SOCIETYOF PETROLEUXENGINEERSOF AIME PAPER ~ZOONorthcentralExpressway NUMBER SPE 2278 Emllas,Texas 7’j2C6

THISIS A PREPRINT---SUBJECTTO COR.RECTIO~~

Marine Pipe Laying Methods Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/68FM/All-68FM/SPE-2278-MS/2063248/spe-2278-ms.pdf/1 by guest on 25 September 2021

By

JollyDwyer,MemberAIME,BechtelCorp.,SanFrancisco,Calif.

@ Copyright 1968 American Institute of Mining, Metallurgical and Petroleum Engineers, Inc.

Thispaperwaspreparedforthe43rdAnnualFallMeetingof theSocietyof PetroleumEngineers of AIKE,to be heldin Houston,Tex.,sept. Zg-od. 2, 1968.Permissionto copyis restrictedto an abstractof notmorethan300words. Illustrationsmaynotbe copied.The abstractshouldcontain

. usuallygranteduponrequestto theEditorof the appropriatejournalprovidedagreementto give propercreditis made. Discussionof thispaperis invited.Threecopiesof anydiscussionshouldbe sentto the Societyof PetroleumEngineersoffice.Suchdiscussionmaybe presentedat theabovemeetingand, withthepaper,maybe consideredforpublicationin oneof thetwoSPEmagazines.

ABSTRACT A number of marine pipelaying laying pipe in deep water. It techniques have developed over the suggests that economical solutions to years, but their potential for in- those problems are within the stalling large diameter pipe in deep capability of present day technology, water is severely limited. A survey without excessive developmental of present day technology is desir- effort. able to evaluate its limitations for the needs at hand, and to determine INTRODUCTION where new techniques are required. All present day techniques have When petroleum discoveries many elements in common. These can stepped from dry land into the be com:~edt~ a variety of ways, and marshes, and eventually into the sea, some combinations offer the associated pipelines had to go possible solutions to the problems of into the water as well. Short lines laying pipe in deep water. in shallow water could readily be This paper describes the most made up on shore and pushed or pulled common components of marine into position. However, long pipe- pipelaying systems, and discusses the lines, even through marsh lands, re- present day combinations. The quired a different solution, and the components include: barges, pipelaying spread took to the water stingers, launchways, reels, winchesD on a lay barge. From these begin- tensioners, pontoons$ caissons, nings various marine pipelaying chambers and submersible vehicles. methods have evolved and are in use The combinations include: lay today. barges, tie-in barges, lowering As the need grows to lay pipe- barge;fiereelbarges, and pull barges. lines of larger diameter in deeper paper then goes on to water, even present day techniques describe the potential appMcations are becoming restrictive. It is of other systems to the problems of desirable to examine present day marine pipelaying technology closely References at end of paper. and to evaluate its potential for 2 MARINB PIPE LAYINGMETHODS SPB-2278 Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/68FM/All-68FM/SPE-2278-MS/2063248/spe-2278-ms.pdf/1 by guest on 25 September 2021

Fig. 1 - Conventionalbarge. Fig.2 - Semisubmersiblevessel. C-

Fig. 3 - Straightlaunchway. Fig.4 - Shapedlaunchway.

Fig. 5 - Straightstinger. Fig.6 - Shapedstinger.

