Research On Functional Reliability Of Tensioning System For Logging Cable Length Calibration

Getting the exact value of borehole depth parameter through demarcating length of welllogging cable has important significance in improving the quality of comprehensiveinterpretation of logging data and insure accuracy of formation evaluation while oil and gasdrilling and well completion evaluation data. Therefore, it is necessary to study how toeliminate the accumulated error of calibration system and abtain the accurate depth ofborehole parameter through demarcating length of well logging cable.This paper analyze the factors that affect the precision when simulate working conditionof underground cable while level calibration through applied load, then it puts forward thestructure and principle of tensioning gear and that provide the basis of assessment objectivesand failure mode of tensioning gear.Disintegrate the tensioning gear in initial debug modefrom the perspective of function and structure, make the function and working principle of allthe systems, parts and components clear. Make mechanical analysis for components and partson load under extreme load using the ANSYS software. Make theoretical calculation on fluidloss of air supply device. Meanwhile, analyze the cooling water circulation subsystemfollowing existing parameters using the MASCAD software and then get the pipelinecharacteristic curve that has guiding significance for cooling water circulation regulation.Through document literature, theory checking, information provided by themanufacturers, structural features of tensioning system, failure data of similar products, findout principal failure mode of subsystem and components using the method of failure modesand effects analysis. Then analyze the tensioning force put out accurately using the method offault tree analysis and put forward operating procedures of tensioning gear on these grounds.Find out main failure parts through qualitative analysis, establish evaluation system oftensioning system function reliability and calculate the weight using AHP method. Deal withscore values of expert evaluation form using trigonometric function of six indicators, decidethe main harmful components using grey relational degree for the results of level fuzzycomprehensive evaluation, and then do fuzzy comprehensive evaluation on vulnerable spot oflow operational reliability and put forward the prevention and control measures. Work out the software using Visual Basic to realize dynamic evaluation of the equipmentaccording to failure probability of all components on-site under long running conditions.