Study On Corrosion Law Of Metal Pipelines In Tahe Oilfield And Application Of New Pipelines

The internal corrosion environment in Northwest Oilfield is very bad,and the production of well flow has the characteristics of "four high and one low" with high H2O,high CO2,high H2S,high Cl-and low pH value.In the system of H2S—CO2—Cl-coexist in a corrosive environment,With the addition of dissolved oxygen,the original corrosive environment system is more complex,and the overall loss caused by corrosion is increasing year by year.In order to solve the serious corrosion problem of the gathering and transportation pipeline,the corrosion protection and corrosion control work has been carried out in the branch,Such as adding corrosion inhibitors,selection of corrosion-resistant metal pipe,application of non-metallic pipes,anti-corrosion coating technology,online pipeline repair technology,Good results have been achieved in reducing the loss of oil and gas,protecting the ecological environment,ensuring the operation of production safety and reducing the maintenance cost.However,with the extension of oil and gas field development,the comprehensive water content is rising continuously,The corrosion of gathering pipelines in oil and gas fields will enter a period of high incidence,How to study the corrosion mechanism,corrosion factor and corrosion law under the condition of H2S-CO2-Cl--O2 coexisting corrosion is the problem that we need to solve urgently.The main contents of this paper include:(1)Study on main control factors of metal pipeline corrosion in oil and gas fieldAccording to the corrosive medium(H2S,CO2,Cl-,salinity,etc.),according to the operating conditions(temperature,pressure,flow rate,production methods)to carry out indoor corrosion factors.Study on the improvement of the material quality of metal pipe line and the boundary condition of steel composition optimization.(2)Study on corrosion characteristics of metal pipelines in oil and gas fieldsAnalysis of metal pipeline corrosion perforation of the pipeline material,perforation time,the number of perforations,perforation position,perforation and other status information,Combined with the operating conditions parameters,the corrosion of the various factors of perforation analysis.The corrosion characteristics of the metal pipeline under different corrosive media environment and operating conditions are summarized.(3)Research and development of corrosion resistant metal pipeline materialBased on the steel available in the oil and gas field,the steel composition is determined by the improvement of the steel grade in the laboratory;Through the laboratory rolling and heat treatment process to determine the best mechanical properties of steel;Through the laboratory welding process test and evaluation research,the optimum welding condition of steel is determined;On the basis of laboratory simulation tests,a new type of steel with high cost performance is developed for the corrosive environment in Tahe oilfield.(4)Study on Corrosion Resistance and Economic Evaluation of New Type TubesLaboratory simulation of field conditions,to carry out the evaluation of new steel corrosion resistance,and the corrosion resistance of existing steel were compared and evaluated,and preliminary determination of 1-2 applicable grades of steel;The typical corrosion environment and production operation condition were selected in Tahe oilfield.The corrosion resistance test was carried out,and the economic evaluation of the new pipe was studied...