Improving the Energy Efficiency of the Use of Borehole Jet Pumps

Abstract

The article presents rationales for choosing the depth of installation of an oil jet pump in the borehole that which ensures maximum efficiency of its operation. The operating parameters of the ejection system are determined by the joint solution of the characteristic equations of the high-pressure jet pump and the hydraulic system. In the process of solving the system of equations, the method of successive approximations, the Delphi software environment and PTC Mathcad resources were used. The equation of the characteristics of the jet pump hydraulic system was obtained by determining the pressures in its distinctive cross-sections and then presenting their values as the relative (dimensionless) head of the ejection system. Alteration the installation depth of the jet pump changes the characteristics of its hydraulic system, the parameters of the operating point of the pumping unit and its efficiency. In this case, the minimum permissible installation depth of the jet pump is determined by the value of the minimum pressure in the elements of the ejection system, which must exceed the value of the elastic pressure of saturated vapors of the oil and gas flow and ensure its operation in pre-cavitation mode. The probability of operation of a jet pump in cavitation mode was studied using the Bernoulli, Darcy – Weisbach and flow continity equations. The inversely dependence of the ejection coefficient and efficiency of the jet pump on the depth of its installation in the borehole has been revealed. If the jet pump is installed in the borehole at the optimal depth, its efficiency is increased by 30 %.

Keywords

• ejector technologies
• ejection system
• pump efficiency
• hydraulic system
• working point of the pump unit
• ejection coefficient
• cavitation in the jet pump