CCS, Oil and Gas Need Olga

Olga Prosjektet Robust, Enhanced and Accurate CO₂ Handling (REACH), has a budget of NOK 28.2 million. CLIMIT contributes 35.5 percent of the funding. The work is led by SLB – with Equinor, Repsol, Gassco, ENI, BP, Shell and later Chevron og ExxonMobil as partners.

The Olga tool has enabled development of oil and gas fields that were previously considered unprofitable or technically too challenging. Now Olga is approaching a new milestone which involves addressing future needs within carbon capture and storage (CCS). The software is being upgraded to deliver accurate simulations of multiphase CO₂ transport, with potential for both technical and economic gains.

From Oil and Gas to CO₂ Management

Olga was developed in the 1980s at the Institute for Energy Technology (IFE), in collaboration with Statoil and Sintef. At the time, it was a groundbreaking tool for simulating complex multiphase flows in pipelines and wells – where oil, gas, and water move simultaneously. Responsibility was later taken over by Scandpower Petroleum Technology, which was subsequently acquired by SLB (Schlumberger).

In recent years, Olga has gained functionality for CO₂ transport. This has been achieved through a series of research and development projects, several of them supported by the CLIMIT program. As early as 2009, the first feature for modelling pure CO₂ was introduced.

Olga – The Next Chapter

Building on the experience of earlier projects, Olga REACH was launched in 2022.

The goal is to develop Olga to handle multiphase CO₂ transport, with the same robustness and accuracy the tool already provides for oil and gas. This entails further development of the software’s very core, its system of equations. In addition, come upgrades to the thermodynamic and hydraulic models used to describe flow. The new functionality will be validated through extensive testing against laboratory and field data. – We want to close the technology gap that has so far limited multiphase simulation of CO₂. Olga must be a tool the industry can rely on, even when transport occurs under demanding conditions, says SLB’s Principal Scientific Computing Engineer, Alexandre Brigadeau.

Multiphase CO₂ Could Be a Key

In today’s CCS projects, CO₂ is usually transported in a single phase – either as a liquid, a supercritical fluid, or in some cases as gas. Allowing multiphase transport makes it possible to reduce pressure without losing flow control, potentially yielding significant cost savings.

Multiphase transport also offers advantages when injecting into low-pressure reservoirs. If liquid CO₂ is injected into a warm gas-filled reservoir, the gas will expand, and the temperature will drop sharply due to the Joule-Thomson effect. This can create large geomechanically stresses in the reservoir. By operating in multiphase conditions, the most extreme temperature drops can be avoided, thereby reducing the risk of damage. – Multiphase CO₂ transport provides greater flexibility and can be more cost-effective, especially when injecting into low-pressure reservoirs. It opens the door to solutions that today are not commercially attractive, explains Brigadeau at SLB.

Technical Challenges That Must Be Solved

Even though the benefits are clear, multiphase CO₂ transport is technically demanding.
CO₂ behaves differently from oil and gas. When CO₂ mixes with impurities, complex thermodynamic conditions arise which require highly accurate models. Challenges are also linked to rapid pressure releases, where thermal and thermodynamic equilibrium is not reached.

Another critical issue is the precise prediction of flow regimes. Errors here may cause significant deviations in the calculation of pressure drops and liquid accumulation. This, in turn, can lead to incorrect pipeline sizing or flawed operational strategies. – We must be able to predict pressure drops and liquid accumulation with high accuracy. Small errors can have major consequences in both design and operation, Brigadeau continues.

Anchored in Experimental Data

A key strength of the Olga project is its solid foundation in experimental data from multiple laboratories. – Verification against real measurement data is essential. Olga users must be able to fully trust the results when making investment decisions, Hoyer says. He emphasizes that this is not only a question of technical quality, but also of building confidence in an industry facing major investments in CCS.

Industrial and Commercial Significance

For large-scale CCS projects, precise simulations can be decisive for profitability. A more robust tool reduces risk of operational disruptions, leaks, or other unwanted incidents. At the same time, accurate calculations can contribute to optimal sizing of pipelines and process equipment, lowering both capital and operating costs.

As more countries and companies commit to reducing CO₂ emissions, the need for reliable simulation tools is growing. Olga is positioning itself as a key contributor to meeting this need, both technologically and commercially. – This is not just a technology investment, but an investment in the ability to realize more CCS projects in a safe and cost-effective way, Hoyer continues.

The Road Ahead

The project is scheduled to conclude in 2025. Already, discussions are underway about an extension to address new needs that may arise as the industry begins to implement multiphase CO₂ transport on a larger scale. – We see this as a journey. CO₂ management technology will develop rapidly over the next decade. Olga will remain at the forefront, concludes Norbert Hoyer at SLB.

Do you want to learn more about the areas of corrosion, measurement, and monitoring? Check out these articles:

“CO₂ Safe & Sour”; How pure must CO₂ be for CCS?

Aiming to Make CO₂ Calculations More Accurate and Accessible

How CO₂ Management Will Become Safer and More Affordable