CA1210598A - Method of launching long pipelines - Google Patents
Method of launching long pipelinesInfo
- Publication number
- CA1210598A CA1210598A CA000408480A CA408480A CA1210598A CA 1210598 A CA1210598 A CA 1210598A CA 000408480 A CA000408480 A CA 000408480A CA 408480 A CA408480 A CA 408480A CA 1210598 A CA1210598 A CA 1210598A
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- CA
- Canada
- Prior art keywords
- pipeline
- line
- water
- seaward
- vessel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Pipeline Systems (AREA)
- Laying Of Electric Cables Or Lines Outside (AREA)
- Electric Cable Installation (AREA)
- Rigid Pipes And Flexible Pipes (AREA)
Abstract
Abstract of the Disclosure A long pipeline is constructed at an on-shore site and then launched into a body of water. A tension force is maintained on the pipeline during launching to hold the pipeline off the floor of the body of water.
Description
12~059~
This invention relates generally to methods of launchin~ pipelines from an on-shore site into a body of water and of maintaining the pipeline above a floor of the body of water during the launching procedure.
The construction of off-shore oil or gas production facilities often requires the placement of a long pipeline on or near the ocean floor, for example, to connect a satellite well to a central producing platform.
The most common way of manufacturing the pipelines and placing them on the ocean floor is to construct the pipeline on a lay barge and to lower the constructed pipeline from the lay barge onto the ocean floor as the pipeline is constructed.
In some situations, however, it is not possible to construct the pipeline on a lay barge and simultaneously lower it onto the ocean floor because of the severe environmental conditions present. This is often the case when production facilities are being constructed in the North Sea area. Also, some flowline bundles are too comple~ to construct on a lay barge.
It has been proposed that an entire pipeline be constructed at an on-shore construction site and subsequently be launched from the on-shore construction site and into a body of water and then towed through the body of water to the installation site.
In some geographic locations particular problems 1~10~i98 sliding along the cable in the rearward direction. If this occurs, the overall main body will merely oscillate back and forth on a section of the ca~le including the tracks rather than sliding forward in the manner described in the above recited Reichman et al patent.
Another problem which has been found to occur when utilizing the continuously engaging cable gripping mechanism associated with the inner tubular segment in the apparatus described above occurs when the cable itself is one which includes external rings. In this case, as the inner tubular sleeve slides forward, its gripping mechanism tends to pull the cable rings together causing the latter to bunch up. Since this cable mechanism is located within and near the front of the overall apparatus body, the buildup of cable rings tends to inhibit forward movement of the main body. While the gripping mechanism associated with the outer sliding sleeve also has the tendency to cause the cable rings to build up, this latter gripping mechanism is disposed behind the apparatus body and hence does not inhibit forward movement of the main body by such a buildup.
In view of the foregoing, it is one object of the present invention to provide a cable following apparatus of the general type described in the above recited Reichman et al patent but one which does not result in the problems described above.
A more specific object of the present invention is to overcome these problems by providing a cable following apparatus with a cable grippïng mechanism which is capable of releasably , . ,~
~2~0~98 ",~
engaging an associated cable in a controlled fashion.
Still a more specific object of the present invention is to provide a cable following apparatus of the particular type described in the Reichman et al patent recited above, but one which utilizes a forwardmost gripping mechanism movable between a ca~le gripping position and a non-gripping position in appropriate synchronism with its associated segment or sleeve for eliminating the previously described problems associated with a continuously engaging cable gripping mechanism.
Yet a more specific object of the present invention is to provide a cable following apparatus having both a for~ard and rearward gripping mechanism of the type just recited.
As will be described in more detail hereinafter, the overall cable following apparatus disclosed herein is one which includes a main body having first and second segments, preferably cylindrical sleeves, interconnected for limited slidable movement relative to one another. The main body is supported to a given cable such that alternating sliding movement of the two segments in the forward direction causes the main body to slide forward along the cable. The means for supporting the main body includes cable gripping means connected with the first sliding segment and mov-able between a first position in engagement with the cable for preventing the first segment from sliding along the cable and a second position out of engagement with the cable. The overall apparatus also includes means for causing the first and second body segments to slide alternately in the forward direction and means cooperating with this last-mentioned means for maintaining ~21~S98 -3a-the gripping means in its cable engaging first position during sliding movement of the second body segment and in its second position out of engagement with the cable during sliding move-ment of the first segment. In one embodiment of the overall apparatus, only one of the sliding segments includes a movable cable gripping means, e.g., the first segment as recited. In a lZ10598 tow cables are kept above the ocean floor so as to prevent problems created by the drag of tow cables on the ocean floor.
