Production of Waxy Low-API Oil from Deep Exploratory Well with Hydraulic Lift System - A Case Study

Abstract

Heavy oil makes up approximately 15% of the world's remaining oil reserves. It offers opportunities that could be commercially viable and often rejected because of the inherent challenges of production. The main challenges for producing heavy oil include flow assurance, produced water separation and treatment, and additional heat and power requirements. In this project, a deep heavy oil well which did not produce naturally during Drill-Stem-Testing (DST) was efficiently revived using jet pump technology.

This paper presents the successful application during a pilot test in which hydraulic jet pumping technology was installed in a deep exploratory well to lift the heavy 11.5° API oil. The candidate well was a single-string completed well flowed from Sakessar-formation at negligible production rates during DST by nitrogen kick-off. Considering the preliminary testing results, jet pump (JP) technology was recommended as the suitable artificial lift (AL) method. The sliding-sleeve-door (SSD) was deployed as a part of initial completion and downhole JP was fabricated as per SSD dimensions. The pump was installed by slickline in the SSD housing and operated to assess the lifted production.

The light crude oil was used as the power fluid during initial phase of pumping. Later, produced fluid was re-injected for continuous lifting operation. The real-time monitoring was carried out for optimizing the parameters of the pump, such as injection parameters, nozzle-to-throat combination, and horsepower. The results of this pilot project demonstrated the successful implementation of jet pump on heavy oil reservoirs. The candidate well produced at an average rate of 300 BOPD at the injection rate of 2,750 BPD with injection pressure of 2,500 psig using an 11X nozzle-to-throat combination. The SSD JP installation was found to be an ideal method to lift heavy oil from the reservoirs, which did not produce by its natural energy. Further, when the well production will decline in future, operators can easily re-optimize JP performance by retrieving it using a slickline for modifying the nozzle and/or throat and re-adjusting the surface injection parameters. The hydraulic lift system enables the operator to improve production while conducting multiple rigless jobs and saving workover cost.

The key objective of this pilot test was to produce heavy oil with minimal OPEX in a deep well. The successful implementation and outcomes of the project identified dynamic applications of the hydraulic lift system technology. This confirmed jet pump as a proven well activation and lift solution even for low API crude and can be used on global practice.