Abstract:For residual gas, especially in two special situations during in-situ gas content testing, including the case when the content of residual gas is too small to measure and the case where the gas content should be obtained quickly, the residual gas field problems in testing are summarized. (1) In the measurement of the content of low rank coal seam gas of slow desorption, the residual gas may be too small so that the conventional methods can not be used or the error will be too large. (2) For rapid desorption test bed methane gas, in the crushed coal sample in the testing of residual gas, a small amount of methane may be lost to make the residual gas results too low. The paper proposes a new numerical regression method (Langmuir curve regression) for residual gas, which is different to the normal test and is quick, accurate and efficient with respect to preparation to the actual measurement data.