Rapid evaluation method for shale oil saturation well site

Abstract

The invention provides a rapid evaluation method for a shale oil saturation well site, and aims at the situation that a rock core is just taken out of a barrel on a drilling site but not limited to the site, and can also be realized in a laboratory. The method comprises the following steps: sequentially carrying out one-dimensional low-field high-frequency nuclear magnetic resonance measurement onblocky ground original, blocky self-absorption water saturation and freeze-crushing manganese saturation state samples to obtain a ground original oil-water total signal containing a substrate (solid-phase organic matter), a saturated water-state oil-water total signal and an oil signal; carrying out rapid oil washing, salt washing and drying treatment on the plurality of samples subjected to three times of nuclear magnetic measurement, and then carrying out one-dimensional nuclear magnetic resonance measurement one by one to obtain a substrate signal of each sample; combining the four nuclear magnetic resonance measurement signals to obtain the total porosity of the shale and the oil saturation of the ground; and finally, obtaining the shale oil saturation under the stratum condition through a stratum saturation recovery algorithm. Parameters such as physical properties and oiliness of shale oil can be rapidly and accurately obtained through four times of one-dimensional low-field high-frequency nuclear magnetic resonance measurement of an on-site rock core.

Description

technical field [0001] The invention relates to a method for quickly evaluating the oil saturation of shale oil at the well site. By performing four one-dimensional nuclear magnetic resonance measurements on the core just out of the barrel, the total porosity and oil saturation of shale oil can be obtained quickly and accurately, which belongs to rock Oil saturation testing field. Background technique [0002] In recent years, as fine-grained sedimentary continental shale oil wells have successively achieved high yields, shale oil has become a more realistic exploration breakthrough target and resource replacement field for major oil fields in China. The degree of exploration of shale oil is relatively low, and its heterogeneity and concealment are stronger. It requires a large number of drilling and coring, and carries out core analysis experiments such as geochemistry, lithology, physical properties, and oiliness to establish the "iron pillar" of shale oil. . Due to the ...

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Problems solved by technology

Due to the tight lithology and poor porosity and permeability of shale, laboratory experiments are costly and time-consuming, especially for oil-bearing analysis. From the core out of the barrel to the laboratory, the fluid loss is serious, and the experimental results are quite different from the real situation of the formation. Big

For sandstone, through three one-dimensional low-field high-frequency NMR measurements on massive cores, reservoir evaluation parameters such as rock porosity and saturation can be obtained quickly and non-destructively; but for organic-rich shale, its solid The NMR signal of organic matter cannot be ignored, and the permeability of shale is extremely poor. Generally, it is difficult for manganese chloride solution with a concentration of 15mg / L to penetrate into the core quickly, and the water signal cannot be completely eliminated. evaluation work

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