Case Study on Fluorocarbons Interior Coating for Anticorrosion and Wax-Deposition Inhibition in ASP Flooding Production
Authors: Liu Yang , Zhuge Xianglong , Wang Zhihua , Huang Bin , Le Xinpeng 
Published: October 2018

Under the hovering background of low oil price, alkali/surfactant/polymer (ASP) flooding technique is proven to be vitally important for enhance oil recovery (EOR) in oil industry. The production practice in Daqing Oilfield (China) shows that the EOR of ASP flooding is more than 10% original oil in place (OOIP) over conventional polymer flooding. However, the problems of corrosion and scaling that surface facilities and pipelines encounter with still remain very challenging in ASP flooding production, especially in the strong alkali (NaOH) ASP flooding fields. In the industrialized-application of ASP flooding process, these problems are drawing more and more attention.

The corrosion behaviors of surface facilities and pipelines that utilized in strong alkali (NaOH) and weak alkali (Na2CO3) ASP flooding fields were characterized with the integration of production practice, the general anticorrosion measures and the failure of internal coating in fields were presented and demonstrated. A coating solution for fluorocarbons surface treatment was proposed and tested in this case study. The performance of interior surface coatings including corrosion-scaling resistance, wax-deposition inhibition and drag reduction was evaluated with the existence of ASP chemicals in produced emulsions, and the mechanism was discussed from both film-forming and reducing surface energy aspect. The distinct competitive advantage of fluorocarbons interior coating for anticorrosion and wax-deposition inhibition in ASP flooding production was presented.

Considerable corrosion and scaling were created and covering the surface facilities such as the storage tanks of ASP chemicals, the pipelines for injection and production, and the heating furnaces in ASP flooding production. Both of the applied physical and chemical protection measures are facing to the challenges of service life, potential environmental threats and unpredictable cost-effectiveness. High bond energy and strong chemistry inertia of fluorinated resins can prevent the coating structure from being destroyed and develop flexibility and weatherability of the coating. The pore resistance and shielding performance of fluorocarbon coating in corrosion environment highlighted actually result from the superior mechanical properties, super-hydrophobicity, and self-cleaning performance. Furthermore, the low surface energy and low coefficient of friction of the fluorocarbon interior coating provide the possibility of pipeline wax-deposition inhibition and drag reduction. The maximum wax-deposition inhibition rate and the maximum drag reduction rate reached 46.42% and 60.00% respectively for high-viscosity ASP flooding produced emulsions in this case study. The reasonable coating configurations and process are certainly indispensable in the potential applications of fluorocarbons surface technology.

The case study contributes to the existing knowledge in the implementation of chemical EOR project for a green oilfield development, and it is also helpful to accelerate industrialized-application of ASP flooding and design another emerging pattern-flood pilot.