Probe into Problem of Calculation Gas-lost in Geological Exploration Desorption Method

摘要

Based on the self-constructed experimental equipments, the gas desorption of coal in drilling mud during coring is simulated. It has been proved that the beginning time of gas desorption of coal during coring are related to gas pressure and mud pressure, and the gas desorption of coal in the medium of drilling mud is a non-uniform pressure desorption process with an increased velocity at first and an attenuated velocity afterwards. The gas desorption characteristics and law of coal in the medium of drilling mud are entirely different from those of coal in the medium of air. And also been proved that China's Geological Exploration Desorption Method (GEDM) for coal gas content measurement exist several technical shortcomings in the calculation of gas-lost.