Abstract: A subsurface safety valve control system including a downhole station 5 for provision in downhole metallic structure (2) of a well installation which comprises a subsurface safety valve V having an open state allowing flow through the valve and a closed state obstructing flow through the valve. The downhole station (5) is arranged for picking up electrical signals from the downhole metallic structure (2) to obtain valve control signals and for outputting control signals for controlling the subsurface safety valve V in dependence on the signals picked up from the downhole metallic structure. The downhole station (5) comprises a hardware electronics channel (5a) for handling electrical signals picked up from the downhole metallic structure and the hardware electronics channel (5a) is arranged for detecting the presence and/or absence of hold valve open signals.

Abstract: Downhole electrical energy harvesting and communication in systems for well installations having metallic structure carrying electric current, for example CP current. In some instances there is a harvesting module (4) electrically connected to the metallic structure (2) at a first location and to a second location spaced from the first location, the first and second locations being chosen such that, in use, there is a potential difference therebetween due to the electric current flowing in the structure (2); and the harvesting module (4) being arranged to harvest electrical energy from the electric current. In addition or alternatively, there may be communication apparatus (4, 5, 6) for communication by modulation of the current, for example CP current, in the metallic structure (2).

Abstract: A well installation comprising downhole power delivery apparatus for delivering electrical power from a surface power source S to a downhole tool T. The well installation comprises downhole metallic structure (2) running down into a borehole. The apparatus comprises an electrical cable (3) for carrying electrical power from the surface power source S, a power transfer arrangement (4) and a power pick up arrangement (5). The cable 3 runs down into the borehole together with the metallic structure (2) to the power transfer arrangement (4) which is provided at a first downhole location for transferring electrical power carried by the electrical cable (3) onto the downhole metallic structure (2) for onward conduction. The power pick up arrangement (5) is provided at a second downhole location, spaced from the first, for picking up electrical power from the downhole metallic structure (2) for supply to the downhole tool T.

Abstract: A downhole communication system for communication between a first and second location in a subsea oil and/or gas well installation. The oil and/or gas well installation comprises out of hole metallic structure comprising a riser 3 running upwards away from the mudline ML, and downhole metallic structure 2 running down into the well. The communication system is arranged so that at least part of a signal path for communications between the first and second locations is provided by the downhole metallic structure 2 such that, in use, data to be communicated between the first and second locations is carried by electrical signals in the downhole metallic structure 2.

Abstract: Downhole electrical energy harvesting and communication in systems for well installations having metallic structure carrying electric current, for example CP current. In some instances there is a harvesting module (4) electrically connected to the metallic structure (2) at a first location and to a second location spaced from the first location, the first and second locations being chosen such that, in use, there is a potential difference therebetween due to the electric current flowing in the structure (2); and the harvesting module (4) being arranged to harvest electrical energy from the electric current. In addition or alternatively, there may be communication apparatus (4, 5, 6) for communication by modulation of the current, for example CP current, in the metallic structure (2).

Abstract: Well installations and methods for constructing wireless ready well installations. The installations comprise downhole metallic structure (2) and downhole repeater apparatus (5) for receiving signals and in response transmitting signals onwards. The repeater apparatus (5) are arranged for at least one of receiving the signals by picking up at least one of electrical and acoustic signals from the downhole metallic structure and transmitting the signals onwards by applying at least one of electrical and acoustic signals to the downhole metallic structure. Various arrangement and methods are described to allow provision of well installations ready for wireless communications.

Abstract: Downhole electrical energy harvesting and communication in systems for well installations having metallic structure carrying electric current, for example CP current. In some instances there is a harvesting module (4) electrically connected to the metallic structure (2) at a first location and to a second location spaced from the first location, the first and second locations being chosen such that, in use, there is a potential difference therebetween due to the electric current flowing in the structure (2); and the harvesting module (4) being arranged to harvest electrical energy from the electric current. In addition or alternatively, there may be communication apparatus (4, 5, 6) for communication by modulation of the current, for example CP current, in the metallic structure (2).

