Abstract: An arrangement for monitoring a submarine reservoir includes a number of sensor units located in an array on the seabed, and an interrogator unit for obtaining data on the reservoir from the sensor units. The interrogator unit includes a transmitter unit for sending optical signals to the sensor array and a receiver unit for receiving modulated optical signals from the array. Optical radiation from an optical source is transmitted along an uplink optical fiber which is split in a number of positions to form the array. The receiver unit includes optical-to-electrical converters for converting the optical signals to electrical signals, a phase demodulator, a multiplexer, a signal processor, and recording unit. The interrogator unit is divided into a concentrator and an interrogator hub, where signals are transmitted between the interrogator hub and concentrator along a riser cable. This enables the interrogator to be moved between a platform and the seabed.

Abstract: There is described an optical seismic cable (2) comprising a number of sensor units (5) spaced along the length of the cable and a number of connection units (4) spaced along the length of the cable, the cable further comprising a number of first optical fibers extending substantially continuously along the cable from one connection unit to the next, and a number of second optical fibers which each extend part-way along the cable between adjacent connection units, and wherein at each connection unit at least one first optical fiber is joined to a second optical fiber, and wherein at the sensor units sensors are joined to said second optical fibers.

Abstract: There is described an apparatus and method for deploying a sensor array comprising a plurality of sensors (5) joined together by connection cables (6) in one or more “chains”, and connected to an input/output device (8). An input/output connection unit (7, 15) is provided on a carrier (10), and the sensors are held on or in deployment devices (14a-14e) mounted to the carrier with their connection cables (6) connected to the input/output connection unit (7, 15). The input/output device (8) may also be mounted to the carrier, and connected to the connection unit (7, 15). The carrier (10), sensors, and input/output device (8) may be delivered as a single package to the area where the sensor array is to be deployed. The sensors are then moved from the carrier to their final positions. The deployment devices (14a-14e) may be detached from the carrier and moved sequentially to the sensor positions, and a sensor may be removed from the deployment device at each sensor position.

Abstract: A pressure apparatus including a first end cap, a second end cap, a hollow housing connected to the first and second end caps, a locking ring connected to the second end cap, a first termination connected to the first end cap, and a second termination connected to the second end cap.

Abstract: An armored cable termination/fiber-optic seal which connects a fiber optic cable—the fiber optic cable including one or more armor wires and one or more cable tubes—to a pressure housing, the armored cable termination/fiber-optic seal including: an armored termination which locks the one or more armor wires in a conical cavity; sealing paths which block water from traveling in the interstitial space between the one or more armor wires and the one or more cable tubes into the pressure housing; and fiber feed-through tubes which block water from traveling in the interior of the one or more cable tubes into the pressure housing.

Abstract: An arrangement for monitoring a submarine reservoir comprises a number of sensor units located in an array (1) on the seabed, and an interrogator unit for obtaining data on the reservoir from the sensor units. The interrogator unit comprises a transmitter unit (20) for sending optical signals to the sensor array and a receiver unit for receiving modulated optical signals from the array. Optical radiation from an optical source (22) is transmitted along an uplink optical fibre which is split in a number of positions 36, 38 to form the array. The receiver unit comprises optical-to-electrical converters (54) for converting the optical signals to electrical signals, a phase demodulator (58), a multiplexer (60) for multiplexing signals from the phase demodulator, a signal processor (68) and recording unit (70).

Abstract: A sensor arrangement for monitoring a oil reservoir comprises a sensor array (1) comprising a plurality of sensor units (5) located over an area to be monitored; an interrogator unit (30) comprising a transmitter (402) for transmitting optical signals and receiver for obtaining data on the reservoir from the sensor units, a demodulator (418) for demodulating the received signals, and a recorder (420) for recording the demodulated signals. The arrangement includes an uplink optical cable (408) for transmitting the signals to the sensor array and a downlink optical cable (410) for transmitting signals from the array to the receiver. At least one of the optical cables has an optical amplifier (412, 414). The arrangement enables the interrogator to be remote from the array, for example 150 km or more, obviating the need for significant power to be supplied at the array.

Abstract: There is described a method and apparatus for deploying and covering undersea seismic sensing cables to improve seismic coupling between the sensors of the cable and the seabed. The method comprises simultaneously deploying a submarine seismic cable and a mat in order to cover at least the sensor units of the cable. The mat may be attached to the cable prior to laying the cable on the seabed, and is preferably simultaneously laid with the cable by unwinding the cable and mat from a drum. The mat may be continuous, or may be in discrete sections attached to the cable at spaced locations.