The Derrick Damage And Stability Study

With the development of oil and gas resources,the object of the drilling work for deeper strata,the application of ultra deep well drilling rig is not uncommon,and drilling efficiency is an important research direction,as the domestic first four single drill rig derrick,comparing to average 9000 m drilling rig,the overall height and platform height are higher,the study the damage and the overall stability of the four single derrick is very necessary.The main part of JJ675/57-K type is the research object,the main research content includes the following several aspects:(1)Analysis of drill derrick structure characteristics,selecting reasonable unit in the ANSYS to establish a model of the derrick;(2)According to the provisions of API Spec 4F “Specification for Drilling and Well Servicing Structures”,selecting of six kinds of working condition of the derrick structure statics analysis,obtained the derrick stress distribution and stress value biggest bar number and location under various operating conditions;(3)According to the result of structure statics analysis,selected three working conditions including condition 1,condition 2,condition 5 for modal analysis of structure damage,damage to the building is divided into a variety of situations,it is divided into three situations including a damage,two damage,three damage,two damage is divided into two situations including symmetric and asymmetric damage,the degree of decline of the natural frequency of the derrick is basically increasing as the rise in the numbers of bar damage and the increase of bar damage degree,the natural frequency is an important data to be used as a derrick long-term health monitoring;(4)The stability of the overall buckling analysis was carried out on the derrick,applicating respectively linear buckling analysis and nonlinear buckling analysis for overall stability analysis,the results of the nonlinear buckling analysis is more accurate than that of linear buckling analysis,the overall stability of the derrick is very good;(5)According to the result of statics analysis under various working conditions,six bar of the largest stress value were selected to build different degree of damage,the overall stability of linear buckling analysis was carried out on the derrick,the analysis results show that the overall stability of the derrick is still good,the local damage of derrick bar will not affect the overall stability of the derrick.