Investigation of the characteristics of an oil jet pump when using a group ground drive
Panevnyk Denis, Kreheľ Radoslav
Abstract
A computer model of the working process of the pump-circulation system has been developed, which includes a series of downhole oil jet pumps and a group ground power drive. The design space of the pump-circulation system is presented as a combination of 3D models of the inlet and outlet collectors with a parallel connection of jet pumps located between them. Boundary conditions in the form of flow rates and pressures of the total working and mixed flows were set in sections before the inlet and after the outlet collectors. The productivity of the ground pumping unit varied in the range from 0.0037 m3/s to 0.01 m3/s, and the pressure in the characteristic sections of the jet pump is from 2.26 to 2.53 MPa. In addition to hydrodynamic parameters, the computational model takes into account the design of wells, the configuration of the flow path of jet pumps and the state of their working surfaces, the physical properties and flow regimes of interacting flows. The generated working space is used to construct a set of discrete volumetric elements, the placement density of which increases in high- gradient flow regions. Calculation procedures for three standard sizes of jet pumps are implemented based on the use of the finite element method with the help of SolidWorks software products. The distribution diagrams of velocities and pressures obtained by modeling are presented in the form of dimensionless regime parameters of jet pumps: ejection coefficient and relative pressure. The conducted studies have established the increasing nature of the dependence of the ejection coefficient of the jet pump on the performance of the ground pumping unit. With an increase in the productivity of the ground pumping unit in a given range, the value of the ejection coefficient increases from 0.12 to 0.52. The results of computer simulation were compared with the classical method for determining the parameters of mixed coaxial flows, based on the use of the laws of conservation of energy and flow continuity. The deviation of the flow characteristics of the jet pump, obtained using the proposed computer model and the classical laws of hydrodynamics, does not exceed 6.47%. The proposed model makes it possible to automate the process of designing optimal operating modes for a group hydro -jet oil-producing pump-circulation unit.