Qualification of Non-Metallic Glass Reinforced Epoxy (GRE) Lined Tubing for CCUS Wells
Authors: Radhakrishnan Gokulnath , Fernandes Alwyn , Yakovchev Encho Zdravkov 
Published: November 2024

The selection of materials for downhole tubing in CO2 injection wells in CCUS projects has garnered significant attention due to the diverse challenges posed by handling supercritical CO2, wet CO2 containing acid contaminants, the Joule-Thomson effects leading to rapid drops in temperature, and the high flow rate erosional effects. The predominant debate revolves around whether to opt for low-alloy carbon steel or higher-grade corrosion-resistant chrome alloys. Amidst this discussion, non-metallic, Glass Reinforce Epoxy (GRE) lined carbon steel tubing, particularly in carbon steel, emerges as a compelling choice. This is attributed to its history in CO2 injection wells for EOR its favourable Life Cycle Costing (LCC) from an economic standpoint and Life Cycle Analysis (LCA) in terms of carbon footprint. However, the adoption of non-metallic lined tubing necessitates effectively meeting the challenges stated above.

The GRE lined tubing system consists of a corrosion resistant fiberglass reinforced epoxy resin composite liner cemented inside carbon steel tubing. A combination of end flares and a polymeric Corrosion Barrier Ring protect the coupling area. Out of the 110 million feet of this solution installed across more than 55,000 wells globally over the past 50 years, 20 million feet have been utilized in CO2 injection and Water Alternating CO2 (WAG) wells. Moreover, during the qualification process of this solution for application in oil and gas producer wells, extensive exposure testing has been conducted under elevated pressure (300 bar / 4,500 psi) and temperature conditions (145°C / 293°F) that match the properties of supercritical CO2.

Furthermore, rapid depressurization effects on the lined tubing solution have been assessed to evaluate permeation collapse effects. Recently, the lined tubing samples were subjected to rapid flash freezing to temperatures as low as −70°C (-94°F), akin to those encountered during uncontrolled decompression of dense phase or critical phase CO2.

Additionally, tests carried out by third parties on erosion effect of high flow rates are captured in this paper. Given the objective is also to reduce carbon footprint during well drilling and completion, the advantages of the rig running speeds installation speeds of low allow carbon steel over alloy steel are also compared.

The paper outlines the findings concerning the behaviour of lined tubing when exposed to supercritical CO2, rapid freezing, and rapid depressurization effects. It shares the changes observed in property parameters as recommended in API RP 15 CLT (Recommended Practices for Composite Lined Tubing) during these tests. The outcomes affirm the solution as a technically viable alternative to standalone steel solutions, offering additional benefits such as lower life cycle costs and a reduced carbon footprint.

Demonstrated across various CO2 injection wells for EOR projects, WAG wells, and oil and gas producer wells, the outcomes recorded from these additional tests instil confidence in Material selection and Completion engineers, prompting them to regard the lined tubing solution as a viable option for CCUS projects.