03a safety systems

Safety Systems

© Schlumberger 2000

Schlumberger225 Schlumberger DriveSugar Land, Texas 77478

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transcribed in any form or by any means, electronic or mechanical, including photo-copying and recording, without prior written permission of the publisher

SMP-7086-3

An asterisk (*) is used throughout this documentto denote a mark of Schlumberger.

Safety Systems ■ Contents iii

Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Riser Sealing Mandrel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3SenTREE 3 Test Tree System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

SenTREE 3 components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Valve assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Latch assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Retainer valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Spanner joint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Subsea Control Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Disconnect times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Standard system features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Deep-sea hydraulic system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Deep-sea electrohydraulic system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Drift-off analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Subsea pressure and temperature carrier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Lubricator Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31E-Z Valve Retrievable Well Control Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Introduction

Safety Systems ■ Introduction 1

This third book in the Schlumberger Testing Services set is divided into two sections. The first describes well control equipment for offshore and land testing operations. The second sec-tion describes well test design, safety considerations and the features and selection of surfaceequipment. Regardless of the downhole conditions and well location, Schlumberger equipmentand techniques meet the critical need for reliable well control.

When drilling operations are conducted from a floating vessel (a semisubmersible or drill-ship), the stack of subsea pressure-control equipment typically has the following arrangement:■ one or two annular blowout preventers (BOPs) at the top of the stack■ one or two BOPs equipped with blind/shear rams■ two or three BOPs equipped with pipe rams to close on drillpipe or test strings.

The riser, which brings the mud back to the surface, is landed on top of the BOP stack with ahydraulic connector that allows disconnection (Fig. 1). The BOPs and the hydraulic connector arecontrolled hydraulically from the surface through hoses running in bundles outside the riser.

During testing, the drillstring running through the BOP stack well is full of oil or gas. If itbecomes necessary to cut pipe and pull the drilling vessel off location, the well is held in controlonly by the blind/shear rams, which may be damaged from cutting the pipe. In this scenario,reentry is impossible because of pressure below these rams. To avoid this set of circumstances,a subsea test tree is inserted into the test string.

A subsea test tree system was originally developed to enable well testing operations from anoffshore floating rig. The subsea test tree contains valves and a latch that allow fast disconnec-tion of the vessel from the BOP stacks when there is rough weather, dragging or loss of anchor,or failure or malfunction of a dynamic positioning system. The subsea test tree system is the pri-mary safety device and provides fast-acting and reliable means to■ isolate the landing string from the test string■ prevent discharge of its contents into the riser■ disconnect the landing string from the test string.

The disconnection sequence is as follows:1 Close the valves in the subsea test tree.2. Close the retainer valve and bleed off the pressure between the valves.3. Unlatch from the subsea tree valve assembly.4. Pull the subsea tree latch and the string above it clear of the BOP stack.5. Close the BOP blind rams.6. Disconnect the riser.

The vessel can then move off location, leaving the well under control.

2

Figure 1. BOP stack with riser connected (left) and disconnected (right).

Riser

Hydraulicconnector

BOP stack

Blind rams

Subsea test treevalve assembly

Subsea test tree latch

Retainer valve

Safety Systems ■ Riser Sealing Mandrel 3

Schlumberger developed the riser sealing mandrel (RSM) (Fig. 2 and Table 1) as an additionalsafety device to meet the requirements of Hazard and Operability (HAZOP) studies during deep-water well testing operations.

With the increase in water depth, a gas or hydrocarbon leak in the landing string close to thesubsea test tree (i.e., leak from inside tubing to the riser) can develop a high-volume gas kick atthe surface. To safely control and divert this volume, the RSM is located at the level of thediverter BOP below the rig floor, and the diverter BOP is closed on it.

All the umbilical hoses are well protected, and the seal around them is ensured with speciallydesigned rubber hose sealing elements.

Features■ The 9.5-in. OD and the modular design enable using the RSM with most BOP sizes and

configurations.■ The rig-up time is shortened with easy-to-install protective plates and specially designed

rig-up tools.■ The protective capacity (26 hose-sealing elements) allows it to be used with various umbilical

hoses:

5 hoses 1 × 2 in. 2 × 11⁄4 in. 2 × 3⁄8 in.

