Large Scale Jet Pump Performance Optimization in a Viscous Oil Field

Abstract

Abstract This paper discusses the performance monitoring and optimization of large scale jet pumping in Mangala field, one of the biggest onshore fields in India. Mangala field is characterized by multi-Darcy sandstones, containing waxy and viscous crude oil. Currently, the field is producing at plateau of 150,000 BOPD. The base development plan for the field included hot water flooding; this also makes water heated up to 80 °C available at the well pads as power fluid for jet pumping. Jet pump was selected as the preferred artificial lift method in deviated wells, as it addresses all flow assurance issues arising due to high wax appearance temperature of Mangala crude. Jet pumps provide the required drawdown for sustained liquid production both at low and high water cut. With significant number of wells operating on jet pump, it has become crucial to monitor the performance and optimize for maximum efficiency application by varying operating parameters, changing the nozzle throat combinations and making other adjustments. Currently, Cairn is monitoring the real time jet pump operating parameters on a daily basis by virtue of DOF (Digital Oil Field). DOF has not only eased the tedious task of jet pump monitoring in bulk but also has reduced the response time to any failures/damage in the pump. Liquid handling capacity of the processing plant has become crucial with increasing field water cut and more jet pump installations. Jet pump performance optimization for maximum efficiency has now started to play an important role in not only reducing the burden of the processing facility but also in improving the production profile of the wells. This paper will discuss the use of a methodology based on an in-house developed algorithm for monitoring the efficiency of the pumps, with supporting field examples. This paper will also make an attempt to analyze the effect of different operating conditions on the pump performance curves published in the literature.