Increasing Oil Production With Jet Pumps by Reducing Pressure Losses in the Jet Pump-Sliding Sleeve Coupling

Abstract

Abstract The pressure losses in the jet pump–sliding sleeve coupling were calculated for the typical completions of wells that produce using hydraulic pumping in the Ecuadorian oil fields. A new jet pump was designed to minimize losses. The field test results showed a significant increase in well production compared to those obtained with a conventional jet pump. Several studies have proposed improvements in jet pump efficiency by optimizing the nozzle, throat, and diffuser geometry. However, they have not considered possible flow restrictions once the fluid leaves the jet pump and goes through the sliding sleeve where the pump is seated. Therefore, computational fluid dynamics (CFD) simulations were performed to analyze the flow through the pump–sliding sleeve coupling in completions with 3.5 in. tubing string and 3.5x2.81 in. sliding sleeves. The simulations were run for different discharge flow rates from the outlet of the pump diffuser to the entry into the annular space. Excluding the characteristic energy losses of Venturi systems, the largest pressure losses were found in the flow through the pump-sliding sleeve coupling. This is because the pump discharge is located below the ports in the sleeve, and to reach the annular space, the fluid must pass through narrow conduits generated by the closing sleeve. Pressure losses in this zone are greater than 40 psi and increase with discharge flow. With these findings, the jet pump was redesigned to align the discharge flow with the ports in the sleeve and minimize pressure losses. The new design was installed in the X1 well of the Ecuadorian state oil company, which was producing 2,318 BLPD with a conventional jet pump. The new pump was installed with the same nozzle-throat combination and was driven with the same hydraulic power. The reduction in pressure losses in the pump-sliding sleeve coupling resulted in a 9% increase in the production of the well. Sliding sleeves were not designed to hold jet pumps. Although this practice has facilitated reestablishing the production of wells with hydraulic pumps using the existing completion, the inefficiency of the pump-sliding sleeve coupling would not allow the productive potential of the wells to be realized. The new jet pump presented in this article eliminates these problems.