UpLIFT New Solver Phase II – CO₂Speed

Background and project purpose?

Carbon Capture and Storage (CCS) is a key technology to fulfill the net zero greenhouse gas (GHG) emission targets by 2050. The captured CO₂ can be transported by long-distance pipelines and injected into a reservoir for permanent storage. Flow of CO₂ in pipes is therefore an important part of the CO₂ management chain, as a possible transport method between the point of capture and the point of storage, as well as for the injection facility in itself (riser/downcomer, sea line, wellbore), which can comprise a complex network of pipes. The flow can be both single- or multi-phase flow of CO₂ or CO₂ with impurities.

The Energy industry, which has the most relevant competence to deal with CO₂ flows in pipes, has a long-lasting culture for flow assurance. This concept means that through careful design and operation, the operational disturbances are reduced as much as possible to ensure a safe and reliable flow in the pipes. This requires modelling tools, mostly relying on one-dimensional, multiphase flow simulators. One dimensional modelling was chosen over three-dimensional CFD models due to numerical simulation time for long pipelines, even though the latter hold better accuracy. One-dimensional models hold sufficient accuracy and require significantly less computational time. However, for CO₂ flows, pipelines may be much longer than for oil and gas tiebacks and numerical computation time becomes a hurdle even for one-dimensional models.

CO₂ transport in pipes is usually restricted to single phase flow (mainly supercritical or liquid phase) due to the lack of confidence for designing multiphase flow systems. However, multiphase flow may be difficult to avoid in normal operation and must be managed during planned or unplanned events. Multiphase flow means the presence of both CO₂ in gas phase and in liquid phase at the same time. Two-phase flow will also be difficult to avoid in the wellbore when injecting into (low-pressure) reservoirs, and during shut-in and restart. Modelling accurately complex fluids and scenarios will come with a computational time expense, as multiphase flow simulations run slower than single phase flow simulations since more complex mathematical modelling is required.

In previous research projects, we have developed and demonstrated a new numerical solver for LedaFlow, which is applied to Slug Capturing and released commercially. What Slug Capturing is about is not important here, but the relevant aspect is that it requires a computational mesh with many cells which require long simulation times. We consequently had to develop a more efficient, numerically accurate and parallelizable numerical solver to run simulations with Slug Capturing. Since we are facing a similar challenge with CO₂ transport and injection networks, the goal of the present project is to add the required functionalities to this new solver to be able to simulate CO₂ while taking advantage of the improved efficiency.

What are the project objectives?

Fast and robust simulators allow industry to optimize the pipeline and injection well infrastructure allowing reduction of cost. The main goal is the demonstration of a new solver technology allowing multicore and multithreading capabilities with higher accuracy which can contribute to lowering the simulation time for CO₂ flow assurance studies. A lower simulation time means that the flow assurance engineers, either working in energy companies or consulting companies, can run more scenarios to safely operate the CO₂ transportation and injection infrastructure. It is important to ensure that the design and operation is not compromised when cost savings are made to make CCS more affordable. The ability to simulate more cases supports such a cost reduction strategy by helping the industry in de-risking CCS infrastructure projects. The project will deliver new solver capabilities for LedaFlow 1D Engineering.
The project goal is to create a commercially available, efficient, and accurate multiphase flow simulator to enable the deployment of safe and cost-efficient CO₂ transport and injection infrastructure. The model accuracy is covered in another project called “CO₂Flow IPN”, while this project focuses on numerical efficiency i.e. the speed of simulation.