METHOD AND MEANS FOR LAYING SUBMARINE PIPE LINES FOR OIL AND GAS TRANSPORT IN SEA AREAS

摘要

1431971 Laying submarine pipe lines S HEIEN 11 July 1973 [12 July 1972] 33115/73 Heading F2P In a method for laying submarine pipe lines, at least one pipe 2 together with at least three supporting cables 4 are surrounded with a casing 5 spaced from the pipe or pipes and the space between the casing and the pipe or pipes is filled with ballasting material before the pipe line is fed from laying means on a vessel. Preferably the ballasting material is fed into the easing through at least three tubes 8 which together with the cables 4 establish a winding former for winding casing forming elements, from winding means 6, therearound. The ballasting material may be concrete with additives for controlling the setting time in accordance with the depth of water and the speed of laying or it can be sand and fine gravel into which a cement grounting can be forced through perforated tubes incorporated in the pipe line. In another embodiment (Fig. 3, not shown) the pipes and the cables are fed through an opening in a rotating table on the laying vessel and the table carries spools containing the casing forming elements which as the table rotates are formed into the outer casing. The table may be mounted to compensate for up and down movements of the vessel. One construction of pipe line wall is shown in Fig. 4 which comprises pipes 11 surrounded by helically wound steel wire 22, steel band 21, nylon reinforced P.V.C. sheet 20, epoxy 23 and aluminium band 19.