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Showing papers on "Submarine pipeline published in 1975"


Patent
22 Jan 1975
TL;DR: In this paper, the authors present a system for purging water from a submerged pipeline including means for handling pipeline "pigs" (i.e., spheres, plug, or other device movable through a pipeline interior in sliding peripheral engagement therewith).
Abstract: Apparatus and methods for purging water from a submerged pipeline including means for handling pipeline "pigs" (ie, sphere, plug, or other device movable through a pipeline interior in sliding peripheral engagement therewith) In the system of the invention a pig launcher is attached at a first pipeline means end and a pig receiver is attached at a second, submerged pipeline means end The pig launcher is operable to propel a plurality of pig elements in sequence through the pipeline under the urging of pressurized gas in order to displace fluid and/or locate obstructions The pig receiver is arranged to exhaust such displaced fluid and receive and store the propelled pig elements The pig receiver may include a fluid discharge system for exhausting propulsion gas into the ambient water in response to the arrival of a pig element and thus provide means to signal such arrival The pig launcher may include a fluid discharge system for exhausting pressurized propulsion gas into the ambient water to signify a successful pig launch

33 citations


Journal ArticleDOI
TL;DR: In this article, an efficient solution technique for determination of the static equilibrium form of a cable or a pipeline suspended between the ocean floor and a laying barge or a stinger is presented.
Abstract: An efficient solution technique for determination of the static equilibrium form of a cable or a pipeline suspended between the ocean floor and a laying barge or a stinger is presented. Variations in bending stiffness, weight and buoyancy and forces due to ocean current are taken into account. The governing non-linear boundary value problem is transformed into a non-dimensional form such that the a priori unknown suspended length of the pipeline or cable acts as a scaling parameter. The numerical solution is then based on successive integrations. The application of the method is illustrated by the analysis of equilibrium curves and stresses in pipelines laid with or without the use of stingers and during abandon and recovery operations.

21 citations


Patent
10 Mar 1975
TL;DR: In this article, an offshore platform riser is attached to the platform in such a way as to provide thermal expansion and to permit detachment when an abnormal loading is encountered, and a submersible capsule is used for completing the joining of the pipeline and riser.
Abstract: Apparatus includes an offshore platform riser subtended by a joint chamber having port means for receiving a subsea pipeline and access means for a submersible capsule. The riser and chamber are attached to the platform in such manner as to provide for thermal expansion and to permit detachment when an abnormal loading is encountered. Platform winch means attached to cable means passing through the riser and chamber are used to pull an end of the pipeline into the chamber. Personnel utilizing the capsule then enter the chamber for completing the joining of the pipeline and riser. The joining and subsequent inspection operations are conducted at substantially atmospheric conditions in the chamber.

17 citations


Patent
23 Sep 1975
TL;DR: In this article, the authors describe a method for laying a submarine pipeline on the bed of a body of water, with a cable attached to the pipeline and a guide rope attached to it at intervals.
Abstract: The present invention relates to devices for laying submarine pipelines, in which the pipeline, associated with floats attached to it at intervals, the whole assembly being contrived in order to produce a certain buoyancy, is equipped with chains resting upon the bed of the body of water and performing the function of a guide rope. The weight of those parts of the chains extending between the bed of the body of water and the pipeline, maintains the latter submerged at a certain distance above the bed of the body of water and the pipeline can be towed, for example by means of a tug, without any risk of it being damaged by striking said bed. The improvement which forms the object of the invention consists in attaching the chains or their equivalent, for example cables, not merely to the pipeline itself, but also to the floats. This has the advantage that when the floats are released in order to lay the pipeline on the bed of the body of water, the chains are returned to the surface by the floats themselves and can therefore be readily recovered.

16 citations


Patent
09 Jul 1975
TL;DR: In this article, a geomagnetic measurement of the distance between a point and a pipeline is measured by an electromagnetic measurement and compared with an echo sounding measurement between measuring point and surface of overburden reveals the thickness of the latter.
Abstract: Pipes for the transport of oil or natural gas from offshore wells which are buried in trenches at the bottom of the sea are located and checked by a geomagnetic measurement. This establishes the location and the run of the pipeline. The distance between measuring point and pipeline is measured by an electromagnetic measurement. Comparison of the latter with an echo sounding measurement between measuring point and surface of overburden reveals the thickness of the latter. This system is a quick and reliable method of locating a buried pipeline. It also provides continuous readings of the thickness of the overburden and of any displacements. Individual pipeline sections can be identified by specific magnetic properties.

9 citations


01 Jan 1975
TL;DR: The offshore tracts presently under lease along the North Slope of Alaska are near shore, mostly in the zone of bottom-fast ice as mentioned in this paper, where engineering problems will be in a different category than those on land.
Abstract: With the Prudhoe Bay oil discovery in 1968, research into arctic processes began in earnest in North America. Now that oil and gas will be transported from the North Slope to more southerly consumers, environmental knowledge will be needed for economical production and transportation and to insure as little change in the landscape as possible. The environment is characterized by long, cold winters; short, cool summers; a long-lasting, ableit thin, snow cover; an ice cover over lakes, rivers, and the ocean for 8 to 9 mo. each year; tundra vegetation; permafrost; and a thin active layer. Although permafrost (as is now known) is present on the ocean bottom, it is thin, mobile sea-ice cover with its numerous, highly varied pressure ridges that is of major concern. The offshore tracts presently under lease along the North Slope of Alaska are near shore, mostly in the zone of bottom-fast ice. Artificial island structures have already been proven possible in shallow water. Still untried is exploration and production in the area of drifting pack ice, where engineering problems will be in a different category than those on land.

2 citations


Journal ArticleDOI
TL;DR: In this article, a rigorous design of offshore gas pipelines with simultaneous flow of liquids requires a point-to-point calculation to account for all the important variables in the system, and correlations were made to show the relationship between the multiphase models and these single-phase gas equations.
Abstract: INTERCOMP Resource Development and Engineering, Inc., and Pipe Line Technologists, Inc., demonstrated that a rigorous design of offshore gas pipelines with simultaneous flow of liquids requires a point-to-point calculation to account for all the important variables in the system. The concept of overall pipeline efficiency is acceptable for initial estimates and evaluation of operational problems. In the past, offshore gas pipelines with simultaneous flow of liquids have been undersized primarily because their initial design used single-phase gas-flow equations and failed to account for the effect of inclination on the flow efficiency. In other cases, the diameter was oversized to ensure maximum deliverability, as in the Red Snapper pipeline system which was submitted to the FPC in 1966 but was never built. Since many offshore designs used in the Panhandle A and the modified Panhandle equations, correlations were made to show the relationship between the multiphase models and these single-phase gas equations. These correlations showed that efficiency does not change with flow rate for horizontal lines but does change with liquid loading and underwater terrain.

2 citations