The Heglig field is operated by GNPOC – the Greater Nile Petroleum Operating Company. Despite the field achieving an oil production rate of 50K bpd, the field water cut rose to an alarming 250K bpd – a serious production impediment. Amidst competition from numerous EMP companies, Nautec in partnership with PETRONAS successfully won the contract to solve the issue of excess water breakthrough.
In conjunction with Petronas Research &Scientific Services (PRSS), Nautec undertook a full field review of Greater Heglig.
Full Field Review (FFR) aimed to assist in rejuvenating the fields through maximisation of recoverable reserves, identifying ways to manage excess water production, identifying problematic wells and providing remedial solutions and productivity enhancements.
Keeping these issues in mind an integrated and validated three dimensional, three phase reservoir geological and simulation models were developed for all the Greater Heglig fields. The in-Depth FDP simulations revealed suboptimal well integrity as the major source of high-volume water breakthrough. Using Nautec’s state of the art TDAS (Technology Deployment and Appraisal System), a way forward for the rejuvenation of Greater Heglig was formulated.
Based on the review findings, Nautec produced several future reservoir management (RMP) strategies for the Heglig fields with a view of accessing the recoverable reserves. Key recommendations included:
- Remediation of existing wells through acute cement channel and micro annuli repair work to mitigate wellbore integrity issues
- Operationalisation of remedial activities to mitigate excessive water production through immediate well intervention programs
- Strategic water disposal injection wells to efficiently drain remaining reservoirs
The Value Added
Proposed remedial well intervention programmes and new infill wells improved Greater Heglig’s simulated field recovery factors by 16% with a maximum peak oil rate of 60,000 stb/d
Through Nautec’s extensive experience in well integrity issues the study and recommendations were completed inside of 6 months (ahead of the industry average of 10-14 months) and within budget parameters
The proposed strategies were delivered to the GNPOC headquarters in Khartoum, Sudan