WO2000001915A2 - Control system for the workover of oil wells - Google Patents

Control system for the workover of oil wells Download PDF

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Publication number
WO2000001915A2
WO2000001915A2 PCT/GB1999/002088 GB9902088W WO0001915A2 WO 2000001915 A2 WO2000001915 A2 WO 2000001915A2 GB 9902088 W GB9902088 W GB 9902088W WO 0001915 A2 WO0001915 A2 WO 0001915A2
Authority
WO
WIPO (PCT)
Prior art keywords
workover
control system
electrical
assembly
switch means
Prior art date
Application number
PCT/GB1999/002088
Other languages
French (fr)
Other versions
WO2000001915A3 (en
Inventor
David John Jones
John Nigel Winchester
David Henry Stewart
Original Assignee
Abb Offshore Systems Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Abb Offshore Systems Limited filed Critical Abb Offshore Systems Limited
Priority to AU45270/99A priority Critical patent/AU4527099A/en
Priority to BR9911630-8A priority patent/BR9911630A/en
Priority to EP99928157A priority patent/EP1144794A3/en
Publication of WO2000001915A2 publication Critical patent/WO2000001915A2/en
Priority to NO20006688A priority patent/NO20006688L/en
Publication of WO2000001915A3 publication Critical patent/WO2000001915A3/en

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Classifications

    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21BEARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B33/00Sealing or packing boreholes or wells
    • E21B33/02Surface sealing or packing
    • E21B33/03Well heads; Setting-up thereof
    • E21B33/035Well heads; Setting-up thereof specially adapted for underwater installations
    • E21B33/0355Control systems, e.g. hydraulic, pneumatic, electric, acoustic, for submerged well heads
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21BEARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B41/00Equipment or details not covered by groups E21B15/00 - E21B40/00
    • E21B41/0007Equipment or details not covered by groups E21B15/00 - E21B40/00 for underwater installations