6 hoses 1 × 11⁄2 in. 2 × 11⁄4 in. 1 × 1 in. 2 × 3⁄8 in.

Riser Sealing Mandrel

Table 1. Riser Sealing Mandrel Specifications

Unit RSM

Service H2S

OD in. [mm] 9.5 [241]

ID in. [mm] 3.75 [95]

Working pressure psi [bar] 10,000 [690]

Working temperature °F [°C] –20 to 250 [–30 to 120]

Make-up length ft [m] 30 [9.1]

Max tensile load lbf at 0 psi [kN at 0 bar] 520,000 [2310]

4

Figure 2. Riser sealing mandrel.

Umbilical

Hose-sealingelements

Protectiveplates

A A′

Section A–A′(sealing elements are compressed)

9.5 in.

Safety Systems ■ SenTREE 3 Test Tree System 5

Johnston-Schlumberger was the pioneer in subsea systems with the introduction of the E-Z Tree*retrievable well control system in 1975. In the mid-1990s, Schlumberger launched a project toredesign the subsea test tree system to meet the latest industry requirements:■ ability to close the shear rams with the latch in place■ latest study requirements (HAZOP) for deep-sea operations incorporated■ ability to close two BOP pipe rams around the slick joint■ ability to close two shear rams.

Following a very successful field test period, the SenTREE* 3 system (EZTM) was commer-cialized at the end of 1997.

The SenTREE 3 test tree (Fig. 3) is hydraulically controlled from the surface and consists ofa dual fail-safe ball valve and flapper valve and a connector (latch) that is landed in the BOPstack. Its modularity (Fig. 4) enables placement of the slick joint either below the valve assem-bly or between the latch and valve assembly to match even very short BOP stack configurations.A set of unique features (verified and approved by Det Norske Veritas) makes the SenTREE 3system the preferred tree for all standard tests and the first choice for deep-sea and high-pressure, high-temperature (HPHT) operations.

Features■ Reduced length and modularity

– 46-in. standard configuration– 16- and 32-in. split configuration

■ HPHT tested and qualified to full pressure and temperature range■ Ability to unlatch at full tension, with an angle of up to 6°■ Backup mechanical unlatch (5 turns)■ Latch fishing profile and dedicated fishing tool■ Chemical injection below or at valve level

With the standard control section, the SenTREE 3 tree is operated through an umbilical hosethat consists of three hydraulic control lines. At the surface, the hose is connected to an air-driven hydraulic power unit (control console). The specially designed deep-sea control systemsavailable are described subsequently in this section.

When a chemical injection hose or a four-line umbilical hose is run, the SenTREE 3 systemallows injection of chemicals (such as hydrate or corrosion inhibitors) either above or below the ball valve.

SenTREE 3 Test Tree System

6

Figure 3. SenTREE 3 standard configuration.

Riser

BOP stack

Blind rams

Pipe rams

Annular BOP

Shear rams

Pipe rams

Retainer valve

Valve assembly

Shear sub

Slick joint

Adjustablefluted hanger

Bleed-off valve

Latch assembly

Spanner joint


Figure 4. SenTREE 3 modular split configuration.

Retainer valve

Valve assembly

Shear sub

Slick joint

Adjustablefluted hanger

Bleed-off valve

Latch assembly

Spanner joint

Riser

BOP stack

Pipe rams

Annular BOP

Shear rams

Pipe rams

Shear rams

8

SenTREE 3 componentsThe SenTREE 3 test tree system includes the following components:■ valve assembly (EZTV)■ latch assembly (EZTH)■ retainer valve (RETV)■ spanner joint.

Valve assemblyThe SenTREE 3 valve assembly (EZTV) (Fig. 5 and Table 2) consists of two hydraulically operatedfail-safe valves. The main valve is a ball type; the second is a flapper valve. This combination hasproved to be the most reliable fullbore subsea system.

