Representative Sector Modeling and Key Factors Impact on Waterflooding Performance of a Large Multi-Layered Sandstone Reservoir

Abstract M1 reservoir is a large multi-layered sandstone reservoir of deltaic environment with oil bearing area more than 500Km2. And M1 is influenced by fluvial, tide and wave, which results in great variations of sand bodies’ distribution, reservoir quality and connectivity. So it is essential to use high resolution models capturing reservoir heterogeneity for this kind of reservoirs. This paper presents an approach to representative sector modeling and key factor impact on waterflooding performance study for a large sandstone reservoir in Middle East. Firstly, Criteria of selecting representative sector models are established combining understanding of geological and dynamic characterization. Take one sector model for example, geological modeling process are detailed, and nine equal-probability geocellular models are built. Then model performances are compared through specific waterflooding patterns. Through detailed performance comparison of each well, each zone and each model of the 9 dynamic models, the reasons for model performance difference and key impacting factors on waterflooding performance are determined. And three models are selected as the optimistic, likelihood and pessimistic model for next development strategy optimization study. For the multi-layered sandstone reservoir, three representative sectors are selected mainly based on the geological features of M1. One typical sector model is selected to show the details workflow of the approach. Nine geocellular models are built for the sector, which combined three different lateral connectivity patterns with three vertical gridding approaches representing different vertical connectivity. And through detailed model performance comparison, eight key factors impacting on waterflooding performance are determined. And four key factors impact on waterflooding performance are shown in detail. This paper offers a case study of representative sector modeling and model selection for a multi-layered sandstone reservoir, and it also provide how to analyze the key factor impact on waterflooding performance. The results lay a foundation for the development strategy study and development plan designing. It also provides a methodology and reference case for engineers to study on other similar reservoirs.