Forcados Wdl Technical Presentation Rev 1

7/30/2019 Forcados Wdl Technical Presentation Rev 1

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TECHNICAL PRESENTATION

REHABILITATION OF FORCADOS

PIPELINE

PRESENTED BY

OIS/GREDOR CONSORTIUM


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CONTRACTNO:NG01002625INTEGRATEDPIPELINESMAINTENANCEANDREPAIRS NG01002625Page : 8

EXECUTIONPLANFORREHABILITATIONOFFORCADSTERMINAL36WATERDISPOSALLINE Rev :0PROJECTEXECUTIONPLAN Date :15Apr,2012

1.0 General Introduction

The 36 x 11.1km Forcados Terminal Water Disposal Pipeline (WDL) was

commissioned in 1997 to evacuate produced water from the Forcados

Terminal oil processing facilities for disposal offshore. The WDL is made up of

two sections viz: 36 x 6km onshore section of Glass Re-enforced Epoxy

(GRE) material and 36x5.1km offshore Carbon Steel section. An underwater

inspection to assess the condition of the diffusers showed that the 500m

diffusers at the offshore section had about 30m severed and completely

detached. This requires repair to restore the diffuser as described below.


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Pipelay

/DerrickBarge


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HOOK RADIUS vs. LIFTING CAPACITY & HOOK HEIGHT

VESSEL DATA SHEET

CHEROKEE


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HOOK RADIUS vs. LIFTING CAPACITY & HOOK HEIGHT

Akpevweoghene

Pi p e la y

D e r r i c k

B a r g e

MOORING EQUIPMENT

No. of Anchors; Weight (8); 30,000 lb (13,608 kg)

Make, type Navy, Stockless

No. of Winches (4) Double DrumMake, type Manitowoc 560Wire (length/diameter) 5,000 ft (1,524 m) / 1.75 in

GENERAL MAIN CRANE

Length (overall) 387 ft (117.96 m) Derrick

Width 100 ft (30.48 m) Make, Model Manitowoc Seacrane 600Depth 25 ft (7.62 m) Type Revolving

Classification USCG, ABS A-1

Year Built 1 9 6 9A u x i l i a r y 260 ft (79.25 m)

Registry (Flag) USA Whip 275 ft (83.82 m)Operating Draft (min/max) 12 ft (3.66 m) / 17 ft (5.19 m) Capacity

Tonnage (gross / net) 7655 / 2296 Main Revolving 600 s. tons @ 70 ft (544 MT @ 21.34 m)Max Deck Load Project Specific Main Fixed 925 s. tons @ 80 ft (839 MT @ 24.38 m)Free Deck Area ( length x w idth) 100 ft (30 .48 m) x 60 ft (18.3 m) Auxiliary 150 s. tons @ 100 ft (136 MT @ 30.48 m)Moon Pool (yes / no) no Whip 50 s. tons @ 250 ft (45.36 MT @ 76.2 m)

Accommodations 174 people

Hospital Beds 6 AUXILIARY CRANE(s)

Transit Speed (econ / max) Towed Make, Model Manitowoc 3900 WHelicopter Max Rating 6,200 lbs Type Crawler

Helicopter Refueling capacity N/A Boom Length 120 ft (36.59 m)

Helideck Dimensions 40 ft (18.16 m) x 40 ft (18.6 m) Capacity 86 s. tons (78 MT)

Boom LengthMain 200 ft (60.96 m)

MACHINERY MISSION EQUIPMENT

Main Engines N/A Pipelay Method(s) Conventional S-Lay

No. of Generators 4N o . o f W o r k S t a t i o n s ( @ 4 0 f t ) 7

Main Power (3) 500 kW Pipe Diameter (min/max) 2 in / 48 in

Auxiliary Power (1) 100 kW emergency Tensioners (make, type) (2) Western Gear

No. of Compressors (3) 125 psi Total Capacity (ea/ttl) 160 kips (72,576 kg) / 320 kips (145,152 kg)

Total Output 1,759 cfm (2,988.54 m /h) Reel Capacity (tonnage) N/A3

Water Makers Sea Recovery Abandon/Rec. Winch

Total Capacity 780 USG/h (2,952.3 L/h) Type (make/model) RentalAR Wire (length/diameter) 4 ,000 ft (1 ,219 m) / 2.5 in

BUNKER CAPACITY Capacity 300,000 lb (12,000 kg)Fuel 350,000 USG (1,324,750 L) Davits N/AFresh Water 1,000,000 USG (3,785,000 L)

Potable Water 138,000 USG (522,330 L) STINGER

Type Truss (Ballast) Stinger 16;

DYNAMIC POSITIONING 2 section Articulated (Ballast) Stinger 14N/A Length (min/max) 160 ft truss; 120 ft articulated

COMMUNICATION SYSTEMS PIPE BURY EQUIPMENT

(1) 125 watt SS Band N/A(1) Inmarsat B Celluar Phone

(4) Modular VHF DIVING SYSTEM

NAVIGATION 650 SAT System with HRC

N/A


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Akpevweoghene

CHEROKEE

CHEROKEE

Profile

37

Plan

[email protected]

Operations Office Head Office


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2. ANCHOR HANDLING AND SUPPLY VESSELPICTURES AND DETAILS OF FENOGS ANCHOR HANDLING AND SUPPLY VESSEL FORMALLY

CALLED: OROGHENE

View of Oroghene Anchor Handling /Supply Vessel in Fenogs Jetty, Warri.


