Oil field redevelopment
Sicily Channel, offshore Italy
90m to 100m
Nilde oil field, located at a water depth between 90m and 100m in the Sicily Channel, offshore Italy, is being redeveloped.
Operated by ADX Energy, the field is anticipated to produce 34.1 million metric barrels (Mmbbl) of oil at an initial rate of 22,000 barrels per day upon redevelopment.
ADX Energy signed a memorandum of understanding (MoU) with Calm Oceans to jointly progress the plan for the Nilde field redevelopment in December 2016. The MoU was later extended until July 2018. COPL constructed a mono column platform (MCP) and is designing a gravity-based mooring, storage and offloading system (RPSO) for the project.
The Italian Regulatory Authority raised doubts over ADX’s financial ability to retain the tenure in January 2018.
ADX Energy signed an agreement to farm-out a 50% interest in the d 363 CR-AX Permit area to SDP Services in October 2018. The farm-out deal includes €20.82m ($23.9m) investment by SDP to fund the work programme and will provide support for the ratification of the licence by the Italian authorities.
Italy passed a bill in 2019 to suspend oil and gas exploration to review the suitability of exploration areas for sustainable prospecting, exploration and development of hydrocarbons. ADX’s request to reduce the permit area by approximately 55% to reduce the impact on the environment was approved by regulatory authorities. The moratorium on the Nilde field operations is expected to continue until the first quarter of 2021.
Nilde oil field redevelopment location
The Nilde oil field lies in the d 363 CR-AX ‘Nilde’ permit area in the Sicily Channel, approximately 60km away from the coast. The permit area also comprises nearby discoveries, including Nilde-Bis, Norma and Naila.
Nilde oil field geology and reserves
Nilde oil field contains a productive reservoir called Nilde Formation, which extends over 1,500m in a stretch of faulted blocks folded upwardly. The formation is a fractured limestone carbonate of the Middle Miocene era. The system has dual-porosity containing fracture and matrix systems.
The permit area is estimated to have contingent resources between 19.2Mmbbl and 65.6Mmbbl of oil and prospective resources between 40Mmbbl and 201Mmbbl.
Nilde oil field discovery and production
Nilde oil field was discovered in 1973 by a joint venture between Eni (formerly AGIP) and Shell and was appraised by drilling six wells.
Nilde is a mature oil field that entered production in 1982. It produced 20.5Mmbbl of oil of 39o API until 1989 via a sub-sea production system tied-back to the FPSO vessel Firenze.
The subsequent water encroachment in the main vertical well, Nilde-2, increased water-cut and resulted in the abandonment of the well prematurely. The oil field was reviewed under an integrated subsurface review by ADX, confirming the presence of 34.1Mmbbl of 2C contingent resources.
Nilde oil field redevelopment details
Nilde oil field will be redeveloped utilising Nilde base case development concept, which will provide a cost-efficient alternative to the sub-sea development options.
A total of three production wells and a gas disposal well with dry well-heads will be drilled by a jack-up rig and tied to a self-installing MCP, which will contain the production facilities with the maximum production rate of 25,000 barrels of liquids per day. The MCP can support drilling rig, gas reinjection, processing equipment, and accommodation facilities. It will facilitate simultaneous drilling and production activity, reducing time and expenditure.
The hydrocarbons will be separated into oil, gas, and water. The oil will be pumped to the customised RPSO from which it will be transported using off-take tankers for further processing.
Other assets of ADX Energy
In addition to the Nilde oil field redevelopment, ADX Energy also holds assets including the Dougga gas condensate and LPG project located offshore Tunisia, and a gas appraisal programme onshore Romania.
The cumulative resources of the three assets of the company are estimated to be 163Mmboe.