1

c -~

= @ ‘-

Fig.7 - Tensioner. Fig.8 - Winch. >E.2278— JOLLY DWYER ~ ————. —...—. . “

forthcoming needs. It isw~;~e desir- matter of expediency in providing an able to determine new inexpensive hull. The shipform techniques might be required to vessel has a definite mobilization overcome the ultimate limitations of cost advantage, because it tows well. present day methods. However its stability is seldom any The next two sections of this better than a barge?s, and can be paper are intended to acquaint the worse. interested engineer with the Semisubmersible vessels (Fig. 2) pipelaying art if he “ are uncommon in marine pipelaying, unfamiliar with it. For t&e ~h~ but are well known in the drilling already know mari;;e pipelaying, a industry. Their stability is good, Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/68FM/All-68FM/SPE-2278-MS/2063248/spe-2278-ms.pdf/1 by guest on 25 September 2021 glance through accompanyingg even in high seas. illustrations will tell the story in adequate detail. Assemblyway COMPONENTS The assemblyway is an area in which the pipe can be aligned and At present the pipe is generally joined into one continuous string. joined at the surface. Consequently It is horizontal when possible, and the techniques have many surface- strai~ht in any case, so that locked- oriented elements in common: working in bending stresses are minimized. platforms; pipe handling, joining and On shore it is usually alongside the launching equipment; and vessel Iaunchway, and the pipe string is positioning equipment. Additionally rolled from one to the other. At sea a number of underwater elements are it is generally in line with the available for use in a system when Iaunchway. desired. Divers are the most common, but chambers and submersible vehicles Launchway have increasing application. The Iaunchway serves to transfer Pipelaying Equipment the fabricated pipe string from the assemblyway into the sea. It is an Whether ashore or at sea, the integral part of the working pipeline has to be fabricated joint platform, although it may be designed by joint. There must be storage to assume different angles racks and an assemblyway; there must configurations. It may be a straig~~ be carriers and a launchway. At sea extension of high-angled a stinger may be used, to carry the assemblyway (Fig. 3;, or it may b~h~ pipe from the vessel to the sea curving transfer system carrying bottom. Pulling winches are pipe from a shallow angle on the required, to pull the pipe from the assemblyway to a steep angle at the land into the sea, or from the barge launching point (Fig. 4). toward the land. Holdback devices may be employed, to keep the pipe Stinger from running down the launchway. There may also be tensioning machines The stinger is unique to the lay to apply horizontal force to the barge. It is a detachable extension pipe. of the launchway, intended to support the pipeline during its descent from Working Platforms the barge to the sea floor. It may be a truss framework firmly attached The most stable working platform to the barge, or a buoyant pipe of all is the land, of course, and it ladder hinged to the barge. It lUay is put to use as a pipe fabrication be straight (Fig. 5), or shaped for base when suitable. More fre uently some purpose (Fig. 6), usually to a seagoing platform is require8, and hold the overbend in the pipe to an a vessel is employed for the purpose. allowable stress limit. Conventional flat-bottomed barges (Fig. 1) are in common use. Tensioner They are relatively low in cost, but have poor characteristics as stable By applying appropriate tension platforms in a seaway. to the pipe, the stinger may be Ships are sometimes converted to shortened, or even eliminated if the pipelaying vessels, usually as a launching angle can be adjusted. 4 MARINH PIPE LAYINGMETHODS SPE-2278 Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/68FM/All-68FM/SPE-2278-MS/2063248/spe-2278-ms.pdf/1 by guest on 25 September 2021

Fig, 9 - Pipereel. Fig. 10 - Pontoon. w 5!?

Fig. 11 - Anchor, Fig. 12 - Positioner.

Fig. 13 - Tug. Fig. 14 - Diver.

Fig. 15 - Chamber. Fig, 16 - Submersible, )E.2278— JOLLY DWYER I

During the welding operation on a lay Positioners may be fully barge, the pipe is gripped firmly, so rotatable right-angle propeller drive that tension must be applied through units (Fig. 12), combinations of main the barge positioning system. When propellers and tun~fl thrusters, or the barge moves forward to launch a other types special marine joint of pipe, however, the pipeline propulsion systems. must be fed out “ continuous tension, and the ten;?oner (Fig. 7) Auxiliary Components comes into play. It maintains a