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Engineering

Bathymetric Survey Diffuser inspection

ng neer ng a cu at ons an es gn na ys s

Deliverablesurvey p an

Diffuser inspection report detailing condition of coating, anodes,diffuser burial and type of material

Calculation report for allowable free spamLifting plan and Drawings

HSE reports

Risk management report

Work method statement Approved for construction Drawings


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Mobilization and Marine Operations

General Site Layout


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Mobilization and Marine Operations (continued)

1. Mobilization

Gredor yard, Warri will be used to support the marine logistics ofthis project.

All Equipment to assemble at FENOG marine base where theAKPEVWOGHENE La Bar e is located.

Materials shall be transported to FENOG marine base wherethey shall be loaded onto the lay barge

to Forcados slot by the OROGHENE tugboat

The spread shall stop for 1day at the Forcados slot for SPDCu as may e ecessary.

There after spread shall leave the Forcados slot through the

Forcados River following the route indicated to the work site. Surveyors shall have marked out the allowable at which the 48

export pipeline can be crossed by the OROGHENE Tugboat andthe AKPEVWOGHENE Barge.


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Mobilization and Marine Operations (cont)


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2 Anchoring

Mobilization and Marine Operations (cont)

2.1 Anchor Mooring System

The APKEVWOGHENE Bar e anchor moorin s stem is shown in the table below

Name of Vessel Akpevwoghene

Length of Overall 117.96 m

Breadth Moulded 30.48 m

Depth Moulded 7.62 m

Max. Draft 5.19 m

Bollard PullMain Engine

Positionin

(anchor) Winch

- Quantity

4 Double Drum

-Manitowoc- Type

- Capacity

- 560 ton

Anchor T e 8 each Nav Stockless

Wire Size x Length 44 mm x1524 m


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.

1. Barge on the same side of the pipeline as anchor

Anchor

Vessel >=100m

ipe ine


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ANCHORAGE CRITERIA (continued)

1. The pipeline lies between the Barge and the anchor

Anchor

>=200m

esse

Pipeline


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ANCHORIAGE PLAN

ay arge w e suppor e y anc or an ng ugs

Lay barge will be moored by 8(eight) Navy, Stockless anchors with44mm (1.75) O.D. cable in 1524 meter len ths.

The length of the mooring lines is based on catenary theory to have

sufficient length of mooring line lying on seabed under expected

While moving barge, the tugs will be responsible for the placementand relocation of the barge anchors

The anchor handling tugs will use their winch to set and retrieve thebarge anchors

Every Anchor position shall be established by the On-Board Surveyteam

lines damage prevention (D.P) buoys will be installed to preventcontact between anchor wire and the pipeline


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Damage Prevention

D. P. Buoy

Pendant Wire

AnchorPosition of D. P. Buoy to be checked by

Diver every 12 hours of operation


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CatenaryTables


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Typycal Anchor Layout

Existing

Existing

Pi elineD. P. Buoy


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LIFTING

1. Items to be Lifted

Above figure is a typical representation of the WDLshowing the damaged Diffuser.

While the severed section is to be salvaged the main

section is to be repaired


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LIFTING (continued)

2. Lifting Methods

or e an ec on e an onmen ecovery .Winch on the Lay barge shall be used

For the Salva in of the Severed Section Davits on theBarge shall be utilized


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LIFTING (continued)

3. Preparation for Lifting

e o owng as een accomp s e

Pre Repair Survey

n a nspec on as een carre ou an repa rscope fully established

Extent of de osition and t e of debris is known

And the following are available on Site

Design Reports and AFC Drawings

Complete Diving and Survey Spreads

Air bags, Lifting and Rigging Tools

Spreader Bars of up to 15m Span


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LIFTING (continued)

4. Step I : Diving Activities

e rs emova

Debris deposited on and around the Diffuser shall be

removed b Water J ettin

Divers will use Air at high Pressure to Air-Lift andhence fluidize debris around and beneath the diffuser .

.

Water currents at the Sea Bed will carry the fluidizeddebris away thereby freeing the Diffuser.

The Boat MV DELTA SKY will support this activity

Installation of Lifting Apparatus

Lifting Slings and Shackles

Air Bags (Main Diffuser Section only)


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LIFTING (continued)

15m

.