Sequential valve closure ensures that the flapper valve closes only after the ball valve is closed.The delay allows wireline or coiled tubing (CT) to clear the flapper after being cut by the lowerball assembly.

The pump-through facility of the valve assembly permits well control if hydraulic control islost. Positive differential pressure applied from above opens a flow area for well kill operationsthat is equivalent to a 11⁄4-in. line.

Table 2. SenTREE 3 Valve Assembly Specifications

Unit EZTV-DA

Service H2S per NACE MR-01-75


Design temperature °F [°C] –4 to 350 [–20 to 177]

OD in. [mm] 13.0† [330]With centralizer 16.1 [409]

ID in. [mm] 3.0 [76]

Test pressure (body psi [bar] 22,500 [1550]only, valves open)

Max tensile load at 90% lbf at 0 psi [kN at 0 bar] 520,000 [2310]yield and 350°F [177°C] lbf at 15,000 psi [kN at 1035 bar] 255,000 [1130]

Injection line working pressure psi [bar] 15,000 [1035]

Bottom connection 5-in. 4 S.A. box

Wireline cutting capability Up to 5⁄16 in. (no assistance required)[Up to 7.9 mm (no assistance required)]

CT cutting capability Up to 11⁄2 in. × 0.156 in. (hydraulic assistance 5000 psi)[Up to 38 mm × 3.9 mm (hydraulic assistance 345 bar)]

Max torque ft-lbf [N⋅m] 7500 [10,200]

Length in. [mm] 32.2 [818]

Weight with centralizer lbm [kg] 1124 [510]

†13-in. OD for the bottom nut only (height 4.1 in.); SenTREE 3 body OD is 12.5 in.


Figure 5. SenTREE 3 valve assembly.

Ball valve

Flapper

Ball piston

10

Latch assemblyThe latch assembly (EZTH) (Fig. 6 and Table 3) is the upper part of the subsea tree and connectsthe landing string to the valve assembly. If hydraulic control is lost, the latch can be disconnectedmechanically. Two shear keys, which break at a known torque value, connect the latch body tothe shear sub. Figure 7 shows the combined latch and valve assemblies of the SenTREE 3 testtree system.

Table 3. SenTREE 3 Latch Assembly Specifications

Unit EZTH-DA




OD in. [mm] 12.5 [318]With centralizer 16.1 [409]

ID in. [mm] 3.0 [76]

Test pressure psi [bar] 22,500 [1550]

Max tensile load lbf at 0 psi [kN at 0 bar] 520,000 [2310]at 90% yield and 350°F lbf at 15,000 psi [kN at 1035 bar] 255,000 [1130]

Top connection 5-in. 4 S.A. pin


Length in. [mm] 16.0 [406]

Weight with centralizer lbm [kg] 860 [390]


Figure 6. SenTREE 3 latch assembly.

Latch dog

Skirt

Piston

12

Figure 7. SenTREE 3 latch and valve assemblies.

Latch dog

Latch profile

Latchassembly

Valveassembly


Retainer valveThe retainer valve (RETV) (Fig. 8 and Table 4) can be run above the SenTREE 3 latch assemblyto retain the fluids trapped in the landing string after disconnecting from the SenTREE 3 valveassembly. When disconnecting, the retainer valve prevents the uncontrolled release of hydro-carbons from the landing string into the riser and the sea. When testing wells in deep water orwhen testing high-pressure gas wells, use of the retainer valve is a safety and environmentalrequirement.

The RETV is controlled hydraulically in sequence with the subsea test tree. An integral bleed-off valve (BOV) vents the trapped pressure between the retainer valve and the test tree to theriser before unlatching. The RETV uses the same ball valve mechanism as the SenTREE 3 systemand is capable of cutting 1.5-in. CT. Hydrocarbons in the landing string can be reversed out as theRETV ball valve is pumped away from its seat with greater pressure below the valve. The RETV isa fail-safe valve when closed, but in case of control line failure, the RETV ball valve can be openedby closing the annular BOP on the spanner joint and pressuring up below.

