OIL AND GAS PRODUCTION FROM OIL AND GAS PRODUCTION FROM SUBSEA WELLSSUBSEA WELLS
2
SUBSEA or SURFACE ?SUBSEA or SURFACE ?SUBSEA or SURFACE ?
PRODUCTION FACILITIESPRODUCTION FACILITIES
Floating Production Storage & Floating Production Storage & Offloading VesselsOffloading Vessels
Turret Mooring Systems
Tension Leg Platforms
Light Well Intervention
Guidelineless Deepwater Trees
Subsea ManifoldSmart Well
Control Systems Subsea TemplateSystems
Standard Subsea Trees
Metering & Control Systems
Surface Well Systems
ROV Tie-In Systems
Subsea Processing
Subsea Drilling Systems
SUBSEA TO BEACHSUBSEA TO BEACHOrmenOrmen Lange Lange
WELLS INCLUDING XWELLS INCLUDING X--MAS TREEMAS TREE
Time (days)
Depth
TD
RKB
7” Production Liner
30” - 36” Conductor
20” Surface Casing
13 3/8” Intermediate Casing
30” - 36” Hole
26” Hole
16” Hole
12 1/4” Hole
8 1/2” Hole
WELL CONSTRUCTION
TVD MD
Gas
Oil
HORISONTALHORISONTALXX--MAS TREEMAS TREE
No valves in the vertical boreAll valves on the sides / horizontal planeTubing Hanger orients, land and lock inside HXTWell head
VERTICAL XVERTICAL X--MAS TREEMAS TREE
Production Master and Swab Valves in the vertical boreTubing Hanger installed in WHWell Head
WELL HEADWELL HEADConnect well to XConnect well to X--MAS treeMAS tree
18 3/4” UWD-15 Wellhead HousingMetal-to-Metal Annulus Seal Assembly7” Casing Hanger10 3/4” Casing Hanger
30” Conductor Housing
13 3/8” Casing Hanger
Permanent Guide Base
CASING STRINGCASING STRING
Casing run after each section of drilled hole to:Prevent caving of unstable formationsProtect weak formationsIsolate abnormal pressure zonesSeal off lost circulation zonesComplete and produce the well efficiencyStructural support for BOPs and wellheads
Multi-position GLV
FLX4 - AVLDM ASV
Seal Stem to PBR
Completion packer
PBR
TRSCSSV
P/T Gauge Hanger
7" Production Tubing
M-Pas open hole packer
6 5/8" Stand alone screen
Bull nose
Shale
Sand
Sand
ICD
OCRE FBIV
Stand alone screens w/ICD,Zone control and
Annulus flow prevention
Upper and Lower completion installed
10 3/4" Casing Shoe
7" Liner
Sand
Sand
ShaleShale
10 3/4" x 7" Screen Hanger w/PBR
Sand
SandSand
Sand
Shale
Shale
Swell packer
WELL COMPLETION
DOWNHOLE TOOLSDOWNHOLE TOOLS
Flow Control SystemSub-Surface Safety SystemPacker SystemSand ControlLiner HangersInstrumentationChemical Injection
H-40 Used for large diameter casing only.J-55 Normally used if adequate (some normalize)K-55 Casing onlyN-80* N&T, C-Mg steel. HRC >24L-80 Q&T, Cr-Moly steel. HRC <23C-90 Q&T Type 1. HRC <25.4C-95* C-Mg steel. HRC >25T-95 Q&T Type 1. HRC <25.4P-110* Replaced P-105. HRC 35Q-125* High strength steelV-150* Extra high strength steel
* Not H2S SSC resistant unless temp high
API TUBULAR GRADESAPI TUBULAR GRADES
Consists of base pipe with drilled holes, wire wrapped screen jacket, consolidated prepack material, outer shroud with punched holes
Jacket and outer shroud are welded or mechanically attached to base pipe
Prepack material thickness ranges from .34” to .41”depending on size
SAND SCREENSAND SCREEN
DOWN HOLEDOWN HOLEMaterial ChallengesMaterial Challenges
Hydrocarbon mixtureCO2, H2S, salts, …
High temperatureHigh pressureSolids/sandDifferent well intervention fluids
Completion and packer brine fluidsMud acids (HCl - hydrochloric acid, HF – hydrofluoric acid)Stimulation fluidsScale inhibitorsChemicals to dissolve scaleMethanol
Local flow condition due to narrow gapsDifficult to monitor and inspect without retrieving the tubing
DOWN HOLEDOWN HOLEMaterial Challenges, cont.Material Challenges, cont.
