The Research On Optimization Design Of Casing String

With the development of drilling technology,the depth of oil and gas wells is increasing,and the geological condition of drilling is more complicated.Therefore,it is very important to carry out the research of casing string optimization,which is of great significance to ensure the integrity of the casing and save the cost of production.Combined with practice research institutes and cementing design demand,integration of API casing geometric parameters and strength calculation formula,based on established geometric parameters of casing database and strength database,the non API casing strength,geometric parameter calculation software;According to the fourth strength theory and the Mises rule,the casing strength calculation model under the three axis stress state is deduced,which makes the strength design of casing string more accord with the actual working condition in the mine.The triaxial stress strength design,using the bottom-up design method,from the lower part of the collapse load screen casing and resistance to internal pressure and tensile check,the upper axial load increase leads to the strength does not meet the requirements of use tensile design until the wellhead.Based on the principle of practical construction,easy construction and low cost,the optimal design model of casing string is established.