Research On Corrosion Inhibitor Of Well Bore And Gathering Pipeline Network In Tazhong-1 Gas Field

Tazhong-1 gas fields belongs to Tarim oilfield which is coming into the development of large-scale gas fields,and it is the one of main gas source in Line Two West-East Gas Pipeline.Tazhong-1 gas fields?TZ62?TZ83?TZ82?were HPHT wells,bottomhole flowing pressure were up to 60MPa and bottomhole temperature were above 120?.And the corrosive environment were very severe,because every-well contained H₂S and CO₂.In view of the characteristics of corrosion destructive in wellbore and gathering gathering pipeline,because Tazhong-1 gas fields is high content of acid gas CO₂ and H₂S,formation water salinity,strong acidity.The experiment used gradual warming of dehydration synthesized imidazoline which utilized oleic acid and diethylenetriamine as raw materials and toluene as carrying agent.Then added Thiourea to synthetise imidazole derivatives,and at last we received imidazole derivative of quaternary inhibitor MZ-3 through benzyl chloride converting quaternary ammonium.The reaction in each step the molar ratio of reactants were determined as follows:Oleic acid:diethylenetriamine:thiourea:benzyl chloride were 1:1.4:1:1.2;and the cyclizated reaction temperature was 220?,reacted time was 4h.In the corrosion environment of CO₂and H₂S/CO₂,90?was the temperature corrosion sensitive point in three types of pipe?P110,P110S,TP110SS?.without corrosion inhibitors,under circumstances of having CO₂corrosion,three models of pipe corrosion rate in the temperature point was P110E<P110S<TPSS;under circumstances of having H₂S/CO₂ corrosion,three models of pipe corrosion rate in the temperature point was P110E<P110S<TPSS;We could use the same content in MZ-3 and HG to synthesis YU-1 corrosion inhibitor.When YU-1 corrosion inhibitor dosage was 300mg/L,it could effectively control CO₂ corrosion environment of wellbore well bore in Tazhong-1 gas fields;According to add the content of 3:2:1 in the MZ-3,HG and triethylphosphate to deserve complex YU-4 corrosion inhibitor.When YU-4corrosion inhibitor dosage was 500mg/L,it could effectively control H₂S/CO₂ corrosion environment of wellbore in Tazhong-1 gas fields,and the corrosion rate of less than0.076mm/a;The MZ-3 corrosion inhibitor could effectively control H₂S and CO₂ corrosion environment of wellbore in Tazhong-1 gas fields;We use survey data and combine with the actual situation in the pipeline ground of Tazhong-1 gas fields,to determine the medicine charging technology in the wellbore and gathering pipelines of Tazhong-1 gas fields.And we identified the medicine charging rules in pipeline borehole and ground of Tazhong-1 gas fields.And we found a cost-effective method for preserving and measures through researching the medicine charging technology and evaluating economic in the production wells.