Production Optimization using Multiphase Well Testing: A Case Study from East Kalimantan, Indonesia

Abstract

Abstract A multiphase flow meter named PhaseTester has been developed for determining oil, water, and gas production rates simultaneously. This new approach of well testing delivers significantly improved data quality and availability, allowing quick well performance trend analysis and immediate well diagnosis. Rapid, accurate production diagnosis allows timely decisions without prior well information or standard rate stabilization periods resulting in shorter, more reliable well tests stored in an easily accessible, user-friendly database. The PhaseTester provides a comparatively lighter operation unit and reduces risk of human error resulting in improved safety. Compared to conventional units, the physical size of the PhaseTester is usually half the size and the extensive pressure lines and safety devices are reduced. The meter is environment friendly since all the well effluents are returned to the production flowline without the need for separation or burning of hydrocarbons during the test. Obtaining periodic, accurate well test measurements is the key factor in Vico Indonesia Indonesia's well production optimization. The PhaseTester was introduced to monitor and optimize the production performance for gas lift wells. Changes in well performance were observed immediately allowing the operations engineer to quickly analyze the production characteristics and make decisions based on true accurate real time test data. Selected case histories demonstrate the results of these tests. Introduction Vico Indonesia operates the Sanga-Sanga Block in Indonesia as a Production Sharing Contractor to PERTAMINA, the Indonesian National Oil Company. The Sanga-Sanga Block is located in the Mahakam delta of East Kalimantan, Indonesia (Figure 1) near the city of Balikpapan and consists of four major fields producing approximately 1.3 BSCF/d of gas and 50,000 STB/d. Periodical well testing is the key factor in monitoring well performance. Two conventional trailer test units have been used for the past three years resulting in testing on average only two wells daily. The PhaseTester provides the freedom to acquire more daily well tests. The unprecedented ability of this multiphase flowmeter to accurately perform instantaneous flow rate measurements in challenging slugging flow conditions allows operations engineers to evaluate in real time the effect of small production setting changes (choke sizes, gas lift volumes and pressures, etc.). A gas lift performance curve can be generated rapidly and the operator can leave the well on the maximum production setting immediately after the test. Multiphase well testing provides well data in a digital format that can be interpreted and stored quicker than a standard test separator. The fast acquisition systems monitor a well's 'heart-beat' throughout the test displayed in real time. This provides the capability to detect production trends as they occur allowing the user to terminate testing as soon as adequate information is obtained rather than analyzing data after a pre-determined test period. Fluid property or flow regime changes do not affect the flow rate measurement.