Carbon Capture Utilization and Storage (CCUS)

The primary objective of CCUS is to reduce CO₂ emissions from industrial sources and thereby mitigate climate change by safely and permanently anaging anthropogenic CO₂.

CCUS - is the process of capturing high concentrations of carbon dioxide (CO₂) emitted by industrial activities such as natural gas production facilities, coal-fired or biomass power plants, chemical plants, and any other industries generating CO₂. The captured CO₂ is transported and either stored in underground geological formations (carbon sequestration) for centuries or millennia in the case of CCS, or utilized for industrial purposes in the case of CCU projects.

Carbon Capture and Utilization (CCU) projects, such as CO₂ injection for EOR (Enhanced Oil Recovery), can be considered Carbon Neutral when assessed on a life-cycle basiss. Part of the CO₂ captured could be produced back at the end of the process. The final balance results in no additional CO₂ generation.

Sequestration (Storage) Clusters

CO₂ storage locations typically are:

1. Depleted Oil or Gas fields that are no longer viable or economic for production. The drivers for using these are the existence of surface facilities and the information availability concerning:
   • Storage capacity
   • Reservoir compartmentalization
   • Injection conditions
   • Cap rock sealability

2. Saline formations that refer to any saline water bearing formation (non-potable). The saline formation must be sealed by a caprock for permanent storage.
   • No risk of CO₂ leakage through un-properly abandoned wells.

Additional types of underground formations for geologic carbon storage have been investigated. These are:

3. Non mineable coal seams which were never exploited
4. Basalt formations
5. Organic-rich shales

Fluids To Be Injected

Captured CO₂ can contain impurities depending upon its origin (associated with natural gas versus combustion byproduct)

Depending on pressure and temperature conditions at well head and along the wellbore, the injected fluid could be gas, liquid or dense phase (supercritical - highly compressible fluid that demonstrates properties of both liquid and gas).

The fluid to be injected can vary from/to:

1. Clean CO₂ – Dry (negligible water content) or with some associated water.
2. Contaminated CO₂ – Presence of impurities or corrosive elements, such as:
   • H₂S (Hydrogen Sulfide)
   • O₂ (Oxygen)
   • NOx (Nitrogen Oxides)
   • SOx (Sulphur Oxides)

Material Selection < - CCS Material selection - >

Injection Phases and Potential Risks

There is a risk of formation water flowing back into the wellbore during injection shut-in periods. In this case, formation water composition will affect the corrosion aggressiveness of the bottomhole environment.

• CO₂ + Formation water (@ bottomhole) ð Potential (*) Risk of Stress Corrosion Cracking of CRA’s
• CO₂ + Condensed water (@ wellhead) ð Potential (*) Risk of Sulfide Stress Cracking

(*): depending upon the well environment and fluids composition.

Monitoring wells

In addition to injection wells, monitoring wells play a critical role in CCS projects by ensuring the long‑term integrity and containment of the injected CO₂ plume. These wells are typically used for pressure monitoring, fluid sampling, and detection of potential CO₂ migration.

Similar to injection wells, monitoring wells may also be exposed to formation water backflow, particularly during pressure fluctuations or shut‑in periods. As a result, the monitoring wellbore environment can become corrosive, even in the absence of continuous CO₂ injection.

Key risks for monitoring wells include:

• CO₂‑saturated formation water leading to localized corrosion or SCC of CRA tubulars
• Ingress of formation brine containing H₂S or other aggressive species
• Long‑term exposure under low‑flow or stagnant conditions, increasing susceptibility to corrosion damage

Therefore, material selection for monitoring wells should follow the same conservative, fit‑for‑purpose philosophy as injection wells, accounting for worst‑case fluid chemistry, temperature, pressure, and long‑term exposure conditions.

workflow (over view)　

- for further information, please visit here < - CCS Material selection - >

This Material Selection concept provides a quick assessment of possible materials to be used for CCUS applications, based on generic parameters such as presence of water, H₂S and impurities. Once the expected environment is clearly defined (fluid characteristics composition, well conditions, etc.), a fit for purpose material selection will be launched using as reference existing Nippon Steel corrosion data base and/or fit for purpose tests meant to define the most cost-effective solution for the application.

Connection Selection

  Tubing Connection behavior under CCUS Loads

CO2 injection wells are expected to be subjected to relatively benign mechanical loads. On the other hand,  temperature variations could represent unusual challenges, specific to CCUS applications:

• Sub-zero temperature, corresponding to CO₂ injection cycles
• Rapid temperature variations transient state
• Extreme cryogenic temperature, down to -80°C, corresponding to uncontrolled decompression

Current industry standards addressing Premium connection validation (ISO 13679 and API RP 5C5) are based on downhole hydrocarbons production conditions, in a positive temperature environment range, up to 180°C.

CCS application, is not covered by these standards, while CO₂ injection brings in additional challenges to connection integrity related to sub-zero and rapid temperature variations.

VAM® Research & Development (partnership established between Vallourec & Nippon Steel Corporation since 1985) analyzed the different CCS application loading scenarios, to establish additional connection technology requirements. VAM® developed a unique methodology of validation, based on ISO 13679 / API RP 5C5, with the addition of CCS low temperature load requirements to include:

• Functional validation of technological elements at low temp.(surface treatment adherence, lubricating system, …)
• Full scale sealability testing at low temp.

 ✓ Sub-zero Thermal and Pressure cycling (500 cycles) 

 ✓ Thermal shock from operational temperature down to -80°C in less than 5 minutes

 ✓ Sealability under imposed temperature differential (Δtemp. = 80°C), between Pin inner and Box outer surface

 ✓ Rapid depressurization test with reduced internal pressure (100 → 0 bar)

As a result, VAM® has designed & validated with CCS leading operators, a relevant qualification testing protocol along with fit for purpose test equipment, allowing to demonstrate VAM® Premium connections mechanical & sealing integrity. Concomitantly, VAM®  successfully tested its latest technology connections to this CCS protocol, demonstrating that VAM® products are fit for CCS applications usage.

  - Connection test record -

Diameter [inch]	Weight [ppf]	Grade [ksi]
2-3/8	4.6	80
3-1/2	10.2	125
4-1/2	13.5	125
5-1/2	23.0	125

 

Prior experience in CCS projects

Nippon Steel has been involved in a number of CCS projects to support Material Selection process. Some of these are:

Large Scale CCS Project (Australia): naturally produced CO2 from offshore gas reservoirs, is separated at the onshore gas plant and re-injected into a giant sandstone formation two kilometers beneath Barrow Island, where it remains permanently trapped.

Offshore CCS Project (Norway): CO2 captured onshore, will be transported by newly designed ships, injected and permanently stored 2,600 meters below the seabed of the North Sea.

Supply record for CCS applications (just representative for each region/country)

Region	CO2 type	Materials	Connection
Australia	Cluster Hub (offshore)	SM25CRW-125	VAM®TOP
Norway	Cluster Hub (offshore-by shippment)	SM25CRU-80, SM25CRW-125	VAM®21, CWD-ST
UK	Cluster Hub (off shore-by pipeline)	SM25CRW-125	VAM®21, TOP-HC
North America	DAC* (onland) *Direct Air Capture	SM25CRW-125	VAM®21
North America	LNG project (onland)	SM25CR-110, SM25CRW-125	VAM®TOP, 21
Middle east	EOR/Blue ammonia (onland)	SM2535-110	VAM®TOP
Asia	※Any award-record ??? (offshore)	???	???

 

Last updated: Apr 2026 | K. Kanki, A. Wada