http://www.youtube.com/watch?v=ZH4FysZ55us PVE-Truong Dinh Hieu Give methods of installation for offshore pipeline. Offpipe User’s Guide General Model Start-up Model Abandonment Model Davit Lift Check DNV F101.
PVE-Truong Dinh Hieu1. METHODS OF INSTALLATION S lay J Lay Reel Lay Tow-in Surface Mid Depth Tow Tow Bottom Tow Off-Bottom Tow
PVE-Truong Dinh Hieu2.CHARACTER METHODS OF INSTALLATION • S Lay: The S-lay is applicable in shallower water, depend on the installation vessel’s capacity and pipe sizes, recommended to use less than 305 m (1,000 ft) of water. In the upper part (the overbend) the curvature is controlled by the laybarge stinger ( a steel structure protruding from the stern of the vessel, that supports the pipeline on rollers). The curvature in the lower part (the sagbend) is controlled by lay tension transferred to the pipeline by tension machines gripping the pipe string on the laybarge. • J Lay: (http://www.youtube.com/watch?v=Phqum0y1nhs) The J-Lay may be installed in water depths exceeding 2000 m . The pipeline from the surface to the seabed is one large radius bend resulting in lower stresses than an S-lay system in the same water depth. There is no over-bend and large stinger as required in S-lay method. The horizontal forces required to maintain this configuration are much smaller than required for an S-lay system. • Reel Lay: Reel Lay is a method of installing pipelines in the ocean from a giant reel mounted on an offshore vessel. Pipelines are assembled at an onshore spool-base facility and spooled onto a reel which is mounted on the deck of a pipelay barge
PVE-Truong Dinh Hieu2.CHARACTER METHODS OF INSTALLATION Reel pipelay can be used on pipelines up to 18 inches in diameter. Reeled pipelines can be installed up to 10 times faster than conventional pipelay. The reel method reduces labor costs by permitting much of the welding, x-raying, corrosion coating, and testing to be accomplished onshore, where labor costs are generally lower than comparable labor costs offshore. The reeled pipeline can be installed in an S-lay method or J-lay method depending on the design of the reel vessel and the depth of water. Reel vessels can have vertical reels or horizontal reels.• Tow Lay: In the tow methods, the pipeline is normally constructed at an onshore site with access to the water. These methods can be used for installing pipelines across inland lakes, across wide rivers, and offshore. This method is applied to short line, usually less than 4 km, (7 km has been laid). The buoyancy of the line is selected and designed to verify that a controlled depth tow can be performed. This method of installation is usually used when several flowlines are fabricated together (i.e. a bundle).
PVE-Truong Dinh Hieu2.CHARACTER METHODS OF INSTALLATION• Other Method Laying: O-lay• http://www.youtube.com/watch?v=JhyAQuUtzdg• http://www.youtube.com/watch?v=g3CtixUcWJo.• http://www.youtube.com/watch?v=ksm4QuF7dys&feature=autoplay&list=PLD6A6 A859CBC2C296&playnext=1
PVE-Truong Dinh Hieu 3.Pipeline Installation Analysis Offpipe Input data Model Local Pipelay Bulking Pipe Initiation Check data Environment Abandonment data and RecoveryLaybarge and Normal Stinger data Pipelay Soil Data
PVE-Truong Dinh HieuA. Offpipe Model1) Pipeline radius of curvature The minimum radius of curvature in the overbend region can be calculated using the following equation (Question 1: this calculation just applied for steel , what happen for concrete coating ?): The curvature at sag bend should be controlled and maintained so that its stress level does not exceed the limits outlined as required in API RP 111: ovality is assumed 0.5%
A. Offpipe Model PVE-Truong Dinh Hieu Bending strains ε1 is not simply nominal (global) bending strains and shall include an allowance for possible strain concentrations. For example, if a pipe is reeled, the nominal bending strain in the pipe on the reel or aligner is given by: Question 2: How could be controlled curvature of sag bend ? Increasing the tension can control the sagbend stress (decreases the bending stresses). In shallow water barges, the increase in tension must be taken up by the anchors. This may lead to slippage depending on the soil conditions on the seabed. Also, the increase in tension leads to a longer suspended span, which may not be desirable. This also leads to higher residual tension of the pipeline on the seabed. On the seabed, spanning of the pipeline over undulation increases with increased tension. Therefore most barges want to use the optimum amount of tension. Question 3: How optimum amount of tension ?
