摘要：Coalbed methane content is one of the important parameters to characterize coal reservoir characteristics.Accurately obtaining coalbed methane content is of great significance for coalbed methane resource exploration and development and coal mine gas prevention.This paper addresses the problem that it is difficult to obtain high-value coal cores in deep coal reservoirs using conventional coal bed methane coring tools and oil and gas well insulation pressure-preserving coring tools.Design,drilling engineering and other theories,methods and means,according to the technical requirements of deep coal seam gas coring,designed a deep ultradeep coal seam gas coring tool with pressure maintaining,insulation function and sealing functions.Simulation tests and closed coring equipment and process research of coal samples of different particle sizes are carried out under variable pressure or temperature conditions.The results show that the technology of closed coring of coalbed methane content in surface wells is formed.The problem of incomplete measurement data caused by the inability of the conventional tool to maintain the core temperature is solved.In the simulation experiment,good results were obtained for the heat preservation rate 89.28% and the temperature change rate 2 ~ 2.5°C/h.The insulation and pressure-preserving function of the inner core tube is realized to ensure that the temperature and pressure of the core are not reduced during the process of drilling and ground transportation,and the accuracy and reliability of the core data are improved.It overcomes the deficiency that the existing coring tools cannot effectively maintain the formation pressure and temperature.
