Breaking the Flow Barrier: An Innovative Data Driven Chemical Solution to Revive Failing Injection Wells in Oman

Water management in remote, arid oilfield locations is critically important for several reasons, including preserving scarce resources, reducing operational costs, ensuring regulatory compliance, and minimizing environmental impact. In areas, where water is a precious commodity, efficient water management is essential for sustainable and profitable oil and gas operations. Re-purposing produced water for re-injection into the reservoir for pressure maintenance and sweep efficiency ticks many of the desirable water management boxes, however this can come at a price, as produced water reinjection (PWRI) is often accompanied by troublesome flow assurance and injectivity challenges due to the complex nature of the salt-rich brine mixture. The study oilfield in Oman employs PWRI for reservoir pressure maintenance and waterflood sweep efficiency. The highly saline field water is generally calcium ion rich and contains other significant multivalent divalent scaling species and suspended inorganic particulates. The oilfield has an ongoing technical program for maximizing production which has yielded impressive results as each successive new production enhancement technology has been introduced, with further enhancements planned across the next 5 year period. Key to the successful exploitation of the 500+ wells draining the source Shuaiba reservoir are introduction of vertical and then horizontal waterflooding technologies, and an extensive ongoing reservoir flow path re-engineering and restructuring program using multiple relative permeability modification (RPM) and water shut-off (WSO) treatments. The next planned optimization project required water injection to increase from 10k to 20k BWPD and the field PWRI system is expected to play a key role in achieving this. The PWRI array performance to-date has been sub-optimal and this is mainly due to periodic well injectivity loss due to solids fouling issues occurring topside and downhole. An Injectivity Improvement taskforce was created to resolve the PWRI injectivity issues and meet the desired current and future injector uptime/injection performance targets. The project group initiated a 2-phased response to the injectivity loss issue; Phase (I) – comprised a comprehensive data-driven system review of the produced water system in conjunction with an intensive sampling and analysis program targeted at sensitive characterization of recovered fouling solids in the injection array via SEM, ICP and XRD.