By Gabriel Ewepu

ABUJA – AN expert on reservoir science and production optimisation, Engr Charles Deigh, whose vast experience cuts across the upstream, midstream, and downstream of the oil and gas sector spanning decades with high professional inputs made to the Industry at different capacities passionately spoke on the Brownfields in the Niger Delta region on effective production optimisation techniques and best practices for maximum benefits for the entire nation.

Revitalisation of Brownfields

Deigh said Nigeria’s upstream petroleum sector faces a pivotal moment. While frontier exploration continues, the country’s most immediate production gains lie not in new discoveries but in the revitalisation of brownfields: the mature oil and gas assets that have produced for decades and now exhibit natural decline due to reservoir depletion, ageing infrastructure, and operational gaps.

He also pointed out that, “With more than half of Nigeria’s onshore and swamp fields classified as mature, optimising these assets is essential for national energy security, government revenue stability, and the long-term sustainability of the Niger Delta petroleum ecosystem.”

Factors negatively impacting Nigeria’s Brownfields

Meanwhile, he expressed deep concern while he highlighted some of the factors negatively affecting Brownfields and said, “Brownfields typically experience declining reservoir pressure, rising water production, sand-control challenges, high gas–oil ratios, declining wellbore integrity, deteriorating surface facilities, and increasing flow assurance complications. Community-related disruptions and evacuation constraints across the Niger Delta terrains further compound these issues.”

Brownfields remain Nigeria’s greatest opportunities

“Yet despite these challenges, brownfields remain one of Nigeria’s greatest opportunities for near-term production growth. Globally, more than 70 per cent of incremental oil production comes from mature assets. In the Niger Delta, where subsurface knowledge, existing infrastructure, and operational footprints are already established, these fields can often produce more economically today than during initial field life, provided operators deploy fit-for-purpose optimisation techniques and disciplined reservoir management.

“An effective optimisation programme begins with a strong understanding of the subsurface. Effective production improvement depends heavily on high-quality data. Routine surveillance, including bottom-hole pressure acquisition, production logging, periodic well tests, GOR/BS&W trending, pressure transient analysis, and dynamic simulation updates, provides the technical foundation for diagnosing impairments and refining depletion strategies.

“Without this data-driven discipline, brownfield optimisation becomes speculative and inconsistent, often leading to costly misplacement of investment.”

Modern reservoir remapping and geomodelling critical

He also strongly emphasized that, “Modern reservoir remapping and geomodelling are also critical. Many mature Niger Delta fields were developed with 2D seismic and early static models that lacked the resolution to capture complex compartmentalisation. Current technologies, such as 3D seismic reprocessing, seismic inversion, multi-attribute analysis, improved petrophysics, and integrated static-dynamic modelling, allow operators to identify bypassed pay, attic oil, and isolated reservoir lobes with greater confidence.

“These advances support reserves maturation and enable more accurate development drilling.
Where new wells are required, infill drilling and step-out wells remain some of the most efficient ways to enhance areal and vertical sweep, offset decline rates, and unlock remaining hydrocarbons.

“A properly positioned infill well can restore production trends and significantly extend field life. Sidetracks and re-entries often yield even higher economic return: by reusing existing wellbores, operators access untapped reservoir segments while minimising CAPEX and shortening cycle times. This approach has delivered some of the most successful brownfield outcomes in the Niger Delta.”

Daily Brownfield management

Speaking on Brownfield management, he (Deigh) said, “Well and production optimisation are central to daily brownfield management. The Well, Reservoir and Facility Management (WRFM) framework, which focuses on restoring, maintaining, and improving well performance, is key to sustainable revitalisation.

“Common interventions include reperforation, zone switching, scale removal, sand control, gas-lift repairs and optimisation, water shut-off treatments, and acid stimulation. These measures often restore 30 to 60 percent of lost deliverability at a fraction of the cost of new drilling. Artificial lift optimisation is also crucial in depleted fields.

“Gas-lift redesign, ESP installation, hybrid systems, and plunger lift for marginal wells can help maintain stable production over time.
Flow assurance is also vital for brownfield performance, particularly in swamp and shallow offshore terrains where wax deposition, hydrates, emulsions, slugging, corrosion, and scale threaten system integrity. Regular pigging campaigns, targeted chemical injection, thermal insulation of flowlines, optimised separator heating, and slug catcher upgrades significantly reduce downtime and deferment.

“Addressing flow assurance issues alone can recover 10–20 per cent of yearly deferred volumes, an impact often greater than that of drilling new wells.
Facility optimisation and infrastructure renewal are essential.

Salient issues about Nigeria’s Brownfields

According to him, “Many brownfields in Nigeria use ageing equipment designed for lower water cuts, gas production, and solids content than current conditions require.

“Debottlenecking, through separator reconfiguration, compressor upgrades, improved water treatment, dehydration enhancements, flare gas utilisation, and corrosion repairs, expands processing capacity and increases uptime. Power reliability is also critical; hybrid gas/diesel systems, micro-turbines, and solar-assisted solutions help minimise downtime from generator failures or fuel shortages.

“Operational stability in the Niger Delta depends on reducing unplanned shutdowns caused by pipeline vandalism, crude theft, community interference, and facility outages. Investments in pipeline surveillance, real-time monitoring, community engagement, redundant evacuation routes, and modular production systems help lower operational risk and improve production continuity.
Enhanced Oil Recovery (EOR) is increasingly important for long-term asset revitalisation.

“Waterflooding is the most established method for restoring reservoir pressure and improving sweep efficiency in mature sandstone reservoirs. Gas reinjection stabilises gas-cap drive and enhances oil rim recovery where field geometry allows.

“Polymer flooding and chemical EOR pilots are emerging for reservoirs with challenging mobility ratios.

Future opportunities for Nigeria’s Brownfields

“Miscible and immiscible gas injection present future opportunities for deepwater and offshore brownfields as gas handling infrastructure develops.
Digital transformation enhances all aspects of brownfield management.

“SCADA systems, smart meters, digital twins, and real-time analytics enable early decline detection, rapid optimisation, and safer remote operations. Combined with a strong WRFM culture, daily monitoring, monthly reviews, and annual reservoir management plans, digitalisation reduces avoidable deferment and improves operational efficiency.

Evolving Govt regulations to support Brownfields

He also counseled that, “Nigeria’s regulatory and fiscal environment must continue to evolve to support brownfield optimisation. Faster approvals for well interventions and infill drilling, incentives for EOR projects, improved metering standards, flexible flare gas utilisation, and strong community development agreements will reduce operational friction and accelerate project execution.

“The Nigerian Upstream Petroleum Regulatory Commission (NUPRC) has made progress through reserves growth and production surveillance initiatives, but ongoing alignment with operators remains essential.

Nigeria’s mature fields are not declining assets; they are undervalued national resources capable of delivering significant incremental production when managed with technical discipline, cost efficiency, and stakeholder collaboration.

“In today’s competitive global oil market, brownfield optimisation is not just a technical choice but a national economic imperative.”