Shale micropore size and fluid distribution analysis method

Abstract

The invention discloses a shale micropore size and fluid distribution analysis method. The shale micropore size and fluid distribution analysis method comprises the following steps that shale gas reservoir rock is collected, and a natural core is manufactured; the relaxation characteristic of hydrogen-contained fluid in core pores is measured through a nuclear magnetic resonance spectrometer, and a relaxation time T2 distribution map of clay water is obtained; the core is processed to obtain a saturated core, and a relaxation time T2 distribution map of saturated fluid and a summation curve are obtained; a T2 distribution map of effective fluid is obtained; a T2 distribution map of irreducible fluid and saturability Swi of bound water are obtained; a T2 distribution map of surplus water and water saturation Sw are obtained; the T2 distribution maps of the fluids are converted into a pore size distribution map, the shale clay deadline and the irreducible fluid deadline are obtained, and then the shale micropore size and fluid distribution are obtained. The nuclear magnetic resonance spectrometer is adopted, the pore size and distribution of the shale and size and distribution positions of water drops in the pores are analyzed quantitatively and qualitatively, and the result is reliable.

Description

technical field [0001] The invention relates to the technical field of rock analysis, in particular to an analysis method for shale microscopic pore size and fluid distribution. Background technique [0002] Determining the pore structure characteristics of shale oil and gas reservoirs is the key to developing oil and gas reservoirs and enhancing oil and gas recovery. The pore throats of shale oil and gas reservoirs are mainly at the micro-nano level, and traditional pore-throat characterization techniques can no longer The research on the microscopic pore structure of tight reservoirs must be realized by using high-precision experimental techniques. The nuclear magnetic resonance rock sample analysis technology generally refers to the technology of using the core nuclear magnetic resonance instrument to detect and experiment with rock samples of different sizes, and to interpret and analyze the obtained data. It is one of the most effective rock analysis technologies at pre...

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Problems solved by technology

Compared with other rocks, the clay content in shale is higher. Under natural conditions, clay contains part of crystal water. The pores occupied by crystal water are not helpful for oil and gas migration. When calculating rock porosity and permeability should be deducted, but the proportion of clay in conventional rocks is very small, basically negligible, so the general nuclear magnetic resonance analysis method does not consider the influence of deducting this aspect, the pore distribution obtained by nuclear magnetic resonance analysis is different from the data obtained by other experimental methods Larger, which also greatly affects the accuracy of shale NMR logging data

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