A. Offpipe Model PVE-Truong Dinh Hieu The simplest model for the calculation of the relationship between tension and sagbend curvature is the catenary model (as figure side). The catenary model ignores the flexural rigidity of the pipeline.
PVE-Truong Dinh HieuB. Analysis of InstallationI. Pipelay Start-upa. Start LFP The laybarge is anchor about 10m water depth (near if can), Pipelay Initiation the pipeline will be pulled to shoreline by winch and cable. Start CPP Start LFP The laybarge will be moved to CPP (platform) when pullhead is fixed at LFP The pipeline will be abandonment nearest CPP possible (200m form CPP to Laybarge), because the length of laybarge and stinger is approach is 200m , they can be hit platform if continuous laying pipeline. Question 4: What the method to connect pipeline with riser? The laybarge turn back installation riser section first, after that connect with pipeline by Middle-spool. All the pipeline routes have a TIE-IN(WYE) point, the laybarge will be abandonment at there (not near CPP place) after that laybarge moved the CPP and connected the pipeline with riser/spool , continuous laying to WYE point, and connected together.
PVE-Truong Dinh HieuB. Analysis of Installationb. Start Platform(CPP) The laybarge will be performed using deadman anchor (DMA) start-up method at CPP (i.e. a anchor will be laying down first, the anchor is connected with cable and pullhead, the length of cable is controlled touchdown point). The laybarge moved to shoreline until can’t laying, pipeline will dropped/ abandonment to seabed . The laybarge turn back, pipeline will be pulled to shoreline by winch and cable. The pipeline will be abandonment after pullhead fixed at LFP. Question 5: What the method to connect together. Davit lift (The laybarge lift two pullhead and welding on laybarge)http://www.youtube.com/watch?v=6oUSV3ci5m4 Diver connected togetherhttp://www.youtube.com/watch?v=cX-Zz2byQpc
PVE-Truong Dinh HieuB. Analysis of InstallationII. Abandonment and Recover Due to weather condition(or other) the laybarge may be abandonment. Abandonment process is modeled byincreasing the length of the laydown cablein a series of steps until pipeline is reseton seabed.• http://www.youtube.com/watch?v=XythKAClIeQ&feature=relatedIII. Normal Pipelay The profile pipe will be modeledon the support.
PVE-Truong Dinh HieuC. Offpipe User’s Guide F4 or F1 for information The graph’s number to plot in a drawing Select the output printed.Enter user’s plot hardwarePrint diagnostic outputThe drawing’s number to plot
PVE-Truong Dinh HieuC. Offpipe User’s Guide Pipe property Properties of pipe coating Properties of cable, used for initiation , abandonment and recovery Define two or more separate pipeline bound together Define fluid contents in pipe span analyses
PVE-Truong Dinh Hieu C. Offpipe User’s Guide SMYS The length of pipe just definedEnter number of pipe when Table index number is different 1 .(i.e. The cable is Unit. include) Redefined Modulus of Elasticity
C. Offpipe User’s Guide PVE-Truong Dinh Hieu Coating property of number of pipe The length of pipe The length of field joint
C. Offpipe User’s Guide PVE-Truong Dinh Hieu Enter pipe tension on laybarge Note 1 Defined pipe support, static position and other data on laybarge Defined properties of pipe support (in support table).Note 1: The value entered in the TENS field is Defined the length and tensionthe total static pipe tension applied to the of davit cablepipeline on the laybarge. When multiple pipe Defined properties of davit cabletensioners are used, the total tension is assumed element into support property tableto be evenly distributed between the tensioner.Ex. The tension 1 =100kN and the tension 2=120kN…How many tension force is required in theTENS field ?