fixed amount of holdback on the The tug (Fig. 13) is the gener- Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/68FM/All-68FM/SPE-2278-MS/2063248/spe-2278-ms.pdf/1 by guest on 25 September 2021 running pipe until the barge reaches al purpose workhorse of the marine its new position, where the positive pipelaying spread. It tows the stop is reset. equipment to the work site, hauls the pipe barges back and forth, moves the Winches anchors, and performs a number of other routine chores. Although a necessary part of an The diver (Fig. 14] is often a anchor positioning system, a winch necessary adjunct to the pipelaying (Fig. 8) is even more vital for operation., Routinely he sets and ad- :~;;:ne i.nstallati.onsby the pull justs the stinger; he ties in flanged where a heavy-duty winch, connections; and he inspects the someti~es capable of l,inepull in the pipeline in place. More importantly 200-ton range or greater, may be he serves as the solution for most required. underwater emergencies: clearing fouled anchors; recovering lost Pipe Reel equipment; and removing obstructions. The open-bottom dry chamber Pipe can be spooled into (Fig. 15), cl~~~ng to Alexander the radius of curvature in the yiel~ Great in and at least to the range and then can be straighten~~ 17th Century in fact, has just lately through the yield point arrived on the pipeline scene. Its unspooled,. with no appreciable change primary use has been for hot taps and dimensional characteristics. repairs, but it shows potential for &ge-diameter reels (Fig. 9) are pipelaying. used to spool pipe for this purpose, Also a newcomer to pipelining, and offer a convenient way to carry and not yet proven for any purpose great lengths of prefabricated but inspection, is the manned sub- pipeline in a small area. mersible vehicle (Fig. 16). Its un- manned counterpart”, the tethered Pontoons vehicle, has only recently flexed its pipelaying muscles, but may some day A sim~?le method to reduce the be a routine part of the operation. stress in a pipe string extending unsupported between the barge and the COM8INATIONS sea floor is to attach pontoons (Fig. 10), which will relieve the submerged The foregoing elements of marine weight of the pipeline. Pontoons may pipelaying systems can be combined in also be used to reduce the subnerged large number of ways. weight of a pipeline being pulled ~evertheless, there are basically along the sea floor$ and consequently only two categories: pipe pulli~~ to reduce the pulling force. systems and pipe laying systems. the pulling systems the pi~>e is Positioning Equipment fabricated at some shore facilzty, in long sections or in its entirety, and In shallow water the lay barge the sections are transported to their or the pull barge can be kept on ultimate location. In the laying position fairly readily by the use of systems the pipeline is fabricated in conventional anchors [Fig. 11) and place on a working platform which lines. In deep water the problem moves along the right of Way and becomes acute, and a solution which lowers the pipe into final position has been applied to floating drill as it goes. rigs is now being discussed for Within these systems the time- pipelaying vessels: dynamic honored variations are: floating pull positioning. (or even push]; bottom pull; tie-in 6 MAJtINBPIPE LAYINGM6THODS SPE-2278 .,. . ‘... . MultiplePipe Sections ,.. .,/ ,, . ,.... .““.-.II 1:::::::::::::::::::::::::::/: , : ..;..I Tie-in Point ~,, 1 .. ‘. . .. . 1!) Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/68FM/All-68FM/SPE-2278-MS/2063248/spe-2278-ms.pdf/1 by guest on 25 September 2021 Fig. 17 - Conventional straight launchway.

Fig. 18 - Launchway curvedtogainworkingareaand properdirection.

., . .. . .“

.,”: ...... ‘...... , #.. .. ”.:

..”. “ , ~n-o~ 11::::::::: .. ,,$ - ,., . Fig. 19 - Hypotheticalcircularlaunchway, to pulllinein one ii!section. -----PI!-22711------.1OLLY -..DWYER----

barge for floating strings; lay taken in tow - by a tug (Fig. 20] for barge; and lowering barge. One a floating line, or by a pull barge hybrid which unites both systems is [Fig. 21) for a submerged line the reel barge. traveling on the bottom. Once the installation begins it must be Pulling Systems completed with dispatch. If the pipeline is launched in a number of In earlier days the most common sections, one must be tied to the technique for installing underwater next. The tie-in may require several pipelines was to assemble them on hours, during which a floating

