Peter Uzoho

The Nigerian Association of Petroleum Explorationists (NAPE) has urged oil and gas operators in the country to invest in improved reservoir modelling, warning that weak understanding of submarine channel architecture was increasing uncertainty and cutting into recovery.

The association noted that deepwater drilling costs had exceeded $1 million per day, making accurate subsurface characterisation essential for reducing exploration and development risks.

President of NAPE, Mrs Olajumoke Ajayi and a geoscientist with TotalEnergies EP Nigeria, Dr. Busari Olarewaju made the calls at the NAPE’s June Technical session held in Lagos.

Busari presented the 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 said detailed knowledge of how deepwater channels form and change over time was critical to reducing subsurface uncertainty, improving reservoir connectivity assessment, 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,” Busari 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, Busari and his team examined over 40 three-dimensional channel systems across the Niger Delta in a research programme that lasted three to four years.

Their findings, he said, 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, he explained, 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.

Busari 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 such 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, Busari 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, but also highlight pockmarks and shallow gas accumulations as major risks in deepwater operations.

In her opening remarks, President of 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.