery equipment,it will cause the wear of the oil recovery equipment.Because of this reason,using mechanical pump to wash well and wash sand is restricted strictly.Jet pump is a kind of pump without mechanical moving parts,which can minimize the wear of the equipment caused by the sand particles in the oil fluid,so it has become an effective equipment for well flushing and sand drainage in the oil field.Jet pump has the advantages of reliable operation,simple structure,safe and convenient use,but also has the disadvantage of low efficiency.Therefore,it is of great significance to study the working principle of jet pump and improve its performance and efficiency.In this paper,based on the study of jet pump and solid-liquid two-phaseflow,the working principle of jet pump is analyzed,and the influence of different geometry and operation parameters on the performance of jet pump is studied by numerical simulation.The main research contents include the following aspects:(1)This paper studies the existing sand flushing technology of oil well,summarizes the research status of jet pump and solid-liquid two-phase flow,and innovates the design and structure in view of the low efficiency of the existing jet pump.A sand disturbing nozzle is added under the original jet pump to impact the sand settled at the bottom of the well and increase the working efficiency.(2)In this paper,the sand washing system of jet pump is studied theoretically,the main structure and working principle of jet pump are studied,and the main parameter definition of double nozzle jet pump is given.According to the formula derivation,the basic characteristic equation of jetpump is obtained,and the theoretical characteristic curve of jet pump is drawn.(3)The structure design of the improved jet pump sand washing system is carried out.The main components such as the upper and lower nozzles,the throat and the diffusionpipe are selected and designed according to the work requirements and the formulas summarized by various experts and scholars.At the same time,the overall design and three-dimensional modeling of the jet sand washing device are carried out.(4)The basic knowledge of computational fluid dynamics is studied.The knowledge of multiphase flow model,turbulence model,boundary condition and algorithm involved in the process of software numerical simulation is studied.Using the software,the grid division and numerical simulation of the device are carried out,and the accuracy of the simulation is verified.(5)By using numerical simulation method,the sand flushing conditions of different sand gravel diameter,nozzle diameter,confining pressure,flushing fluid type and other parameters are simulated,and the volume fraction of sand particles in the well is monitored.Carry on the jet sand flushing simulation experiment,and compare with the numerical simulation result,draw the reasonable conclusion. |
PDF Full Text Request