PVE-Truong Dinh Hieu C. Offpipe User’s Guide The number of stations (pipe support, tensioners and davits) includes unsupported pipe or cable nodes The method used to defined the elevation at each station on the laybarge.(more detail see next page) Enter tension force. The angle and elevation of point on laybargeThe laybarge offset from can be referenced to the water surface byinitial position(only davit lift) setting deck height. The coordinates (X,Y) of tangent point and angle between straight pipe ramp and tangent point The coordinates (X,Y) of Stern Shoe point(final support on the laybarge) Property of pipe support (more detail see next Page) Noted: The minimum radius enter in this filed will be consider in Section A.1
PVE-Truong Dinh HieuC. Offpipe User’s Guide Used for davit lift analysis. Or the elevation each pipe support is calculated and given explicitly. The Radius of curvature combined with straight ramp forward of the tangent point and coordinate of tangent point (X.Y) is specified. The Radius of curvature combined with straight ramp forward of the tangent point and coordinate of stern shoe point GEOM Option (X.Y) is specified. Stern Shoe: The pipe support closest to the stern on the laybarge Used to model small. The elevation of pipe support is defined by the coordinated and angle of the tangent point. Used to model “J-Lay”. The coordinate of point on the pipe ramp is assuming parallel to the deck. After the ramp is rotated about upward the angle specified in APIV field (here) and the center of rotated are given in the XPIV and YPIV fields.
PVE-Truong Dinh Hieu C. Offpipe User’s Guide 1oo. Un-support pipe node: Can used both pipelaying a davit lift. This point is description place Property of pipe support additional between support point. 1. Simple pipeline support: The support resist downward displacement . The pipe are free to lift Just required in davit lift off the support. analysis. The length of pipe between present davit sling and preceding davit sling. 2. Pipe Tensioner or A/R winch: The support resist both upward and downward. 3. Inverted pipe support: the support resist upward displacement. Type of support 4. Full encirclement support: TheY coordinate of pipe support (entered when support resist both upward andGEOM =1 and davit lift analysis) downward.X coordinate of pipe supportused for all GEOM option 5. Simple axial force davit: The davit cable is modeled by simple 5. True catenary davit :The davit cable is and straight , axial force element. modeled by a curved , that is determined by weight and tension of davit cable
PVE-Truong Dinh HieuC. Offpipe User’s Guide Defined the stinger, geometry and structural configuration. Defined the weights and displacements of stinger elements. Specify the ballast contents of stinger elements. Specify the net buoyancies of stinger elements. Defined properties of pipe support (in support table). Defined properties of stinger (in stinger element table).
PVE-Truong Dinh Hieu C. Offpipe User’s Guide The number of stations (pipe support, hinges) includes unsupported pipe or cable or stinger nodes Defined the stinger geometry (more detail see next page) Type of stinger model to be used (more detail see next page) The coordinated of reference point or temporary origin. Used for GEOM =1 & 2 The coordinated of tangent point (X,Y). Property of pipe support on stinger (more detail see next Page)Thecoordinated ofHitch (X,Y) Noted: The minimum radius enter in this filed will be consider in Section A.1
PVE-Truong Dinh HieuC. Offpipe User’s Guide 1. The coordinated of support on stinger will be entered (X,Y). When this option is used, the pipe radius , coordinates and angel of the tangent point must entered. 2. The coordinated of support on stinger will be entered (X,Y). When this option is used, the pipe radius , X coordinates tangent must entered. Y coordinated and angled are calculated. 3. The stinger element lengths and radius will beGEOM Option entered. When this option is used, the pipe radius , coordinates and angel of the tangent point must entered. 4. The stinger element lengths and radius will be entered. When this option is used, X coordinates tangent must entered. Y coordinated and angled are calculated. 5. The X coordinated of support on stinger will be entered. When this option is used, the pipe radius, coordinates and angel of the tangent point must entered. 6. The X coordinated of support on stinger will be entered. When this option is used, the pipe radius, X coordinates tangent must entered. Y coordinated and angled are calculated.
