Cold heavy oil production using CO2-EOR technique.
MetadataShow full item record
TCHAMBAK, E.N. 2014. Cold heavy oil production using CO2-EOR technique. Robert Gordon University, PhD thesis.
This thesis presents results of a successful simulation study using CO2-EOR technique to enable production from an offshore heavy oil field, named here as Omega, which is located offshore West Africa at a water depth around 2000 m. The findings and contributions to knowledge are outlined below: 1. Long distance CO2 transportation offshore – The solution to the space and weight constraints offshore with respect to CO2-EOR, is a tie-back via long distance CO2 dense phase transportation from onshore to offshore. 2. Cold heavy oil production (CHOP) using CO2-EOR technique - Based on conditions investigated, Miscible Displacement was found to be more efficient for deepwater production. However, Immiscible Displacement can offer greater reliability with regards to CO2 sequestration. 3. CO2 sequestration during CHOP using CO2-EOR technique – Lower CO2 may be released post start-up operation, followed by gradual decline of CO2 retention after the production peak. CO2 retention increases with increasing reservoir pressure, starting with 17.7 % retention at 800 psig to 32.8 % at 5000 psig, based on peak production analysis. 4. Techno-economic Evaluation – Miscible displacement is asssociated with higher cash flow stream that extend throughout the lifetime of the asset due to continuous production while Immiscible Displacement has a longer payback period (in order of 22 years) due to the time lag between the CO2 injection and the incremental heavy oil production. 5. Mathematical Modelling – Improved mathematical models based on existing theories are proposed, to estimate the CO2 requirement and heavy oil production during CHOP using CO2-EOR technique, and to provide an operating envelope for a wide range of operating conditions. As part of further work, the proposed models will require more refinement and validation across a broad range of operating conditions, could be adapted and modified to increase its predictive capability over time.