Experience: In most of the oil companies Well & Well completion are treated by a special group of people.These people are working separate from the material-and corrosion group in the company.This is a challenges due to transfer of experience and knowledge
MATERIALS SELECTION FOR WELLSMATERIALS SELECTION FOR WELLS
NORSOK M-001
ISO/CD 21457
DOWN HOLEDOWN HOLEUsed materialsUsed materials
Casings made from carbon steelTubings made from
CS 13CrHigher alloyed SS for aggressive hydrocarbon mixtures
Downhole completion equipmentDifferent types of materials both CS, SS and Ni-alloys
Challenge for new high pressure, high temperature sour wells
Sour service requirement to be fullfilled for the actual CRA (Corrosion Resistant Alloy)Probability of hydrogen embrittlement (HE)
Reference article:P.R.Rhodes et.al.: Pushing the limits of metals in corrosive oil and gas well environments. CORROSION – Vol. 63, No. 1 2007
THROUGH TUBING ROTARY DRILLING
SUBSEA PRODUCTION SYSTEMS, SUBSEA PRODUCTION SYSTEMS, PIPELINES AND RISERSPIPELINES AND RISERS
TEMPLATE AND MANIFOLDSTEMPLATE AND MANIFOLDS
27
MANIFOLDMANIFOLD
Ormen Lange Ormen Lange –– Mating of manifold and Mating of manifold and foundation structurefoundation structure
Manifold for Baobab during fabrication Manifold for Baobab during fabrication
Example of piping manifold (Example of piping manifold (OsebergOseberg J) during J) during fabricationfabrication
SUBSEA X-MAS TREE
CHOKECHOKE
GATE VALVEGATE VALVE
SLAB GATESLAB GATE
FLEKSIBLE PIPEFLEKSIBLE PIPE
FLEXIBLE PIPE FLEXIBLE PIPE DesignDesign
1. Stainless steel carcass2. Thermoplastic liner3. Carbon steel pressure
armour4. Carbon steel tensil
armour, two centra-wound layers
5. Thermoplastic outersheath
SUBSEA PROCESSINGSUBSEA PROCESSING
Definition:Subsea Processing is any active handling and treatment of produced fluids at or below the seabed.
To date, the following have been given most attention:
Boosting / pumpingSeparation processesWetgas boosting / compression
SUBSEA PROSESSINGSUBSEA PROSESSINGWhy?Why?
Tieback to platforms enable use of existing infra structureEnable longer tiebacksBulk separation and re-injection of produced waterBoost flowing well head pressureGas compression
Re-injectionExport
Raw seawater injectionHydrate suppression
Remove water from well stream
TORDIS OIL/WATER SEPARATORTORDIS OIL/WATER SEPARATOR
SUBSEA PROCESSINGSUBSEA PROCESSINGNeeded equipmentNeeded equipment
SolidsSeparator
Water Injection Pump
Compressor
LiquidPump
ControlValve
HVTransformer
UltrasonicLevel
Indicator
SeparatorTank
ControlModule
Cooler
SUBSEA GAS COMPRESSIONSUBSEA GAS COMPRESSION
SUBSEA PRODUCTIONSUBSEA PRODUCTIONChallengesChallenges
Water depths between 100 m and 3000 mReservoir pressures up to 15.000 psi (1035 bar)Temperatures;
-200 C to + 1500 C normally( -500 C to + 2000 C in extreme cases)
Design life of 20 years + (up to 50 years)
SUBSEA PRODUCTIONSUBSEA PRODUCTIONChallengesChallenges
Material technology and fluid compatibilityFlow assurance & insulationLong distances to topsideProcess equipment subsea
Increased complexityEnvironment protection
Zero emissionFishingDecommissioning
TYPICAL SUBSEA EQUIPMENTTYPICAL SUBSEA EQUIPMENT
Wellheads & X-mas trees for well control
Piping manifolds (large-bore piping for hydrocarbons and water injection, small-bore piping for hydraulics and chemicalinjection.)
Pipe spools, flowlines (pipelines)
Connectors
Structures
Riser, workover equipment, tools
Control system (hydraulic, electrical)
In future, more and more ”complex” equipment, such as separators and gas compressors will be located subsea.
SUBSEA APPLICATIONSUBSEA APPLICATIONRequirementsRequirements
All subsea applications have very high quality requirements, since possibilities for inspection and maintenance are verylimited, and replacement costs for non-conforming equipmentare very high.
Limited possibilities for monitoring and replacements
Seals and other non-metallic materials must be designed and qualified for full lifetime of field (typically 10-50 years)
Metallic materials must in general be resistant to internalcorrosion for the full lifetime of the field (pipelines with simple and predictable flow conditions may be in carbon steel withcorrosion allowance combined with corrosion inhibitors.)
