Materials Performance in CCS Wells

This joint industry project is to address the damage modes associated with downhole and well head materials for CCS applications.

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As the world strives for a cleaner energy future through Carbon Capture and Storage (CCS), the need for efficient CO₂ transport and storage solutions is paramount. The Materials Performance in CCS Wells Joint Industry Project (JIP) is a collaborative effort dedicated to addressing the challenges posed by the transportation and storage of CO₂. Our mission is to comprehensively understand and characterize the damage mechanisms that corrosion-resistant alloys (CRAs) face in CCS well applications, which include both depleted gas fields and new fields. By doing so, we aim to facilitate materials selection, define operational windows, and ensure the long-term performance of materials in CCS storage wells.

Challenge

The storage of CO₂ underground presents unique challenges, particularly concerning downhole and wellhead equipment. CO₂ from various sources often contains impurities such as SO₂, NO₂, and O₂, which can lead to localized corrosion and stress corrosion cracking (SCC) in CRAs, even at temperatures and chloride concentrations not typically of concern in conventional oil and gas production environments. Understanding these damage mechanisms is crucial to selecting the right materials and defining safe operating conditions for CCS storage wells.

Anticipated differences between the chemistry of typical O&G production systems and CCS well applications

Objective

The primary objective of the JIP is to develop guidelines for the use of CRAs in CCS well applications. We aim to achieve this objective by:

1. Identifying the role of key environmental factors on damage modes in CRAs based on preliminary thermodynamic calculations.
2. Characterizing the performance of CRAs and establishing environmental limits for localized corrosion and SCC in CCS storage wells.
3. Creating a framework to translate qualification test observations into long-term performance predictions in service.

Approach

Our approach involves assessing localized corrosion behavior as a function of key impurities using electrochemical techniques. We leverage existing information and models to define starting conditions and evaluate the effects of temperature and impurity concentrations on corrosion potential. Long-term corrosion potential measurements, slow strain rate (SSR) tests, and 4-point bends/C-rings SCC tests will provide further insights into materials' performance. Ultimately, these data will enable development of a framework for translating qualification tests to long-term performance in service, guide the selection of materials and integrity strategies for long-term CO2 storage.

Benefits

By participating in the JIP, members can expect the following benefits:

1. Clear understanding of operational windows for various materials in CCS well applications.
2. Valuable input for designing gas cleaning specifications before injection.
3. A framework to evaluate qualification test results and predict long-term performance in service.

Project partners

Exxonmobil, CNPC, Shell, OneSubsea, Vallourec, JFE Steel Corporation and TFMC.

Project details

The project starts in December 2023 and is anticipated to conclude current scope in two years. The scope of our project includes:

• Leveraging literature and OLI® modeling to understand localized corrosion behaviour
• Conducting electrochemical polarization scans at varying temperatures and chloride concentrations with different O₂/NO₂ and SO₂ concentrations
• Measuring long-term corrosion potential and performing electrochemical impedance spectroscopy (EIS) scans
• Conducting SSR-based SCC tests on various alloys
• Performing long-term materials qualification tests using 4-point bends/C-rings and crevice coupons
• Developing an acceptance framework for observed features in tests.

In summary, the Materials Performance in CCS Wells JIP is dedicated to advancing the understanding of materials in CCS storage wells, ultimately contributing to the success of CCS as a vital component of the energy transition. Join us in this crucial effort to drive sustainable energy solutions forward.