The SureFlo-298EX is the industry’s first electronic fullbore access downhole flowmeter. The innovative design incorporates differential pressure technology with a fullbore mechanical construct revolutionizing the measurement of:

• Bottomhole pressure and temperature;

• Equivalent surface flow rates for each fluid fraction;

• Fluid fraction — water cut;

• Gas breakout indicator downhole (Boolean output); and

• Measurement confidence provided in percentage (0% - poor confidence and 100% - high confidence).

The pressure sensors utilized are high-resolution pressure and temperature sensors — SureSENS 175 provided by Baker Hughes. Data is transmitted through two different tubing encapsulated cables to a subsea pod and then up to the platform where a surface data acquisition unit houses the flow calculation module. Real-time data is updated from the flowmeter and the gauges every 0.1 seconds. However, the communication to the surface may be limited by the polling rate from the subsea pod.

Utilizing downhole flowmeters minimizes downtime associated with well testing that has to be performed periodically to allocate production from subsea or multizone wells. The SureFlo-298EX provides real-time data, which can be updated every 0.1 seconds from individual zones or individual wells, depending on the chosen configuration by the customers.

Intelligent completion for the Agbami project consisting of a dual-zone production using a single SureFlo-298EX flowmeter to measure production from the well. (Image courtesy of Baker Hughes)

The fullbore construct minimizes pressure loss from the well while minimizing slip effect between the liquid and gas phase. The flowmeter also does not impede any intervention wireline jobs in the well. Most important of all, the highly accurate measurement that is provided by the flowmeter (less than 2% uncertainty) ensures that relevant real-time information is provided to the operator to assist in production optimization, prudent reservoir management, flow assurance, and infrastructure management. The information aids in the decision making during the production cycle of the wells and the reservoir.

The Agbami project offshore Nigeria utilizes the SureFlo-298EX flowmeter. The producer wells are completed with a single 5½-in. flowmeter that measures the total flow in the well (Figure 1a). In dual zone producers, this provides a total of the commingled production rate from both the upper and lower zones. The injector wells are equipped with a 4½-in. flowmeter for the lower zone and a 5½-in. flowmeter for the upper zone. The 4½-in. flowmeter provides the injection rate to the lower zone, while the upper zone allocated injection rate is determined by subtracting the measured injection rates of the 4½-in. flowmeter from the 5½-in. flowmeter.

In the producer wells, the provision of water cut and flow rate measurement provides an insight on the productivity and the hydrocarbon contribution from each of the wells. This is vital, as often multiple wells are produced up a single riser to the floating production, storage, and offloading unit. Therefore, the only method of determining individual well rates is through the downhole flowmeter or a well test. In the injector configuration, the flowmeters are used to reflect the allocation of the injection rate to individual zones within the reservoir as a function of the ICV controlled interval. Another vital role that the flowmeters play for the injector wells is to monitor the erosional threshold of the completion. High injection rate of water has a tendency of eroding pipelines and tubular, especially if there are solids in the injected fluid, such as sand. These are part of the infrastructure management that is being used in Agbami to manage the integrity of the infrastructure to ensure the longevity in the project.

Based on initial analyses using the data from SureFlo-298EX in conjunction with flow control valves shows the recovery impact may vary from an additional 30 to 103 MMbbl of oil being recovered, depending on the reserve level associated with the field.