Maximizing the Value of Gas Lift for Efficient Field Development Plan Optimization Through Smart Gas Lift Optimization in a Giant Onshore Carbonate Oilfield

Abstract

Conventional gas lift optimization methods in reservoir simulation prioritize naturally flowing wells over wells requiring gas lift to meet production mandates. However, maximizing the value of gas lift wells may unlock significant untapped reserves. This paper presents the application of a Smart Gas Lift Optimization (SGLO) workflow on a complex giant onshore carbonate oilfield to maximize production and recovery through an efficient gas lift optimization method. The Smart Gas Lift Optimization consists in restructuring the well group hierarchy to define parallel structures for naturally flowing wells and gas lift wells to enable existing wells with gas lift to be produced with a higher priority, hence maximizing their production potential using gas lift optimization. Wells meeting certain conditions defined on production, gas-oil ratio, water cut, or pressure would be automatically assigned to the different entities of the gas lift group structure to maximize their production and enable the gas lift optimization mechanism to obtain the most optimal gas lift rate under the constraints specified. The workflow was applied on a giant onshore carbonate oilfield with a complex structure and a very high well count through an automated tool that was developed for setting up the full SGLO workflow by automatically parsing reservoir simulation model input files and define the required group structure, along with all necessary settings for gas lift optimization and SGLO. Results between the non SGLO case and the SGLO case were compared to assess the difference in production between these two scenarios. The SGLO case provided a substantial boost to the total oil production compared to the non SGLO case and the duration of the production plateau target was extended further. The gas lift optimization allocation is effectively allocating gas lift even if the production plateau is already reached and proposing a gas lift rate allocation that maintains the existing gas lift wells alive and improves the total reservoir recovery while reducing by-passed oil in place. The allocation prioritized to gas lift wells significantly increases the value of the existing gas lift wells that are pushed to their largest potential, reducing requirements for infill drilling. Although the Smart Gas Lift Optimization uses all the principles of regular gas lift optimization combined to an additional logic that triggers the gas lift wells to produce with an optimum gas lift rate based on an economic gradient defined. The tool was fully automated to apply the SGLO workflow in a matter of minutes even for a highly complex reservoir model.