Study On The Gas Desorption Law Of Coal Core Under The Non-uniform Pressure Condition In The Medium Of Dring Mud

In this paper, based on Fick's law and Transfusion-diffusion theory, the theory equation of gas desorption of coal under the non-uniform pressure condition in the medium of dring mud was developed. Using mathematics physics method and the numberical method, obtain the formula of Gas desorption quantity. The gas desorption in drilling mud under different primitive gas pressure, different dring mud pressure and different raises drills speed on the simulates experimental equipments, obtains the gas desorption rule in the medium of drilling mud at the time of geological prospecting. Used the improves Logistic building-up curve model building calculation to compare the drill hole to take the core process coal still burning at the center gas stock losses the empirical formula.It has been proved that the gas desorption characteristics of coal core in the medium of drilling mud is differert fron those of coal core in the medium of air, the velocity of the gas desorption in the medium of drilling mud is increased at first and reduced afterwards.Through laboratory and locate experiment, Use the improves Logistic building-up curve model to be able to describe well raises drills the process coal still burning at the center gas desorption rule the new experience formula had high calculation precision of gas loss quantity during coal coring, it is clear that the accuracy and reliability of coal seam gas content measured by direct method can be remarkably increased.