DISCUSSION ON KEY POINTS OF GAS DRILLING

The gas of gas drilling has some features of low density and viscosity, and low pressure affected on wellbore. The advantages of gas drilling are: high drilling efficiency, effectively controlling formation damage, preventing from lost circulation and adhesive drill pipe sticking. In order to fully bring into play its advantages, based on contrast between gas drilling and general drilling, key points of gas drilling are discussed from design, drying wellbore, drilling, making a connection and etc. The key points are: formation suitable for gas drilling must been selected at first, reasonable injection gas rate is determined, and matching design is well done; the foundations of improving drilling efficiency are good bottom hole assembly and reasonable drilling parameters, while necessary jobs(such as drying wellbore )must been done well; abnormal condition is judged exactly, rational technical measurements are used rapidly, drilling fluid transformation is done successfully.All these are key jobs which guarantee success of gas drilling.