Abstract: An electrical power and/or electrical signal transmission system for transmitting electrical power and/or electrical signals from a location on a first side of a metallic wall to a location on a second side of the metallic wall includes a transmitting apparatus having an electrical source and a first transformer. A receiving apparatus has a receiving module for receiving electrical power and/or electrical signals and a second transformer. First and second ends of a primary winding of the second transformer are electrically connected to respective spaced locations on the second, opposite, side of the metallic wall for picking up electrical power and/or electrical signals from the metallic wall. The receiving module is electrically connected to a secondary winding of the second transformer to enable electrical power and/or electrical signals to be transmitted from the electrical source to the receiving module.

Abstract: A perforating gun (50) for use in a wellbore comprises a body (52) configured to be displaced within the wellbore, and first and second charge arrangements mounted on the body (52) and configured to be detonated independently of each other. In one embodiment the body (52) is configured to be moved axially within the wellbore between detonation of the first and second charge arrangements and at least portions of the first and second charge arrangements are provided within a common axial length of the body (52).

Abstract: A downhole signal receiving system where a pair of setting devices (51) are used to electrically connect with downhole structure and are connected to one another by a bulk conductor (52). Signals are extracted by using a detecting means (53) that does not interrupt the conduction path. The tool provides a low impedance conduction path along which signals from the surrounding structure can flow to facilitate detection.

Abstract: This invention relates to apparatus for setting a plug in, or retrieving a plug from, a horizontal xmas tree. The apparatus comprises a housing with a throughbore adapted to be releasably connected at a first end to a horizontal xmas tree, the housing including an at least one axially moveable member which also includes an at least one radially moveable element and a tool deployable within the housing throughbore by an elongate support and adapted to be releasably connected to the plug. The tool has an outer surface portion profiled to releasably engage with an engagement surface the at least one radially moveable element whereby, in operation, engagement of the at least one radially moveable element with the tool outer surface portion permits the plug, connected to the tool, to be set in the horizontal xmas tree or retrieved from the horizontal xmas tree by axial movement of the at least one axially moveable member.

Abstract: A flowline electrical impedance generation apparatus for generating a local electrical impedance in a metallic tubing portion of a flowline may be used in place of insulation joints in various systems. The impedance generation apparatus is tuned or tuneable to achieve maximum impedance at chosen frequencies, i.e., frequencies which it is desired to block.

Abstract: Downhole electrical power generation apparatus and methods of using stored pressurized gas and/or ambient downhole pressure. One example comprises first and second fluid receiving chambers, a fluid communication path for allowing flow of fluid from the first chamber via the fluid communication path to the second chamber and a turbine generator disposed so that fluid flowing from the first chamber via the fluid communications path to the second chamber operates the turbine generator to generate electrical power.

Abstract: A well installation including metallic structure having downhole metallic tubing for conveying product towards the surface, a sub surface safety valve disposed in the downhole metallic tubing for interrupting flow of product towards the surface when closed and allowing flow of product towards the surface when open. Also, valve control means are disposed downhole and arranged for detecting electrical signals in the downhole metallic tubing and for holding the valve open while receiving an electrical signal, and surface signaling means for applying an electrical signal to metallic structure of the well for transmission via the downhole metallic tubing towards the valve control means so as to hold the valve open. The system can be made more robust by ensuring that the control means will only hold the valve open while receiving a signal of given characteristics to help prevent stray currents erroneously holding the valve open.

Abstract: Methods and systems are described for communicating with downhole locations and transmitting power to downhole locations. Use is made of a cable passing someway down into the well. This cable may be connected to a downhole sensor and may be used primarily for communicating with that sensor, but also used in the current techniques described herein. Electrical connection is achieved between the cable and the metallic structure of the well to allow signals to be transferred between the communications tool and the surface via the cable.

Abstract: A winch assembly (10) comprises a winch drum (18) rotatable about a first axis and carrying a spoolable medium, such as wireline (14) for use in deploying and retrieving tooling into and from a well bore. A carriage sheave (30) mounted on a drive screw (34) is positioned adjacent the winch drum (18), wherein the drive screw (34) is rotatable about a second axis substantially parallel to the first axis. In use, the carriage sheave (30) engages the spoolable medium and is translated by the drive screw (34) in reverse directions to follow the fleeting motion of the spoolable medium as the medium is paid out and/or in from the winch drum (18). In a disclosed embodiment, the winch drum (18) is mounted vertically on a tubular body (22), through which tubular body (22) the spoolable medium extends into the well bore. In one embodiment the winch assembly (10) forms part of a subsea well intervention system.

Abstract: A deployment system (12) for deploying equipment from a vessel (10), such as sea going vessel, comprises a support structure (18) adapted to be mounted on the deck (14) of a vessel (10) and a cradle (20) mounted on the support structure (18) and adapted to be support equipment (16) to be deployed, wherein the cradle (20) is configurable between storage configuration and a deployment configuration. A carriage (22) is mounted on the cradle (20) and is adapted to engage equipment (16) to be deployed, wherein the carriage (22) is translatable relative to the cradle (20) to move equipment (16) between stored and deployed positions. In one disclosed embodiment, the deployment system (12) is arrangement for use in deploying an elongate structure, such as a subsea well intervention system, for a sea going vessel (10).