Features■ Fail-safe closure■ Ability to cut 1.5-in. × 0.15-in. CT with pressure assist■ Integrated bleed-off valve■ Pump-through facility with the spanner joint■ Pressure tests from above■ Reverse circulation (U-tube)■ Ports for high-rate injection

Table 4. SenTREE 3 Retainer Valve Specifications

Unit RETV-DA




OD in. [mm] 13.0 [330]

ID in. [mm] 3.0 [76]

Test pressure (valves open) psi [bar] 22,500 [1550]


Connection 5-in. 4 S.A. box with lock key

Max torque ft-lbf [N⋅m] 15,000 [20,300]

Overall length including ft [m] with 5-ft spanner 10.6 [3.2]spanner joint ft [m] with10-ft spanner 15.6 [4.7]

Overall weight including lbm [kg] with 5-ft spanner 2000 [910]spanner joint lbm [kg] with 10-ft spanner 2400 [1090]

14

Figure 8. SenTREE 3 retainer valve.

Ball valve

Pins

Seal retainer

BOV Open BOV Closed

Ball cage

Piston

Ball spring

Sequencing valve


Spanner joint The spanner joint (Fig. 9 and Table 5) sits on top of the retainer valve and allows closing theannular BOP. This safety feature was introduced in 1997. The spanner joint was developed to fulfill the following functions:■ enable closure of the annular BOP on the landing string to pressurize the annulus to open the

ball valve if hydraulic controls are lost■ enable, through the hydraulic block manifold, the operating sequence of the SenTREE 3

system and the RETV valves■ protect the control hoses when closing the BOP.

Table 5. Spanner Joint Specifications

Unit Spanner Joint



Design temperature °F [°C] –4 to 350°F [–20 to 177]

OD in. [mm] 10.75 [273]

ID in. [mm] 3.0 [76]

Test pressure psi [bar] 22,500 [1550]


Connection 5-in. 4 S.A. box with lock key

Max torque ft-lbf [N⋅m] 15,000 [20,300]

Sealing length ft [m] 5 or 10 [1.5 or 3.0]

16

Figure 9. Spanner joint.

Skirt

Hydraulic sequencingmanifold

Centralizer

Hydraulic hose

Retainer valve


AccessoriesFigure 10 shows the SenTREE 3 components in both a short configuration and a standard con-figuration. The spanner joints, retainer valve and shear sub extensions are required in both configurations.

Figure 10. SenTREE 3 accessories.

EZSJ-FAIntegral slick joint 46-in. configurationwith ported line

EZH-IAIntegral bottomsub/hangerwith ported lines

EZSJ-DASlick joint 16-in. configurationwith ported lines

EZHP-DAHanger ported line

EZH-DBHanger nonported

EZSJ-GASlick jointwith portedline

EZSJ-HASlick jointnonported

High-strength shear sub

Shear sub extensions

RETV-DA

Spanner joints

CrossoverSuper short configuration Standard configuration

Standard shear sub

EZHR-ASlim 2.5-in. ID nonported line

Retainer valve

Riser sealing mandrel

Safety Systems ■ Subsea Control Systems 19

The type of subsea control system used to operate the subsea test tree depends on the waterdepth. Schlumberger has developed three systems (Fig. 11) to accommodate different depthsand optimize the disconnect time of the latch assembly:■ standard system for depths to 1500 ft [457 m]■ deep-sea hydraulic system for depths from 1500 to 4500 ft [457 to 1372 m]■ electrohydraulic system for depths from 4,500 to 10,000 ft [1372 to 3048 m].

Subsea Control Systems

Figure 11. SenTREE 3 control systems.

4500 ft

Deep-SeaHydraulic System

Use only withmoored vessel

SenTREE 3system + RETV

Hydraulicpod

AccumulatorConsole Reel Reel

10,000 ft

Deep-SeaElectrohydraulic System

Always use with dynamicallypositioned vessels

Electro-hydraulicpod

HPU

EPU


1500 ft

Standard System

Console Reel


Surface accumulatorcan be used to decrease

disconnect time

20

Disconnect timesThe disconnect time for any hydraulic system depends on the landing string configuration, onwhether a retainer valve is used and on the umbilical hose length.

