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Tendeka examines wireless-downhole monitoring techby Arabian Oil & Gas Staff on Jan 11, 2013
Tendeka’s Garth Naldrett and Tor Inge Åsen explore the implications for operators of adopting wireless technology for downhole monitoring
The trend of increasing wellbore complexity for extended reservoir contact, and greater reservoir heterogeneity, are demanding improved monitoring and control solutions.
Traditionally the only option has been the deployment of a cabled system but this limits the application of intelligent well technology to new installations or workovers.
In any case, cabled systems are not always possible in new installations, especially where the completion is discontinuous, and slim hole or monobore completions may not allow cables to be deployed along the tubing string.
Wireless technology is proving a more flexible alternative to addressing the issues of permanent downhole monitoring. One product, Tendeka’s wireless gauge, which has been successfully deployed in the North Sea, allows real time flowing bottom hole pressure (FBHP) to be efficiently transmitted to surface, an attractive option for wells where the cabled gauge system has failed, or was not initially installed.
Originally designed to 3.5”, the company has produced a 2.25” version which has trialled successfully in the North Sea and is expected to have a wider global appeal
Benefits of Wireless Technology
The system transmits data from the lower completion to the surface via pressure pulses. A novel tool design allows the well’s production to be partially choked for a very short time to create a pressure pulse, which is detectable on the surface pressure gauge.
The well’s energy is used to transmit data to surface, thereby reducing power consumption, and the system requires no additional surface installation or pickup, since an existing tubing head pressure gauge can be used to detect the pulse train.
For most operators, the system can be deployed by a single intervention, allowing highly accurate data to be sourced almost instantaneously for a fraction of the cost of a re-completion.
Compared with a memory gauge system, it allows data to be collected in real time and provides a continuous confirmation of operation. The gauge can be set in blank pipe, giving optimal freedom for installation depth, and it can be installed as close to the producing interval as required.
A significant benefit of using pressure pulse transmission is the ease of installation. No retrofitting of topside equipment is required, and many of the technical and contractual issues when introducing a new monitoring system are avoided.
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