MATERIAL SELECTIONMATERIAL SELECTIONPrinciplesPrinciples
Materials must be selected based on:
Strength (yield, tensile) and hardnessDuctilityFracture toughness (Normally Charpy-V, sometimes fracture mechanics testing)PriceAvailability (Small quantities, global fabrication)Fabrication methods (welding, induction bending, cold bending etc.), industry experienceDecision on solid material or low alloy steel with CRA cladding where corrosion resistance is required
ENVIRONMENTAL EFFECTENVIRONMENTAL EFFECT
External corrosionSeawater
Internal corrosionHydrocarbon systemInjection water
De-oxygenated seawaterRaw-seawaterProduced water
Internal erosionDue to solids (sand) in the fluid
WearDue to relative motion between components
Hydrogen Induced Stress cracking (HISC) or Hydrogen embrittlement (HE)
HYDRROGEN EMBRITTLEMENTHYDRROGEN EMBRITTLEMENT
H2S corrosion ”sour service” in oil & gas systems, controllede.g. by hardness (max 22HRC for carbon steels). Guideline for material selection given in ISO15156/ NACE MR0175. (This is the same effect whether the equipment is subsea or topside.)
For submerged equipment, cathodic protection reactions mayin addition give atomic hydrogen on steel surface. Criticalfor carbon/ low alloy steels with a hardness aboveapproximately 35HRC or SMYS above appr. 700 MPa, or for duplex steels if highly stressed.
FOINAVENFOINAVEN
FOINAVEN HUB FAILUREFOINAVEN HUB FAILURE19961996--19971997
GISLE RGISLE RØØRVIK, STATOILHYDRORVIK, STATOILHYDROPresentation at NTNU, October 2008Presentation at NTNU, October 2008
HISCHISCWhat is important?What is important?
Access to hydrogenWelding and CP (plus internal corrosion (H2S))
Certain strain/stress level (global and local)Load and geometry
MicrostructureSelected material
HYDROGEN STRESS/STRAIN
MATERIAL
All these are needed at the same time!
A PHONE CALL FROM A SUPPLIERA PHONE CALL FROM A SUPPLIER
I’m going to supply a subsea clamp to an oil company and am aware of the HE problem. My clamp is made from
a polymer material – probably GRP. This clamp is attached to the subsea unit by use of bolts made
from 25% Cr SDSS. Which bolt tension (stress) can I accept and still avoid HE to damage the bolts?
STRESS/STRAIN
MATERIAL
HYDROGEN No HE
HOW CAN WE PREVENT HE?HOW CAN WE PREVENT HE?
Hydrogen Hydrogen EmbritlementEmbritlement of of 25% Cr SDSS25% Cr SDSS
DESIGNDESIGN
Design with acceptable local stress / strainSTRESS/STRAIN
For duplex stainless steel
ACCESS OF HYDROGENACCESS OF HYDROGEN
Reduced protection potentialWelding with low hydrogen inputAlways “bake” bolts or other components with HDG or electrolyttic zinc coating (2500C / 4 hours)Use coating that prevent hydrogen to penetrate into the metal
HYDROGEN
Subsea template retrieved after 4 years
HOW BIG IS THE HE PROBLEM SUBSEA?HOW BIG IS THE HE PROBLEM SUBSEA?
STATOIL:From early 1990’s
Several subsea fields developedwith 22% Cr DSS and 25% CrSDSS in
Piping, Manifolds, ValvesInstruments……
25% Cr SDSS standard for umbilical tubes
Today275 wells + 50 subsea templates> 1000 km small bore umbilicaltubing
Subsea template with SDSS pipingSource: Ø.Strandmyr, Duplex 2007, Grado Italy
NORSOK MNORSOK M--001001SubseaSubsea
External protectionChapter 4.3.4, 4.3.5, 4.3.6
Weld overlay (e.g. flange surfaces)Chapter 4.4
PipelinesChapter 4.3 (Corrosion evaluation), 4.5, 4.6, 5.6.1 (Bolting materials), 5.7, 5.8
Chains and mooring systemsChapter 5.9
Structural materialsChapter 6.2
ISO/CD 21457ISO/CD 21457SubseaSubsea
External protectionChapter 4.5.1, 4.5.4
Weld overlay (e.g. flange surfaces)6.11
PipelinesChapter 4.3 (Corrosion evaluation), 4.5.4, 4.6, 5.5, 6.2, 6.3, 6.4, 6.5.1, 6.8.1, 6.8.2, 6.9, 6.10, 6.13
MATERIAL SELECTION FOR XMATERIAL SELECTION FOR X--MAS MAS TREETREE
Composite valve block (CVB):Low alloy steel w/ Inconel 625 overlay on all wetted parts or F6NM (13Cr 4Ni) martensitticstainless steel w/ 625 overlay in seal areas.
Production wing blockAs for CVB or solid 25Cr superduplex stainless steel.
Annulus valve block and X-overflowloop:Carbon/ low alloy steel w/ 625 overlay in seal areas.
Metal gaskets:Inconel 625, Incoloy 825 or other CRA.