Definitions

  • This invention relates to workover of wells. It is particularly, but not exclusively, related to installation of and intervention into subsea wells, for example subsea production wells.
  • An oil or gas well hereinafter referred to as a well, is constructed by drilling a borehole
  • the wellhead well accessible at the surface, for example on land or on the seabed, is referred to as the wellhead.
  • run means to install the equipment in a well (even if only
  • surface means the subsea wellhead.
  • a conduit for carrying extracted fluids from a lower region of the well to the surface
  • a completion is inserted into the casing and extends from the surface to the
  • tubing or a tubing string.
  • the completion is supported from an upper end by a tubing
  • hanger which rests on, and is locked into place on, the wellhead.
  • This process may also include testing seals and joints between the wellhead and the
  • tubing hanger the tubing hanger and the completion and between the Christmas tree and the wellhead.
  • the Christmas tree is locked into place on the wellhead and controls operation of the well.
  • the completion is placed in the wellhead
  • a horizontal Christmas tree or a spool or lateral tree
  • a Christmas tree can weigh more than twenty
  • intervention to take place. This requires production of
  • This includes running sensing apparatus to monitor well temperature and
  • a workover control system comprising a hydraulic power unit an electrical control unit an electrohydraulic umbilical
  • electrohydraulic switch means is also provided which switches hydraulic power to
  • a plurality of workover devices are controlled by the electrohydraulic switch.
  • the same umbilical is used to
  • control at least one workover device during an installation operation and an intervention
  • the electrohydraulic umbilical Whilst it is convenient for the electrohydraulic umbilical to be a single umbilical, it may
  • the electrical signal control unit receives a control instruction from control
  • each workover device provides a function which enables workover to
  • the or each workover device is selected from a retainer valve, a subsea test tree, a tubing hanger running tool, a tubing hanger, and a lower marine riser package.
  • the electrohydraulic umbilical controls at least one valve
  • the switch receives hydraulic power through a single hydraulic supply line.
  • supply line may supply hydraulic fluid at low pressure and the other line may supply
  • the system is used to workover a horizontal Christmas tree.
  • it is
  • the system is used to workover wells which have subsea wellheads.
  • the electrohydraulic switch contains an electrical module.
  • the electrohydraulic switch contains an electrical module.
  • electrical module receives an electrical control signal to operate a particular workover
  • valves to route hydraulic power to operate one or more workover devices.
  • Figure 1 shows a workover control system
  • Figure 2 shows a completion being installed in a well
  • Figure 3 shows a well intervention
  • Figure 4 shows detail of a Christmas tree during well intervention
  • Figure 5 shows an exploded view of a riser control module
  • Figure 6 shows a perspective view of the module of Figure 5;
  • Figure 7 shows a hydraulic schematic of the module of Figures 5 and 6;
  • Figure 8 show an electronic schematic of the module of Figures 5 and 6;
  • Figure 9 shows an alternative electronic schematic of the module of Figures 5 and 6.
  • Figure 1 shows a workover control system 10 being used in the installation of a
  • the workover control system 10 is used to control
  • the well 14 has a wellhead 16 on which is located a horizontal Christmas tree (XT) 18.
  • XT horizontal Christmas tree
  • BOP blow-out preventer system
  • LMRP marine riser package
  • the BOP riser 24 extends from a vessel, such as a ship or an oil rig, (not shown) to a vessel, such as a ship or an oil rig, (not shown) to a vessel, such as a ship or an oil rig, (not shown) to a vessel, such as a ship or an oil rig, (not shown) to a vessel, such as a ship or an oil rig, (not shown) to a vessel, such as a ship or an oil rig, (not shown) to
  • the completion riser 26 is
  • completion string installation assembly 25 and the completion riser 26 is called a completion string.
  • the installation assembly 25 comprises a plurality of individual workover devices, or
  • workover devices devices which are discussed below.
  • workover devices devices which are discussed below.
  • the devices are controlled by a workover control station 28 and a hydraulic
  • HPU power unit
  • an umbilical 32 extending from a reel 34 on the vessel.
  • the installation assembly 25 has a continuous bore through which fluid can pass, from the completion 12 to the
  • completion riser 26 and thence to a surface test tree. It is usual to perform a well test
  • the installation assembly 25 has a completion riser control module (RCM) 36, a retainer
  • RV right valve
  • SSTT subsea test tree
  • THRT tubing hanger running tool
  • TH tubing hanger
  • the RCM has been assembled and joined together to form the installation assembly 25.
  • the RCM has been assembled and joined together to form the installation assembly 25.
  • the RV 38 is a
  • connection between the RV 38 and the SSTT 40 is broken. This may occur if the
  • RV right
  • Installation occurs as follows.
  • the XT 18 is carried down into place on the wellhead 16
  • TRT tree running tool
  • riser 24 (incorporating the BOP 20 and LMRP 22) is placed on the XT 18 and then the
  • completion string (comprising the completion 12, the installation assembly 25 and the
  • completion riser 26 is lowered so as to run the completion 12 through the BOP riser 24 and then the XT 18 and then into the well 14. Operation of the XT 18 is controlled by a workover subsea control module (SCM) 66.
  • SCM workover subsea control module
  • the TH 44 is locked onto the THRT 42 and carried by it into the wellhead 16.
  • T ⁇ 44 is located and locked into place in the wellhead 16, the THRT 42 is unlocked from
  • the TH 44 When in place, the TH 44 supports the completion 12 in the well 14. It also allows for access by wireline services into the completion 12.
  • the umbilical 32 provides a hydraulic supply 70 and an electrical supply 72 to the RCM
  • the RCM 36 provides hydraulic supplies 70a, 70b and 70c to the RV 38, SSTT 40
  • the RCM 36 also sends an electronic signal to the surface which indicates whether the hydraulic supply has reached the required pressure to operate completion
  • Hydraulic and electrical supplies 70d and 72b travel from the TH 44 downhole to
  • SCSSV surface controlled sub-surface safety valve
  • LV lubrication valve
  • a surface test tree (not shown) is located on the vessel, above the LV. When the completion 12 is correctiy located in the well 14, the well is tested to make sure
  • THRT 42 is disconnected from the TH 44 and the completion riser 26 is retrieved
  • the TH 44 is then sealed with a crown plug and internal tree cap to prevent hydrocarbons from flowing out of the well.
  • hydrocarbon oil or gas
  • Figure 2 is another illustration of installation of a completion 12 into a horizontal well.
  • the LV 48 is controlled via an umbilical 54 supplied by a reel 56.
  • signals from the HPU 30 pass down an umbilical 50 and are used to
  • the umbilical 50 is supplied by a reel 52. Commands
  • umbilical 50 is also removed and replaced by a production jumper. This operates a production subsea control module (SCM) 46 (shown in Figure 4) which controls the XT 18 during production.
  • SCM production subsea control module
  • Figure 3 shows an intervention into the well after production has been occurring.