shore and pull them into position. pipeline is at the mercy of the Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/68FM/All-68FM/SPE-2278-MS/2063248/spe-2278-ms.pdf/1 by guest on 25 September 2021 This technique is still in use for currents and weather and a submerged most river crossings~ some marsh pipeline is particularly in danger of lines, and for relatively short adhering to the bottom or even marine pipelines with one terminus on becoming embedded. shore. It is generally practical for Eventually the entire pipeline lines up to 10 miles long. is launched, Usually the leading end Exceptionally, it has been used for is connected to some offshore the 19-mile crossing between Ganaweh facility, such as a production and Khargu in the Persian Gulf. platform or a tanker berth, and the The pipe pulling method requires trailing end remains on shore for a long working area on shore, connection to other facilities. adjacent to the water. The entire However, it may be pulled off the pipeline is fabricated in one length land in its entirety and snaked into if practicable. Otherwise, pipe position between two offshore sections are fabricated in the facilities. longest length circumstances permit. A floating pipeline is These are stored on racks, with continuously vulnerable to weather suitable arrangements for rolling or conditions, and may also be hazarded lifting them onto the adjacent by the lowering process in deep launchway. water. Traveling in contact with the The launchway is usually perpen- bottom, the submerged pipeline is dicular to the shoreline [Fig. 37), safer from the elements but is much but it may be angled or even cururd more difficult to maneuver into (Fig. 18), and circular launc[-~, position and to connect. [Fig, 19) are theoretically posslb~... Whatever its configuration, the Tie-In Barge launchway must provide for carrying the pipe sections into the sea one by One noteworthy variation an the one. This is commonly done with pulling theme “ the “floating tracks and small rail cars, or with string” method. W&e the pipeline stationary rubber-tired units on location is distant from the shore which the pipe can roll along the fabrication yard, it is sometimes launchway. Where a large amount of possible to float the individual land pipelaying equipment is pipeline sections onto location and available the pipe sections may even sink them into position one by one be carried to the sea by a number of after each is joined to the preceding sideboom tractors. at the surface by a tie-in barge The advantages of shore (Fig. 22). The technique permits fabrication are obvious. A small installing the pipeline in very long crew-can work at a leisurely pace sections, but the tie-in is even more over an extended period, or many time consuming at sea than ashore. crews can h’orksimultaneously to meet The delay amplifies. the hazards a deadline. There is no 1arge inherent in floating pipelines, and investment in floating equipment, and so the technique is generally there is no long-term exposure to the confined to relatively protected and elements. The pipeline installation not overly deep bodies of water. itself can be planned around a short period of clement weather. ~ing Systems Pulling Equipment The laying systems all have two major elements “ common: When the pipeline installation fabrication platfor& and a pip: commences, the first pipe section is lowering technique. The physical 8 MARINE PIPE LAYINGMETHODS SPB-2278 Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/68FM/All-68FM/SPE-2278-MS/2063248/spe-2278-ms.pdf/1 by guest on 25 September 2021

\ . / .Y,,,( .-, / ,....W, , ~. ,

Fig. 20 - Pipeline under tow, po~tooned for positive buoyancy.

Positioning Anchor Winches Pulling Winch -I- ~ f v \ / ~

Positioning Anchor Lines ( not shown ) —Pipe Pulling Line Pul Iing Anchor

J ,. ..

Fig.21 - Pipelineunderpull,weightedfornegatik’ebuoyancy,

F Iotation Pontaons - \ —v

Pontoons remova.

