Abstract: A quadrilateral building panel (1) has a length, a width, and a thickness, the length being an integral number of panel widths. The panel has at least two degree rotational symmetry when rotated about a central axis (8) extending perpendicularly to a plane containing a major surface (9) of the panel (1). Each edge (2,3) of the panel includes at least one inwardly stepped portion (5) and at least one outwardly stepped portion (6) and each inwardly stepped portion (5) is dimensioned to receive an outwardly stepped portion (6) on the edge of an adjacent panel, each outwardly stepped portion (6) projecting a distance corresponding to the panel thickness beyond the inwardly stepped portion (5). This enables the panel to be assembled in an interengaging manner with other like panels to form a three-dimensional structure so that their major planes are generally parallel and coincident or perpendicular.

Abstract: A system for controlling the operation of devices (61, 62, 63) of a hydrocarbon production system has two reprogrammable central controllers (100) contained-in a retrievable module (49a) of a seabed facility (20?) associated with a hydrocarbon field (170). Local controllers are configured to control the operation of specific devices, such as actuators (61), sensors (62) and valves (63) within the module (49a) and within tree wellheads (30?) of the field (170) and are locally connected to these devices (61, 62, 63). A single common data bus (130) links the central controllers (100),and the local controllers and enables data to be transmitted between the central controllers (100) and the local controllers in response to the central controllers (100) receiving signals.

Abstract: An underwater system (1) has a hydrocylone (5) for separating sand from seawater, and a pump (8) downstream from the hydrocylone (5) for drawing seawater upstream of the hydrocylone into the hydrocylone. The sand separated from the seawater is collected in a sand storage device (6) below the hydrocyclone. The pump (8) pumps the seawater from which the sand has been removed into a water injection well (16) and a portion of the seawater is diverted into a sand extraction device (7) beneath the sand storage device (6) to flush away the sand collected therein.

Abstract: A system (1) for combating the formation of emulsions in production fluid has a control system which compares the volumetric flow rates of oil and water separated from production fluid in a separator vessel (16). When the ratio of the separated oil approaches that where emulsions are expected to form, a portion of the separated water is diverted into a fluid mixing device (10) and commingled with the production fluid being conveyed to the separator vessel (16) so that the commingled fluid has an oil to water ratio outside the range of oil to water ratios at which emulsions are likely to form. Alternatively, instead of comparing the volumetric flow rates of separated oil and water, the system can detect the presence of emulsions in the fluid in the separator vessel (16) by having a nucleonic level sensor in the vessel, the sensor being linked to the control system.

Abstract: A valve (2) has a body (4) defining a flow inlet (6), a flow outlet (8) and a valve chamber (10). A compression coil spring (24) is contained within the chamber (10) and its coils (32) divide the inlet (6) from the outlet (8). One end of the spring (24) is seated against a reaction block (20) and an actuating rod (16) extending into the valve chamber (10) bears on the block enabling it to be lowered or raised. This action causes the size of the helical gaps (34) between the coils (32) of the spring to be altered which adjusts the flow of fluid through the valve.

Abstract: A pressure protection system (32) has a docking manifold (44) to which an upstream portion (36) and a downstream portion (38) of a pipeline (34) are connected. Also connected to the docking manifold (44) is a retrievable module (64) which has a conduit circuit (66) that connects the upstream and downstream portions of the pipeline (34) enabling fluid to flow between the two portions (36, 38). The conduit circuit contains two fail-safe valves (72) which are controlled by a control module (80) within the retrievable module, and two pressure transmitters (76) co-operable with the control module (80). When wither pressure transmitter (76) senses fluid pressure in the conduit circuit (66) to be above a threshold value then it causes the control module (80) to effect closure of the valves (72) preventing the pressure rise from reaching the downstream portion (38) of the pipeline (34).

Abstract: A system (1) for extracting subsea hydrocarbon fluid has five discrete subsea developments (10, 12, 14, 16, 18) for hydrocarbon extraction linked to four hydrocarbon receiving facilities (2, 4, 6, 8) by a pipeline network (94). Each subsea development (10, 12, 14, 16, 18) has a manifold to which pipelines of the network (94) are connected, and a pair of retrievable modules (22) docked on the manifold. Each module has a control pod which is able to control flows of fluids between the subsea developments and between the subsea developments and the receiving facilities, and each control pod is connected to monitoring devices for monitoring parameters pertaining to the subsea developments. Parameters are monitored at a first one of the subsea developments and a requirement for a first fluid type is identified and parameters at another second one of the subsea developments are monitored and a surplus of the first fluid type is identified.

Abstract: An electric motor (30) is accommodated in a first portion (42) of a housing (40) and is arranged to drive a compressor (32) accommodated in a second portion (44) of the housing separated from the first housing portion (42) by a wall (46). An umbilical (48) introduces dry motor protection gas into the first housing portion (42) and a passage (54) between the first and second housing portions (42,44) allows a leakage of the motor protection gas from the first housing portion (42) into the second housing portion (44) at a higher pressure than gas supplied to the compressor (32) via an inlet pipe (58) thereby preventing moisture laden gas from the compressor (32) entering the first housing portion accommodating the electric motor (30).

Abstract: Gas is supplied from a host facility (2) to an underwater gas compressor (10) via a connecting pipeline (6) and the gas compressor is connected to a plurality of gas injection wells (7) for a hydrocarbon reservoir via well supply flowlines (8). The gas compressor (10) compresses the supplied gas to a higher pressure, and drives the gas into the reservoir via the flowlines (8) and gas injection wells (7) at a pressure at least as high as the pressure of the production fluid in the reservoir. This raises the overall pressure in the reservoir to drive production fluid there to the host facility (2). The compressed gas may alternatively be injected into production fluid in a production well to provide a gas lift effect.

Abstract: Production fluid is received in a seabed facility (3) from a hydrocarbon reservoir and water is separated from the production fluid by a fluid separator vessel (15) in the seabed facility (3). The production fluid is then conveyed to a host facility (2) by a production fluid pipeline (4). The separated water enters a fluid clean-up unit (19) which removes hydrocarbons from the water, and the water is then passed through a photo-chromatic device (20) which measures the amount of oil in the water. Providing that the water is measured to contain not more than the predetermined threshold maximum limit of oil in water, it is disposed of into the sea surrounding the seabed facility (3).

Abstract: Production fluid mixture is directed through a sand removal unit (12) in a retrievable module (1) installed in a modular seabed processing system, and the unit (12) collects sand from the mixture. The production fluid mixture then enters a fluid separation chamber (17) in the module (1) where it is separated into a gas and a mixture of oil and water. Seawater is drawn in from outside the module and is pumped into the sand removal unit (12) to flush the collected sand. The mixed flushed sand and seawater is commingled with the mixture of oil and water downstream of the fluid separation chamber (17) and the commingled mixture is conveyed to a host facility. There, the sand is separated from the commingled mixture and is disposed of.