Method for full-scale characterization of pore throats of tight sandstone or shale oil reservoir

Abstract

The invention provides a method for full-scale characterization of the pore throats of tight sandstone or shale oil reservoir. According to the method, microcosmic pore throat multi-scale distributioncharacteristics of tight sandstone / shale oil reservoir are quantitatively characterized in a mode combining the three pore throat radius testing methods including low-temperature nitrogen adsorption,high-pressure mercury injection and constant-speed mercury injection; according to the measurement precision ranges of different test instruments, pore throats with a radius of 2-25nm are characterized in a low-temperature nitrogen adsorption and high-pressure mercury injection test data linear interpolation mode; pore throats with a radius of greater than 25nm are jointly characterized by high-pressure mercury injection and constant-speed mercury injection test data, therefore, full-scale characterization is carried out on pore throat radius distribution of the tight sandstone / shale oil reservoir, a pore throat radius full-scale distribution atlas of the tight sandstone / shale oil reservoir is made according to the full-scale characterization, so that pore diameter full-scale distributioncharacteristics of the tight sandstone / shale oil reservoir are effectively characterized.

Description

technical field [0001] The invention relates to the technical field of oil and gas development experiments, in particular to a method for full-scale characterization of tight sandstone or shale oil reservoir pore throats. Background technique [0002] Tight oil / shale oil is another new hot spot in global unconventional oil and gas exploration and development after shale gas. my country has great potential for tight oil / shale oil reservoir resources, and large oil fields such as Changqing, Southwest, Jilin, and Daqing have a large number of proven tight oil / shale oil reserves. Tight oil / shale oil reservoirs have the characteristics of poor pore throat structure and strong heterogeneity, which not only control the physical properties of the reservoir, but also directly affect the production and recovery of tight oil wells. The microscopic pore throat radius has always been It is a hot topic of research by scholars at home and abroad. [0003] At present, there are many metho...

AI Technical Summary

Problems solved by technology

Tight oil / shale oil reservoirs have a large pore-throat scale span. Taking tight oil samples in Sichuan as an example, the pore diameters are mainly distributed between 2-350000nm. Due to the different principles and identification accuracy of each test method, the low-temperature nitrogen adsorption pores The effective test accuracy of the throat radius is between 1.8nm-500μm, which can finely describe the distribution of nano-scale pores, but the effective range is narrow and the jump is large; the effective test accuracy of the high-pressure mercury injection pore-throat radius is 1.8nm-500μm, which can respond in a wide range For the distribution of pores, high-pressure mercury causes artificial cracks, and the error in testing small pores is large; the effective measurement accuracy of constant-speed mercury injection pore-throat radius is greater than 0.1 μm. This method can distinguish pores and throats, and the measurement accuracy of large-scale pores is high. Dense, mercury saturation is less than 10%, only 0.1μm can be measured

Therefore, it is difficult to fully characterize the micro-nano-scale pore throats of tight sandstone reservoirs only by a single test method.

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