The Corrosion Control Technology for High H2S and CO2 Content Natural Gas Gathering and Transportation System
The corrosion control and pipeline protection for high hydrogen sulfide and carbon dioxide content natural gas gathering and transportation system after six years production was introduced in the paper. Puguang Gas field is the largest proven sour gas field in China with annual sour natural gas production of 10.6x109 m3.The H2S concentration is about 13~18% and the CO2 concentration is about 8%~10% in volume. As a consequence of hydrogen sulfide present, corrosion control is the key parameter for safe and stable development of the sour gas field. A series of comprehensive anti-corrosion methods were explored and applied for effective corrosion control in the moist gas gathering and transportation system of Puguang gas field. The inner corrosion is controlled by applying hydrogen sulfide resistant steel and Inhibitor to the gathering and pipeline system, and the outer corrosion is controlled by applying cathodic protection and coating. The real time monitor measures for pipeline system involved corrosion coupon (CC), electrical resistance probe (ER), Linear Polarization Resistance (LPR) Probe and field signature method (FSM), while the intelligent pigging and ultrasonic thickness gage was employed in test measures. Sour natural gas is an important source of hydrocarbons. The major challenges of utilizing sour gas include disposal of the hydrogen sulfide and carbon dioxide, corrosion prevention and cost control. In this article, the advantages and disadvantages regarding the corrosion control technology applied in the sour natural gas gathering and transportation is discussed and evaluated based on the field application data, providing references for design and operation of other sour gas field.