AGR were assigned by the International Petroleum Associates Norway (IPAN) to perform the technical studies and training, concentrating on best methodology for the Enhanced Oil Recovery of Heglig oilfield in Sudan. The EOR activity in Sudan was administrated by the Norwegian Petroleum Directorate (NPD) on behalf of the Oil for Development (OfD) programme which provides foreign assistance focusing on petroleum policy including legal and institutional framework, resource and HSE management.
Heglig oilfield is situated within the north-west to south-east trending Muglad Basin in south-west Sudan, part of the Central African Rift System. Heglig boasts much of Sudan’s proven oil reserves. The oilfield was first developed in 1996 by Arakis Energy and is today operated by the Greater Nile Petroleum Operating Company, GNPOC. Production reportedly peaked in 2006. The field is connected to Khartoum and Port Sudan via the Greater Nile Oil Pipeline.
The assignment resulted in recommendation for further planning of the selected Pilot(s). Recommended work prior to the Front-End Engineering Design (FEED) phase evolved from the study:
G & G
- Re-process seismic to improve frequency content
- Interpret shallow events to see if they can explain features in depth
- Implement G&G and Petrophysical work in field static model for a detailed geological analysis of pilot area(s)
- G&G input to history matching
- Take fluid samples analysis for viscosity and asphaltene content
- Analysis of final results from core experiments and update simulation model
- Multidisciplinary effort
- Detailed geological evaluation of selected area
- Well design & borehole stability study
- Risk and contingency planning
- Pilot design and detailed planning
- Design pilot facilities (front-end engineering design)
- Impact assessments: Production facilities & Environmental
- Plan infrastructure and logistics
The Heglig oilfield EOR study was challenging on many levels, particularly due to the lack of availability of a complete data set and field history.
Multidisciplinary interaction proved critical to the overall study through the integration of knowledge and information so the three main EOR scenarios could be investigated, from the Reference Case of the existing plan, to the action of drilling infill horizontal wells and to more advanced chemical EOR by polymer injection, and combination of the two.
The Heglig oilfield study also conveyed the importance of providing knowledge transfer by training the Sudanese geoscientists and engineers to enable future sustainability of the much-needed Sudanese petroleum industry.