The downhole hydraulic pod system with surface accumulator was tested and qualified bothonshore and offshore. Using the SenTREE 3 system and RETV, the complete cycle (close, bleed-off and disconnect) times are 41 s at 4400 ft [1341 m] and 52 s at 7400 ft [2255 m].

The electrohydraulic pod with 8500 ft [2591 m] of umbilical hose was also tested and qualified both onshore and offshore. Using the SenTREE 3 system and RETV, the complete cycle(close, bleed-off and disconnect) time is 10 s at water depths to 8500 ft.

Standard system featuresThe standard system (Fig. 12 and Table 6) intended for SenTREE 3 operation in shallow waterdepths to 1500 ft comprises■ console■ reeler■ hose bundle, 4500-ft long.

A hydraulic logic diagram for the standard control system used with the SenTREE 3 system is shown in Fig. 13. A diagram for use with the SenTREE 3 system and retainer valve is shown inFig. 14.

Table 6. Standard Control System Reeler and Console Specifications

Unit Reeler Console

Reeler motion Air driven

Reeler capacity three-hose bundle ft [m] 4500 [1370]

Footprint ft [m] 10.5 × 6.9 [3.2 × 2.1] 2.9 × 2.0 [0.9 × 0.6]

Height ft [m] 6.6 [2.0] 3.8 [1.2]

Weight lbm [kg] 5500 [2500] 660 [300]


Figure 12. SenTREE 3 system with standard control system.

1500 ft

SenTREE 3 system

Console Reel

Retainer

Spanner joint

22

Figure 13. Hydraulic logic diagram for standard control system used with SenTREE 3 system.

BA CCI

Latch UnlatchUnlatch

Latch

Close Open

Ball valve

Chemical injection

Flapper valve

Close Open

Close

Open

Close

Open

Latch connector


Figure 14. Hydraulic logic diagram for standard control system used with SenTREE 3 system with retainer valve.

Close Open

Latch UnlatchUnlatch

Latch

Close Open

Ball valve

Chemicalinjection

Flappervalve

Close Open

Close

Open

CloseOpen

Latchconnector

Close OpenClose

Open

HF C

I

Retainervalve

BOV

Open

Close

CBACI

Spannerjoint

Chemicalinjection

Vent to annulus

Sequence valve

24

Deep-sea hydraulic systemThe deep-sea hydraulic system (Fig. 15 and Table 7) is for operation of the SenTREE 3 system inmedium water depths, between 1500 and 4500 ft. The system comprises■ deep-sea console■ accumulator surface unit■ reeler■ hose bundle, 4500 ft long■ hydraulic control pod.

Table 7. Deep-Sea Hydraulic System Component Specifications

Unit Pod

Service H2S

OD in. [mm] 13.0 [330]

ID in. [mm] 3.0 [76]

Mandrel working pressure psi [bar] 15,000 [1035]

Mandrel test pressure psi [bar] 22,500 [1550]

Max tensile load lbf at 0 psi [kN at 0 bar] 520,000 [2310]lbf at 15,000 psi [kN at 1035 bar] 255,000 [1130]


Connection 5 in. 4 S.A. box up × pin down

Accumulator Surface Unit

Working pressure psi [bar] 5000 [345]

Capacity gal [L] 2 × 13 [2 × 50]

Nitrogen pressure psi [bar] 2600 [180]

Footprint ft [m] 8.2 × 2.0 [2.5 × 0.6]

Height ft [m] 2.2 [0.7]

Weight lbm [kg] 1430 [650]

Reeler


Reeler capacity three-hose bundle ft [m] 6000 [1830]


Figure 15. SenTREE 3 system with deep-sea hydraulic control system.

4500 ft

SenTREE 3 system

Retainer

Spanner joint

Hydraulic pod

Accumulatorsurface unitConsole

Reel

26

Deep-sea electrohydraulic systemThe deep-sea electrohydraulic control system (Fig. 16 and Table 8) is for remote control of theSenTREE 3 system in water depths to 10,000 ft.

