Deployment of Produced Water Re-Injection; A Tale of Operational Excellence Where Challenges are Realized into Opportunities

Abstract This paper presents the full-scale implementation of Produced Water Re-Injection in ADNOC Onshore's largest Oil Producing Field. The paper also engulf the comprehensive detailing of the significant deployment milestones right from the selection, defining, successful pilot demonstration leading to a full-scale re-injection of 95000 BWPD produced water. This paper also penlights the challenges encountered during the course and states how challenges were realized into to the opportunities and waste stream was converted to game changer in reservoir pressure support and sustainability drive by eliminating the need of 19600 MW/year of electrical power and 30 Metric Ton of CO2 / Year. Normally, produced water is considered as waste stream and is disposed to shallow reservoirs. The selection process of various treatments options, identification of suitable reservoir and philosophy of full-scale deployment was executed in three stages: Sub-surface evaluation to define the required produced water specifications to sustain PWRI whilst managing the fracture growth. Surface infrastructure & technological requirements to deliver the required specification, along with the facilities configuration, plot sizes and network to handle the current produced water volumes as well as productions profiles projections to cater future requirements. 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 different formations and physical measurements from core flood tests, predictive runs and sensitivities collection were utilized to finalize the mode of re-injection to fractured injection. Facility was than designed 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 earlier the premier source of reservoir pressure support was replaced with Produced water volumes of 95000 BWPD, which was being dumped in the disposal wells. 05Electrical submersible pumps stopped with the change of source, resulted in saving of 1.27 MM USD in terms of power tariff and 30 Metric Ton eq. CO2 / Year, facilitating ADNOC in meeting sustainable operations mandates. This paper also demonstrates how the system can reduce the aquifer water consumption, increase the oil recovery factor, minimize the environmental impacts, and optimize the operational costs. Technical challenges and solutions for designing, installing, and operating the system along with an insight about harnessing a new technology right from the concept to full scale implementation covering all major phases e.g. Concept, PoC, Pilot Demonstration, Business Case Study, detailed engineering, execution, realization fiscal benefits in terms of CAPEX, OPEX value addition towards the ESG realization. The paper also highlights lessons learned and best practices for future replication by other Oil & Gas Producers.