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.

Study on NW solids free aerated drilling fluid for under-balanced drilling;

A double-wall drill tool has been developed to solve problems arising in the process of controlling the wellbore trajectory using conventional downhole mud motor and MWD in under-balanced drilling with aerated drilling fluid.

Therefore, using aerated drilling fluids and under balanced drilling techniques can not only meet with the geologic requirements but also ensure the normal drilling.

The study and application of a new MEG drilling fluid system;

Effect of drilling fluid system and its viscosity on gas measuring borehole logging;

Evaluation on the performance of HXO drilling fluid system;