SensorDynamics Ltd. has developed a unique sensor deployment system which will address the integrated surveillance of subsea oil and gas production. The deployment system together with fibre-optic temperature, pressure, acoustic and seismic sensors will offer solutions to many of the challenges associated with subsea production, even in deep waters. These challenges include leak detection and location, wellhead pressure, multiphase flow, valve and choke, hydrate and wax drop-out, sand production, gas lift and ESP monitoring.
Deep water oil field developments include the following characteristics
Reservoirs are produced using subsea completions
Subsea wells are concentrated in clusters. Flowlines from individual wells combined in a manifold at the subsea production control centres
Multiphase pipelines connect the production control centre to the nearest platform, where separators process the fluids, alternately the produced fluid is handled by a floating production system or by a tanker loading terminal
Platforms can be very remote from the subsea completions
The deep water production infrastructure can be divided into subsea well heads, flowlines, manifold and subsea control system and pipelines.
The ocean floor infrastructure consists of the well heads, the flowlines and their associates valves, the manifold and the associated subsea control system, and delivery system for the produced fluids.
The sensor highway and the new generation of fibre-optic sensors offer solutions to many of the challenges associated with subsea production, even in deep waters.
Sensor highway can be conveniently located at or near all points of the subsea control system and at or near all flowlines and pipelines
Sensor highways can reach downhole locations in subsea wells. After the highway is in place, sensors can be deployed to their intended measurement positions
The highway is relatively simple to install, is cost effective, allows in-situ calibration and permits up-grading or replacement of sensors in the event of sensor failure
The fibre-optic sensors can survive lont-term at high temperatures
Sensors that are compatible with deployment along the highway include. Pressure (already developed), temperature profile (already developed), acoustic array (in development), the seismic array(in development) and possibly an electric current sensor array. In principle all these sensors can coexist in the same highway
Upgrading the sensors at an affordable cost, to enhance data for reservoir management and production control becomes possible with the sensor highway. Cost effective technology upgrades are particularly important in the mature phase of a field where investments are most difficult to justify
Sensor installation, and replacement does not interfere with normal production and can be achieved with modest surface vessel and ROV
Installation of the sensors does not have to coincide with well completion, but can be carried out at any time after the well has been completed. Sensors are installed using a proprietary deployment systems developed by SensorDynamics. The process can be accomplished without interrupting normal production and without the need for heavy equipment.