The system is designed for a closure and unlatching time of 10 s at any water depth. A singleumbilical hose is used for all functions, including two surface readout lines for the pressure andtemperature monitoring sub. The system comprises■ surface control unit■ umbilical hose and air-driven reeler■ deep-sea pod (hydraulic accumulators and solenoid valves).

Table 8. Deep-Sea Electrohydraulic System Component Specifications

Unit Pod

Service H2S

OD in. [mm] 14.5 [368]

ID in. [mm] 3.0 [76]

Mandrel working pressure psi [bar] 15,000 [1035]

Mandrel test pressure psi [bar] 22,500 [1550]



Length ft [m] 22.4 [6.8]


Connection 5-in. 4 S.A. box up × pin down

Reeler and Surface Control Unit


Reeler capacity three-hose bundle ft [m] 10,000 [3050]

Footprint ft [m] 13.5 × 8.5 [4.1 × 2.6]

Height ft [m] 8.9 [2.7]

Weight lbm [kg] 25,000 [11,340]


Figure 16. SenTREE 3 system with deep-sea electrohydraulic control system.

SenTREE 3 system

Electrohydraulicpod and accumulator

Reel

Retainer

Surfacecontrol unit

T and P surfacereadout

10,000 ft

Spanner joint

28

Drift-off analysisDrift-off analysis defines the disconnect philosophy and establishes the times required for dis-connection of stack components in the subsea test tree.

As an example, consider a drift-off analysis for North Sea conditions, where a complete dis-connect is required in 37 s or less, including pull-off from the BOP stack. This leaves 20 s for thecomplete sequence. Of the three control systems, only the electrohydraulic system is capable ofmaking these disconnect times. In the analysis in Fig. 17, the subsea test tree must close, disconnect and clear the riser connector before the emergency disconnect sequence (ESD) procedure can begin.

Figure 17. Deep-sea drift-off analysis example.

9

8

7

6

5

4

3

2

1

0

Elapsed time (s)

Startemergencydisconnect

37-s SenTREEdisconnect

25-sdisconnect

Riserdisconnect

Drilling

Testing

0 20 40 60 80 100

Storm environment: 1-knot current, 55-knot wind

Vessel offset(% water depth)


Subsea pressure and temperature carrierThe subsea pressure and temperature carrier (EZGC) (Fig. 18 and Table 9) is used to monitorpressure and temperature at the subsea tree level. The well effluent pressure and temperatureare recorded in surface readout or recorder mode.

This sub is recommended for use in HPHT tests, particularly to measure temperature at theBOP level and to ensure that the maximum temperature rating of the BOP elastomers is notexceeded. The other application is for hydrates control, especially during deep-sea operations.

Two UNIGAGE* H-Sapphire* pressure gauges are included with the tool. One gauge shouldhave a high-resolution thermometer for direct effluent temperature measurement.

Table 9. Subsea Pressure and Temperature Carrier Specifications

Unit EZGC-A

Service H2S

OD in. [mm] 7.9 [200]

ID in. [mm] 3.0 [76]


Working temperature °F [°C] 375 [190]

Make-up length ft [m] 10.6 [3.2]




Connection 5-in. 4 S.A. box × pin with lock key

30

Figure 18. Subsea pressure and temperature carrier.

UNIGAGE H-Sapphire

SRO module

Direct temperature reading

Jumper cable

Safety Systems ■ Lubricator Valve 31

During offshore testing where slickline, wireline or CT operations are performed, it may beadvantageous to use a valve that limits lubricator height above the flowhead. The lubricator valve(LUBV), usually located about 90 ft below the flowhead, enables the upper part of the string tobe used as a lubricator. The LUBV is a balanced system and remains in the position in which itwas last placed (open or closed) (Fig. 19). If the valve is closed, however, application of 1800-psidifferential pressure from above allows pump-through to kill the well. The LUBV can be pressuretested from above (with hydraulic pressure maintained in the closed line); the valve contains anequalizing device to remove any differential prior to opening.