Yet another object of the present invention is the pro-vision of methods for launching long pipelines wherein thepipeline will be launched at relatively high speeds to take advantage of tide changes.
And another object of the present invention is the pro-vision of methods for launching pipelines at high launching speeds wherein the launching speeds are controllable through a braking system.
Other and further objects, features and advantages of the presnt invention will be readily apparent to those skilled in the art upon a reading of the following disclo-sure when taken in conjunction with the accompanying draw-ings.
Brief Description of the Drawings FIGS. 1-5 comprise a sequential series of schematic plan drawings illustrating the method of the present inven-tion.
FIG. 6 is a schematic elevation view of a pipelinebeing towed in a catenary fashion between a leading tow ves-sel and a trailing tow vessel.
FIG. 7 is a side elevation view of a pipeline system
This invention relates generally to methods of launchin~ pipelines from an on-shore site into a body of water and of maintaining the pipeline above a floor of the body of water during the launching procedure.
The construction of off-shore oil or gas production facilities often requires the placement of a long pipeline on or near the ocean floor, for example, to connect a satellite well to a central producing platform.
The most common way of manufacturing the pipelines and placing them on the ocean floor is to construct the pipeline on a lay barge and to lower the constructed pipeline from the lay barge onto the ocean floor as the pipeline is constructed.
In some situations, however, it is not possible to construct the pipeline on a lay barge and simultaneously lower it onto the ocean floor because of the severe environmental conditions present. This is often the case when production facilities are being constructed in the North Sea area. Also, some flowline bundles are too comple~ to construct on a lay barge.
It has been proposed that an entire pipeline be constructed at an on-shore construction site and subsequently be launched from the on-shore construction site and into a body of water and then towed through the body of water to the installation site.
In some geographic locations particular problems 1~10~i98 sliding along the cable in the rearward direction. If this occurs, the overall main body will merely oscillate back and forth on a section of the ca~le including the tracks rather than sliding forward in the manner described in the above recited Reichman et al patent.
Another problem which has been found to occur when utilizing the continuously engaging cable gripping mechanism associated with the inner tubular segment in the apparatus described above occurs when the cable itself is one which includes external rings. In this case, as the inner tubular sleeve slides forward, its gripping mechanism tends to pull the cable rings together causing the latter to bunch up. Since this cable mechanism is located within and near the front of the overall apparatus body, the buildup of cable rings tends to inhibit forward movement of the main body. While the gripping mechanism associated with the outer sliding sleeve also has the tendency to cause the cable rings to build up, this latter gripping mechanism is disposed behind the apparatus body and hence does not inhibit forward movement of the main body by such a buildup.
In view of the foregoing, it is one object of the present invention to provide a cable following apparatus of the general type described in the above recited Reichman et al patent but one which does not result in the problems described above.
A more specific object of the present invention is to overcome these problems by providing a cable following apparatus with a cable grippïng mechanism which is capable of releasably , . ,~
~2~0~98 ",~
engaging an associated cable in a controlled fashion.
Still a more specific object of the present invention is to provide a cable following apparatus of the particular type described in the Reichman et al patent recited above, but one which utilizes a forwardmost gripping mechanism movable between a ca~le gripping position and a non-gripping position in appropriate synchronism with its associated segment or sleeve for eliminating the previously described problems associated with a continuously engaging cable gripping mechanism.
Yet a more specific object of the present invention is to provide a cable following apparatus having both a for~ard and rearward gripping mechanism of the type just recited.