  • SCSSV (not shown) is closed. This stops production, by preventing hydrocarbons
  • the completion riser 26 is used to lower an intervention
  • the intervention assembly 58 onto the XT 18.
  • the intervention assembly 58 comprises, in order from top
  • stress joint 60 is simply a joint provided to accommodate relative movement between the
  • An LV 48 is located at the top of the completion
  • the intervention assembly 58 is analogous to the installation assembly 25 as
  • the installation assembly 25 additionally has the function of supporting the completion during installation. Intervention equipment, such as wireline tools and
  • umbilical 32 can be used both in installation and intervention.
  • LMRP 22 Located on the XT 18 is the LMRP 22. Located on the LMRP 22 is an emergency
  • RCM 36 is not used in this configuration.
  • the umbilical is connected direcdy to the EDP
  • the umbilical 32 from the reel 34 is universal and is used both in installation, as shown in Figure 4a, and intervention, as shown in Figure 4b. Therefore, a single umbilical is
  • the HPU 30 receives pneumatic and electrical supplies from the workover vessel and
  • the power and control signals are combined into an umbilical jumper 64 which runs to
  • the reel 34 is powered and is used to deploy and retrieve the workover umbilical 32 and
  • tubing hanger running tool umbilical as required, in a controlled and safe manner
  • the reel 34 receives pneumatic power from an external source via the
  • An electrical control circuit controlled by a THRT control unit 62 monitors the status of
  • control modules one being the production SCM 46 on the XT 18 which controls all of
  • SCM 66 which controls additional functions associated with the EDP 63 and LMRP 22 such as connections between the XT 18 and the wellhead and the EDP 63 and the XT 18.
  • ROV remotely operated vehicle
  • LMRP 22 both to the production SCM 46 and the workover SCM 66. They are used to
  • the XT 18 can be controlled by a hydraulic supply from the production SCM 46 or a hydraulic supply from the workover umbilical 32.
  • valve located on the XT 18 switches between each of these hydraulic supplies.
  • the RCM 36 is shown in Figure 5 in exploded view. It is a discrete section of the
  • installation assembly 25 adjacent to the RV 38. It is an electrohydraulic package,
  • LP pressure (LP) hydraulic supplies are connected to connectors 80 in a manifold block 88
  • HP hydraulic supplies are connected to connectors 82 in the manifold block 88 where
  • 80 and 82 are l A" female JIC fittings. They are located at the top of the RCM 36. Two
  • electrical connectors 84 and 86 respectively. Electrical conduits run from the electrical
  • the RCM 36 has a steel casing comprising a pair of steel covers 90 and a baseplate 92.
  • the covers 90 and the baseplate 92 are bolted onto the manifold block 88 to protect
  • the manifold block 88 itself provides a support on which to
  • the covers 90 and the baseplate 92 are
  • compensator is a rubber bladder located and covering a port in the casing.
  • bladder is a barrier between the dielectric oil on the inside of the casing and production
  • RCM passes down the BOP riser 24 static pressure in the production fluid increases. This acts on the dielectric fluid through the bladder and thus pressure is equalised.
  • a pressure valve is installed in the casing at its lower end to vent dielectric fluid in the
  • Suitable inlet and outlet ports for the dielectric fluid are provided in the casing.
  • Cathodic protection in the form of sacrificial anodes is provided within the casing to
  • Threaded connections at the top of the RCM 36 provide attachment to the completion
  • the baseplate 92 is deep enough to provide protection for eighteen V " female JIC
  • sixteen are for LP hydraulic supply lines and two are for HP hydraulic supply lines.
  • the manifold block 88 comprises a machined gallery carrying eighteen directional
  • DCVs control valves 95, sixteen of which are LP function and two of which are HP function.
  • the RCM 36 also contains an electrical or electronics module which is described further below with reference to Figures 8 and 9.
  • the assembled RCM 36 is shown in Figure 6. It is generally cylindrical in shape having
  • the single bore is appropriate for use with a monobore completion riser. Two bores would be provided if a dual bore completion riser was used. The purpose of the
  • the RCM 36 is provided with pairs of LP and HP hydraulic supplies. These are shown on Figure 7 as two LP hydraulic supplies from the connectors
  • Pressure transducers 93 are
  • a pressure transducer can be provided for each line controlled by a DCV.
  • the signals from the pressure transducers 93 are multiplexed in the electrical module of
  • Each hydraulic supply is filtered by its own supply line filter 94 each of which is a 20
  • filter manifold which is a sub-assembly bolted to the manifold block 88.
  • This filter manifold is integral with the internal structure of the manifold block 88 of the RCM 36.
  • the filters 94 are part of a valve sub-assembly comprising check valves to prevent
  • flow valve is provided to allow forward flow in the event of the filter becoming clogged.
  • Each pair of the LP and HP hydraulic supplies (from connectors 80 and 82) is
  • FIG 7 shows a schematic of the hydraulic system of an RCM 36. It should be noted that its functionality is dependent on its particular purpose.
  • the system is of an open loop design with returned hydraulic fluid being vented to the
  • HP hydraulic supply is provided to two HP DCVs 104 and 106 which control the operation of the SCSSV.
  • LP hydraulic supply provides LP pilot pressure to all of the
  • DCV outputs pass through the hydraulic connectors in the baseplate 92 to take place.
  • the DCV outputs may open and close the RV
  • FIG. 8 illustrates schematically part of the electronics module of the RCM 36. This
  • module receives incoming electrical control signals by means of, for example, modem
  • Microprocessor 122 translates the serial messages from the modem as simple shut
  • the microprocessor 122 directs these commands
  • solenoid driver boards such as board 123 (only one solenoid driver
  • the DCVs 95 are solenoid operated three-way, two-position valves. Energising the
  • solenoid directs hydraulic fluid to the function line and thence to the associated workover
  • the output of DCV 95 is arranged to activate an actuator 126 to
  • signals are sent to the microprocessor 122 via a 4-20 milliamp board 125. Signals from
  • Figure 9 illustrates an alternative electronic configuration to that shown in Figure 8.
  • the microprocessor 122 is arranged merely to process signals from the
  • the PLA 128 decodes the modem output commands and routes them to the
  • the PLA is an array of
  • a solenoid must be continuously energised to maintain the hydraulic supply to its
  • Actuators which are provided with return springs, for example the SSTT valves, close
  • the RCM 36 connects and disconnects connections between workover devices. It also connects and disconnects connections between workover devices. It also connects and disconnects connections between workover devices. It also connects and disconnects connections between workover devices. It also connects and disconnects connections between workover devices. It also connects and disconnects connections between workover devices. It also connects and disconnects connections between workover devices. It also connects and disconnects connections between workover devices. It also connects and disconnects connections between workover devices. It also
  • RCM which uses a single low pressure supply and a single
  • the RCM 36 is a
  • the RCM 36 operates the appropriate workover device.

