Low-seepage compact sandstone reservoir fluid saturation degree correction method

Abstract

The invention discloses a low-seepage compact sandstone reservoir fluid saturation degree correction method, which comprises the following steps of performing sequencing according to the sum of the water-containing saturation degree and the oil-containing saturation degree; performing partitioning; 2, performing linear regression by using the oil-containing saturation degree as the x-coordinate and using the water-containing saturation degree as the y-coordinate according to the partitioning result obtained in the first step; solving the slope and the intercept; 3, converting the indoor test fluid saturation degree into the original stratum state through setting the two parameters of the crude oil rest rate c and the stratum water rest rate d; solving the crude oil rest rate c and the stratum water rest rate d according to the slope and the intercept in the second step; 4, correcting the water-containing saturation degree and the oil-containing saturation degree of the corresponding partitions according to the two parameters of the crude oil rest saturation rate c and the stratum water rest rate d solved in the third sep in each partition. The method has the advantages that the operation is simple; the calibration precision is high; the real fluid saturation degree can be accurately reflected; the coincident rate with the oil test result is higher.

Description

technical field [0001] The invention relates to the field of saturation testing of low-permeability tight sandstone reservoirs, in particular to a method for correcting fluid saturation of low-permeability tight sandstone reservoirs. Background technique [0002] The low-permeability tight oil and gas reservoirs in the reservoir are mainly characterized by "low permeability, low pressure, and low abundance", and it is extremely difficult to develop them. The main manifestations are: (1) It is difficult to identify oil and gas layers; (2) It is difficult to restore the actual fluid saturation of reservoirs; (3) There are some differences between the fluid saturation of oil and gas layers measured by the laboratory of some wells and the actual oil test results, etc. The solution to these problems is mainly in the fluid saturation correction model. Therefore, it is particularly important to establish a suitable reservoir fluid saturation interpretation model. [0003] At pres...

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Problems solved by technology

However, due to the influence of factors such as mud filtrate immersion, degassing, and volatilization of light components during drilling, coring, sampling, sample storage, and analysis and testing, the final measured oil-water saturation data is significantly different from the true formation saturation. Based on a large number of core physical experiments, Song Yanjie et al. studied the variation of cementation index and saturation index under different conditions through carefully designed experimental procedures to quantitatively evaluate the saturation of low-resistivity oil layers. , the experimental operation of these fluid saturation correction models is complex, and the quality requirements for the measured rocks are relatively high, and generally only the influence of a single factor is considered, and the calibration accuracy is not high

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