Implementation of Real-time Gas-lift Optimization in Dubai Offshore Fields

Abstract

Abstract Dubai Petroleum (DP) has recently deployed software interface systems to perform real-time optimization of gas lifted wells offshore. Prior to this, gas lift optimization was initiated manually and was done four times a year. This paper presents the various aspects of the real-time optimization project and the benefits that are coming out of the project. The real-time optimization (RTO) is a giant step forward as it helps optimize the asset more frequently. This also makes it possible to identify under-performing wells as and when problems develop. In the past this often took several days, in an offshore environment with manpower and logistics constraints. The benefits of the RTO system would include the following: As the RTO interface feeds the latest well data into the well models held in a live server, the optimization system estimates the expected production from the wells and automatically identifies wells that are sub-optimal in their performance. The system flags those wells for immediate attention.The well models get automatically calibrated whenever a new production test becomes available. The result of the well model calibration (success or failure) is communicated with details as required.The wells will be optimized more frequently, and with the less use of engineering manpower.Using the real-time optimization systems the daily production from the asset can be accurately predicted. Integrating with bulk metering systems, the production can be back allocated to specific wells and the source of downtime / loss identified.By linking the RTO system to corporate KPI's e.g. targets (or capacities) engineers and managers can at a glance check the performance of the asset againt key production targets and spot possible optimization opportunities. They can then drill down into individual wells for detailed analysis.Some level of reservoir monitoring can be achieved by using the allocated production and injection to calculate Voidage Reservoir Ratio over time and also look at cumulative injection and production and the net offtake in the reservoir. Real-time optimization systems add significant value in large complex gas-lift operating systems. The available gas compression capacity often changes due to equipment related problems, maintenance activities and ambient conditions. It has been proven that for minor system upsets it is more efficient to redistribute the available lift gas rather than shutting-in wells. The real-time optimization system provides the best way to manage the field with the available lift gas at any point in time. As the system calculates the production from the asset using the live data and recently calibrated asset models, the production back allocation is more accurate and reliable.