Abstract: A method of using an umbilical between a surface location and an underwater location of an underwater fluid extraction well system is provided. The umbilical includes an electrical power conductor configured to transmit electrical power at a first frequency from a source at the surface location to the underwater location. The method comprises detecting that the umbilical has been compromised by the ingress of water. In response thereto, the method comprises converting electrical power from the source to electrical power at a second frequency, wherein the second frequency is lower than the first frequency or DC electrical power; transmitting the electrical power at the second frequency or DC electrical power to the underwater location via the conductor; and converting, at the underwater location, the electrical power at the second frequency or DC electrical power to electrical power at a frequency used by the underwater equipment of the well system.

Abstract: A method of using an umbilical between a surface location and an underwater location of an underwater fluid extraction well system is provided. The umbilical includes an electrical power conductor configured to transmit electrical power at a first frequency from a source at the surface location to the underwater location. The method comprises detecting that the umbilical has been compromised by the ingress of water. In response thereto, the method comprises converting electrical power from the source to electrical power at a second frequency, wherein the second frequency is lower than the first frequency or DC electrical power; transmitting the electrical power at the second frequency or DC electrical power to the underwater location via the conductor; and converting, at the underwater location, the electrical power at the second frequency or DC electrical power to electrical power at a frequency used by the underwater equipment of the well system.

Abstract: A method of supplying electrical power to at least one device at a tree of an underwater fluid extraction well is disclosed. The method comprises using magnetic resonance coupling for wirelessly transmitting power from a supply to each device.

Abstract: A method of removing oil from the surface of a body of water is provided. The method comprising collecting oil on the surface using a plurality of floating booms moved by a vessel floating on the surface, skimming oil collected by the booms using a moving continuous belt carried by the vessel and removing from the belt oil which has been skimmed from the surface.

Abstract: A boom for retaining oil on the surface of a body of water is provided. The boom comprising a sensor for detecting the oil and electronic circuitry coupled with the sensor.

Abstract: A method of supplying electrical power to at least one device at a tree of an underwater fluid extraction well is disclosed. The method comprises using magnetic resonance coupling for wirelessly transmitting power from a supply to each device.