subsea - page 7

Connectors

Subsea Engineers Handbook Section 7

In-Spec Inc. 1999 Connectors

Table Of ContentsSection 7

Page

1. Introduction 1

2. Cameron Model 70 2

3. Cameron Model HC 5

4. AX Gasket Detail 6

5. Vetco H-4 7

6. Vetco H-4 HAR 11

7. Typical Connector Problems 13

8. Connector Operation and Inspections Points 13


In-Spec Inc. 1999 1 Connectors

Connectors

1) Introduction

a) Use to remotely latch the BOP stack onto the wellhead and to latch the LMRPonto the BOP stack.

b) Cam ring with a 4o taper on the ID is forced down by operating pistons. As thering travels down the ID decreases and drives the connector dogs or colletfingers inward locking the connector.

c) Just like a flange the connector creates a clamping force, called preload,between the two hub faces.

d) A 4o taper is considered a locking taper in that the dogs or segments attemptingto back out generate more friction on the cam ring than they can generate upforce on the cam ring while attempting to unlock the connector.

e) We have 2 primary functions for the connector, latch and unlatch, plus a third, thesecondary unlatch.

f) Use 2 separate and redundant unlatch functions to ensure added reliability. The2 unlatch functions have separate operating chambers and seals inside theconnector plus 2 separate circuits in the control system for complete systemredundancy.

g) With improper lubrication, that is a lubricant which is easily washed away, thefriction force between cam ring and dog may be excessive. The connector maybe very difficult to unlatch at the completion of the well.

h) When the LMRP is disconnected, hydraulic latching pressure is lost on thewellhead connector. It must stay latched due to friction between the locking dogsand the cam ring.

i) With improper lubrication, that is one which is too slick, the friction force may notbe great enough to stop the cam ring from rising when the connector is underwell bore pressure and locking pressure is released.

j) This backwards or unlatching movement is called backdriving.

k) To eliminate the possibility of backdriving, a pilot operated check valve, POCV,can be placed in the latching port of the connector to trap hydraulic latchingpressure in the connector in the event of a emergency disconnect.



l) To allow the release of latching pressure when it is desired to open the connectorthe POCV is connected to the open port. Not only does opening pressure forcethe check valve open but it also opens the connector.

2) Cameron Model70

The Cameron Model-70 is typically used as an LMRP connector. For the 18 size, its highest rated working pressure is 10,000 psi.



In the drawing above the 4o contact surfaces, left oval, should not be greasedwithout providing a POCV in the locking line to hold the connector latched ifcontrol system latching pressure is lost. 1 The contact area between thesegments and the hub faces, right oval, should be greased.

1 See Cameron Engineering Bulletin #842-M for additional details.



The Model 70 uses hydraulic hoses to internally connect the hydraulic cylinders.There is one latch port used to latch the connector with 6 cylinders. The Primaryunlatch port is connected to the same 6 cylinders to unlatch the connector. Thesecondary unlatch port is connected to the additional 3 cylinders to provideadditional unlatching force when activated.



3) Cameron ModelHC

SecondaryPiston

Secondary UnlockChamber

LockingChamber

Locking Piston

The Cameron HC, high capacity,. is typically used as a wellhead connector. In the18 size, it is available with a rated working pressure of up to 15,000 psi.

The actuator ring is shown as the dark ring in the diagram above. The lower lightring is the locking piston while the area above the upper light ring is the unlockingarea. The area below the upper light ring is the secondary unlocking area.

The HC connector, like the Model-70 has 3 ports if it is ordered with the optionalsecondary unlatch piston. Operating the secondary and primary unlatch functionswill not give any additional unlatching force. Its only function is to provide a backuphydraulic chamber in the event of a leak.



4) AX Gasket Detail



5) Vetco H-4

The Vetco H-4 is used as a wellhead connector or a LMRP connector.

Closing hydraulic pressuredriving down the piston and cam

ring into the closed poisiton.

