Study On Downhole Explosion And Its Early Warning In Well Drilling With Gas

Recently,gas drilling is developing quickly in C hina.Gas drilling has remarkable advantages comparing with the traditional drilling and it is widely used in various oil field.But some safety problems have been found in practical application,for example,wellbore instability,formation water,downhole explosion etc.The downhole explosion is one of the most serious problems.When using compressed gas as a circulating medium to well drilling,it has the probability of downhole explosion.So it is necessary to study the early warning technology of downhole explosion.This paper sums up the discriminated method of downhole explosion in well drilling with gas,design a set of gas drilling sampling and analyzing device,analyzes mechanism of downhole explosion and comes up with the explosion risk index as the s-tandard of evaluating downhole explosion based on literature research.The paper also analyzes the factors of affecting explosion risk index and builds up the explosion index calculation model.The paper designs and develops monitoring and early-warning software of downhole explosion based on the new model and conducts field test,coming up with a new solutio n for early-warning of downhole explosion of gas drilling.