CO₂ Flow Assurance for Cost-effective Transport (CO₂FACT)

Background and project purpose ?
Many CCS projects were designed and operated with flow assurance tools that were developed for oil & gas operations and not for CO₂. In order to mitigate the lack of suitable thermodynamic and flow-dynamic models for CO₂, engineers were forced to apply large safety margins for design and operations, and this resulted in very expensive CCS projects world-wide. The qualification of the existing flow assurance tools for CO₂ application requires the systematic testing of dedicated data of both laboratory scales and field operation.
All previous and existing projects (CO₂VIP, DeFACTO) do not have a systematic approach to validate the existing flow assurance tools. In the CO₂FACT JIP, the comprehensive experimental study has been planned to address all different flow behaviors of CO₂ in transport pipeline and injection well. The operational data from Snøhvit CO₂ transport is collected. The data from both laboratory and field operation will be used to test the performance of the existing flow assurance tools for CO₂ applications.

What was the project objective ?
The project’s goal is to validate, tune and further develop tools for flow models. This is done based on experiments with pure CO₂ and also CO₂ with impurities (CH4 or N2). Here, various pipes and well operations will be simulated, including:
• Steady-state (dense liquid, supercritical, two-phase)
• Depressurization (full and controlled)
• Fluid hammer, shut-in and restart, phase change, etc.

The main delivery of the project is the best practice report describing how the tools are used to simulate various operations and describe the uncertainties in the simulation results so that engineers can reduce their margins of uncertainty in the design and operation of new CO₂ plants.

What has the project done in terms of activities?
The following activities were carried out:
• Extensive experimental study has been performed for various phenomena of pure CO₂ flow & CO₂ with impurities at IFE’s CO₂ flow rig via sub-contract;
• Snøhvit operational data have been collected and used to test the existing flow assurance tools (OLGA and LedaFlow codes);
• The PVT models available within OLGA and LedaFlow have been assessed for CO₂ fluid with various impurities by existing available data;
• Extensive testing of the existing flow assurance tools against the experimental data from IFE’s CO₂ flow rig was conducted; The technology gaps of the existing flow assurance tools were also identified;
• Improvement of the existing flow assurance tools has been made for some CO₂ applications.
• The best practice document of the existing flow assurance tools for CO₂ applications
What has the project achieved ? Did the project achieve its objective?
The achievements obtained are:
• High quality data from both laboratory and field operation have been obtained, this is critical for the benchmark and further development of the flow assurance tools for CO₂ applications;
• The existing flow assurance tools are qualified for CO₂ applications as long as the pipeline and well is operated under single-phase flow condition;
• As for CO₂ two-phase flow applications, a number of technology gaps of these flow assurance tools have been identified; The best practice documents of these flow assurance tools have been generated for CO₂ applications. Large uncertainties for some applications are expected.

The major target of the project was on secure high-quality data (both laboratory and field operation), this has been achieved. The detailed technology gaps of the existing flow assurance tools have been identified via systematic testing of the tools against the data obtained in this project. The detailed analysis of the experimental data obtained requires additional resources. Some selected results from this project have been disseminated in both CLIMIT Digital (2021), TCCS-20 (2019), SPE-CCUS(2020), GHGT-2021, and Northern Lights project.

Future plans ?
More detailed analysis of the experimental data needs to be carried out to improve the performance of the existing flow assurance tools to the next level. These data can be used to improve the physical models for two-phase CO₂ flow, benchmark these tools for transient and development flow with two-phase CO₂ stream in the system. Some results will be published in relevant conferences and Journals. The technology gaps of these flow assurance tools identified in this project requires dedicated R&D program to resolve in the future.