MATERIAL SELECTION FOR XMATERIAL SELECTION FOR X--MAS MAS TREETREE, cont., cont.
Valve internal parts:Variuos types of nickel alloysand stainless steels.
Seal surfaces: Overlay welded with Inconel625.
Components not exposed to well fluid:Normally carbon or low alloysteel.
TYPICAL MATERIALS USEDTYPICAL MATERIALS USEDSubseaSubsea
Piping systems (oil/ gas/ water injection):Carbon steel or low alloy steel (typically ASTM A350 Grade LF2, AISI 8630 or ASTM A182 Grade F22) with UNS N06625 overlayweld on components like hubs and valves.
For smaller dimensions, use of solid stainless steel forgings may be more economical. HIP (Hot Isostatic Pressing) may be an alternative to forged material.
Martensittic stainless steel type F6NM (13%Cr 4%Ni) may be used where high strength is required. Has limited corrosion resistance, normally overlay welding with Inconel 625 is required on all sealsurfaces.
22Cr/ 25Cr duplex stainless steels may also be used.
TYPICAL MATERIALS USEDTYPICAL MATERIALS USEDSubseaSubsea
Smallbore piping systems (hydraulics and chemical injection), typically 3/8” to ¾”:
AISI 316 where low strength is acceptable. (Alternatively colddrawn AISI 316 where higher strength is required, and if weldingis not required).
22Cr Duplex or 25Cr Superduplex where extra strength is required. This has been ”standard” material selection for more than10 years.
Cold bending (min. bending radius 2,5xD, max hardness 360 HV) used in fabrication, and has never caused problems with hydrogen embrittlement.
MATERIALS FOR SEAWATER MATERIALS FOR SEAWATER
Seawater resistant materials are used for piping systems for ”rawseawater” (i.e. seawater with high oxygen content) and for components where cathodic protection (CP) cannot be ensured or where CP have to be avoided (e.g. due to problems with calcareousdeposits).
25Cr superduplex (Note: With PRE-value and other properties accordingto Norsok M-630.)
6MoUNS N06625 (Inconel 625)TitaniumFibre Reinforced Epoxy
MATERIAL SELECTION MATERIAL SELECTION TO AVOID HISCTO AVOID HISC
In later years, we have seen an increased focus on risk for HISC (Hydrogen Induced Stress Cracking) from several oil companies. This has resulted in additional requirements on several projects, such as:
Restrictions on use of HISC-sensitive materials, such as 22Cr- or 25Cr-duplex. Alternatives are C-steel with internal overlay weld (typicallyUNS N06625/ Inconel 625) or alternatively austenittic stainlesssteels. Austenittic stainless steels are often impractical due to lowstrength.
Detailed design requirements with restrictions on local stresses and strains, smooth cross sectional changes, restrictions on cold bending ofpipes etc. (Ref. e.g DNV (Draft) RP-F112 and Norsok WA-01.)
Special coating on all duplex piping, such as vulcanized polychloroprenerubber, to prevent hydrogen formation on the steel surface.
CAN SOMETHING GO WRONG?CAN SOMETHING GO WRONG?
Use of wrong material – not according to specificationNo Cathodic Protection applied – not electrical contact between sacrificial anodes and structureHISC due to a combination between stress, hydrogen and susceptible materialSolids in the fluid – causing catastrophic metal loss followed by a leakComposition of process fluid out of control causing severe corrosionCorrosion inhibitor not supplied or mal-functioning causing severe corrosion
CAN SOMETHING GO WRONG?CAN SOMETHING GO WRONG?continuecontinue
Fatigue due to system vibration (including free span of pipelines)Fatigue in wellhead/casing due to overload during work-over operationNo or “wrong” inspection program implemented……….
EXAMPLEEXAMPLEElectricalElectrical penetratorpenetrator
25% Cr Duplex materialSubsea without CP30 - 35 % sigma phase due to incorrect heat treatmentSevere corrosion attack due to the sigma phase
(In this case, the correct material had been selected, but due to
incorrect heat treatment, material had not got the
required properties.)
CORROSION PROTECTION IS IMPORTANT CORROSION PROTECTION IS IMPORTANT TO SECURE STRUCTURAL INTEGRITY!TO SECURE STRUCTURAL INTEGRITY!
USE OF ELASTOMERS OFFSHOREUSE OF ELASTOMERS OFFSHORE
Thermal insulation SealsCable and flowlineprotectionBearing systemsFendering and buoyancyHoses++
FAILED ELASTOMER SEALSFAILED ELASTOMER SEALS
ALEXANDER KIELLAND ULYKKENALEXANDER KIELLAND ULYKKEN27. mars 1980 27. mars 1980 –– 123 123 menneskermennesker omkomomkom
EN SLIK ULYKKE VIL VI IKKE HA IGJEN!
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