Study of the size distribution of drill cuttings;

Quantitative analysis and controlling method for pipe string erosion in gas drilling;

Development and application of drill pipe valve used in gas drilling;

Causes of and solutions to easy deviation of gas drilling track;

A debris-gas sample collecting device for air drilling;

But on the other hand, air drilling adopted air as the circular medium and so hydrocarbons like natural gas and oil mixed with air will cause downhole explosion if only the mixture reaches the explosion limit under any possible explosive condition, which will certainly threaten the safety during operations of air drilling.

The advantages of air drilling,such as much faster in footage,protect the reservoir from contamination and less cost, make its widely application in oil fields, whereas the pressure distribution in circulation,the drilling machinery choice and the configuration of drilling parameters is distingu.