Lessons Learned from First Application of Polymer Dispersed System (PDS) Chemical Water Shut-Off Technology in Carbonate Reservoir: A Case Study for Water Production Management in Mature Oil Field, UAE

Abstract Excessive water production in oil reservoirs is a common challenge in mature fields, reducing oil recovery efficiency and increasing operational costs. Chemical Water Shut-Off (CWSO) techniques have emerged as a promising solution to control unwanted water production, thus enhancing oil recovery and extending the productive life of reservoirs. Through a detailed case study, laboratory experiments, and a comprehensive workflow, the key selection criteria was investigated for applying Chemical Water Shut-Off (CWSO) treatment within heterogeneous carbonate formations. This examination focused on the use of advanced Polymer Dispersed System (PDS) technology, which offers enhanced selectivity and efficiency in controlling unwanted water production. The workflow guided the diagnostic evaluation of water production sources, the design of tailored treatment plans, and precise chemical placement techniques. Overall, this study will demonstrate the application and evaluation of the first CWSO treatments using the PDS technology in one of the mature oil fields in UAE. This new technology was applied in one oil producing well in Onshore, UAE where the well was producing with more than 90 % W.C and low oil production. Reservoir characterization, PLT and other diagnostic tools were utilized to design the job using new chemical technology. The pumping schedule and chemical amount was optimized during the job. However, a deviation from the planned injection program was necessary due to concerns for increasing bottomhole pressure, likely the result from different reservoir properties than expected from data analysis. Comprehensive pre and post job monitoring was utilized for assessing the treatment's effectiveness. This monitoring includes tracking reservoir response, production changes, and the movement of fluids within the reservoir. The analysis and lessons learned are presented to optimize the planning of future water shut-off jobs in the same reservoir. Our findings demonstrated that the success of CWSO is highly dependent on proper diagnostic evaluation, precise chemical placement, and pre/after job monitoring. When executed successfully, CWSO can significantly enhance reservoir performance by reducing water production, improving oil recovery, lowering operational costs, and extending the productive life of oil fields.