AnTech customizes GoM sensor system

AnTech has customized a sensor system for a major oil service company’s well intervention operations in the Gulf of Mexico.

Offshore staff

EXETER, UK -- AnTech has customized a sensor system for a major oil service company’s well intervention operations in the Gulf of Mexico. The deepwater, high-pressure field is in over 6,000 ft (1,829 m) of water, and is being developed using a permanently moored semisubmersible production and drilling facility.

Known as the Triple Sensor Tool Joint Detection System, or MDET-S, the equipment monitors tool joints in risers by measuring changes in magnetic fields triggered when a pipe joint passes through the field.

The new MDET-S was developed to improve the safety and efficiency of deploying tubing strings under pressure. To achieve this, AnTech’s client developed a hydraulic workover (HWO) system to support the deepwater GoM field. The system is located under the rig floor, with heave compensation provided by the rig’s riser tensioning system. The HWO provides a high-strength method to intervene and operate under pressure from a floating vessel in deep, high-pressure reservoirs. Special rig-assist HWO equipment, combined with a purpose-built BOP stack, are used to deploy the tubing strings under pressure.

Traditionally, locating tool joints is done by manual measurement and careful positioning of the tubing string in relation to a specific point above the BOP stack. AnTech’s objective was to replace this manual method with a device that automatically detects tool joints and alerts the technician when the joint had moved into the field of sensors.

The device senses the magnetic distortion caused by the additional thickness of the metal joint. No markers are required on the pipe joints. Whenever it detects a shift of this magnetic field, the sensor transmits an electrical signal to the control box. The control box responds by indicating that a tool joint has passed by a pair of sensors. The control box also transmits digital and analog signals to an external data acquisition system that transfers the readings produced to a file on the technician’s laptop

07/28/2009

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