Mariano Guerrico, Global Technology Manager, Tracerco, describes how cutting-edge technology has transformed flow control and monitoring, showcasing a case study from the Santos basin offshore Brazil.
Ensuring consistent, efficient production in offshore oil and gas operations has never been more challenging. As reservoirs mature and fields become increasingly complex, operators must contend with issues such as slugging, hydrate formation, and sand production, all of which can compromise flow assurance and pipeline integrity.
Traditional measurement and inspection methods are often intrusive and disruptive, and don’t provide the real-time insights needed to optimise production and maintain regulatory compliance. Non-intrusive, real-time diagnostics help operators maximise uptime, reduce costs and enhance safety.
Overcoming flow assurance challenges through non-intrusive monitoring
Flow assurance issues pose a constant risk to production efficiency. Severe slugging can cause unstable production rates and increase wear on equipment, while hydrate formation can lead to blockages that require costly shutdowns to resolve. Sand production further complicates operations, risking erosion damage and compromising pipeline integrity.
Historically, identifying and diagnosing such problems relied heavily on intrusive monitoring tools or required halting production to conduct inspections – both of which not only impact operational efficiency, but can also expose personnel to greater safety risks during physical intervention.
Operators today face ever-tighter regulatory scrutiny, making continuous, accurate monitoring essential not only for production optimisation, but also for environmental and safety compliance.
Diagnosing challenges in deepwater operations
A recent collaboration with Brava Energia in the Atlanta Field, located in the northern Santos Basin approximately 185 km southeast of Rio de Janeiro, perfectly illustrates the benefits of Tracerco’s approach. The field holds an estimated 1.8 billion bbls of original oil in place (OOIP). Discovered in 2001, this ultra-deepwater field sits beneath 800 m of overburden at a water depth of 1550 m. It is operated by a consortium led by Brava Energia (80%) and Westlawn (20%).
This case study showcases the evolution of oil and water contribution by using Tracerco tracers and also Autonomous Inflow Control Devices (AICD). Atlanta Field is a post-salt heavy oilfield. Several challenges of the field needed to be considered: unconsolidated sandstone, heavy/viscous oil (14° API, 228 cP), high water cut risks, and no injection wells - making precise reservoir management critical.
The primary reservoir, located in the Eocene interval, comprises high-quality sandstone with net-to-gross ratios between 82 - 94%, porosity averaging 36%, and permeabilities ranging from 4 to 6 Darcy. However, despite its favourable rock properties, the oil is heavy (14° API), viscous (228 cP), and acidic (TAN = 10 mg KOH/g). The reservoir benefits from a strong bottom aquifer, eliminating the need for injection support.
To manage technical and economic risks, the field development was phased in two parts:
- Early production system (EPS) from 2018 to 2024, with four horizontal producers and a 30 000 bpd capacity FPSO.
- Full field development (FFD) to expand to 12 producers connected to a new FPSO (ATLANTA FPSO) capable of handling 50 000 bpd.
To optimise production and mitigate water breakthrough risks, Tracerco deployed oil and water polymer tracers across multiple horizontal wells. These were paired with AICDs (wells ATL-4HB and ATL-5H) and Open Hole Horizontal Gravel Pack completions. The goal was to assess oil inflow distribution along the wellbore, early water ingress, and AICD effectiveness in moderating flow and extending well performance.
The EPS was projected to de-risk reservoir uncertainties such as: well productivity, inflow performance along the horizontal section of the well, and aquifer support.
Mariano Guerrico, Global Technology Manager at Tracerco, said: “Understanding these unknowns was essential to define the drainage strategy and Full Field Development (FFD) design. To improve economic results, long Open Hole Horizontal Gravel Pack wells were required. After the completion of the first two wells, the decision was made to integrate Autonomous Inflow Control Devices (AICDs) into the screens. To evaluate oil inflow distribution, water breakthrough, and AICD performance along the horizontal well sections, oil and water tracers were strategically placed at different positions along the screens.
“Tracer production data, combined with EPS dynamic data such as PDG pressures, build-up tests, water cut trends, and Gas-to-oil Ratio (GOR) behaviour, delivered a new level of insight into aquifer drive dynamics, water production, and well productivity index performance. This robust dataset was instrumental in shaping the updated FFD plan for Brava Energia at the Atlanta Field.
“The successful application of tracers played a vital role in mitigating reservoir risk and optimising the development of this heavy oil deepwater asset with a significant underlying aquifer. With encouraging first results from the Atlanta FPSO’s full production phase, the Early Production System project stands as a clear success that de-risked and accelerated the path to full-field execution.”
Tracer deployment and methodology
Tracers were installed in four key EPS wells and high-frequency oil sampling along with lab GC-MS analysis were used to track flow from individual zones. Tracer results were used to refine the Full Field Development (FFD) design, including artificial lift (seabed multiphase pumps). To understand the behaviour of each sand zone identified in the Atlanta reservoir, the tracers were strategically positioned considering at least one oil and water tracer per each sand zone. Also, at least one oil and water tracer was positioned in the well heel and toe.
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