High-rank coal seam free gas content measuring device and measuring method

Abstract

The invention discloses a high-rank coal seam free gas content measuring device and a measuring method. The high-rank coal seam free gas content measuring device comprises a drill rod, a pressure supplementing and purifying tank, a sampling and measuring device, a first guide pipe and a second guide pipe, wherein the pressure supplementing and purifying tank capable of stretching up and down is arranged in the drill rod, and the interior of the pressure supplementing and purifying tank is independently divided into an upper pressure supplementing tank and a lower purifying tank; a measuring tank is coaxially mounted at the lower end of the pressure supplementing and purifying tank, a sampling and measuring device is arranged in the measuring tank, the upper end and the lower end of the first guide pipe are communicated with the upper left end of the pressure supplementing tank and the upper left end of the measuring tank respectively, and the upper end and the lower end of the second guide pipe are communicated with the lower right end of the purifying tank and the lower right end of the measuring tank respectively.

Description

technical field [0001] The invention relates to the technical field of oil and gas exploration, in particular to a device and method for measuring free gas content in high-rank coal seams. Background technique [0002] The coalbed methane in the free state obeys the general gas state equation and can move freely. The amount of free gas in coal seams depends on the size of gas storage pores and fracture spaces, as well as factors such as temperature, pressure, and gas compressibility. Under certain temperature and pressure conditions, the amount of free gas and adsorbed gas in the pores (cracks) is in a state of dynamic equilibrium. The free gas can diffuse in the coal rock matrix due to the concentration difference, and the gas can permeate due to the pressure difference in the cracks whose width exceeds the free path of gas molecules. Most of the existing free gas measurements directly measure the porosity to obtain the content of free gas, and judge the content and quali...

AI Technical Summary

Problems solved by technology

Most of the existing free gas measurements directly measure the porosity to obtain the content of free gas, and judge the content and quality of the coalbed gas in the strata where the coal seam is located. However, due to the coalbed gas in the pores of the coal seam In a state of dynamic equilibrium, there are two states of gaseous state and liquid state. Affected by factors such as temperature and pressure, changes in free gas content and concentration values ​​in pores, as well as changes in liquid content values, lead to changes in the content of the stratum where the coalbed methane is located. , The measurement data of the quality has a large error

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