Gas injection pressure-stabilizing drilling method

The invention discloses an air-injection stable-pressure well-drilling method and relates to a well-drilling method for petroleum and natural gas exploration and exploitation, in particular to a well-drilling method that can overcome the difficulties of fluid formation leakage, blowout and narrow safety window; the invention resolves the following difficult problems in prior well-drilling technologies: Not possible to adapt to leakage, blowout and narrow safety pressure window reservoirs, but easy to result in blowout, leakage or both during the well-drilling process; during the course of drilling fluid circulation, the invention adopts an air-injection method with suitable volume of air to eliminate the auxiliary friction resistance and dynamic pressure in drilling fluid circulation; before stopping the circulation, coming out of the hole or going into the hole, or in idling await status, repeatedly adopt pressure building, degasification, grouting amd release high-pressure gas to fulfill balanced killing; before the air-injection stable-pressure well-drilling is excuted, utilize a MWD method to test reservoir parameters, so as to determine whether utilizes the method and how to utilize the method. The invention discloses the well-drilling method to decrease the downhole pressure variation window into a narrow line, so that the window can be completely included in the leakage and blowout safety pressure window; therefore, the invention adapts to well-drilling in exploration and development of oil and natural gas.