Remaining Oil Characterization through Surveillance Data Analysis for a Mature Giant Sandstone Reservoir in Middle East

摘要

M reservoir is a mature giant sandstone reservoir in Middle East with more than 60 years' production history, which has been developed via natural aquifer support followed by peripheral water injection of low salinity waters. Understanding of water flooding swept characteristics can significantly improve the understanding of remaining oil distribution. This paper presents a detailed study on remaining oil characterization mainly based on surveillance data. Firstly, a workflow for remaining oil characterization mainly based on production logs and saturation logs are proposed. Then based on the surveillance data and the proposed method, lateral and spatial distribution of fluid saturation are gained by gridding surveillance data, and a series of predicted saturation maps by layer and by year are generated. And through comparison with saturation maps of different years, habitats of remaining oil are determined, and corresponding development strategies are proposed. In this study, more than 300 wells with saturation logs and production logs were tested within 5 years for M giant multi-layered reservoir. Maps of every layer of each year between 2012 and 2015in M reservoir for remaining oil saturation and pure oil thickness were generated, and remaining oil spatial distribution are also generated for each year respectively. The remaining oil change of different years illustrate the variability of waterflooding patterns, swept characteristics and waterflooding drive mechanisms. And habitats of remaining oil were also determined, and corresponding development strategy are also proposed. This study helps determine the locations of new wells and better development and adjustment strategy decision for mature multi-layered sandstone reservoir. Most importantly, the methodology presented can be adopted in other similar multi-layered sandstone fields.