Calculation Method of Original Oil Saturation in Water-flooded Formation of Coring Wells in Extra-high Water-cut Period

Abstract

The invention provides a calculating method for initial oil saturation in a water flooded layer of a core drilling well during a high water cut period. The method comprises observing construction of oil deposit and reservoir geological condition, collecting effective porosity of an oil layer of the core drilling well under the initial condition as well as initial oil saturation data of coring analyses; taking oil and water saturation data on routine analyses of rock samples as a base and obtaining underground oil and water saturation; utilizing effective porosity after compressed and correction and oil saturability after degassed correction, taking sand-parting layer groups, sand-parting segments or oil-separating groups to respectively create regression equations; clarifying the sub-well scanning rule and determining pairs of sub-wells in the initial conditions corresponding to all layer sections of the enclosed core drilling well during a high water cut period; solving the initial physical parameters during a high water cut period; and taking sand-separating layer groups of restored physical reservoir parameters to the regression equations such that initial saturation during the water cut period can be solved. The calculating method for initial oil saturation in the water flooded layer of the core drilling well during the high water cut period has following beneficial effects: big calculating errors are avoided in the conventional method for solving initial oil saturation in the water flooded layer of the core drilling well during the high water cut period.

Description

technical field [0001] The invention relates to the field of petroleum development oil layers, in particular to a method for calculating the original oil saturation of a water-flooded layer in a coring well during an extra-high water-cut period. Background technique [0002] At present, it is necessary to study the change of reservoir oil saturation in the evaluation of oilfield water flooding effect and water flooding degree. Coring wells play an important role in oilfield exploration and development, and their data are first-hand data for intuitive, accurate, and quantitative analysis of reservoir characteristics, remaining oil distribution, etc. Analyze the characteristics and exposure problems of different development stages of the oilfield, grasp the production status of oil layers in different periods, study the characteristics and laws of oil layer water washing, and accurately analyze the water flooding status of oil reservoirs and the distribution of remaining oil. ...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a method to solve the problem of large calculation error existing in the existing method for obtaining the original oil saturation of the water-flooded layer of the coring well during the ultra-high water-cut period. degree calculation method

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