Method for determining piercing leakage situation and position of drilling tool through tracing gas

The invention discloses a method for determining the piercing leakage situation of a drilling tool through tracing gas. The method comprises the steps that (1) the pipeline delay time t2 is measured firstly, wherein the pipeline delay time t2 includes the operation time of a gas sample from a degasser to an analyzer pipeline and the gas sample analyzing time; (2) the tracing gas is put into a drilling rod or directly injected into a drilling liquid inlet pipeline when a single joint is connected, and the pump starting time is recorded after putting-in or injecting; (3) the gas measuring displayed time is recorded on a gas measuring instrument, during normal drilling, the gas measuring displayed time is the time of a cycle and includes the time t0 that the gas moves downwards along the drilling tool, the time t1 that the gas returns to a wellhead from an annulus and the pipeline delay time t2; and (4) in the drilling process, whether piercing leakage occurs or not is judged according toa gas measuring curve fo