Abstract
In 2017, a change in the environmental agency IBAMA's understanding of Total Oil and Grease (TOG) analysis for produced water discharge into the sea mandated the reinjection of produced water in six production units in Marlim Sul and Roncador fields. Platforms not originally designed for reinjection underwent topside adaptations for additional treatment and necessary interconnections to blend produced water with sea water for injection into wells. Failure to achieve this goal could result in production losses of up to 250 thousand barrels per day, leading to platform restrictions and shutdowns due to the inability to dispose of produced water. When injected into the reservoir, produced water impurities cause injector well plugging, resulting in reduced field injection capacity. Hence, platform adaptations included a project that reconciled platform limitations with reservoir requirements. Acid treatment of injector wells and restoration of injection capacity involved installing supports and connections on the platform's side to perform acidification by directly connecting stimulation vessels to the production unit. This adaptation allows interventions without the need for a rig, substantially optimizing costs and downtime of injector wells. Innovatively, geomechanical studies and simulations were conducted to enable mechanical well stimulation operations through pressure pulses. This maneuver, independent of external platform resources, incurs no additional costs. By manipulating flow and pressure variations in wells, controlled reservoir fracturing is induced, resulting in a significant 50% increase in injectivity in many cases. This measure yielded approximately USD 10 million in savings by optimizing acidification costs with vessels and preserving the potential of producer wells through sustained injection. This work illustrates the outcome of a proactive field management approach, the application of technologies, innovative practices, and the optimization of production/injection in Petrobras' Marlim Sul and Roncador mature fields.
