Preliminary Analysis on Structure Feature of Drilling and Sampling in Soft Coal and CBM

Abstract:

The necessities of drilling and sampling in soft coal and CBM in China and the special requirements for sampling tools are put forward. Based on the summary on the techniques of improving recovery rate and coring quality, the paper described and analyzed the structure of new drilling tool for soft coal and gas drilling. Coal sampling tools should have the functions of single action, advance, exclusion of water, anti-vibration and thread off prevention; and besides, gas sampling tools shoule have more functions of sealing, freezing and gas collecting.