The LUBV can be used alone or as a backup for a conventional lubricator system. It is a surface-operated hydraulic valve that is run on tubing or drillpipe during testing operations (Table 10).It is normally run in conjunction with the SenTREE 3 system and its retainer valve or with an E-Z Valve* device. The LUBV can be actuated as many times as required for wireline operations.Conversely, the SenTREE 3 or E-Z Valve products are safety devices and should be actuated onlyin emergencies.

Lubricator Valve

Table 10. Lubricator Valve Specifications

Unit LUBV-CC LUBV-CCB

Service H2S H2S

Working pressure psi [bar] 15,000 [1035] 10,000 [690]

Working temperature °F [°C] –4 to 350 [–20 to 175] –4 to 350 [–20 to 175]

Fail-safe Closed Closed

Pump-through differential psi [bar] 1800 [125] 1800 [125]

Max tensile load lbf at 0 psi [kN at 0 bar] 520,000 [2310] 520,000 [2310]lbf at 15,000 psi [kN at 1035 bar] 255,000 [1130] 255,000 [1130]

Shearing wireline capability Up to 15⁄32-in. [11.9 mm]

Shearing CT capability 11⁄4-in. × 15⁄32 in. wall [32-mm × 11.9-mm wall]

Connection (box/box) 5-in. 4 S.A. 5-in. 4 S.A.

Length ft [m] 5.0 [1.5] 5.0 [1.5]

OD in. [mm] 8.25 [210] 8.25 [210]

ID in. [mm] 3.0 [76] 3.0 [76]

Weight lbm [kg] 700 [320] 700 [320]

32

Figure 19. Lubricator valve.

Double checkvalve

Hydraulicfluid

Ball valve

Valve Open Valve Closed Injection Line

Bottom plug

Injection point

Safety Systems ■ E-Z Valve Retrievable Well Control Valve 33

The E-Z Valve (EZV) retrievable well control safety device is designed for installation in the BOPstack of a jackup or land rig during well testing when there is no unlatch facility (Table 11). Thepipe rams close around a slick joint above the valve, protecting the annulus, while the E-Z Valveball closes to secure the well at BOP level.

The E-Z Valve device is normally closed by a spring and nitrogen pressure and is opened byhydraulic pressure applied from a console on the rig floor (Fig. 20). The valve is designed pri-marily to hold pressure from below, but it can be pressure tested from above to 5000 psi withnormal hose and console or to 7500 psi with a high-pressure set. A hydrate inhibitor such asglycol or methanol can be injected below the valve.

E-Z Valve closure can also be assisted by hydraulic pressure, enabling the ball to cut wirelineor 11⁄4-in. CT in an emergency. Standard and two optional installations are shown in Fig. 21.

E-Z Valve Retrievable Well Control Valve

Table 11. E-Z Valve Specifications

Unit EZV-CC

Service H2S


Working temperature °F [°C] –4 to 350 [–20 to 175]

Fail-safe Closed

Shearing wireline capability Up to 15⁄32 in. [11.9 mm]

Shearing CT capability Up to 11⁄4 in. [32 mm]

Pump-through differential psi [bar] 1800 [125]

N2 precharge psi [bar] 1200 [83]

Connection (box/box) 5-in. 4 S.A.

Body length ft [m] 3.8 [1.1]

Valve only length ft [m] 5.0 [1.5]

Slick joint length ft [m] 5.7 [1.7]

E-Z Valve system length ft [m] 16. [5.1]

OD in. [mm] 8.25 [210]

ID in. [mm] 3.0 [76]

Slick joint and valve weight lbm [kg] 1230 [560]

Adjustable hanger kit weight lbm [kg] 1500 [680]

34

Figure 20. E-Z Valve operation.

Hydraulicfluid

Nitrogenand spring

Ball valve

Valve Open Valve Closed Valve Closedwith Assistance

Injection Line

Doublecheck valve

Injectionpoint

Bottom plug

Slick joint

Safety Systems ■ E-Z Valve Retrievable Well Control Valve 35

Figure 21. E-Z Valve installation options.

CBA

Option 2(only from 95/8-in. casing)

Option 1Standard Installation

Slick joint

E-Z Valve

E-Z Valve

E-Z Valve

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