PVE-Truong Dinh Hieu C. Offpipe User’s Guide 1. The stinger is modeled as a rigid extension of the laybarge. No structural. 2. The stinger is modeled structurally. Except first element, the stinger is assumed straight when undeformed. 3.The stinger is modeled structurally. Undeformed shape of the stinger is assumed to be initial geometry. TYPE Option 4. For future use. 5. Stinger is model as a rigid extension of the laybarge. No structural, using special features provide by OFFPIPE. 6. The stinger is modeled structurally, using special features provide by OFFPIPE.Question 6: Do you understand “Structurally” and “Modeled”?
PVE-Truong Dinh Hieu C. Offpipe User’s Guide Property of pipe support on stinger Type of supports are defined as support on laybarg . 1. Tensioner not used on 1. Simple pipe Support stinger. 3. Inverted pipe Support 4. Full Encirclement Support. 5,6. Davit not used on Stinger. 100. Un-support node pair: a pair of pipe and stinger nodes. This nodes 200. Un-support Pipe node : are not as support.X coordinated of pipe support on stinger. only pipe node( may be insert aRequired in GEOM 1,2,5,6. The coordinate force on the pipe).system can determined following to laybargecoordinate system or other convenient 300. Un-support Stinger node :reference point on the stinger only stinger node (may be description to associate elements stinger together). Y Coordinate of pipe support on stinger, just required with GEOM 1,2 The coordinated of reference point or temporary origin. Used for GEOM =1 & 2
PVE-Truong Dinh Hieu C. Offpipe User’s Guide Property of pipe support on stinger The length of stinger segment, required with GEOM =3,42.Hinged 1.Fixed 1.Fixed 2.Hinged
PVE-Truong Dinh HieuC. Offpipe User’s Guide Defined the geometry of the pipe/cable in the sagbend. Vary the length of pipe element in the sagbend. Enter the soil properties of seabed Defined the velocity profile for steady current. Model simple buoys and point floatation devices attached to pipe. Defined the seabed elevation for pipe span analysis.
PVE-Truong Dinh Hieu C. Offpipe User’s Guide Constant pipe length to be used in the sagbend and seabed.( pipe joint length ) Specify the end condition at the lower end in the sagbend. Specify the length of pipe span in the sagbend is to be calculated for the given pipe Insert water depth tension . X coordinated of the point on the Depth and vertical angle of the pipe point right-of- way. This value stinger in the sagbend..only used must specified when the value of when the free end is defined as slope of seabed is entered is pinned connection. nonzeroEstimated the length of sagbend Slope or angle of the seabed relative to the water surface. Just analysis when the seabed not parallel waterEstimated the length between the surface NOTE: The profile of sagbend willtouchdown point and the pointfixed at the end of the pipe stinger. be calculated by OFFPIPE. This Direction and heading in which the field just is required to entered bottom slope is measured. water depth (other condition isX coordinate of free end of the relative seabed) and sagbendpipeline on the seabed before the element length.lift, just use in davit liftX coordinate of the end at point of fixity at the lower end the sagbend. Just required in the fixed span length.
PVE-Truong Dinh HieuC. Offpipe User’s Guide Stiffness of soil with pipeline displacement in the vertical direction. Static vertical deflection of the soil under. Approximated equal submerge weight of pipe. Stiffness of soil with pipeline displacement in the horizontal direction. Soil coefficient of friction used for pipeline displacement in the horizontal direction. The number of numerical integration point (default). The number of water depth for the current velocity and direction. The water depth for the current velocity and direction are specified. Current velocity is specified. Direction of current flow (assumed 90 degree). Question 7: How about the wave is included in static analysis ?