Fig. 22 - Floating string method with tie-in barge. ,------—. . -—. -

equipment comprising the components bracing or trusses, leaving the water of these systems can differ greatly clear between them. Several A-frames from one to another, but the basic are evenly spaced along the barge, concepts do not change. straddling the space between the The fabrication platform is hulls. Each A-frame carries a usually some form of barge. The lowering winch, with enough cable to lowering technique for t~ro~escending reach the bottom. pipeline can vary nearly Fabrication and lowering occur complete support by a stinger (as in stepwise. Fabrication is performed the conventional lay barge) to fully on the forward barge while the after unsupported suspension by tension (as barge holds the descending pipeline Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/68FM/All-68FM/SPE-2278-MS/2063248/spe-2278-ms.pdf/1 by guest on 25 September 2021 in the reel barge). in an acceptable static S-curve configuration. When the forward Lay Barge Method section is ready, the winches on both barges are operated sequentially to Basically there is only one way move the S-curve into the same to fabricate a pipeline: weld it relative position on the forward together joint by joint. This simple barge. The after barge then releases technique is the heart of the lay all pipe and moves ahead to ali~ barge operation (Fig. 23). The with the other barge, so that the two pipeline is fabricated by adding one vessels now exchange roles. This joint of pipe at a time and moving leapfrog operation continues until the barge forward in even steps to the pipeline is completed. pass the joint through a series of The system is very simple, and a welding stations along the variety of elaborations can be made assemblyway until the joining process on it. Unfortunately none of these is complete. Further forward will overcome its basic sensitivity movement of the barge passes the to weather and sea conditions, and joint through the radiographic, the method is confined almost coating, and concreting stations exclusively to calm, sheltered along the launchway as required to waters. complete its integration into the pipeline. Reel Barge Method The pipe then passes onto the stinger and begins its descent to the As mentioned, the reel barge sea floor. Somewhere it must leave method (Fig. 25] is a hybrid. the stinger and enter an unsupported Fabrication is done in a shore yard, span between the points of departure as for a pipeline pull, and the 1ine and touchdown. This span is is in fact pulled aboard the bargeT~~ generally the most critical part of spooling it onto the reel. the pipeline. If the stinger is spooled pipeline is carried onto short and the water is deep? so that location, where the free end is the too long, the pipe may attached to an anchored cable, or fail %a~ b~~m under the loading of pulled to an initial starting point its own weight. If the span is short on the bottom. The barge ther moves but the bend is sharp, the pipe may forward under tow, paying out fail from high bending stresses. If pipeline as a lay barge might, but in the barge backs down on the one smooth, rapid movement. Except unsupported span$ the pipe may buckle for a shaped Iaunchway at the stern, from eccentric compressive loading. the descending pipeline is unsupported between the barge and the Lowering Barge Method sea bottom. However the reel can be controlled by a brake, and the pipe The lowering barge (Fig. 24] is controlled by a tensioner, so as to sometinles used in calm, shallow keep the descending pipeline in waters to minimize the submerged sufficient tension to prevent equipment in the lowering system. In overstress in bending. its simplest form it consists of two identia.al catamaran barges, each LIMITATION serving alternately the fabrication element and the a;owering None of the common methods element of the system. described here can readily and safely Each barge has twin hulls, install long, large-diameter rigidly connected through overhead pipeline inavery deep water (say 50 SPE-2278 10 MARINE PIPE LAYINGMETHODS

Assembly way

Overbend f r ~

rted S n —Anchor Lines Stinger 7 Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/68FM/All-68FM/SPE-2278-MS/2063248/spe-2278-ms.pdf/1 by guest on 25 September 2021 Sag Bend

~T ./, ,. /\. ,..,. . ..’.,

Fig. 23 - Conventional lay barge method, with straight stinger and no tension.

