Lawani Raymond Leads High-Density Gravel Pack Innovation for Nigeria’s Landmark Assa North Gas Development

As Nigeria ramps up its natural gas production to meet soaring domestic and export demands, the successful completion of the Assa North-Ohaji South (ANOH) gas development project marks a turning point in the country’s energy strategy. At the center of this groundbreaking project is the pioneering work of Lawani Raymond, whose technical expertise and collaborative leadership were instrumental in designing and flawlessly executing a high-density fluid gravel pack strategy, setting a new standard for offshore completions.

The ANOH development, recognized as one of Nigeria’s most significant gas and condensate projects, is a cornerstone of the country’s National Gas Master Plan. Targeting an estimated 4.3 trillion standard cubic feet (Tscf) of gas and nearly 200 million stock tank barrels (MMstb) of condensate, the project’s success directly supports Nigeria’s strategic vision of boosting domestic gas utilization and positioning itself as a leading exporter.

However, achieving these ambitious objectives required overcoming formidable technical challenges. High-pressure formations, unconsolidated sands, reactive shales, and over-pressured gradients exceeding 0.67 psi/ft all demanded innovative sand control solutions that would not only ensure wellbore stability but also guarantee long-term production efficiency. It was within this complex environment that Lawani Raymond’s contributions proved pivotal.

Technical Complexity Meets Innovative Completion Design
At the heart of the ANOH project was the need to deliver high-performance gas wells while maintaining operational safety and minimizing formation damage. Sand production risk was a key concern, particularly given the high-permeability, unconsolidated nature of the reservoir. Traditional gravel pack methods would not suffice. Instead, the team needed a solution tailored to the field’s unique challenges.

Lawani Raymond, working closely with Schlumberger’s multidisciplinary team, took the lead in developing a robust, technically advanced gravel pack strategy. Recognizing that effective sand control would be essential to sustaining production, Raymond championed the use of high-density fluid gravel packs combined with a carefully formulated water-based drill-in fluid (DIF).

One of the first tasks was ensuring that the drill-in fluid system would not compromise wellbore integrity. Raymond advocated for a non-polymeric viscoelastic surfactant-based fluid system, designed specifically to minimize formation damage, offer excellent filter cake cleanup properties, and suspend proppant efficiently under high-pressure conditions.

His leadership in validating fluid formulations and ensuring compatibility with downhole conditions was crucial. Raymond was actively involved in overseeing comprehensive laboratory testing, including rheology assessments, return permeability evaluations, and fluid loss analyses. Special attention was given to the compatibility of the drill-in fluid with formation water and reservoir shales, both of which posed potential risks due to their reactive nature.

“Our objective was clear: engineer a system that balances production optimization with safety and environmental compliance,” Raymond stated. “Every parameter was scrutinized to ensure seamless deployment under the demanding reservoir conditions we faced.”

Selecting the Right Gravel Pack Equipment and Execution Strategy

Beyond fluid formulation, Raymond’s contributions extended to the selection and deployment of the appropriate gravel pack equipment. The completion design incorporated 7-inch by 9⅝-inch alternate path (AP) screen assemblies, chosen for their ability to deliver uniform gravel placement in wells with high deviation and large diameter boreholes.

Given the field’s over-pressured nature, the team opted for a 14.0 ppg calcium bromide (CaBr₂) brine as the carrier fluid. While this high-density fluid was optimal for well control and gravel suspension, its hazardous characteristics necessitated meticulous risk assessment and safety planning. Raymond led the development of stringent protocols for handling and deploying the brine, ensuring full compliance with HSE regulations.

A key innovation in the execution strategy was the use of viscoelastic surfactant (VES) fluids to carry the gravel. This system offered enhanced proppant suspension, efficient fluid loss control, and rapid filter cake removal post-treatment—all critical factors for maximizing reservoir contact and minimizing formation impairment.

Raymond also championed the use of real-time monitoring systems, enabling the team to track downhole conditions and surface parameters throughout the completion operation. This allowed for on-the-fly adjustments and ensured that gravel placement efficiency remained above 100%.

“Achieving uniform gravel placement without premature screen-out was non-negotiable,” Raymond emphasized. “We leveraged every available technology to maintain operational control and protect the well’s integrity.”

Execution Excellence: Zero Downtime, Maximum Efficiency

Flawless execution defined the ANOH project. Lawani Raymond played a hands-on role throughout the deployment, from overseeing equipment loadouts to coordinating surface control systems and monitoring real-time data.

The lower completion operation was executed without a single non-productive time (NPT) incident—an impressive feat given the complexity of the project. Gravel placement efficiency exceeded expectations, with more than 100% packing confirmed via post-job evaluation.

Inflow testing of the formation isolation valve (FIV) further validated the well’s integrity. Raymond’s leadership extended through the successful deployment of the 7-inch tubing and subsequent well clean-up, using inhibited water under underbalanced conditions to facilitate efficient wellbore stabilization.

The production results were outstanding. The well delivered production rates that exceeded initial projections, achieving low skin values and optimal drawdown, underscoring the effectiveness of the gravel pack design.

Reflecting on the project, Raymond commented, “This success is the result of collaboration, attention to detail, and a shared commitment to technical excellence. Every stakeholder played a vital role in ensuring we delivered a solution that met Nigeria’s energy objectives.”

Broader Industry Impact: A New Benchmark for Offshore Completions

The ANOH project is now recognized as a model for high-efficiency completions in challenging offshore reservoirs. Raymond’s leadership and technical contributions underscore the importance of integrating advanced fluid systems, rigorous quality assurance, and real-time monitoring to achieve sustainable production outcomes.

Beyond the immediate success of the project, Raymond views this experience as a blueprint for future developments across Nigeria’s offshore sector. The meticulous approach to sand control, environmental safety, and production optimization demonstrates how collaborative engineering can overcome even the most complex challenges.

“The lessons learned here are applicable across the region,” Raymond noted. “Whether dealing with high-pressure reservoirs, reactive formations, or strict regulatory environments, a data-driven, collaborative approach can deliver results that benefit both operators and the broader energy landscape.”

Looking Ahead: Knowledge Sharing and Continuous Innovation

As Nigeria continues its drive to increase domestic gas production and strengthen its position in the global energy market, Raymond remains committed to sharing insights and fostering knowledge transfer. His focus includes refining gravel pack fluid systems, enhancing HSE protocols, and exploring new technologies to further streamline completion operations.

He also emphasizes the importance of capacity building within Nigeria’s energy sector. “Technical excellence must be paired with talent development,” he remarked. “Investing in local expertise ensures that the successes we achieve today are sustained and replicated in future projects.”

Through industry conferences, technical papers, and mentorship initiatives, Raymond is actively contributing to the next generation of Nigerian engineers and positioning the country’s offshore sector at the forefront of global best practices.