Abstract

A workover control system (10) has a hydraulic power unit (30) and an electrical signal control unit located on a vessel and a control module (36) located proximate to a subsea well (14). An electrohydraulic umbilical (32) transmits electrical and hydraulic power and signals from the vessel to the control module (36). During workover of the well, workover devices (12) are operated by hydraulic signals provided by an electrohydraulic switch in the control module. The hydraulic signals are produced in response to electrical signals from the vessel.

Description

WELLS
This invention relates to workover of wells. It is particularly, but not exclusively, related to installation of and intervention into subsea wells, for example subsea production wells.
An oil or gas well, hereinafter referred to as a well, is constructed by drilling a borehole
and then lining it with a steel casing. The upper end of the well, that is the part of the
well accessible at the surface, for example on land or on the seabed, is referred to as the wellhead.
In the following, the terms run and retrieve have specific meanings. When used in
relation to equipment, run means to install the equipment in a well (even if only
temporarily) and retrieve means to bring the equipment out of the well and up to the
surface. For a subsea well, surface means the subsea wellhead.
A conduit for carrying extracted fluids from a lower region of the well to the surface,
referred to as a completion, is inserted into the casing and extends from the surface to the
lower region where extraction occurs. The completion is also referred to as production
tubing or a tubing string. The completion is supported from an upper end by a tubing
hanger which rests on, and is locked into place on, the wellhead.
The process of placing the tubing hanger on the wellhead, inserting the completion into
the casing and fitting a flow control device referred to as a Christmas tree to the wellhead
so that the well is ready for production is a workover process referred to as installation. This process may also include testing seals and joints between the wellhead and the
tubing hanger, the tubing hanger and the completion and between the Christmas tree and the wellhead.
The Christmas tree is locked into place on the wellhead and controls operation of the well. In a so-called "conventional" Christmas tree the completion is placed in the wellhead
before the Christmas tree is locked into place on the wellhead. Another type of Christmas
tree, referred to as a "horizontal" Christmas tree (or a spool or lateral tree), is locked into
place on the wellhead before the completion is installed in the well. The completion is
run into the production casing and thus into the well through the Christmas tree. An
advantage of a horizontal Christmas tree is that a part of the completion can be changed
without moving the Christmas tree. Since a Christmas tree can weigh more than twenty
tonnes moving it is undesirable.
Once the well is on-stream (that is in production), it may be necessary for another
workover process referred to as intervention to take place. This requires production of
the well to cease and a tool or a device to be run downhole, typically down the
completion. This includes running sensing apparatus to monitor well temperature and
pressure or to monitor downhole formations, retrieving and re-installing sensing
apparatus, operating a zone control valve, running remote viewing apparatus such as a
TV camera to view tubing damage or investigate other matters, locating and retrieving
objects dropped down the well and running downhole gas lift assemblies.
According to a first aspect of the invention there is provided a workover control system comprising a hydraulic power unit an electrical control unit an electrohydraulic umbilical
and a workover assembly comprising a plurality of workover devices characterised in that
electrohydraulic switch means is also provided which switches hydraulic power to
operate at least one of the workover devices in response to receiving signals from the electrical control unit.
Preferably a plurality of workover devices are controlled by the electrohydraulic switch.
In this embodiment the electrohydraulic switch supplies hydraulic power to one or more
of the workover devices as a consequence of being instructed to do so by one or more electrical switch signals.
Preferably there is a single umbilical. Most preferably the same umbilical is used to
control at least one workover device during an installation operation and an intervention
operation.
Whilst it is convenient for the electrohydraulic umbilical to be a single umbilical, it may
comprise a plurality of umbilicals bundled together or otherwise. For example, hydraulic
power and electrical signals may pass down separate umbilicals.
Preferably the electrical signal control unit receives a control instruction from control
means instructing the or each workover device to be operated. This may include
switching the workover device on or off, operating valves or ports to open or close or
causing it to lock onto or unlock from another device. Preferably the or each workover device provides a function which enables workover to
occur. The or each workover device is selected from a retainer valve, a subsea test tree, a tubing hanger running tool, a tubing hanger, and a lower marine riser package.
According to a second aspect of the invention there is provided electrohydraulic switch
means for switching hydraulic power to at least one workover device in a plurality of workover devices.
Preferably an electrical signal produced by the electrical signal control unit and conveyed
to the electrohydraulic switch by the electrohydraulic umbilical controls at least one valve
to provide hydraulic power to the or each workover device.
Preferably in the switch hydraulic power is switched through individual directional
control valves.
Preferably the switch receives hydraulic power through a single hydraulic supply line.
Most preferably it receives hydraulic power through two hydraulic supply lines. One
supply line may supply hydraulic fluid at low pressure and the other line may supply
hydraulic fluid at high pressure.
Preferably the system is used to workover a horizontal Christmas tree. Alternatively it is
used to workover a conventional Christmas tree.
Preferably the system is used to workover wells which have subsea wellheads. Preferably the electrohydraulic switch contains an electrical module. Preferably the
electrical module receives an electrical control signal to operate a particular workover
device and activates one or more electrical actuators to operate a particular valve or group
of valves to route hydraulic power to operate one or more workover devices.
An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings in which:
Figure 1 shows a workover control system;
Figure 2 shows a completion being installed in a well;
Figure 3 shows a well intervention;
Figure 4 shows detail of a Christmas tree during well intervention;
Figure 5 shows an exploded view of a riser control module;
Figure 6 shows a perspective view of the module of Figure 5;
Figure 7 shows a hydraulic schematic of the module of Figures 5 and 6;
Figure 8 show an electronic schematic of the module of Figures 5 and 6; and
Figure 9 shows an alternative electronic schematic of the module of Figures 5 and 6.
Figure 1 shows a workover control system 10 being used in the installation of a
completion 12 into a well 14. The workover control system 10 is used to control
operation of a Christmas tree during workover, that is installation of a completion or
intervention into the well.
The well 14 has a wellhead 16 on which is located a horizontal Christmas tree (XT) 18.
Located on the XT 18 is a blow-out preventer system (BOP) 20 which supports a lower marine riser package (LMRP) 22. The LMRP 22 is disposed at a lower end of a BOP
riser 24 down which the completion 12 is lowered. It is introduced into the well through
the LMRP 22, BOP 20 and XT 18.
The BOP riser 24 extends from a vessel, such as a ship or an oil rig, (not shown) to
provide a conduit through which the completion 12 travels from the vessel to the well 14.
As the completion is lowered into the well, it is supported by an installation assembly 25
at the end of a completion riser 26 such as a monobore riser. The completion riser 26 is
used as a landing string for running the completion 12 into the wellhead 16. It also
provides a vertical pressure retaining point of entry from the surface into the XT 18
during installation of the completion. The combination of the completion 12, the
installation assembly 25 and the completion riser 26 is called a completion string.
The installation assembly 25 comprises a plurality of individual workover devices, or
packages, which are discussed below. By workover devices is meant devices which
operate during workover to assist in installation of the completion and intervention into
the well. The devices are controlled by a workover control station 28 and a hydraulic
power unit (HPU) 30 which are both located on the vessel. In addition to hydraulic
power generation means, and means to generate hydraulic control signals, the HPU 30
also comprises an electrical power unit and a control system. Control of the workover
devices is via an umbilical 32 extending from a reel 34 on the vessel.
It should be noted that the workover devices of the installation assembly 25 are each
provided with a bore so that, once connected together, the installation assembly 25 has a continuous bore through which fluid can pass, from the completion 12 to the
completion riser 26 and thence to a surface test tree. It is usual to perform a well test
after installation to make sure that the well is operating properly. It should also be noted
that the completion 12, installation assembly 25 and the completion riser 26 form a long continuous conduit.
The installation assembly 25 has a completion riser control module (RCM) 36, a retainer
valve (RV) 38, a subsea test tree (SSTT) 40, a tubing hanger running tool (THRT) 42 and a tubing hanger (TH) 44. These workover devices are discrete and separate units which
have been assembled and joined together to form the installation assembly 25. The RCM
36 is connected to the completion riser 26 by a threaded connection. The RV 38 is a
safety valve which retains pressure and fluid within the completion riser 26 in the event
