Methodology for Selecting an Internal Plastic Coating to EPA Class VI Well Permit Specifications for CCUS Applications

Abstract This paper discusses the laboratory development and evaluation of internal plastic coatings (IPC) for related utilization and sequestration for carbon capture environments, as well as the recommendation process in conjunction with the EPA Class IV wells permitting specifications. CCUS is the process in which carbon dioxide is collected from a power supply and industrial generator for storing underground and or re-use (Figure 1). Coatings provide a protective barrier to the substrate to improve well capabilities and increase longevity of assets for transportation and injection tubulars. For evaluation, coatings are tested through various laboratory methods utilizing enhanced performance techniques to determine versatility in different carbon capture, usage, and sequestration (CCUS) related environments. Upon testing and approving coatings’ capabilities, the EPA has incorporated the usage of coatings as a standard practice in well construction as noted in their document, "U.S. EPA Class VI Carbon Dioxide Injection Permit". Coatings are evaluated through rigorous tests to determine suitability for CCUS environments. To replicate field conditions per CCUS parameters, coatings are tested in an autoclave vessel and evaluated through a rocker arm test, which will be described in detail within this paper. The purpose of these tests is to determine suitability and durability of the coating systems when placed in such environments. Pass criteria for evaluation is the coating must not exhibit blisters and or disbondment from the metal surface. The results from evaluating the coatings confirmed suitability of an IPC for utilization and sequestration environments. Among the selected and quantified coatings, the transfer of knowledge of coatings’ capabilities in oil and gas operations were in place for carbon utilization applications including and not limited to, enhanced oil recovery or EOR and a water alternating gas injection or WAG. EOR is the process in which captured carbon is utilized in already existing exploratory technologies where CO2 increases pressure enhancing oil production once again. A WAG system is a method utilized in EOR and the option for geological carbon storage. The addition into sequestrating or the process of storing carbon indefinitely is a lengthier process. Technical criteria created by the EPA for Class VI Wells, delegates several components to storing carbon in geological formation without disrupting aquafers and cause a potential a CO2 leakage. A protective barrier (Figure 2), such that as an internal plastic coating is recommend to maintain gases and fluids within a transport system. An IPC provides a novel addition to protecting assets in harsh CCUS environments to reduce tubular failures and ultimately provide a cost-effective alternative.