Material Selection for Carbon Capture and Storage (CCS) Wells

The goal of the Paris Agreement is to limit global warming to below 2°C, preferably 1.5°C, compared to pre-industrial levels. While the world is slowly transitioning to more sustainable energy sources to reach this target, one of the ways to reduce the CO₂ in the atmosphere is to capture it and store it in depleted gas fields. Multiple of these so-called Carbon Capture and Storage (CCS) projects are being developed and they require a different design philosophy compared to conventional hydrocarbon projects. The material selection is an important and integral part of that. This paper shows how to assess and develop steel tubulars for the conditions in a CCS well. Potential failure scenarios due to low temperature embrittlement, environmentally-assisted cracking and corrosion are reviewed. Low temperature suitability is explored for carbon and low alloy steels using available test data, e.g. Charpy impact energy and fracture toughness data. A fracture toughness model is validated for low alloy material grades L80-1 and proprietary 110 ksi sour grade in this paper to support the CCS wells design framework. This is combined with other material selection strategies to mitigate the corrosion and cracking threats, and to achieve a safe and cost-effective material selection for the CCS wells.

The goal of the Paris Agreement is to limit global warming to below 2°C, preferably 1.5°C, compared to pre-industrial levels.¹ While the world is slowly transitioning to more sustainable energy sources to reach this target, one of the ways to reduce the CO₂ in the atmosphere is to capture it and store it in depleted gas fields. According to the IOGP¹, the total number of CCS projects in Europe is 65 in 2022.² The aim of these projects is to store around 60 MtCO₂/yr by 2030.

Multiple Carbon Capture and Storage (CCS) projects are being developed to store CO₂ subsurface, resulting in many new challenges compared to conventional oil & gas wells. The lifetime of the well, operational planning, and environmental conditions in the well are just a few examples. Table 1 provides some examples of typical differences between conventional oil & gas wells and CCS wells with respect to temperature, pressure, and chemical conditions. This study focusses on the Oil Country Tubular Goods (OCTG) required for CCS wells for either new developments or re-use of existing wells.