that the connection between the RV 38 and the SSTT 40 is broken. This may occur if the
vessel moves off-station. This can occur during any workover operation. The SSTT 40
is used to contain pressure in the completion in the event that the completion riser 26, RV
38 and RCM 36 are retrieved.
Installation occurs as follows. The XT 18 is carried down into place on the wellhead 16
by a tree running tool (TRT) (not shown). A hydraulic command from the HPU 30 on
the vessel causes the XT 18 to lock to the wellhead 16. The connection and seal between
the XT 18 and wellhead 16 are tested. The TRT then returns to the vessel. The BOP
riser 24 (incorporating the BOP 20 and LMRP 22) is placed on the XT 18 and then the
completion string (comprising the completion 12, the installation assembly 25 and the
completion riser 26) is lowered so as to run the completion 12 through the BOP riser 24 and then the XT 18 and then into the well 14. Operation of the XT 18 is controlled by a workover subsea control module (SCM) 66.
The TH 44 is locked onto the THRT 42 and carried by it into the wellhead 16. When the
TΗ 44 is located and locked into place in the wellhead 16, the THRT 42 is unlocked from
the TH 44. When in place, the TH 44 supports the completion 12 in the well 14. It also allows for access by wireline services into the completion 12.
The umbilical 32 provides a hydraulic supply 70 and an electrical supply 72 to the RCM
36. The RCM 36 provides hydraulic supplies 70a, 70b and 70c to the RV 38, SSTT 40
and THRT 42 respectively. It provides an electrical control signal 72a which passes through the THRT 42 and is used to interrogate downhole pressure and temperature
sensors. Data provided by such sensors is in the form of an electrical communication
signal 74 which passes through the THRT 42 directly to the vessel or is relayed by the
RCM 36. The RCM 36 also sends an electronic signal to the surface which indicates whether the hydraulic supply has reached the required pressure to operate completion
tools. Hydraulic and electrical supplies 70d and 72b travel from the TH 44 downhole to
control and are used to monitor a surface controlled sub-surface safety valve (SCSSV)
and downhole pressure and temperature sensors.
Located in the vessel at the top of the completion string is a lubrication valve (LV). This
is not shown in Figure 1. Its purpose is to permit the passage of wireline services into the
well 14. A surface test tree (not shown) is located on the vessel, above the LV. When the completion 12 is correctiy located in the well 14, the well is tested to make sure
that hydrocarbons in the well are under sufficient pressure to flow from the well. Valves
are opened in the LV, RV 38 and SSTT 40 to allow the hydrocarbons to flow up the
completion 12 and through a surface test tree present on the vessel. Once testing has been satisfactorily completed, the valves in the LV, RV 38 and SSTT 40 are closed, the
THRT 42 is disconnected from the TH 44 and the completion riser 26 is retrieved
together with the majority of the installation assembly 25. The TH 44 is left in place in
the wellhead 16. The TH 44 is then sealed with a crown plug and internal tree cap to prevent hydrocarbons from flowing out of the well.
Also shown in Figure 1 are emergency shut down panels 120. These are provided on the
vessel at suitable locations such as the driller's station and the surface test tree operating
station to enable shut-down of the well in the event of an emergency such as leakage of
hydrocarbon (oil or gas) on the vessel.
Figure 2 is another illustration of installation of a completion 12 into a horizontal well.
Features which are common to Figures 1 and 2 have been given corresponding reference
numerals. The lubrication valve (LV) mentioned above is shown designated by reference
numeral 48. The LV 48 is controlled via an umbilical 54 supplied by a reel 56.
During workover, signals from the HPU 30 pass down an umbilical 50 and are used to
operate the workover SCM 66. The umbilical 50 is supplied by a reel 52. Commands
from the workover control station 28 are supplied down electrohydraulic umbilical 32 to
the RCM which then operates appropriate workover devices to enable installation to occur. Following installation, when the BOP 20 and LMRP 22 are retrieved, the
umbilical 50 is also removed and replaced by a production jumper. This operates a production subsea control module (SCM) 46 (shown in Figure 4) which controls the XT 18 during production.
Once installation workover is complete the well is ready to be brought on-stream for production to begin.
Figure 3 shows an intervention into the well after production has been occurring. The
SCSSV (not shown) is closed. This stops production, by preventing hydrocarbons
flowing into the XT 18. The completion riser 26 is used to lower an intervention
assembly 58 onto the XT 18. The intervention assembly 58 comprises, in order from top
to bottom, the RCM 36, the RV 38, a stress joint 60, the LMRP 22 and the SSTT 40. The
stress joint 60 is simply a joint provided to accommodate relative movement between the
completion riser 26 and the XT 18. An LV 48 is located at the top of the completion
string. The intervention assembly 58 is analogous to the installation assembly 25 as
shown in Figure 1. They are both located at the end of the completion riser 26 and their
functions are respectively to provide control of the completion during intervention and
installation. The installation assembly 25 additionally has the function of supporting the completion during installation. Intervention equipment, such as wireline tools and
services, is passed down the completion riser 26 and passes through open valves in the
LV 48, the RV 38, the stress joint 60, the LMRP 22 and the SSTT 40 and then enters the
well. It should be noted that the same umbilical, umbilical 32, can be used both in installation and intervention.
The foregoing describes the invention applied to workover of a horizontal Christmas tree.
It can also be used in the workover of conventional Christmas trees. This is described in
relation to Figure 4. This shows a topside control system similar to that of Figure 1
located on a vessel being used in workover of a conventional Christmas tree. Installation is shown as Figure 4a in which the umbilical 32 from the reel 34 is attached to the
installation assembly 25. Intervention is shown in Figure 4b in which the umbilical 32
from the reel 34 is attached instead to the XT 18 via workover equipment.
Referring to Figure 4a installation is generally similar to the installation procedure
described above in relation to horizontal wells and so will not be described here. Of
course the major difference is that a completion is installed in the well using controls
transmitted along the umbilical 32 and then the XT 18 is locked onto the wellhead, again
following a command which is transmitted along the umbilical 32.
Referring to Figure 4b, intervention into a conventional well will now be described.
Located on the XT 18 is the LMRP 22. Located on the LMRP 22 is an emergency
disconnect package (EDP) 63. The completion riser 26 terminates into the EDP 63. The
RCM 36 is not used in this configuration. The umbilical is connected direcdy to the EDP
63.
The umbilical 32 from the reel 34 is universal and is used both in installation, as shown in Figure 4a, and intervention, as shown in Figure 4b. Therefore, a single umbilical is
used in these two operations. According to the invention a single umbilical is used in these two operations in horizontal Christmas trees.
The HPU 30 receives pneumatic and electrical supplies from the workover vessel and
converts them into hydraulic and electrical power supplies and electrical control signals.
The power and control signals are combined into an umbilical jumper 64 which runs to
the reel 34. The hydraulic supplies and electrical signals then travel along the umbilical
32 to the workover SCM 66 where they are switched to provide hydraulic control signals
to operate various hydraulically actuated latches and valves on the EDP 63, LMRP 22,
XT 18 and downhole SCSSV. The system also enables testing of various seals at
connections between workover devices and enables signals from pressure and
temperature transmitters mounted on the XT 18 and downhole to be connected to a
monitoring system in the HPU 30 on the vessel.
The reel 34 is powered and is used to deploy and retrieve the workover umbilical 32 and
the tubing hanger running tool umbilical, as required, in a controlled and safe manner
without damage. The reel 34 receives pneumatic power from an external source via the
umbilical jumper 64.
An electrical control circuit controlled by a THRT control unit 62 monitors the status of
control valves in the RCM 36 to check that they are supplying and not supplying
hydraulic fluid as commanded. For conventional Christmas trees the EDP 63 and LMRP 22 are located below the
completion riser. Control of the EDP 63 and the LMRP 22 during a light workover
operation, for example wireline downhole intervention, is shared between two subsea
control modules, one being the production SCM 46 on the XT 18 which controls all of
the functions normally under control during production and the other being the workover
SCM 66 which controls additional functions associated with the EDP 63 and LMRP 22 such as connections between the XT 18 and the wellhead and the EDP 63 and the XT 18.
It is used to lock and unlock these connections and to test their integrity when they are
locked.
Electrical flying leads 68 installed by a remotely operated vehicle (ROV) connect the
LMRP 22 both to the production SCM 46 and the workover SCM 66. They are used to
monitor tree and downhole instrumentation.
The XT 18 can be controlled by a hydraulic supply from the production SCM 46 or a hydraulic supply from the workover umbilical 32. A three-way, two-position isolation
valve located on the XT 18 switches between each of these hydraulic supplies. The valve
is switched by an ROV.
The RCM 36 is shown in Figure 5 in exploded view. It is a discrete section of the
installation assembly 25, adjacent to the RV 38. It is an electrohydraulic package,
supplied from the vessel at the surface with hydraulic and electrical supplies. Two low
pressure (LP) hydraulic supplies are connected to connectors 80 in a manifold block 88
