L&T-Valdel Engineering Pvt. Ltd.
www.lntvaldel.com
Complete Engineering Solution Provider for Upstream Oil &
Gas Industry
STRUCTURAL DISCIPLINE
TYPICAL WELLHEAD STRUCTURE
CONTENTS
Objectives of this presentation Range of services - Structural
Discipline Salient Features Structural Engineering Activities
Platform Analysis and Design Higher End Capabilities Software Used
Past Project References
OBJECTIVES OF THIS PRESENTATION
We present LTVs Structural Engineering capabilities, projects
executed and the activities of LTVs Structural discipline in the
following slides.
RANGE OF SERVICES
Conceptual / FEED Designs Pre-Bid Engineering Engineering
Surveys Detail Engineering for Greenfield and Brownfield Projects
Procurement Engineering Installation Engineering Project Management
and Consultancy Services Review and Verification of Basic/ Detail
design (For Lloyds Registrar, UK)
SALIENT FEATURES
Wellhead Platforms Process & LQ platforms Water depths Pile
Depths Pile Diameters Topside Lift Weights Bridges
: : : : : : :
35+ 3 10 to 80 meters up to 120 Meters 30 to 72 Inch 320 MT to
2000 MT 35m to 120m
ACTIVITIESPlatform Analyses and Design Drawings / Modelling Two
Dimensional Three Dimensional Bulk MTO Weight Control Miscellaneous
Design Vortex Shedding Padeye and Trunnion Design Joint Design wave
slam
PLATFORM ANALYSES AND DESIGN Sea Fasteners
Jacket Design In Service AnalysisIn-place analysis Seismic
Analysis Fatigue Analysis Wave Response
PLATFORM ANALYSES AND DESIGNSea Fasteners
Jacket Design Pre Service AnalysesLoadout Analysis Tow Analysis
Launch Analysis Floatation Analysis Up-ending Analysis Offshore
Lift Analysis Structural design of Padeyes, Trunnions Sea
Fasteners
PLATFORM ANALYSIS AND DESIGNDeck Design In-place Analysis
Seismic Analysis Equipment Skid Design Modular Support Frame Design
Dropped Object Analysis Loadout Analysis Tow Analysis Offshore lift
analysis
PLATFORM ANALYSIS AND DESIGN ACTIVITIES
Foundation Design Review of Geo-Technical Report & Data Pile
Sizing & Optimization Pile Driveability Analysis On-bottom
Stability Mudmat Analysis Anchor Pile Design including Drilled
& Grouted
HIGHER END CAPABILITIES ACTIVITIES
Engineering for North Sea Jacket Dynamic Response Analysis
Spectral Fatigue Analysis LRFD Compliance analysis Jack-up Rig
Punch Through Study Selection Of Jack-up In Different Subsoil Rock
Dumping Study for Spudcan Support Stabilization
SOFTWARE USED ACTIVITIESSACS 5.1 for Offshore Structures Designs
Precede Pro SACS IV Postvue Seastate Joint Can Fatigue Pro Pile
MTO, Combine PSI Dynpac Dynamic Response Wave Response Launch
Floatation TOW
Staad Pro 2004 For Finite Element Modeling, Equipment Skid
Designs GRL Weap Version 2005 for Pile Driveability Analysis
AUTOCAD 2006 for Drawings PDS Inhouse Developed MS Excel
Speadsheets & Mathcad Design Sheets for various stand-alone
& followup Designs.
SNAP SHOTS
PANNA DEVELOPMENT PROJECT - A/C BRITISH GAS / CLOUGH OIL &
GAS
The Detail Engineering for the PH/PJ Wellhead Platforms at Panna
field & the new Wellhead platform STD at South Tapti field are
currently going on. The platforms PH & PJ will stand at a water
depth of 40.6 m & 52.30 m respectively. The STD platform has
water depth of 22.8 m.
N9/N10 WELLHEAD PROJECT - A/C ONGC / L&T
Project has been completed in 2004. The two Wellhead platforms
N9/N10 consist of each 8+1 30/20 well slots. The Jacket
substructures of N9/N10 complete with skirt piles stands at a water
depth of 70.5 & 66.4m respectively. The Topside Lift weight of
each platform is about 812MT. For this project the modular Rig load
for the platform design has been considered.
FATIGUE ANALYSIS
Deterministic Fatigue for most projects. Spectral Fatigue for
few projects. Natural Period of Jacket from 0.7 to 2.5 seconds.
SACS Module of FATIGUEINTERACTIVE used in addition to SACS Inplace
Modules.
INPLACE ANALYSIS
Water Depths 10m to 80m. Extreme Storm Wave Heights from 10m to
20m. Jacket Weights from 600MT to 3200MT. SACS Modules, Precede,
Seastate, PSI, SACS IV, Postvue adopted.
SEISMIC ANALYSIS
Strength level seismic analysis conforming to API RP 2A and IS
1893 codes. Natural Periods from 1.0 to 2.5 seconds. SACS DYNPAC
Module adopted apart from other SACS Modules.
WAVE RESPONSE
Dynamic Wave Response Analysis carried out in Persian Gulf
Project. Natural Periods around 0.7 seconds. Wave period around 8.0
seconds.
LOAD OUT ANALYSIS Performed for Skid Loadout and Trailer
Loadout. Jacket Weights up to 1550 MT Deck Weights up to 1890 MT
Bridge Loadout analyses performed. Loadout frame conceptual and
detailed design developed.
TOW ANALYSIS Jacket Weights up to 1550 MT Deck Weights up to
1890 MT Tow accelerations as per Noble Denton Criteria Tow analysis
performed to Motion Response Accelerations Tow Seastate from 5.5m
to 6.0m Barge natural period of about 9.0 seconds Tow Distances of
up to 100 km
LAUNCH FLOATATION ANALYSIS
Jacket Weights up to 1550 MT launched in 60m water depths.
Reserve buoyancy checks carried out for intact and damaged
conditions of jacket legs. SACS LAUNCH module adopted. Structural
Analysis for Launch condition are carried out.
OFFSHORE UPENDING / LIFT ANALYSIS
Lift analysis for upending jackets up to 1500 MT performed. Lift
analysis for decks of weights up to 1890 MT performed. HEEREMA,
SHELL, API guidelines are used.
PADEYES, TRUNNIONS, SEA FASTENERS
Hand calculations for Upending and Lift Padeyes, Deck Lift
Padeyes prepared. Sea Fasteners designed and prepared for most of
the Jackets, Decks.
Tripod Double Hook Two block Upending
Tripod Offshore Lift ; Lift Weight = 1000MT(Static)
Jacket Lifting Trunion
together tomorrowa world of difference
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