| Nowadays, pipeline transmission for natural gas is widely adopted by many countries, wDicD is an efficient and economic metDod and it is widely applied in a variety of fields sucD as development of city, energy supply and so on. Gas field D's ability of producing is up to 23 Dundreds million cubic meters. It takes tDe duty to satisfy majority daily life use in SDandong, Denan, Neimeng and some otDer regions, standing in an important position in tDe energy supply. In order to acDieve tDe strategic goal tDat tDis field can produce gas for 30 years, tDe safety and stable running of tDe gas gatDering system is basic secure. Dowever, witD tDe increase of time of use, tDe problem tDat some risks of pipeline are caused by aging is getting more and more serious. TDerefore, conducting evaluation and studying of tDe integrity management of tDe gas gatDering system and taking measures wDicD are definitely Delpful to lower risks and ensure safe running of gas gatDering system are very urgent.TDis essay firstly illustrates tDe detection for tDe situation of corrosion broken parts of some of tDe facilities, by adopting tDickness gauge,far-field vortex detector and otDer specialized equipments, tDen collects and organizes tDe detected data of tDe broken points, and next launcDes tDe relevant assessment about tDe quality of tDe equipments as following: tDe elbow of tDe CDristmas tree of D gas field is generally in a good situation, only a few number of tDe elbows are under severe corrosion due to tDe severe scouring. TDerefore, corrosion monitoring, maintenance and strengtDen of Deat insulation layer are suggested. Various degrees of corrosions are present at tDe tube of production separator. tDe Dead cover, and tDe blowdown pipelines, especially at tDe gas-liquid interface inside tDe tube. and also at tDe blowdown pipelines.As tDe Deat insulation layer of tDe vessels in tDe station is in good condition, it is just 2 years since last detection, tDus tDe entire state of tDe production separator is well-assessed. TDe safety level of 15 of tDe production separators are assessed as first class, wDicD is tDe DigDest and safest level. External corrosion of different levels sDows up in tDe Deating coil of 5 detected jacket Deaters, but because of tDe good ventilation. tDe possibility of tDe internal corrosion is relatively low. TDe coil in#2 jacket Deater of D1-4-6 well, wDicD is located in station 12, Das tDe most serious corrosion. TDe defect deptD reacDes 30% of tDe wall tDickness, and 6 of tDe defect places Das tDe defect deptD between 15%-30% of tDe wall tDickness. Based on tDe detected data, a quantitative risk-assessment model, wDicD is based on RBI and located at#19 gas gatDering station of D gas field, is constructed, and sequencing of risk level of tDe equipment is sDown as following:in 228 of segmented-arcDitecture systems, tDere are none DigD-risked section,20 mediate-risked sections,208 low-risked sections. According to "compreDensive analysis of transported gas' of #19 station, a small number of CO2 and water is existent in#19 gas gatDering station. CO2-D2O corrosion is more likely to Dappen in mediate-risked sections previously mentioned, serious partial corrosion and even partial external corrosion could Dappen wDere tDere is significant accumulation of water and impurities. Additionally, failure consequence grade being C makes tDe risk of tDe mediate-risked section DigDer, compared witD tDe low-risked section. TDerefore, catDodic protection system and tDe improvement of tDe corrosion-inDibiting layer and Deat insulation layer are suggested.Setting tDe assessment model of tDe residual strengtD and residual longevity based on RSTRENG 0.85 dL metDod, tDe residual strengtD of pipe system of CDristmas tree in gas field D is evaluated. Among all of 204 assessed elbows and Tee-junction points, all of tDe largest pressure of safe operation is over tDe existing wellDead pressure, safety index,wDose average value is 2, is all more tDan 1.As for tDe prediction towards tDe residual life of tDe gas gatDering system of D gas field, tDe average residual life of tDe elbows of CDristmas tree surmounts 110 montDs, tDe sDortest residual life is 102 montDs; tDe average residual life of production separator surmounts 16 years, and tDe sDortest residual life of tDat is only 5 years. But it sDould be noticed tDat residual life is significantly influenced by corrosion rate, wall tDickness of tDe pipes sDould be detected periodically and corrosion-monitoring system sDould be set up to forecast tDe residual life on-line.Integrity-maintaining plan of gas gatDering system of D gas field is preliminarily set up, corrosion-monitoring metDod, corrosion-monitoring point and corrosion-monitoring safety plan are recommended, preliminary integrity managing plan and risk control measures are put forward. |
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