where they are consolidated together by means of a shuttle valve. Two high pressure (HP) hydraulic supplies are connected to connectors 82 in the manifold block 88 where
they are consolidated together also by means of a shuttle valve. The hydraulic connectors
80 and 82 are lA" female JIC fittings. They are located at the top of the RCM 36. Two
pairs of electrical control wires and two pairs of electrical power wires are connected to
electrical connectors 84 and 86 respectively. Electrical conduits run from the electrical
connectors 84 and 86 and into the manifold block 88. The electrical connectors 84 and
86 are manually mateable bulkhead mounted underwater electrical connectors.
It should be noted that the duplication of the LP and HP supplies, and electrical power
and control wires (that is the provision of pairs of all of these features), is for dual
redundancy. Therefore in the event of failure of a main supply, a spare is provided.
The RCM 36 has a steel casing comprising a pair of steel covers 90 and a baseplate 92.
The covers 90 and the baseplate 92 are bolted onto the manifold block 88 to protect
various hydraulic fittings. The manifold block 88 itself provides a support on which to
locate the covers 90 and the baseplate 92. The covers 90 and the baseplate 92 are
provided with ring seals at their joints to provide a leakproof seal to prevent escape of a
dielectric oil which is enclosed within the casing. A pressure and temperature
compensator is fitted within the casing to accommodate any changes in fluid volume due
to changes in temperature and hydrostatic pressure. The pressure and temperature
compensator is a rubber bladder located and covering a port in the casing. The rubber
bladder is a barrier between the dielectric oil on the inside of the casing and production
fluid on the outside of the casing, for example brine located in the BOP riser 24. As the
RCM passes down the BOP riser 24 static pressure in the production fluid increases. This acts on the dielectric fluid through the bladder and thus pressure is equalised.
A pressure valve is installed in the casing at its lower end to vent dielectric fluid in the
event of malfunction of the pressure and temperature compensator or in the event of
leakage of hydraulic fluid. Suitable inlet and outlet ports for the dielectric fluid are provided in the casing.
Cathodic protection in the form of sacrificial anodes is provided within the casing to
protect the interior of the RCM 36 against any production fluid which penetrates into it.
Telemetry readbacks from downhole pressure, temperature and choke position sensors
are made through two telemetry electrical connectors (not shown) which are located at
the bottom of the manifold block 88.
Threaded connections at the top of the RCM 36 provide attachment to the completion
riser 26 and at the baseplate 92 to an adjacent workover device.
The baseplate 92 is deep enough to provide protection for eighteen V " female JIC
hydraulic fittings 91 and the two telemetry electrical connectors. Of the JIC fittings,
sixteen are for LP hydraulic supply lines and two are for HP hydraulic supply lines.
The manifold block 88 comprises a machined gallery carrying eighteen directional
control valves (DCVs) 95, sixteen of which are LP function and two of which are HP function.
The RCM 36 also contains an electrical or electronics module which is described further below with reference to Figures 8 and 9.
The assembled RCM 36 is shown in Figure 6. It is generally cylindrical in shape having
a single axial bore running through it from an upper end to a lower end. It should be
noted that the single bore is appropriate for use with a monobore completion riser. Two bores would be provided if a dual bore completion riser was used. The purpose of the
bore is discussed above.
As mentioned above, the RCM 36 is provided with pairs of LP and HP hydraulic supplies. These are shown on Figure 7 as two LP hydraulic supplies from the connectors
80 and two HP hydraulic supplies from the connectors 82. Pressure transducers 93 are
used to measure the pressures of the pairs of hydraulic supplies before they are each
consolidated. The pressure transducers 93 can be seen in Figure 5. In an alternative
embodiment a pressure transducer can be provided for each line controlled by a DCV.
The signals from the pressure transducers 93 are multiplexed in the electrical module of
the RCM and returned to the workover control unit 28 by means of, for example, twisted
pair wires.
Each hydraulic supply is filtered by its own supply line filter 94 each of which is a 20
micron assembly. These filter the supplies before they are consolidated. The filters are
all contained in a filter manifold which is a sub-assembly bolted to the manifold block 88. This filter manifold is integral with the internal structure of the manifold block 88 of the RCM 36.
The filters 94 are part of a valve sub-assembly comprising check valves to prevent
reverse flow through the filter and allow reverse flow around the filter. A forward check
flow valve is provided to allow forward flow in the event of the filter becoming clogged.
In this embodiment these check valves work at a differential pressure across the filter of
1.2 to 3.0 bar.
Each pair of the LP and HP hydraulic supplies (from connectors 80 and 82) is
consolidated into a single hydraulic supply through shuttle valves 96 which are fitted to
the lower end of the manifold block 88. The filtered and consolidated hydraulic supplies
are then connected to distribution galleries within the hydraulic manifold block 88.
Referring specifically to Figure 7, this shows a schematic of the hydraulic system of an RCM 36. It should be noted that its functionality is dependent on its particular purpose.
For example sixteen rather than eighteen DCVs may be present.
The system is of an open loop design with returned hydraulic fluid being vented to the
annulus or to the sea depending on operating mode via O-ring check valves 100 and 102
mounted in the baseplate 92. Separate vent circuits are provided for each of the HP and
the LP hydraulic supplies venting through the check valves 100 and 102 respectively.
HP hydraulic supply is provided to two HP DCVs 104 and 106 which control the operation of the SCSSV. LP hydraulic supply provides LP pilot pressure to all of the
DCVs 95 and function line pressure to the sixteen LP DCVs 108. The function line
outputs from all of the DCVs 95 have flow controllers 110 which enable valve profiling
to take place. DCV outputs pass through the hydraulic connectors in the baseplate 92 to
operate workover devices. For example, the DCV outputs may open and close the RV
38, open and close valves on the SSTT 40, latch or unlatch the SSTT 40 to and from
another workover device, lock and unlock the TH 44 onto the wellhead 16 or the XT 18 and latch and unlatch it onto the THRT 42.
Figure 8 illustrates schematically part of the electronics module of the RCM 36. This
module receives incoming electrical control signals by means of, for example, modem
121. Microprocessor 122 translates the serial messages from the modem as simple shut
or open commands for the DCVs 95. The microprocessor 122 directs these commands
to the appropriate solenoid driver boards, such as board 123 (only one solenoid driver
board is shown in this diagram for clarity), in order to control the required DCV, or group
of DCVs.
The DCVs 95 are solenoid operated three-way, two-position valves. Energising the
solenoid directs hydraulic fluid to the function line and thence to the associated workover
device. For example, the output of DCV 95 is arranged to activate an actuator 126 to
operate a valve 127, in order to route hydraulic power to a workover device. Sensors 124
may be provided to monitor the DCV 95 and/or the associated workover device. Sensor
signals are sent to the microprocessor 122 via a 4-20 milliamp board 125. Signals from
the sensors are then transmitted, by means of the modem, for example to the vessel. Figure 9 illustrates an alternative electronic configuration to that shown in Figure 8. In
this embodiment, the microprocessor 122 is arranged merely to process signals from the
sensors 124. In order to translate the incoming messages to the modem 121 into
commands for the DCVs, a programmable logic array (PLA) 128 and associated circuitry
is provided. The PLA 128 decodes the modem output commands and routes them to the
appropriate DCVs 95 via their respective solenoid drivers 123. The PLA is an array of
hard wired logic devices, typically low cost. This arrangement removes total dependence
on the correct operation of the microprocessor 122 to effect control of the DCVs 95, and
hence improves reliability. The PLA 128, and any interface circuitry required, could be
mounted on the microprocessor board in order to share its packaging and power supply
interfaces.
A solenoid must be continuously energised to maintain the hydraulic supply to its
respective workover device. Loss of the electrical signal causes the function line to de-
pressurise. Purely hydraulic actuators which require a first hydraulic signal to open
followed by a second hydraulic signal to close, for example the actuators to lock and
unlock the tubing hanger running tool, remain "as is" on loss of hydraulic power.
Actuators which are provided with return springs, for example the SSTT valves, close
on loss of electrical or hydraulic power.
Monitoring functions and test lines from the THRT control unit 62 pass straight through
the RCM 36 and go to the appropriate workover device. Therefore they either terminate
at upper and lower riser interface/connection flanges between adjacent workover devices
or go directly into the appropriate workover device. The RCM 36 connects and disconnects connections between workover devices. It also
enables downhole mounted sensors to be monitored. It operates control and safety valves
downhole. The use of the RCM, which uses a single low pressure supply and a single
high pressure supply, duplicated for redundancy of course, to switch hydraulic fluid to
all of the workover devices provides a workover system which is particularly suitable for
operating in deep water, such as 1000 to 4000m. Effectively the RCM 36 is a
demultiplexer of control signals which operates various of the workover devices. By
decoding appropriate address information, whether electrically or hydraulically addressed, the RCM 36 operates the appropriate workover device.

