Integrated Water Injection Analysis for a Giant Brown Field

Abstract

Rejuvenation of mature assets plays a crucial role in current low oil price scenario, allowing improving production with limited investments and risks. Nevertheless, brown field rejuvenation is often very demanding in terms of complex integrated reservoir studies, mainly due to the huge mass, heterogeneity and reliability of available data. In this context, it is crucial to shortly identify the key parameters that allow to robustly detect the main flow paths in the reservoir, their current status and any possible optimization. An integrated workflow is proposed for brown fields where oil production is mainly driven by water injection. Produced water salinity plays a key role, acting as natural tracer whenever a huge contrast in salinity exists between formation and injected water. Production and geological data throughout all the different field deployment phases are deeply integrated. The outcomes are conceptual models where the evolution of fluid paths in time is clearly identified, providing a valuable support for both validating the geological vision of the reservoir and driving the dynamic model history match. Once the 3D model is available, streamline analysis is performed to verify its robustness, compute the efficiency of the current injection scheme and drive the deployment strategy optimization. This paper is focused on a mature Egyptian field characterized by an extremely complex heterogeneity, more than 60 years of production and about 500 wells drilled. The field is undergoing a rejuvenation process including water injection optimization and chemical EOR. Despite the amount of data, some uncertainty in the field behavior is still present, mainly due to the high impact of commingle production. Due to ESP well completions and similar oil characteristics in all layers, both PLTs and geochemical analysis could provide only a marginal support to the analysis. In this context, the proposed workflow allowed detecting the main connections without any additional data collection, thus reducing costs and timing. The results of the analysis improved the understanding of some critical aspects both on static and dynamic sides: validation of fluid contacts, well integrity issues, aquifer support, faults impact and commingle contributions. The results achieved show that in a framework characterized by the presence of a huge number of measured data, a systematic approach for their analysis and interpretation can help in extrapolating the main fluid paths from the complexity of brown reservoirs and thus providing a valuable support to speed up and optimize fields analysis and rejuvenation.