Investigation of the flow twist influence on the well jet pumps characteristic

Abstract

The scope of downhole ejection systems is limited by the low value of the efficiency of the jet pump, the value of which usually does not exceed 35 %. Significant energy losses when mixing flows are the reason for the low efficiency of the jet pump. The energy performance of the downhole ejection system can be increased by creating swirling vortex circulating currents in the flow part of the jet pump. This optimizes the nature of the flow mixing and increases the energy performance of the jet pump. In the process of studying the structures, features of the working process and usage experience of ejection systems designed for drilling, operation and repair of oil and gas wells, it is established that the twisting of the working medium in downhole jet pumps can be carried out using guide elements placed at a certain angle in the oncoming flow and rotation of individual parts of the ejection system by means of an external drive and hydraulic turbines. The use of guide elements and hydraulic turbines necessitates the use of part of the energy of the working flow, which drives the downhole jet pump, to spin the working medium. In oil and gas ejection systems, the twisting of working, injected and mixed streams can be realized, as well as the combined simultaneous twisting of several streams. In the process of analyzing the experience of using vortex jet devices, it has been found that the flow twist allows to increase the injection coefficient of the jet pump by 38.1 %, efficiency – up to 70 %, vacuum in the receiving ch amber – up to 40 %. The increase in the basic geometric pa-rameter of the jet pump reduces the effect of flow twist on the characteristics of the ejection system. Flow twisting in downhole jet pumps can be recommended in the implementation of long-term processes, for example, in the ex-traction of formation fluid, when the value of the efficiency of the ejection system significantly affects the cost of oil production.

Дослідження Гідравлічних Характеристик Свердловинного Струминного Насоса

“…According to the results of comparative analysis (Fig. 2) of the energy characteristics obtained using equations ( 9), (10) it is established that the twisting of the injected flow allows to increase the maximum value of the efficiency of the jet pump by 25 %. According to the obtained results, the value of the dynamic pressure caused by the twisting of the injected flow and the injection coefficient of the jet pump are directly proportional.…”

“…In the transfer of energy from a high-pressure working to a low-pressure injected flow, not only friction forces take part, but also centrifugal forces caused by the rotation of liquid particles, as a result of which jet devices acquire additional properties of dynamic pumps characteristic of the working process. In the process of analyzing the comparative efficiency of vortex jet devices, it is found that swirling the flow makes it possible to increase the injection coefficient up to 38.1 %, the efficiency up to 70 %, and the vacuum in the receiving chamber up to 40 % [10]. Despite a significant number of researches devoted to the working process of vortex jet pumps [11][12][13][14], the authors, as a rule, limit themselves to determining the experimental characteristics of ejection systems.…”