Claims

1. A workover control system comprising a hydraulic power unit an electrical
control unit an electrohydraulic umbilical and a workover assembly comprising a plurality of workover devices characterised in that electrohydraulic switch means is also
provided which switches hydraulic power to operate at least one of the workover devices
in response to receiving signals from the electrical control unit.
2. A workover control system according to claim 1 characterised in that the workover assembly is connected to the end of a completion riser to form a completion
string.
3. A workover control system according to claim 1 or claim 2 characterised in that
the electrohydraulic switch means is part of the workover assembly.
4. A workover control system according to any preceding claim characterised in that
the workover assembly is an installation assembly.
5. A workover control system according to any of claims 1 to 3 characterised in that
the workover assembly is an intervention assembly.
6. A workover control system according to any preceding claim characterised in that
the electrohydraulic switch means is an in-line unit in the workover assembly.
7. A workover control system according to any preceding claim characterised in that
the workover assembly and the electrohydraulic switch means are connected together to form a common conduit through which fluid can flow.
8. A workover control system according to any preceding claim characterised in that
the electrohydraulic switch means comprises a cental node which receives all of the hydraulic supplies used in operating the workover devices.
9. A workover control system according to any preceding claim characterised in that
the electrical signals produced by the electrical signal control unit and conveyed to the
electrohydraulic switch means by the electrohydraulic umbilical controls at least one
valve to provide hydraulic power to the or each workover device.
10. A workover control system according to any preceding claim characterised in that
the same umbilical is used to control at least one workover device during an installation
operation and an intervention operation.
11. A workover control system according to any preceding claim characterised in that
the or each workover device is operated to carry out an action selected from a group
consisting of switching the workover device on or off, operating valves or ports
associated with it to open or close and causing it to lock or unlock from another device.
12. A workover control system according to any preceding claim characterised in that
in the electrohydraulic switch means hydraulic power is switched through individual directional control valves.
13. A workover control system according to any preceding claim characterised in that
the electrohydraulic switch means receives hydraulic power through two hydraulic supply
lines one supplying hydrauUc fluid at low pressure and the other supplying hydraulic fluid at high pressure.
14. A workover control system according to any preceding claim characterised in that the system is used to workover a horizontal Christmas tree.
15. A workover control system according to any of claims 1 to 13 characterised in
that the system is used to workover a conventional Christmas tree.
16. A workover control system according to any preceding claim characterised in that
the system is used to workover wells which have subsea wellheads.
17. A workover control system according to any preceding claim characterised in that
the electrohydraulic switch comprises an electrical module which receives the electrical
control signals to operate a particular workover device and activates one or more
electrical actuators to operate a particular valve or group of valves to route hydraulic
power to operate one or more workover devices.
18. A workover control system according to claim 17 characterised in that the
electrical module includes a microprocessor arranged to activate one or more electrical actuators in dependence on the received electrical control signals.
19. A workover control system according to claim 17 characterised in that the
electrical module includes an arry of logic devices arranged to activate one or more
electrical actuators in dependence on the received electrical control signals.
20. A workover control system substantially as described herein with reference to
Figures 1 to 7 of the accompanying drawings.
21. Electrohydraulic switch means for switching hydraulic power to at least one
workover device in a plurality of workover devices.
22. Electrohydraulic switch means according to claim 20 characterised in that it is
adapted to be incorporated into a workover assembly comprising the plurality of
workover devices.
23. Electrohydraulic switch means according to claim 20 characterised in that the
workover assembly comprises a common conduit through which fluid can flow.
24. Electrohydraulic switch means for switching hydraulic power to at least one
workover device substantially as described herein with reference to Figures 1 to 9 of the
accompanying drawings.
PCT/GB1999/002088 1998-07-01 1999-07-01 Control system for the workover of oil wells WO2000001915A2 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
AU45270/99A AU4527099A (en) 1998-07-01 1999-07-01 Wells
BR9911630-8A BR9911630A (en) 1998-07-01 1999-07-01 Well reconditioning control system
EP99928157A EP1144794A3 (en) 1998-07-01 1999-07-01 Control system for the workover of oil wells
NO20006688A NO20006688L (en) 1998-07-01 2000-12-28 Brönner

