An Integrated Approach To Production Optimization In Ageing Gas Lifted Fields- Ikanto Field Experience

In many ageing fields, there is a constant need to optimize production performance of the wells to ensure that they continue to deliver value. As a field matures, with high water and sand cut production from the wells, water breakthrough from water flooding projects and other artificial pressure maintenance programs, the produced fluid water cut and gas-oil ratio will be changing. For such fields, the optimal use of existing surface facilities is critical to sustaining and increasing well rates leading to a corresponding reduction in production costs. In the Ikanto field, Gas Lift is the preferred artificial lift method, and has been so for over twenty years. However, with increased water production from the wells, the field separating train is faced with handling produced water in the separator train. Other challenges in the gas lift system including obsolete field metering equipments, meter calibration and maintenance challenges, etc, have impacted optimization opportunities from the gas lifted wells. The resulting consequence is the inability to fully determine optimal lift gas injection rates if the lift gas injection into the well is over or under-injected in line with advised lift gas rates from well performance models. An important input for gas lift optimization is the volumetric flow rate of injection gas. This data can help experienced Production engineers and field technicians determine if the lift gas injection into the well is optimal, thus providing directional guidance on what change(s) should be made to improve the well performance. In order to ensure that the asset value is enhanced, an integrated approach to maximizing production from the field was deployed ranging from the upgrade and automation of the existing gas lift infrastructure in the field vis-à-vis carrying out gas lift system optimisation, carrying out de-bottlenecking of parts of the production system, and the installation of real time surface monitoring systems. In this paper, the results of the optimization efforts in the Ikanto field are discussed. The analysis of the results has resulted in an upscale of total daily production from the field by over thirty percent (30%).