Abstract: Downhole electrical energy harvesting and communication in systems for well installations having metallic structure carrying electric current, for example CP current. In some instances there is a harvesting module (4) electrically connected to the metallic structure (2) at a first location and to a second location spaced from the first location, the first and second locations being chosen such that, in use, there is a potential difference therebetween due to the electric current flowing in the structure (2); and the harvesting module (4) being arranged to harvest electrical energy from the electric current. In addition or alternatively, there may be communication apparatus (4, 5, 6) for communication by modulation of the current, for example CP current, in the metallic structure (2).

Abstract: A monitoring well installation comprising metallic casing (2) running down from the surface into a borehole and a sealing material plug (6) provided downhole for blocking the interior of the casing and sealing the borehole against the egress of fluid from a zone below the plug. There is an axial spacing (2A) between adjacent casing portions (2) in the region of the plug (6) such that there is an uncased length of borehole in which the material of the plug seals against the formation. There is provided a sensing tool (3) located below the plug (6) for sensing at least one parameter below the plug (6) and a communication arrangement (3, 4, 5) for use in transmitting data from the sensing tool (3) towards the surface. The communication arrangement comprises across plug communication apparatus (5) for facilitating transmission of signals carrying data across the plug (6) towards the surface.

Abstract: A well installation comprising downhole power delivery apparatus for delivering electrical power from a surface power source S to a downhole tool T. The well installation comprises downhole metallic structure (2) running down into a borehole. The apparatus comprises an electrical cable (3) for carrying electrical power from the surface power source S, a power transfer arrangement (4) and a power pick up arrangement (5). The cable 3 runs down into the borehole together with the metallic structure (2) to the power transfer arrangement (4) which is provided at a first downhole location for transferring electrical power carried by the electrical cable (3) onto the downhole metallic structure (2) for onward conduction. The power pick up arrangement (5) is provided at a second downhole location, spaced from the first, for picking up electrical power from the downhole metallic structure (2) for supply to the downhole tool T.

Abstract: A downhole power delivery system for use in a well comprising downhole metallic pipe (2) running in a borehole of the well with a downhole sealing plug (31) provided in a bore or annulus at least partly defined by the downhole metallic pipe. The power delivery system comprising below plug apparatus (5) located in the borehole below the plug (31) including a downhole device (53) requiring electrical power and downhole power supply apparatus (6) located in the borehole above the plug (31). The power supply apparatus (6) comprises at least one battery (64) for powering the downhole device and the downhole power supply apparatus (6) and below plug apparatus (5) being arranged for delivering electrical power from the downhole power supply apparatus (6) to the downhole device (53) across the downhole sealing plug (31).

Abstract: Downhole electrical energy harvesting and communication in systems for well installations having metallic structure carrying electric current, for example CP current. In some instances there is a harvesting module (4) electrically connected to the metallic structure (2) at a first location and to a second location spaced from the first location, the first and second locations being chosen such that, in use, there is a potential difference therebetween due to the electric current flowing in the structure (2); and the harvesting module (4) being arranged to harvest electrical energy from the electric current. In addition or alternatively, there may be communication apparatus (4, 5, 6) for communication by modulation of the current, for example CP current, in the metallic structure (2).

Abstract: A monitoring well installation comprising metallic casing (2) and a sealing material plug (6) provided downhole in the borehole for sealing the borehole against the egress of fluid from a zone below the plug. There is an uncased length of borehole at least 10 m in length in which the plug seals against the formation. There is provided a downhole sensing tool (3) located below the plug (6) and a communication arrangement (31, 5, 4) for use in transmitting data from the sensing tool towards the surface, which comprises an across plug communication apparatus (5) comprising a pair of spaced contacts (51) contacting the casing and/or the formation and a transmitter located below the plug (6) for transmitting signals carrying data across the plug towards the surface.