Method for analyzing pore distribution of sediment by virtue of saturation change of gas hydrate

Abstract

The invention belongs to the field of geological exploration and resource development of gas hydrates and relates to a method for analyzing the pore distribution of sediment by virtue of the saturation change of a gas hydrate. According to the method, the gas hydrate is generated in the sediment by virtue of pressurization temperature reduction. In the decomposition process of the generated gas hydrate, the temperature remains unchanged. In a mode of gradually reducing the pressure, the hydrate is promoted to be gradually decomposed. The signal strength of water in the sediment in each decomposition stage and the pore distribution situation of the decomposed hydrate are measured by virtue of nuclear magnetic resonance imaging equipment. The size and total quantity of pores occupied by the gas hydrate decomposed in each stage are determined by virtue of the temperature and pressure of each decomposition stage, so that the pore distribution characteristics of the sediment are calculated and described by virtue of an image shot by nuclear magnetic resonance imaging. The method has the advantage that under the condition that the natural core structure is not destroyed, the internal porosity distribution characteristics of the sediment can be clearly identified by virtue of the generation decomposition process of the hydrate. The method is easy to operate.

Description

technical field [0001] The invention belongs to the fields of gas hydrate geological exploration and resource development, and in particular relates to a method for analyzing sediment pore distribution by using gas hydrate saturation changes. Background technique [0002] With the depletion of traditional fossil fuel resources, the discovery of natural gas hydrate is undoubtedly a huge breakthrough in the energy field. In nature, natural gas hydrates are mainly distributed in deep sea sediments or permafrost on land, which brings great difficulties to the exploitation and utilization. Accurate characterization of sediment particle size distribution, sedimentary structure, and pore structure and other microscopic physical properties can obtain reliable geological data and provide important data support for the exploration and development of gas hydrates. [0003] At present, the commonly used methods for analyzing sediments include mercury intrusion curve, X-ray diffraction,...

AI Technical Summary

Problems solved by technology

However, since natural gas hydrate deposits are mostly dispersed, the traditional method of testing usually destroys the natural sediment structure, affecting the accuracy of the test

Images