Case Study Intelligent completion helps Agip and NPDC make first-oil date
Commingled production meets Nigerian regulations, doubles expected offshore production.
For high-reliability production control with fewer hydraulic lines
TRFC-HN tubing-retrievable flow control valves provide surface-actuated downhole control of reservoir flow. They can be part of an integrated intelligent approach or installed as stand-alone tools to optimize well performance by reducing unwanted water and gas production.
Use of multiple TRFC-HN valves allows reliable zonal control of a reservoir to improve production or injection sweep. Operators can enhance dynamic reservoir characterization through periodic zonal tests without need for interventions. Using surface-controlled chokes eliminates the costs and risks of several other well interventions too (e.g., to adjust the chokes) that would otherwise be required. When used in conjunction with PT gauges, the valves enable accurate production allocation.
Metris™ permanent monitoring systems can be used in conjunction with the valve to monitor downhole pressure and temperature. Using both technologies, operators have clear understanding and precise control of their reservoirs in real time.
The actuation method uses pressure cycles to shift the valve to the selected choking position. A single dedicated hydraulic control line, operated at surface, actuates the choke; oil- or water-based control line fluids can be used. The choke position is controlled by a specially designed J-slot indexer that moves the choke through each position, enabling precise flow regulation and control. A nitrogen precharge secures the choke in the desired position even after control line pressure is bled down, ensuring that vibrations do not accidentally move the valve.
In its standard configuration, the valve has up to 11 positions—fully open, fully closed, and nine intermediate choke positions. It can be easily adapted to specific reservoir needs because the choke area at each position can be customized and the indexer can be configured for the required number of positions. The valve has been supplied in on-off, three-position, and four-position configurations, mainly to increase the number of flow control valves dropped from one control line.
Two versions of the valve are available. The annular valve (AP) controls flow between the annulus and tubing, while the inline valve (LP) controls flow within the tubing. The LP version has a shroud across the choke section and a retrievable plug installed immediately below the choke section. Flow is directed into the shroud before it reenters the tubing through the choke.
Field-proven control line connections can be externally pressure tested. Both annular and inline valves use an integrated selective nipple profile to land plugs or packoff sleeves for isolating zones as a contingency measure.
A rugged design makes the valves suitable for severe environments with scale deposits, erosion, and other demanding conditions. Valves are manufactured in a variety of materials, all meeting NACE specification MR0175. Positive closure extends to TVDs greater than 12,000 ft [3,658 m].
TRFC-HN valves eliminate the requirement for downhole interventions to adjust zonal flow. They incorporate a closed hydraulic system that is neither affected by nor in communication with the annulus or tubing. As a result, they are insensitive to annulus pressure drops, which enables a larger operating envelope than conventional single-line- actuated valves.