Accurate shale oil-water saturation testing method

Abstract

The invention discloses an accurate shale oil-water saturation testing method. The method comprises the steps of sampling shale cores, extracting water in samples, removing oil in the samples, and calculating the oil-water saturation of a shale reservoir. According to the method, a refrigeration liquid nitrogen drilling technology is adopted, and therefore it can be ensured that the oil-water content and the pore structure of the samples will not change in the sample preparing process; for the shale cores, in the experimental verification of water content accuracy, the water content measured by the method is higher than that measured by other conventional methods by more than 20%, the water extraction rate is 98.5%, and the water in the core samples can be fully extracted; organic reagent washing oil is adopted, and therefore dehydration of clay minerals in the cores can be avoided; a trace water meter is used for testing extracted liquid, the extracted liquid is corrected through standard liquid, and therefore the precision of the tested samples is improved; the method greatly improves the accuracy of test data of the oil-water saturation of the shale cores, shortens the experimental cycle, and improves the work efficiency.

Description

technical field [0001] The invention relates to a simulation test technology for the oil-water saturation of a reservoir, in particular to an accurate test method for the oil-water saturation of mud shale. Background technique [0002] In recent years, all countries in the world have set off an upsurge in the development of shale oil and gas. China's shale oil and gas resources are very rich, but breakthroughs in new technologies and methods are urgently needed in development. Mud shale oil and gas accumulation includes mudstone oil and gas, shale oil and gas, etc. It is characterized by tight rock, the main reservoir space is nano-scale pore-throat system, and micron-millimeter-scale pores are locally developed. Because of these characteristics, there is currently no effective method for testing the oil-water saturation of shale in China, and there is no experience that can be used for reference. The contradiction of low water saturation measured by conventional experimenta...

AI Technical Summary

Problems solved by technology

[0008] Therefore, the distillation extraction method, atmospheric carbonization method, and coulometric method are mainly used to test the oil-water saturation of medium-high permeability samples. For shale samples with tight rocks and the main reservoir space is nano-scale pore-throat system. The measured water saturation data are generally low. Although the immersion method is suitable for testing the oil-water saturation of shale, the long test period limits its specific application.

Images