A method of installing at sea a double-walled preheated undersea pipe for transporting fluids, wherein for each new pipe section to be assembled to a pipe that is already installed at sea: the method involves preheating the inner wall unit element inside the outer wall unit element of the new pipe section; assembling the inner wall unit elements of the new pipe section to the inner wall of the pipe that is already installed at sea; assembling the outer wall unit element of the new pipe section to the outer wall of the pipe that is already installed at sea; lowering the new pipe section into the sea; and repeating the above for other new pipe sections to be assembled so as to prestress the pipe while it is being installed at sea.

A skin effect heating system for long pipelines includes a heater cable disposed in a ferromagnetic or other conductive heat tube. A semiconductive jacket contacts the inner surface of the heat tube, where the charge density of the return current carried by the heat tube is at its highest. The semiconductive jacket material has a resistivity that is sufficiently low to reduce or eliminate arcing events such as corona discharge by allowing accumulated charge on the heat tube to dissipate. The resistivity is also high enough to prevent the return current from flowing into or through the semiconductive outer layer, so that heat production capacity of the system is maximized.

A skin effect heating system for long pipelines includes a heater cable disposed in a ferromagnetic or other conductive heat tube. A semiconductive jacket contacts the inner surface of the heat tube, where the charge density of the return current carried by the heat tube is at its highest. The semiconductive jacket material has a resistivity that is sufficiently low to reduce or eliminate arcing events such as corona discharge by allowing accumulated charge on the heat tube to dissipate. The resistivity is also high enough to prevent the return current from flowing into or through the semiconductive outer layer, so that heat production capacity of the system is maximized.

A water content sensor is positioned within a flowline downstream of a well-choke. The water content sensor is configured to determine a water content percentage of a production fluid flowing through the flowline. A temperature sensor is positioned downstream of the well-choke. The temperature sensor is configured to determine a temperature of the production fluid flowing through the flowline. A heating jacket surroundings at least a portion of the flowline. The heating-jacket is configured to transfer heat into the flowline. A controller is configured to receive a signal from each of the water content sensor and the temperature sensor, and control the heating jacket in response to a signal from each of the water content sensor and the temperature sensor.

A water content sensor is positioned within a flowline downstream of a well-choke. The water content sensor is configured to determine a water content percentage of a production fluid flowing through the flowline. A temperature sensor is positioned downstream of the well-choke. The temperature sensor is configured to determine a temperature of the production fluid flowing through the flowline. A heating jacket surroundings at least a portion of the flowline. The heating-jacket is configured to transfer heat into the flowline. A controller is configured to receive a signal from each of the water content sensor and the temperature sensor, and control the heating jacket in response to a signal from each of the water content sensor and the temperature sensor.

A quick connect fluid connector that is detachably connectable to a fluid system to process a gas into or from the fluid system through the quick connect fluid connector. The quick connect fluid connector includes one or more temperature sensors that can sense the temperature of the gas within the fluid connector during processing. Based on the sensed temperature(s), an alert can be generated to alert a human operator conducting the processing and/or automatically shut-off the processing if the sensed temperature becomes too high. The operator will therefore be alerted if the cylinders are being processed too quickly or if the processing duration could be shortened.

A quick connect fluid connector that is detachably connectable to a fluid system to process a gas into or from the fluid system through the quick connect fluid connector. The quick connect fluid connector includes one or more temperature sensors that can sense the temperature of the gas within the fluid connector during processing. Based on the sensed temperature(s), an alert can be generated to alert a human operator conducting the processing and/or automatically shut-off the processing if the sensed temperature becomes too high. The operator will therefore be alerted if the cylinders are being processed too quickly or if the processing duration could be shortened.

A clamping device (40) for providing an electrical connection between a subsea pipeline (1) and an electrical conductor (31). The device has a clamp element (41) comprising a first leg (41a) having a first leg end (41c) and a second leg (41b) having a second leg end (41d). The legs (41a, 41b) are configured to be provided on respective sides of the pipeline (1). The clamping device has a releasable tensioning device (48) connected to one of the legs (41a, 41b). The clamping device (40) has a first state, in which the ends (41c, 41d) of the first and second legs (41a, 41b) are provided at a first distance (d1) away from each other. The clamping device (40) has a second state, in which the tensioning device (48) is tensioned, causing the ends (41c, 41d) of the first and second legs (41a, 41b) to be at a second distance (d2) away from each other, the second distance (d2) being larger than the first distance (d1). The clamping device (40) has a template hole (42) provided in one of the legs (41a, 41b). The clamping device (40) comprises a connector member (44) provided in the template hole (42). The connector member (44) is mechanically connected to the clamp element (41). The clamping device (40) has a third state, in which the tensioning device (48) is released, causing the connector member (44) to be pressed towards the pipeline (1).

A clamping device (40) for providing an electrical connection between a subsea pipeline (1) and an electrical conductor (31). The device has a clamp element (41) comprising a first leg (41a) having a first leg end (41c) and a second leg (41b) having a second leg end (41d). The legs (41a, 41b) are configured to be provided on respective sides of the pipeline (1). The clamping device has a releasable tensioning device (48) connected to one of the legs (41a, 41b). The clamping device (40) has a first state, in which the ends (41c, 41d) of the first and second legs (41a, 41b) are provided at a first distance (d1) away from each other. The clamping device (40) has a second state, in which the tensioning device (48) is tensioned, causing the ends (41c, 41d) of the first and second legs (41a, 41b) to be at a second distance (d2) away from each other, the second distance (d2) being larger than the first distance (d1). The clamping device (40) has a template hole (42) provided in one of the legs (41a, 41b). The clamping device (40) comprises a connector member (44) provided in the template hole (42). The connector member (44) is mechanically connected to the clamp element (41). The clamping device (40) has a third state, in which the tensioning device (48) is released, causing the connector member (44) to be pressed towards the pipeline (1).

A pure electric modular subsea test tree is provided, which includes a connect-disconnect device, wherein the first channel is formed in the connect-disconnect device; the connect-disconnect device is provided with a locking assembly and a connection drive mechanism for driving the locking assembly, and the first electrical connection plug is embedded in the connect-disconnect device, and the connection drive mechanism is electrically connected with the first electrical connection plug; a shear-seal assembly, wherein a second channel communicated with the first channel is formed in the shear-seal assembly; the shear-seal assembly includes at least one shear-seal device capable of plugging the second channel; a connection part is formed on the shear-seal assembly; a heating device is arranged at one end of the shear-seal device far from the connection part. The disclosure relates to a pure electric modular subsea test tree, which has fast response speed and high operation safety.