PVE-Truong Dinh HieuD. Summary In above section, the basis parameter must used for modeled pipeline installation by OFFPIPE software. The input data is summarized as: Step 1: Calculated the curve of the pipe on the laybarge. Step 2: The pipeline will be modeled with GEOM =4 , the coordinates of tangent point will be entered . Step 3: Run and check allowable stress at overbend. If violate , increase the curve of the How did you controlled Y coordinated pipe as a method. of support on laybarge? (if no data)
PVE-Truong Dinh Hieu D. Summary Y coordinates of supports is defined as sum deck height Increase the curve of the pipe in *Barg field or reduce Tensioner and the height of support on force as a method to reduce deck. percent yield on the laybarge. The method reduce percent yield of pipe on the stinger as increase tension force or reduce the curve on the singer in the *STIN field. Noted when increase tension force, or reduce the curve on the singer the percent yield of pipe on laybarge will be increased. (Be careful) Question 8: What method to controlled percent yield of pipe on the Over bend?Percent Yield of pipe on the Overbend Max 72% SMYS .and The percent yield of the pipe in the sag bendMaximum allowable strain at sag bend is 85% SMYS.(reference is always smaller in the over bend (if don’tAppendix 1). have specifically ). If user controlled percent yield on the overbend, no need to check percent yield on the sagbend.
PVE-Truong Dinh HieuE. Application for analysis installationI. Start Up Initial installation is start from Platform, the pipe line will be modeled include cable as example below: END=1 is modeled the cable which pinned by dead man anchor. YEND, AEND are modeled the Y coordinates and vertical angle of end cable which pinned by dead man anchor. *LENG field is modeled as distance from first support to pullhead. This field is description as pipe segment laydown slowly Initial installation is start near shoreline to seabed . The cable will be consider as pipe segment. In this case, the purpose of cable is fixed end of pipe or pull. Due to CABL field is defined as ROW=2
PVE-Truong Dinh Hieu E. Application for analysis installationII. Abandonment/Recovery Abandonment and recovery : In abandonment case, the pipe will modeled as increase the length of the cable. Recovery case will modeled as reduce the length of cable. The cable will be consider as pipe segment. In this case, the purpose of cable is abandonment pipe. Due to CABL field is defined as ROW=1 Support used to davit lift analysis. (X,Y) coordinatesIII. Davit Lift Davit lift: Modeled pick up the free end of a pipeline laying on the seabed Davit lift are performed in the installation of pipeline riser (how), on fixed offshore platforms. May be also be used to reposition a pipeline laying on the seabed, to facilitate to making of a underwater connection. Davit lift may be used to connect two section pipeline on the laybarge(Ex at shore approach). In Davit lift analysis need controlled cable length and tensioner force to ensure percent yield not exceed. Davit length XEND
PVE-Truong Dinh Hieu E. Application for analysis installation GEOM=1 only used for davit lift analysis. Un-support node is modeled for free end (pullhead) or between two support.. X coordinate =100m and Y coordinate =2m of support 1, Type of support =6 or 5(see section C ), distance form free end to support 1=20m (spacing between slings) XEND or XTOP =120m is total length of pipe from free end (pullhead) to global coordinate system .When the length of a davit line is specified, whether davit line is slack OFFPIPE will determined line tension. IF the tension indavit line is specified, OFFPIPE calculated the corresponding length of the davit line.The length and tension cannot both be specified for the same davit. The length of at least of one cable (nearest the free end) mustalways be given.Davit line tension is specified approximately equal to the weight of the pipe span between davits.
PVE-Truong Dinh Hieu E. Application for analysis installationY coordinate of the free end = 3.97m The initial length of davit line number 1 = Maximum Percent Yieldabove seawater surface. 10m . of pipe 72% SMYS. Question 9: How do you controlled percent yield ?Support reaction of support Increase the length of davit line or modeling lift barge displacement as addition XOFF forward X direction(+). Be careful when the method above to used will be increase support reaction of support and reduced Y coordinates of the free end. A other method is increased the tension line all the remain support as below example.
PVE-Truong Dinh HieuE. Application for analysis installationII. J Lay
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