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9814114.6 1998-07-01
GBGB9814114.6A GB9814114D0 (en) 1998-07-01 1998-07-01 Wells

Publications (2)

Publication Number Publication Date
WO2000001915A2 true WO2000001915A2 (en) 2000-01-13
WO2000001915A3 WO2000001915A3 (en) 2001-12-06

Family

ID=10834655

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1999/002088 WO2000001915A2 (en) 1998-07-01 1999-07-01 Control system for the workover of oil wells

Country Status (6)

Country Link
EP (1) EP1144794A3 (en)
AU (1) AU4527099A (en)
BR (1) BR9911630A (en)
GB (2) GB9814114D0 (en)
NO (1) NO20006688L (en)
WO (1) WO2000001915A2 (en)

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WO2011041525A2 (en) * 2009-10-02 2011-04-07 Schlumberger Canada Limited Method and system for running subsea test tree and control system without conventional umbilical
US9528340B2 (en) 2014-12-17 2016-12-27 Hydrill USA Distribution LLC Solenoid valve housings for blowout preventer
US9759018B2 (en) 2014-12-12 2017-09-12 Hydril USA Distribution LLC System and method of alignment for hydraulic coupling
US9803448B2 (en) 2014-09-30 2017-10-31 Hydril Usa Distribution, Llc SIL rated system for blowout preventer control
US9828824B2 (en) 2015-05-01 2017-11-28 Hydril Usa Distribution, Llc Hydraulic re-configurable and subsea repairable control system for deepwater blow-out preventers
US9989975B2 (en) 2014-11-11 2018-06-05 Hydril Usa Distribution, Llc Flow isolation for blowout preventer hydraulic control systems
US10048673B2 (en) 2014-10-17 2018-08-14 Hydril Usa Distribution, Llc High pressure blowout preventer system
US10202839B2 (en) 2014-12-17 2019-02-12 Hydril USA Distribution LLC Power and communications hub for interface between control pod, auxiliary subsea systems, and surface controls
US10876369B2 (en) 2014-09-30 2020-12-29 Hydril USA Distribution LLC High pressure blowout preventer system

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US6349770B1 (en) 2000-01-14 2002-02-26 Weatherford/Lamb, Inc. Telescoping tool
WO2001051764A1 (en) * 2000-01-14 2001-07-19 Weatherford/Lamb, Inc. Telescoping tool
US6659180B2 (en) 2000-08-11 2003-12-09 Exxonmobil Upstream Research Deepwater intervention system
WO2002029202A1 (en) * 2000-10-06 2002-04-11 Abb Offshore Systems Limited Control of hydrocarbon wells
US6564872B2 (en) 2000-10-06 2003-05-20 Abb Offshore Systems Limited Control of hydrocarbon wells
GB2401888B (en) * 2003-05-01 2007-02-07 Cooper Cameron Corp Subsea choke control system
GB2401888A (en) * 2003-05-01 2004-11-24 Cooper Cameron Corp Subsea electro/hydraulic choke control system
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GB2426536B (en) * 2003-12-17 2008-11-19 Fmc Technologies Electrically operated actuation tool for subsea completion system components
WO2006059223A2 (en) * 2004-12-03 2006-06-08 Vetco Gray Scandinavia As Electro-hydraulic process control system and method
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WO2011041525A3 (en) * 2009-10-02 2011-07-07 Schlumberger Canada Limited Method and system for running subsea test tree and control system without conventional umbilical
US8336629B2 (en) 2009-10-02 2012-12-25 Schlumberger Technology Corporation Method and system for running subsea test tree and control system without conventional umbilical
GB2488054B (en) * 2009-10-02 2015-02-18 Schlumberger Holdings Method and system for running subsea test free and control system without conventional umbilical
GB2488054A (en) * 2009-10-02 2012-08-15 Schlumberger Holdings Method and system for running subsea test free and control system without conventional umbilical
WO2011041525A2 (en) * 2009-10-02 2011-04-07 Schlumberger Canada Limited Method and system for running subsea test tree and control system without conventional umbilical
US9803448B2 (en) 2014-09-30 2017-10-31 Hydril Usa Distribution, Llc SIL rated system for blowout preventer control
US10876369B2 (en) 2014-09-30 2020-12-29 Hydril USA Distribution LLC High pressure blowout preventer system
US10048673B2 (en) 2014-10-17 2018-08-14 Hydril Usa Distribution, Llc High pressure blowout preventer system
US9989975B2 (en) 2014-11-11 2018-06-05 Hydril Usa Distribution, Llc Flow isolation for blowout preventer hydraulic control systems
US9759018B2 (en) 2014-12-12 2017-09-12 Hydril USA Distribution LLC System and method of alignment for hydraulic coupling
US9528340B2 (en) 2014-12-17 2016-12-27 Hydrill USA Distribution LLC Solenoid valve housings for blowout preventer
US10202839B2 (en) 2014-12-17 2019-02-12 Hydril USA Distribution LLC Power and communications hub for interface between control pod, auxiliary subsea systems, and surface controls
US9828824B2 (en) 2015-05-01 2017-11-28 Hydril Usa Distribution, Llc Hydraulic re-configurable and subsea repairable control system for deepwater blow-out preventers

Also Published As

Publication number Publication date
WO2000001915A3 (en) 2001-12-06
EP1144794A2 (en) 2001-10-17
AU4527099A (en) 2000-01-24
NO20006688L (en) 2001-03-01
GB2338971A (en) 2000-01-12
NO20006688D0 (en) 2000-12-28
GB9814114D0 (en) 1998-08-26
GB9915409D0 (en) 1999-09-01
EP1144794A3 (en) 2002-09-11
BR9911630A (en) 2002-01-15

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