Abstract: Methods of and apparatus for a downhole communication in a well. The well has a metallic structure which includes an insulated metallic, fluid carrying, control line. The method comprises the steps of applying signals to the control line at a first location and extracting the signals from the control line at a second location. There is also provided a downhole communication system for use in a well having a metallic structure. The metallic structure includes an insulated metallic, fluid carrying, control line. The system comprises means for applying signals to the control line at a first location and means for extracting the signals from the control line at a second location. The control line acts as a signal channel. Other methods and apparatus making use of control line carrying no fluid and/or the metallic shielding of cable having insulated metallic shield are also described.

Abstract: A data communication technique for use in producing wells. Signals are transmitted through the product (p) by varying and monitoring flow rate at respective ends of the communication channel. At low data rates robust communication can be provided.

Abstract: Methods and apparatus for conserving battery energy used in transmitting signals carrying data from a downhole location, using a transmission system where a predetermined set of data is to be transmitted once during a predetermined period. The method can comprise the steps of: transmitting at least one signal during said period to transmit the set of data; selecting the time of transmission of said at least one signal; and representing at least some of the data to be transmitted in terms of the time of transmission of said at least one signal.

Abstract: A self-contained well intervention system which can be deployed from a lightweight vessel and coupled directly to a wellhead is described. The system includes valve means for providing a suitable well barrier and sealing the intervention system to allow an emergency disconnect. Within the intervention system, a tool magazine is provided which contains at least one deployable intervention tool. The intervention system also contains a tool selection and deployment means based on a winch located in close proximity to the magazine and which is operable from the surface for selecting a particular tool from the magazine and for deploying the selected tool through the intervention system and the wellhead into the well. The tool magazine has a plurality of magazine pockets each of which may have a deployable tool therein.

Abstract: Method systems and apparatus for signalling within pipelines. The systems methods and apparatus make use of a unit locatable within a tubular piece of metallic structure for the transmission and/or reception of signals. The unit includes a magnetic material core (6) which provides a path for magnetic flux through the unit (4). A coil (81) is wound around a portion of the magnetic material core (6) to allow the detection and/or application of magnetic flux in the magnetic core (6). At each end of the core (6) there is pair of arms (63) which are arranged for location adjacent the inside surface of the tubular structure. In use magnetic signals flowing in the tubular structure pass through the core (6) and can be detected via the coil (81) in receive mode and similarly signals flowing in the coil (81) can cause magnetic flux to flow through the core (6) and into the metallic structure in transmit mode.

Abstract: Methods of subsea communication in which a cathodic protection anode is used as a transmitting antenna. The signals are received at a second location by two electrodes which are spaced apart by different distances from the transmitting antenna.

Abstract: A well testing system and well testing method is described which can be operated as a closed system with no production of hydrocarbons outside the well or gas can be separated and flared at surface giving minimal environmental impact with the liquid hydrocarbon being re-injected. This is achieved by providing a string with at least two well conduits which may be arranged in a concentric or non-concentric parallel configuration. One conduit is used to produce formation fluids to surface or to produce/store unrepresentative initial flow products and the other conduit is used to store formation fluid. The storage conduit can be filled from the top (surface) or the bottom of the well. In a preferred arrangement a valve is provided between the storage conduit and the well annulus for well pressure control, and a shut-in or test valve, which is controllable from surface, is disposed in the non-storage production conduit.

Abstract: Data transmission in pipeline systems A first set of apparatus is arranged for transmitting data from a point in a cased section of a well 1, 3 to a remote location. The apparatus may be used as a relay station 6 to increase operational depth. Signals are applied to and received from the string 1 at the relay station 6 and a selected length of the string 1 is provided with insulating spacer means 9 on either side of the relay station to ensure that the string 1 and casing 3 are effectively isolated for a selected minimum distance. This enables potential differences to be both applied to and detected from the string 1, thus allowing data transmission and reception. A second set of apparatus is arranged for transmitting from an internal unit 408 inside a cased section of the well 401, 403 to the immediate surrounding area outside the casing 403. The internal unit 408 injects current into the string 401. A toroid 415 which surrounds the casing 403 is provided to pick up signals.

Abstract: A self-contained well intervention system which can be deployed from a lightweight vessel and coupled directly to a wellhead is described. The system includes valve means for providing a suitable well barrier and sealing the intervention system to allow an emergency disconnect. Within the intervention system, a tool magazine is provided which contains at least one deployable intervention tool. The intervention system also contains a tool selection and deployment means based on a winch located in close proximity to the magazine and which is operable from the surface for selecting a particular tool from the magazine and for deploying the selected tool through the intervention system and the wellhead into the well. The tool magazine has a plurality of magazine pockets each of which may have a deployable tool therein.

Abstract: A flowmeter, and a method of, measuring the flow of a multi-phase fluid is described. The flowmeter has a first pressure sensor located in a conduit for measuring a first pressure differential at a first location and a second response sensor spaced along the conduit for measuring a second pressure differential at a second location. The flowmeter includes pressure drop creation means for causing a drop in fluid pressure between the first and second locations, and a water fraction meter upstream of the first location or downstream of the second location for measuring the fraction of water in the multi-phase fluid. Various embodiments of the invention are described and in a preferred arrangement the first and second pressure measuring means are venturi flowmeters.