Abstract：
The prediction models of CO2 corrosion rate are summarized, and the corrosion mechanism, corrosion morphology, and influence factors of each model are compared and analyzed in combination with CO2 corrosion experiments under actual production conditions in the Bohai oil field. There are three types of CO2 corrosion prediction models around the world. They are the empirical prediction model, semi-empirical prediction model and the mechanism prediction model. The empirical model is built considering less corrosion mechanism but more experimental data and field data. And the Norsok M-506 model is one of the most famous empirical models. The semi-empirical model is established by fitting experimental data and field data based on the dynamics process and the medium transmission process. The DWM, DW91, DW93, and DW95 are well-known semi-empirical prediction models for calculating the CO2 corrosion rate. The mechanism model uses dynamic formula to calculate the CO2 corrosion rate, which has a clear physical meaning and is less integrated with experimental data and field data. The Nesic model is most classic mechanism model to predict the CO2 corrosion rate. Based on a semi-empirical and semi-mechanical model, the CO2 corrosion rate prediction model is built in this paper fully considering the effects of temperature, CO2 partial pressure, flow rate, CO2 corrosion product film, and the CO2 corrosion rate correction factor. Besides, a CO2 corrosion experiment under actual production conditions in Bohai oilfield is conducted in order to let the CO2 corrosion rate prediction model more suitable for the Bohai oilfield. The comparative study of the model established in this paper with DWM, ECE, and BP semi-empirical models re vealed that this paper’s developed model has the smallest average relative error and is similar to the actual rate of CO2 corrosion in the Bohai oilfield, confirming that the CO2 corrosion rate prediction model built in this paper has great prediction effects and is more accuracy. Both the results of the corrosion experiment and model predictions in this paper have revealed that N80 pipe has the worst resistance to CO2 corrosion and the 13Cr pipe has the best resistance to CO2 corrosion. The ranking of four kinds of pipes for CO2 corrosion resistance is N80 < 1Cr < 3Cr < 13Cr. The wellbore corrosion rate distribution forecast contrasts the CO2 corrosion rate of various pipe materials, which provides a theoretical framework for the optimization of oil production and casing
pipes in the Bohai oilfield.
Key words：Bohai oilfield; CO2 corrosion; CO2 corrosion rate prediction; feasibility analysis; pipe optimization
Corresponding Authors：hanguoqing@163.com
Cite this article：PENG Long, HAN Guoqing, YANG Jie, LANDJOBO PAGOU ARNOLD. CO2 corrosion rate prediction model of production systems in the Bohai Oilfield. Petroleum Science Bulletin, 2020, 04: 531-540
