Double lower limit low permeability-compact sandstone reservoir classification method

Abstract

The invention relates to a double lower limit low permeability-compact sandstone reservoir classification method, comprising: calculating physical property lower limit of reservoirs of different depths, obtaining a changing curve of the physical property lower limit long with depth change; identifying day economy capacity lower limit and a function thereof changing with the depth, determining a relation between the day economy capacity lower limit and the porosity and permeability of the reservoir; obtaining an economic capacity curve of the porosity and permeability of the reservoir changing with depth according to the relationship between the function and the relation; respectively establishing a relational graph of the day economy capacity porosity lower limit with the effective reservoir porosity lower limit and the depths, and a relational graph of the day economy capacity permeability lower limit with the effective reservoir permeability lower limit and the depths. The classification method provided by the present invention effectively solves application of reservoir physical property lower limit changing with depths in reservoir evaluation, combines drilling and economy capacity in production, and helps to establish an objective, accurate, intuitive and easy reservoir classification evaluation program.

Description

Technical field [0001] The invention relates to the field of geology, and in particular to a reservoir classification method under double lower limit constraints. Background technique [0002] The basis of reservoir classification is the physical properties of the reservoir, that is, the porosity and permeability of the reservoir. For conventional sandstone reservoirs, classification based on the physical properties and capillary pressure characteristics of the reservoir is a commonly used reservoir classification and evaluation method. They are generally divided into Class I to Class IV reservoirs, of which most Class III and Class IV reservoirs belong to Low permeability - tight reservoir. For low-permeability and tight reservoirs, due to their low to extremely low porosity and permeability, they are classified as poor reservoirs or even non-reservoirs in conventional reservoir evaluation. [0003] With the improvement of oil and gas exploration and process technology, t...

AI Technical Summary

Problems solved by technology

However, the low-permeability-tight characteristics of such reservoirs also determine that conventional reservoir classification methods and schemes are difficult to meet the evaluation requirements, and it is urgent to develop corresponding classification schemes.

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