Abstract: Apparatus for enabling electric signals to be transmitted between a device such as a sonde (46) positioned inside a tubing (38) of a well (30) and a region outside the tubing. In a preferred embodiment the apparatus comprises a transmitter coil (58) in the sonde (46) and a receiver coil (42) coupled to the tubing (38). The sonde (46) is coupled via wireline (48) to the surface and the receiver coil (42) is also coupled to the surface via a permanently installed cable (44). At least one measurement instrument (56) is located in the sonde such that measurement signals passed to said transmitter (58) are coupled to said receiver coil (42) and to the surface. The transmitter and receiver permit bidirectional communication and electrical power can be transmitted from the surface via said permanently installed cable such that single-phase or multi-phase power can be transmitted to drive downhole equipment, which may be coupled to the sonde.

Abstract: A lightweight intervention system is described for use with single bore and dual bore intervention operations and which can be used with both horizontal trees and conventional trees and with wellheads without trees mounted thereon. The system is based on a two-part intervention apparatus; the lower part provides the pressure control and consists of an xmas tree or wellhead connector and structural housing in which a sub-sea test tree is located and is coupled to the xmas tree and an upper part, a disconnectable section, attaches to the lower part and consists of a sub-sea test tree latch housed within an xmas tree connector and additional pressure control equipment as required. This general structure can be configured in various ways to create different embodiments for use with horizontal trees and conventional trees which have a single through-bore requirement and a dual bore requirement respectively.

Abstract: A lightweight intervention apparatus is described for use with a single bore intervention operation and which is suitable for use with a sub-sea horizontal tree with a tree cap and integral ball valve. The lightweight intervention apparatus is adapted to be coupled to the horizontal tree and that when so coupled the integral ball valve within the tree can be actuated via the intervention apparatus and cycled between an open and a closed position. The annulus line within the horizontal tree is adapted to be coupled through the lightweight intervention apparatus to a separate annulus line such that the annulus line is separate from the main bore to facilitate control of the annulus for certain well functions. A significant advantage of this arrangement is that the internal diameter of the main bore is not reduced in any way by apparatus or equipment for separating the annulus line from the main bore so that full bore diameter may be used.

Abstract: A dual bore riser system is described which includes a conventional monobore riser (12) for production access and an independent coil tubing (14) disposed in parallel with the monobore riser (12) for providing annular access. The monobore riser includes discrete A joints of tubing, casing or drill pipe and the coil tubing riser may be any suitable size but is normally between 23/8" and 27/8" outside diameter. The standard monobore riser (12) and coil tubing riser (14) is fed from a coiled tubing reel (78), which is conventional, via a sheave (80) and straightening rollers into the well with the tubing riser. The coiled tubing is clamped to the tubing riser by clamps (16) at intervals along its length corresponding to a joint every 30 ft. The upper end of the landing spool adaptor (28) receives the tubing (14) and also contains a termination for the coiled tubing which is typically a swage device (32). The 5".times.

Abstract: A safety valve for use with horizontal subsea trees as described which uses a two-part (10, 12) safety valve system. The first part (10) containing a valve mechanism (16, 18, 22, 26) remains in the wellhead and is normally biased to a closed position. The valve mechanism (16, 18, 22, 26) remains in the wellhead at all times during production and can be actuated to an open position by latching in a second part (12) which contains control cables (58) and a moveable valve actuator (62, 70, 40, 26) operable from the surface during workover to actuate the valve (18) in the wellhead portion (10) open. This provides for greater safety during the workover phase in comparison to a wire set plug and allows safer re-entry to the well.

Abstract: A well testing system is described which comprises a ball valve (10) having a plurality of fluid lines coupled thereto (20a, 20b, 20 c). The ball valve (10) is located between a process fluid flow line (16) and a vent line (18) with each fluid line (20a, 20b, 20c) being coupled to a respective piece of well-test equipment rated at a certain pressure value. Pressure relief means (22a, 22b, 22c) are located in each fluid line (20a, 20b, 22c) between the piece of equipment and said valve (10) and each pressure relief means (22a, 22b, 22c) is operable when the in-line fluid pressure exceeds a predetermined value to pass said fluid to said ball valve(10).

