Quantitative analysis device and method for saturation spatial distribution of fluid in rock

Abstract

The invention belongs to the technical field of petroleum scientific research. Aiming at the current situation that the quantitative analysis of the saturation distribution of fluid in rock does not reach a pore scale, the invention provides a quantitative analysis device and method for the saturation spatial distribution of fluid in rock. The method comprises the following steps of: injecting liquid in the overburden pressure state (no liquid exists), performing three-dimensional imaging on a rock core to obtain D1 and D2,and performing three-dimensional registration on the D1 and D2; obtaining D3 matched with D1 through the sampling of the D2; determining a threshold T1 based on overburden pressure porosity, and converting the D1 into a gap-matrix binary matrix; determining a threshold T2 based on the total fluid saturation, and modifying the value of the corresponding pixel in the D1 according to the gray scale of the gap pixel in the D3; extracting a pore network based on the gap pixel of the D1 to obtain pores, pore throats and corresponding pixel lists; counting the number of pixels occupied by two fluids in the pores and the pore throats and the total number of pixels to obtain pore fluid saturation; and counting the number, spatial distribution and shape factor relationship of the pores under different fluid saturations. According to the method, the spatial distributionof the fluid saturation of the pore size in a rock core can be obtained nondestructively and quantitatively.

Description

technical field [0001] The invention belongs to the technical field of petroleum scientific research, and relates to a testing technology for fluid saturation inside rocks, in particular to a quantitative analysis device and method for the spatial distribution of fluid saturation inside rocks. Background technique [0002] Petroleum-bearing reservoir rock is a typical porous medium. During the process of oil and gas accumulation, after oil and gas are generated in source rocks, they migrate to the reservoir through the transport system under a certain driving force, displacing the original saturated water in the pores. In the process of oil and gas development, methods such as water injection or gas injection displacement are often used to enhance oil and gas recovery. Due to the complexity of the pore structure, the interaction between the fluid and the rock wall and other factors, it is impossible to completely expel a certain fluid. Therefore, rock pores usually contain...

AI Technical Summary

Problems solved by technology

In addition, there are still some problems in actual operation: 1) Due to the influence of imaging quality and resolution, the gray value of water at different locations in space may have certain changes, which is difficult to express with a single value; During this period, potential factors such as instrument stability and noise may have a certain offset in the overall gray value even under the condition of constant moisture, and the method of determining the change in water content by direct gray-scale subtraction may include this part of the offset inside, leading to spurious biases, so it is not realistic to directly use the absolute value to characterize the saturation

However, in the process of fluid filling or displacement of actual rocks, images with continuous grayscale are obtained. There are how to obtain digital images of different fluid injection states of actual rock samples, rock skeleton, voids, division methods of different phase fluids, thresholds and According to how to determine the undisclosed problems of the invention

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