Overcoming Production Constraints by Enhancing PWRI Through Design Debottlenecking and Innovative Operational Methodologies

Abstract This paper demonstrates the real time challenges encountered during full-scale deployment of Produced Water Re-Injection in ADNOC Onshore's largest Oil Producing Field. The paper will illustrate the comprehensive detailing of substantial deployment milestones right from the selection, definition, evaluation, successful pilot demonstration and eventually to a full-scale produced water re-injection deployment of 100,000 Barrel/day. This paper also covers the design & operations related key challenges encountered during the execution and states how challenges were tackled and converted to opportunities and waste stream was converted to a enabler for reservoir pressure support thus enhanced operational sustainability by eliminating the need of 2.5 MW/hr of electrical power and 18000 Metric Ton of CO2 / Year. Following challenges were encountered during the course of 100% PWRI deployment: Uncertainties in production profiles.Facilities Bottlenecking.Fluctuation in composition.Presence of schmoo.SIMOPS and Construction in brown field without compromising the integrity and sustainable production rates. The detailed selection process of various treatments options i.e. selection of reservoir and operating philosophy of full-scale deployment was executed in three stages: Sub-surface evaluation to benchmark the required produced water outlet specifications, to maintain sustained produced water reinjection without impacting the fracture growth.Modifications of Surface Installations and technological screening to ascertain the required produced water specification, along with the facilities hookup requirements, plot plans and piping network to handle the current volumes of produced water as well as predicted productions profiles to cater future requirements due to maturity of Field and Gas lift phase - II.Troubleshooting of uncertainties encountered, Identification of opportunities and realization in OPEX optimization, reduction in downtime and sustainability implications.The potential of produced water re-injection under the matrix and fractured injection conditions was evaluated. Following the quantification of reservoir rock mechanical properties, determination of stresses in the different formations and physical measurements from the core flood tests, predictive runs and sensitivities collection were utilized to finalize the mode of re-injection to be fractured injection. Facility was than designed and PWRI network was established to cater the current produced water volumes at central processing facility as wells as future foreseen till 2030, to ensure re-injection into the reservoir for reservoir pressure support. Shallow Aquifer water previously the premier source of reservoir pressure support was replaced in phased manner with Produced water volumes of up to 100,000 BWPD, which was being dumped in the disposal wells. 05 Electrical submersible pumps stopped with the change of source, resulting in saving of 1.6 MM USD in terms of power tariff and 18000 Metric Ton eq. CO2 / Year, facilitating ADNOC in decarbonization of operations, meeting sustainable operations mandates and concerning shallow aquifer reservoirs. This paper demonstrates the novel methods of addressing the challenges and uncertainties encountered during the full-scale deployment of Produced water for re-injection. It reflects how this operational philosophy can reduce the aquifer water consumption, increase the oil recovery factor, Decarbonize the Operations and slashes the operational costs. The paper will provide an insight about managing uncertainties, design bottlenecking and harnessing new technologies from the concept to full scale implementation covering all major phases e.g. Concept, PoC, Pilot Demonstration, Business Case Study, detailed engineering, on ground execution, realization fiscal benefits in terms of CAPEX, OPEX and value addition towards the ESG realization. The paper will highlight the lessons learned and the best practices for future replication by other Oil and Gas Producers.