Abstract: An apparatus for burning crude oil has a conduit (12) without a flow restriction orifice and which receives oil to be burned. The conduit (12) has a plurality of inclined nozzles (28) which are also arranged about the longitudinal axis of the bore (30) so as to be substantially tangential to the interior surface. A supply of high velocity air is passed through an inlet manifold (32) and inside a housing (18) surrounding the conduit (12) in the vicinity of the nozzles (28) where it passes through the nozzles (28) into the bore (30) of the conduit (12). The high velocity air breaks the fuel up into particles and pounds the particles with an angular velocity causing the particles to swirl or rotate as a fine mist in one direction about the longitudinal axis at the outlet (16).

Abstract: A pressure compensated plug for use with subsea trees is described in which a reservoir of compressible fluid is located from a cavity within a horizontal tree (10) whereby allowing temperature induced volume changes to be absorbed by the compressible fluid without resulting in significant increase in pressure. This is achieved by providing a pressure compensation apparatus (80) in the cavity, the apparatus comprising a housing (82) with a floating piston (86) in a chamber (84). The lower face (96) of the chamber is exposed to compressible fluid in the form of an inert gas, such as nitrogen, which is pre-charged at the surface to the appropriate hydrostatic pressure of the seabed. The volume of gas trapped between the lower piston face and the lower face of the cylinder forms the gas reservoir (94). A compensation cylinder can be attached to the upper section of the lower plug (70) and run and retrieved at the same time as the plug, thereby reducing the number of intervention runs.

Abstract: A dual bore completion sub-sea test tree (10) is described which has main bore (18) and an auxiliary or annulus bore (20). Two identical ball valves (22, 24) are located in series within the main bore (18) and two smaller identical ball valves (26, 28) are located in series in the annulus bore (20). The ball valves (22, 24, 26, 28) are operated by respective independent control lines acting on the operating mechanisms of the respective valves within the test tree (10) to move the valves between open and closed positions to allow or deny communication through the respective bores (18, 20). The completion sub-sea test tree (10) provides isolation of the main bore (18) and/or the annulus bore (20) when required by application of hydraulic pressure to assist closure to spring forces sufficient to cut coil tubing in the event of an emergency situation requiring rapid disconnect.

Abstract: Apparatus and a method for killing a live well after activation of a well blowout preventer is described. This is achieved by providing apparatus in the form of a shear or kill sleeve (34) in a string (26) above a sub-sea test tree and which is located between the pipe rams (22, 24) and shear rams (18) of a blowout preventer (12). In the event that the shear rams (18) are activated and seal the string above the kill sleeve (34), the sleeve includes a pressure sensitive valve (84) which may be opened, by pressurising between the blowout preventer rams (18, 22), to permit fluid to be pumped from the blowout preventer (12) through the valve (84) and into the string (40), to choke or kill the well. After the well has been killed, the blowout preventer (12) may be opened to permit removal of the well tools. Embodiments of the invention are described.

Abstract: Apparatus and method of isolating a well to allow intervention equipment to be installed in the upper section of tubing and surface equipment to be tested prior to running in the well is described which enables a surface test tree to be leak-off tested on a regular basis and enables the SSTT valves to be pressure tested before opening and after relatch. This is achieved by providing a completion lubricator valve comprising a fail open valve (18) located above a conventional downhole safety valve (20), the fail open valve (18) being closable by the application of hydraulic closure pressure (42) to allow a pressure differential to be supported from above. The valves (18, 20) are flapper valves and are spring-biased to open or closed positions as necessary. This allows the intervention equipment to be installed in the upper section of the tubing and the surface equipment to be tested prior to running in the well and enables the injection head to be installed immediately upon the production tree.