Fig. 24 - A-frame lowering barges,

Pipe Reel

t -— v

Forward Tension

Pipeline Pull-off Line

Fig. 25 - Reel barge method, using tension to. keep pipe stress acceptable. SPl?-227fl------JOLLY---—. DWYER-. .-—-. 1

miles of 42-inch pipe in 500 feet). impracticable for either purpose at The ultimate limitation in any barge some point. The drilling industry laying or floating tie-in system is a has already provided the answer for need to lower the pipe froyt t;: station keeping, by the use of surface without overstressing dynamic positioning equipment, Its an unacceptable degree. If the pipe ability to produce adequate thrust to is to be one solid piece of metal meet high tension requirements from end to end, all joints must be remains to be proved. welded. Whether the pipeline “ A further problem with the lay

fabricated joint by joint on the si~~ barge is the need to be a stable Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/68FM/All-68FM/SPE-2278-MS/2063248/spe-2278-ms.pdf/1 by guest on 25 September 2021 or brought to location in long platform under a wide range of sea sections to be joined at intervals, and weather conditions. Once again present-day methods require welding the drilling industry has pointed the at the surface, with the concomitant way, by giving us the semisubmersible necessity to lower the welded joint vessel with its inherently good sea- safely to the sea floor. All keeping qualities. applicable methods suffer at this A combination of these solutions point because pipe stress may become was suggested as long ago as 1965, in excessive somewhere in the lowering the concept of a semisubmersible2~~y process. The question is whether barge for deep water (Fig. this limitation can be overcome, or Recent articles in the offshore trac’~ possibly bypassed. journals now report that similar systems are under serious SOLUTIONS consideration, indicating that technology is already capable of The statement of a problem solving the problems discussed here. sometimes leads almost halfway to the solution, There are two problems Tight Joints which make present day methods unsuitable for deepwater pipelining: If flanges may be used (today’s control of the descending section in pipeline thinking does not accept surface methods, and assurance of a them wholeheartedly], a strong case tight joint in underwater methods. can be made for the bottom pull method, with the tie-ins made on the Descending Pipe Control sea floor. The technique can be engineered to reduce the pull to a In the lay barge method, direct tow and to minimize the problems of mechanical support of the descending positioning and aligning the ends. pipe has reached the stage of wagging :~~ remaining problem is to make up the dog, and efforts are now being flanged joint. Present-day bent toward sh~~~ening or eliminatin~ methods would employ divers, but with stingers. most promising large pipe the working conditions possibility appears to be further become extremely difficult even in development of the tension sys;;g shallow water, and ultimately exceed which has recently been added to the safe limits of human physiology lay barge method. In fact, the reel in de~p water. Completely automated barge depends almost entirely on mechanical systems, engineered tension to keep pipe stress within specifically around performance tolerable limits. If the pipe is requirements for the joint itself and large and has a high submerged for rornotecontrol of the jointing weight, there are practical limits to process (whether fro~ the surface or the amount of tension that can be from a submersible), may provide an applied, whether at the barge or ultimate answer. CertainZyigomghg~ through the pipe. The weight may be todayts developments point relieved to some clegreoby pontooning direction (Fig. 27). or by furnishing other auxiliary If the pipeline must be solid support, these techniques metal throughout some welding increase the cor,lplexityof the system technique is needed. The problen~sof rindpose operational difficulties. raising the pipe and lowering it Additional problems for the lay again make surface tie-in unsuitable. barge in deep water are the vessel Until recently no form of underwater positioning system and the tension welding was suitable either. Wet transfer system. Conventional welds could not begin to meet mooring equipment becomes pipeline specifications, and dry 12 MARINE PIPE LAYINGMETHODS SPE-2278

Tie-in Point Tilting Pipe transfer Rack- LF~ Pivot r. * ~ v

v

Dynamic Positioning Units 1’ Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/68FM/All-68FM/SPE-2278-MS/2063248/spe-2278-ms.pdf/1 by guest on 25 September 2021

. .. . . ‘.

Fig. 26 - Semisubmersible lay barge with pivoting la~lnchway.

A

Mooring Lines

\

r ““~ Maneuvering Cables -

~ -~

,.

*“ Fig. 27 - Unmanned tethe red vehicle tie -in method,

Air Hoses and — Welding Leads

)-

......

