The Optimization Design Of Myanmar-china Gas Pipeline Project For Crossing Kalaba Trench

With the prosperity of long-distance pipeline industry construction in China,no-dig technology of underground pipeline laying tends to be widely applicable.No-dig construction utilizing horizontal directional drilling technology gradually becomes the mainstream.Horizontal directional drilling technology is a combination of traditional pipe-jacking technology and oil gas field drilling technology.Since it enters into the engineering construction market,thanks to its advantages of fast construction speed,low construction cost,small hole diameter and small ratio of crossing pipe diameter,the good economic and social benefits have been obtained.In recent years,utilizing horizontal directional drilling technology in pipeline crossing engineering is the best way for laying long distance high pressure gas and oil-gas pipeline,meanwhile,it is also the best solution to protect natural physiognomy and environment.The China-Myanmar Gas Pipeline Project,listed as national major investment project,is the super-huge infrastructure constructing project of the country.The total length of this pipeline is about 3000 miles and its investment volume is 57.2 billions RMB.The project has to cross many rivers,lakes and other hydraulic engineering,which will have bad influence on the stability,security,people's life and even property.Therefore,it is necessary to carry out the research on dominant engineering facilities to guarantee the safe implementation of project.As an important part of the whole project in Myanmar,how to implement the Kalaba Trench project properly under serious consideration is the most crucial part.In this paper,according to systematical analysis on the application of horizontal directional drilling technology under conditions of heavy-calibre,long distance and coplicated geological conditions,combining with the relevant data and theories,the optimal scheme was determined.The main contents of the work were as follow:1.By an comprehensive analysis on the time limit for the project,economy parameters and engineering quantities,this paper thoroughly discussed and calculated large amount of data,compared the application of pipe jacking and directional drilling in Kalaba trench crossing,concluded the advantages,disadvantages and implement conditions of the two solutions,then illustrated the necessity of application of horizontal directional drilling technology,which provided a reference for the construction of such large-scale crossing projects in the future.2.By analyzing the selected horizontal directional drilling programme,the wall thickness,stress,stability and aseismic index of the horizontal directional drilling section of the pipeline were calculated and checked.The results of the safety requirements were satisfied,and the feasibility of the scheme was confirmed.3.In order to provide technical support to main technologies,through improving the designed programme on Kalaba trench crossing engineering,the method of establishing path curve and calculating requirements of the back to drag force were concluded,such as the use of equipments,the application of technologies,slurry ratio etc..By analyzing implementing process,the processes proceeded in Kalaba trench crossing engineering,such as the pilot hole drilling,reaming,the cleaning hole,the back to drag etc.were analyzed,moreover,the relevant rules and solutions were put forward to guarantee a reasonable project time,which laid a solid basis for this engineering.