Research On The Disaster Mechanism Of Blowout In Sangao Gas Field

The status of natural gas in petrochemical resources is more and more important,and it is an important primary energy and clean energy.The demand and consuming for natural gas in our country is increasing to promote exploration and development of the three high gas field and make its scale.Three high gas field generally refers to the high yield,high pressure and high sour gas fields.In order to prevent the three high gas blowout accident and reduce casualties and economic losses,the causes disaster mechanism and the cause of disaster have studied.First of all,this paper analyzed the three stages:the process of drilling,cementing and completion process.30 three high oil and gas or gas blowout out of control accidents have been extracted from oil drilling blowout accidents happening in the 1970-2009.The blowout accident tree,tripping drilling process blowout accident tree and blowout out of control accident tree have been drawn.From the Angle of mechanics,it is concluded that the factors are related to the three high gas blowout.The factors include drilling fluid(gas),throttle manifold,bop,kill manifold,casing(corrosion),drilling tools(hydrogen embrittlement).Using principal component analysis,and determine the index weight:53.79%,25.05%,11.51%,5.85%,3.80%.Stress concentration caused by corrosion hole and uniform corrosion to the influence of casing intensity have been studied.The single ram blowout preventer model was established based on SolidWorks,and the simulation carried on with corrosion thickness of 0 mm,0.5 mm and 1 mm,2 mm,3 mm,4 mm.Using the fluent software to simulate throttle manifold with the valve opening of 20%,40%,60%,40%,when methane gas content at 20%.Throttle manifold also was simulate with methane gas content of 20%,30%,40%,50%,when the valve opening was 20%.The calculation formula of bubble volume was deduced,and the bubble volume calculation formula was validated with fluent.Simulation results of hydrogen embrittlement hollow are analyzed through ANSYS,and tensile limit was down about 44%.Finally,the fuzzy linear programming model was established for safety,under the mechanical constraints of five factors that Casing,bop,throttle manifold pressure Wells,drilling fluid,downhole hydrogen embrittlement.