CO2 Flow Assurance for Cost-effective Transport (CO2FACT)
Project partnersEquinor Energy AS (Project owner), Total E&P Norge AS, Gassco, LedaFlow Technologies DA, Schlumberger Information Solution AS, Shell Global Solutions International, Chevron
Project period10/18 – 12/21
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.
In recent decades, great efforts have been made to develop the necessary thermodynamic models and flow dynamic tools dedicated to CO2. The project partners contributed to several R&D projects to build suitable test rigs for CO2 Flow Assurance and also finance first validation work. For example, the project CO2VIP led to a very flexible but short test rig at IFE and some important validation attempts. In the DeFACTO project, a test rig is being built at SINTEF with a considerable vertical length. In addition, SINTEF has developed a relatively long horizontal test rig (ECCSEL/DEPRESS) for pressure relief experiments. All these rigs provide a good infrastructure to conduct experimental study, the data from which can be used to verify Flow Assurance tools.
All previous and existing projects 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, etc.
The main delivery of the project will be a best practice report describing how the tool will be 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. To achieve this, the high-quality experimental study is critical.
What has the project done in terms of activities?
The following activities have been carried out so far:
• Extensive experimental study has been performed for various phenomena of pure CO2 flow 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 impurities of CH4 and N2 by existing available data;
• Testing of the existing Flow Assurance tools against the experimental data from IFE’s CO2 flow rig was conducted;
What has the project achieved ? Did the project achieve its objective ?
The project is still on-going, the experimental study in the original scope will be completed by summer, 2021. The achievements obtained so far 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 major target of the project was on secure high quality of data (both laboratory and field operation), this has been and will be achieved. There is a need to have more resource than planned in the project to address technology gaps identified.
The project team will complete the rest activities planned within this project within 2021, the main activities are: experimental study of the impact of impurities on the flow behavior, test of the Flow Assurance tools with the data obtained. The best practice of the existing Flow Assurance tools for CO2 applications will be issued, however, some technology gaps will remain after the current project. There is a need to have experimental data with larger pipe diameter and longer pipe length to ensure the flow models are applicable for a real pipe system which is operated under the condition where two-phase flow may occur.
Shell Global solutions internationals, Chevron joined project in 2021.