Opening hydraulic pressuredriving the piston and cam

ring up into the open position



a) H-4 Internal Connection of Hydraulic Cylinders

The H-4 connector has 4 ports, a primary and a secondary locking ports plus aprimary and a secondary unlocking ports. of the operating cylinders areconnected to the primary systems and of the cylinders are connected to thesecondary cylinders. With hydraulic hoses the 2 closing ports are Teedtogether to operate in unison. The 2 unlatching ports are connected to separatecontrol system unlatching hydraulic circuits. Operating the secondary andprimary unlatch functions in unison will give twice the unlatching force.



b) Hydraulic Gasket Retaining Pin



6) Vetco H-4 HAR

The Vetco Model-HAR, high angle release, is typically used as an LMRP connector.It has the hydraulic operating cylinders above the cam ring to reduce the amount ofswallow on the mandrel.



a) HAR Hydraulic Schematic



7) Typical Connector Problems:

Connector gasket (VX, or AX) not holding wellbore pressure. Connector requiring excessively high unlatching pressure to operate. Leaking hydraulic operating chambers. AX gasket retainer pins damaged and not retaining properly.

8) Connector Operation and Inspection Points

i) All Connectors in general Unlatching forces are usually greatest when unlatching from the wellhead

after having been latched for the duration of the well. Check Indicator Rod for accuracy and service for reliability. Visually inspect connector opening, should release from stump. Hydraulic operating pressure for open and close is usually 1500 psi. But,

3,000 psi is the max WP of the connector operating chambers. Internal leak from operating system during testing will be a visible leak at

the opposing ports on the connector. External leak on the operating system will seen as fluid dripping from the

connector bottom. Service connector Pilot Operated Check Valves (if POCV is used)

between wells and test for leaks. AX or VX gasket leaks will been seen dripping down the outside of the test

stump or inside surface of the connector.

ii) Cameron Model 70 Collet Connector Collet fingers for latching onto well head profile - visually inspect for even

segment distribution. Has separate hydraulic cylinders for actuation. 6 cylinders for the Open

and Close function and 3 additional cylinders only for secondary Openfunction.

Test operating system to 3,000 psi for leaks. Visually inspect and function test AX gasket retainers between well

intervals. Test for leaks and operation (1,000 psi operating pressure). Do not use grease on the segments in contact with the actuator ring. This

will reduce the mechanical locking taper of the actuator ring and maycause the connector to unlatch when well bore pressure is applied with noLatching hydraulic pressure applied.

iii) Cameron HC Collet Connector Collet fingers for latching onto well head profile - visually inspect for even

segment distribution. Annular Piston type cylinder for actuator ring movement.



Test hydraulic operating system to 3,000 psi for leaks. Secondary Unlatch is a separate annular piston and has the same force

for Unlatching. No gain is achieved by using both primary andsecondary unlatch.

When secondary Unlatch is used, vent off the Primary Unlatchpressure.

Visually inspect and function test AX gasket retainers between wellintervals. Test for leaks and operation (1,000 psi operating pressure).

Do not use grease on the segments in contact with the actuator ring. Thiswill reduce the mechanical locking taper of the actuator ring and maycause the connector to unlatch when well bore pressure is applied with noLatching hydraulic pressure applied.

iv) Vetco H-4 Connector Has mechanical locking dogs for latching onto the well head profile. Hydraulic Connection primary and secondary Latch ports must be

connected together. Excessive overpull when Unlatching the connector may indicate out of

tolerance between dog and wear ring. Check dog to wear ring clearance (.031 max.), service if required. Use approve H-4 and HAR connector lubricant on the dogs and cam ring:2

Jet Lube Alco EP-73+,

Equivalents are : Almagard 3752Lubriplate 630 AA,Lubriplate 930 AA

Use approve H-4 HD connector lubricant on the dogs and cam ring :

Jet Lube Kopr-Kote

2 From ABB Vetco Operating and Service Procedure #335.

BACK TO E-MANUALS TRAININGCoverTable of ContentsForewordSection 1 Overview of Drilling a WellSection 2 Basic ConceptsSection 3 Flange Hub ConnectionsSection 4 BOP Hydraulic Control SystemsSection 5 BOP Multiplex Control SystemsSection 6 Surface Well Control EquipmentSection 7 ConnectorsSection 8 Ram PreventersSection 9 AnnularsSection 10 Gate ValvesSection 11 LMRP ComponentsSection 12 Subsea BOP Stack ArrangementsSection 13 Riser EquipmentSection 14 Riser TensionersSection 15 BOP Pressure TestingSection 16 Codes and StandardsSection 17 Typical Operations ProceduresSection 18 Subsea Resources

H4 Connector:

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