Shiyou shiyan dizhi (Jan 2021)
Controlled reserve upgrade standard for middle-deep low permeability glutenite reservoirs in Jiyang Depression, Bohai Bay Basin
Abstract
Glutenite reservoirs are one of the major targets for petroleum exploration, and some important breakthroughs have been made in many oil-bearing basins in recent years. Through 2019 glutenite reservoirs in the Jiyang Depression of Bohai Bay Basin accounted for 15% of the total low permeability controlled reserves of SINOPEC. However, due to the lack of upgrade standards and the unclear main control factors, which of these controlled reserves can be upgraded is also unclear. Based on the status analysis of upgraded reserves and the characteristics of proved reserves in low permeability glutenite reservoirs, it is suggested that reservoir effectiveness, productivity and economy are the main factors that influence the controlled reserve upgrade. The key parameters for characterizing and controlling reserve upgrading were determined, and the methods for determining rational production and decline rate were studied in detail. A two-level standard for the upgrading of controlled reserves in low permeabilityglutenite reservoirs was established under different geological conditions and oil prices. First, the lowest limit for reservoir effectiveness was assessed under different permeability and burial depth, such as in situ crude oil viscosity, effective thickness, effective porosity and oil saturation. Second, the lowest limit for single well productivity and minimum economic recoverable reserves of individual wells under different burial depth and oil price was considered. The results provide a basis to evaluate the upgrading potential of controlled reserves of low permeability glutenites in the middle and deep layers of Jiyang Depression. The selected upgrade potential of a block is basically consistent with the subsequent upgrade effect of that block, which verifies the reliability and rationality of the above upgrade standard.
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