Explorers Call for Improved Reservoir Modeling as Nigeria's Deepwater Drilling Costs Reach $1 M per Day

Peter Uzoho

The Nigerian Association of Petroleum Explorationists (NAPE) has called on oil and gas operators in Nigeria to invest in more advanced reservoir modelling. The association warned that a limited understanding of submarine channel architecture is increasing uncertainty and reducing recovery rates.

NAPE highlighted that deepwater drilling costs have surpassed $1 million per day, underscoring the need for accurate subsurface characterisation to minimise exploration and development risks.

During NAPE’s June Technical session in Lagos, President Mrs Olajumoke Ajayi and TotalEnergies EP Nigeria geoscientist Dr Busari Olarewaju delivered the remarks.

Dr Olarewaju presented a technical paper titled “Geomorphology and Evolution of a Pleistocene Submarine Channel‑Levee Complex in Deepwater Nigeria: Implications for Reservoir Modeling and Field Development Strategy.”

He explained that detailed knowledge of how deepwater channels form and evolve is essential for reducing subsurface uncertainty, improving assessments of reservoir connectivity, and optimising hydrocarbon recovery.

“The message here is that we understand the detailed interactive presence of the flow to make sure to maximise the production and you delay water cut as much as possible,” Dr Olarewaju said.

The study focused on a north‑south erosive‑constructive channel‑levee complex in eastern deepwater Nigeria.

Using seismic datasets covering more than 1,000 square kilometres, alongside well data, gamma‑ray logs and high‑resolution near‑surface seismic, Dr Olarewaju and his team examined over 40 three‑dimensional channel systems across the Niger Delta in a research programme that spanned three to four years.

Their findings revealed complex architectural elements within the channel system, including lateral accretion packages, vertically stacked channels, outer levees, mass‑transport deposits and hemipelagic drapes.

The channel evolved from a V‑shaped to a U‑shaped geometry and shifted from symmetrical to asymmetrical configuration. Variations in incision depth along the channel reflected the influence of underlying structural features, particularly a deep‑seated thrust‑related structure that forced the system to adjust erosion patterns to maintain equilibrium.

Dr Olarewaju said the researchers reconstructed the channel’s evolutionary history in five stages, from initial erosion and sediment bypass through to abandonment and deposition of hemipelagic drapes.

He stressed that this evolutionary history forms the foundation for facies modelling and reservoir modelling, which in turn guide field development decisions.

He noted that heterogeneity within channel systems directly impacts fluid movement, sweep efficiency, water breakthrough and overall production performance. For reservoir quality targets, he identified lateral accretion deposits as the most attractive components due to their sedimentary characteristics.

On geohazards, Dr Olarewaju said the shallow study area was not significantly affected by abnormal pressure, but researchers identified pockmarks around the channel complex. These suggest fluid migration from deeper levels and confirm an active petroleum system, while also highlighting pockmarks and shallow gas accumulations as major risks in deepwater operations.

In her opening remarks, President NAPE Ajayi said deepwater geology remains one of the most challenging areas of geoscience but also one of the world’s most prolific hydrocarbon provinces.

“Deepwater drilling operations cost more than one million dollars daily, making it imperative for operators to accurately understand subsurface structures and reservoir characteristics before committing significant investments,” Ajayi stated.

She said a thorough understanding of deepwater geology is essential to reduce exploration risks and maximise returns in Nigeria’s offshore sector.

Ajayi described the meeting’s theme as timely for Nigeria’s upstream growth, noting that the country cannot take full advantage of deepwater opportunities “without understanding how to explore effectively and efficiently.”

Chairman of the session, Dr Wilson Osung, said the presentation demonstrated how integrated seismic stratigraphy and seismic geomorphology can improve understanding of architectural elements, channel evolution and reservoir behaviour, while also revealing structural controls that influence submarine channel systems.