30m

Severed Section ofDiffuser

amage n o

Diffuser

20m 20m 20m

on r

BagLifting Sling


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LIFTING (continued)

5. Step II : Lifting

e erm ne a owa e ree span o e ame er p pe yengineering calculation. Previous computation for similar size of

pipe at 50barg established the allowable free span at between.

Controlling Factor is the minimum allowable radius ofConcrete coating determined for previous test as equal to800m

To work within this range previous practice shows that for

down is about 110m from the barge stern and a bendingradius more than 800m


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LIFTING (continued)


A b di di f 1000 h ll b li d i thi lifti Abending radius of 1000m or more shall be applied in this lifting

Based on Engineering computations to be done before the actual

lifting the horizontal distance to achieve this will be determined.g

10ton Air Bags shall be installed at 20m intervals over theentire length of the diffuser in order to achieve this.

Determine the minimum distance between the end of the thediffuser and the barge stern (Minimum X). From previous

analysis the minimum X for 36 diameter pipe was found to be

58m.


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LIFTING (continued)


Pipeline

towards the end of the diffuser. Pre-ballast the stinger.

Pass lifting cable around the end of the diffuser and attach to amarker buoy.


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LIFTING (continued)


Lifting Head

Determine the minimum distance between the end of the

.analysis the minimum X for 36 diameter pipe was found to be

58m.

Position lay barge so that the A/R head is no closer than a

minimum X meters from stern of the barge.


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LIFTING (continued)


Lifting Head

Using tug thread cable tied to the pipe through the stinger andpipe ramp, attach end to the A/R winch drum.

Inflate airbags beginning with the one farthest from and end withthe one nearest to the lay barge.


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LIFTING (continued)


Liftin Head

Maintain barge position and reel in wire until the Lay Tension isreached.


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LIFTING (continued)


Direction of Movement of Barge

Lifting Head

Slowly move barge towards the diffuser end position andmaintainin the tension. As this is done the diffuser end rises

gradually.


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LIFTING (continued)


Direction of Movement of Barge

LiftingHead

moves up the stinger, past the ramp and through the tensioners.

Transfer tension from the A/R winch to the tensioners. Detachthe pull cable from the end of lifted diffuser. Prepare for cutting

and welding.


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WELDING

of work

Welders to be qualified based on the Qualified WPS

to e eve ope an ua e at t e t me o or xecut on

Shielded Metal Arc Welding (SMAW) Process shall used for all Welding

Works Hot Cutting shall be adopted for Pipe cutting and bevelling

Joint Alignment shall be with both Internal and External Line-Up Clamps

-during a typical pipe laying activity

Details of Welding and NDE can be found in Appendix A to Section 6.5 ofthe Work Execution Plan

Quality of Welds

Welds shall undergo 100% Radiographic Inspection

Other Tests to be at the request of SPDC

JOINT COATING


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JOINT COATING

External Coating shall consist of the appropriate Anti-Corrosionfollowed by Concrete Coating

Internally Surface of the Pipe shall be lined with 10mm thickconcrete coating

Internal coating shall require the worker going into the pipe with ona trolley and lighting. Ventilation of the inside of the pipe shall also

be necessary.

Generally procedures for working in confined spaces shall beadopted in order to safely execute the internal coating work

LAUNCHING (LOWERING)


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.

involved

Sling the flanged end with the A/R cable

Gradually transfer Tension from the Tensioners to the A/RWinch

Gradually Move the Lay barge away from the diffuser until it isinside water

-

the line is not unduly stressed Remove the A/R cable



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.

involved

Sling the flanged end with the A/R cable

Gradually transfer Tension from the Tensioners to the A/RWinch

Gradually Move the Lay barge away from the diffuser until it isinside water

-

the line is not unduly stressed Remove the A/R cable

Special Note

A piece shall be welded to the flanged exit of the diffuser toprovide a bevel for relatively smooth passage across the rollers



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Typical Diffuser Launch



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Transition PieceDiffuser Pipe

for Launching

DIFFUSER PORT OPENING


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DIFFUSER PORT OPENING

WDL Port Plug Non Metallic.

Requires a Key to open

Diffuser Port Plug Key to be

fabricated

SCOOPING OF TOPSOIL)


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SCOOPING OF TOPSOIL)

This will be done by scooping the specially marked area with agrab bucket dredge using the deck crane of the lay barge.

disposed onshore at an SPDC designated location

CATHODIC PROTECTION SYSTEM REPAIR


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CATHODIC PROTECTION SYSTEM REPAIR

When required sacrificial Anodes shall be installed by Divers.

REINSTATEMENT

Sand for deposition shall be imported from other areas onbarges and shall be placed using the deck crane and a grab

Concrete Mats shall be placed using the deck crane andspreader bars.


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Forcados Wdl Technical Presentation Rev 1

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