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.