Fig. 28 - Dry welding chamber tie -in method. SPE-2278----- . . JOLLY DWYER 13

welds were an unknown art. This potential: the tension lay barge condition has changed radically with with stabilization; and the bottom the recent advances in underwater dry tow method with underwater tie-ins. weldi~.g$and it is now possible for technology to provide a satisfactory REFERBNCIX tie-in technique for pipe strings on I the ocean bottom. A complete listing of all ~he Very long pipe sections can be pertinent material on marine pzpe- strung along the right of way in ad- laying would run to many pages. The vance. The necessary tie-in equip- various trade journals do an excel-

ment can be mounted on a small barge lent job of repo;ting the state of Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/68FM/All-68FM/SPE-2278-MS/2063248/spe-2278-ms.pdf/1 by guest on 25 September 2021 and can be taken quiclclyfrom one lo- the art as it develops. Any good cation to the next (Fig. 28). Tie- literature searc?lcan produce worth- ins can.be deferred until the weather while articles from the sources is favorable, and if it turns bad listed below. during the operation, a partially Books which even touch on the welded joint can be abandoned without subject are rare, and generally not serious hazard to the p~peline. up to date. The proceedings and The tie-in depth Imitations are journals of the professional soci- a function of human physiology, and eties sometimes carry detailed tech- t’le probability of a completely nical papers on specific pipelaying automated system seems remote. operations and techniques. Still, welded tie-ins at 200 feet are feasible today, and tie-ins at 500 Trade Journals feet appear well within the limitations of human physiology. Oil G Gas Journal Offshore There may be serious question of Pipe Line Industry Ocean Industry exceeding 1000 feet in th;ed~~:: World Oil Dock and Harbour future but practical Pipeline Engineer Authority investigators and experienced diving firms are working ~;rd to force a Pulling Systems breakthrough. it comes, I physiology may suddenly outstrip General technology once more. I Aside from the metallurgical and “Design and Construction Practices of physiological considerations, several Offshore Pipelines’’,-J.L.Krieg; practical problems surround the ASCE Proceedings, Feb. 19, 1962 concept, such as: dewateri]lg flooded “Designing, Laying and Maintaining pipe ends; equalizing interior pipe Underwater Pipelines:,-M. J. Lamb pressure with chamber pressure; and Pipeline Engifieer,,December1966 maintaining the pressure balance. ~’SubmarineAqueducts ~eliver Water to Each such problem has a number of Venezuelan Islands” - F. R. Sherma possible solutions, some more and D.R.Miller; Civil Engineerin& promising than others. It may March, 1961 ultimately require some experimental “Submarine Pipeline in Australia” - work to develop a suitable system, L.C.Wellman; The Military EngineeT and will require at least a few trial Julv-Aumst 1367 operations to eliminate all the bugs. “NaphthaOUse~ to Submerge Submarine Pipeline” - R. Burnett; Pipeline CONCLUSION Engineer, October 1964 With serious drilling a~lr:${ Laying Systems underway or even completed in I of 1000 feet and more, the time is “Hostile Environments Spur New Tech- ripe for development of a pipelaying niques, Equipment” - W. Gard ad system which will provide economical W. Bauerschlag; Ocean Industry, marine pipelines of all sizes in deep November 1966 water$ to offset the high costs of “Just Ahead: Greater Depths, Larger drilling and producing in these Pipe...Are Todayts Lay Barges depths. A careful examination of the Big Enough for Them?” - economic feasibility must be made in Oil ~ ——Gas Journal, December 12, all cases, but the technology is =6 available today to implement two candidate concepts which show good 14 MARINE PIPE LAYING METHODS SPE-227 Special Systems I “Laying Pipe in the North Sea” - J.F. Lynch; Offshore$ Junet 1966 “Unreeling Pipe from a Spool” - Pi e Line Industr flunm~n’~DeVl *e5%%ce %E. tions in 600-Foot Waterf’- R. W. Scott; World Oil; February 23, ~— Downloaded from http://onepetro.org/SPEATCE/proceedings-pdf/68FM/All-68FM/SPE-2278-MS/2063248/spe-2278-ms.pdf/1 by guest on 25 September 2021