As will be described in more detail hereinafter, the overall cable following apparatus disclosed herein is one which includes a main body having first and second segments, preferably cylindrical sleeves, interconnected for limited slidable movement relative to one another. The main body is supported to a given cable such that alternating sliding movement of the two segments in the forward direction causes the main body to slide forward along the cable. The means for supporting the main body includes cable gripping means connected with the first sliding segment and mov-able between a first position in engagement with the cable for preventing the first segment from sliding along the cable and a second position out of engagement with the cable. The overall apparatus also includes means for causing the first and second body segments to slide alternately in the forward direction and means cooperating with this last-mentioned means for maintaining ~21~S98 -3a-the gripping means in its cable engaging first position during sliding movement of the second body segment and in its second position out of engagement with the cable during sliding move-ment of the first segment. In one embodiment of the overall apparatus, only one of the sliding segments includes a movable cable gripping means, e.g., the first segment as recited. In a lZ10598 tow cables are kept above the ocean floor so as to prevent problems created by the drag of tow cables on the ocean floor.
Yet another object of the present invention is the pro-vision of methods for launching long pipelines wherein thepipeline will be launched at relatively high speeds to take advantage of tide changes.
And another object of the present invention is the pro-vision of methods for launching pipelines at high launching speeds wherein the launching speeds are controllable through a braking system.
Other and further objects, features and advantages of the presnt invention will be readily apparent to those skilled in the art upon a reading of the following disclo-sure when taken in conjunction with the accompanying draw-ings.
Brief Description of the Drawings FIGS. 1-5 comprise a sequential series of schematic plan drawings illustrating the method of the present inven-tion.
FIG. 6 is a schematic elevation view of a pipelinebeing towed in a catenary fashion between a leading tow ves-sel and a trailing tow vessel.
FIG. 7 is a side elevation view of a pipeline system
2~ supported by a plurality of ground engaging movable support means.
FIG. 8 is a front elevation view of the system of FIG.
7 taken along line 8-8 of FIG. 7.
FIG. 9 is an exploded view of an alternative fcrm of ground engaging support means which includes a floatatian means so that the support means will float once it is dis-engaged from the pipeline.
FIG. 10 is a graph describing the buoyancy of the sys-tem of FIG. 9 in relation to the depth of submergence of the float.
FIG. 11 i5 a schematic plan view illustrating several alternative methods of retrieving the floating support means ~210S98 \
of FIG. 9 after they are disengaged from the pipeline.
Detailed Descri tion of the Preferred Embodiment .. . P . ._ ..
The methods of the present invention are particularly adapted for use with a pipeline system and for use with subsequent methods of towing such a pipeline.
Referring now to FIGS. 7 and 8, a pipeline system 10 n,ncludes a pipeline 12 having a plurality of chain weights 14 attached thereto. As can be seen in ~IG. 6, the pipeline system 10 also includes a leading pipeline sled assembly 16 defining a seaward end of pipeline 12 t and includes a trailing pipeline sled assembly 18 defining a landward end of pipeline 12. Pipeline 12 itself has a positive buoyancy. ~Chain weight 14 givesthe entire system 10 a negative buoyancy, so that in the absence of any lifting forces from outside sourcespipeline system 10 will assume a position with pipeline 12 floating off bottom and chain weight 14 engaging the bottom of body of water ~0 .
As shown in FIGS. 7 and 8, the pipeline system 10 is supported at an on-shore construction site by a plurality of ground engaging support means 20 which are spaced along a length of the pipeline system 10. The support means 20 are connected together by a support connecting line 22 which may be a steel cable. The connecting line 22 may be a continuous cable being attached at intermediate points to the various support means 20, or it may be comprised of a plurality of cable segments having their ends attached to adjacent support means 20.
The support means 20 are movable relative to the ground surface so that when the pipeline system 10 is towed into the ocean, support means 20 will move with the pipeline system 10.
~2~0S98 that the soil initially surrounding the cable is usually relatively free of rocks ~ince the cable as originally installed was most likely placed in an open trench back-filled with soil. This, of course, makes it easier to ream around the cable by means of water jets or the lïke. Both the water under pressure and the hydraulic fluid, preferably oil, can be portably ~rought to station 10. As illustrated in Figure 1, overall apparatus 16 includes a source of high pressure water, that is, a water tank generally indicated at 24 and an electrically powered water pump 26 for providing water jets for reaming around the soil.
The apparatus also includes a hydraulic pump 28 along with a supply of hydraulic fluid 30 and suitable control valves generally indicated at 32 in Figure 1, all of which are provided for powering the cable follower. All of these components, that is, the source of high pressure water and the hydraulic compon-ents can be carried to the site on a truck 34.
With the exception of cable follo~er 20 and the specific way in which the cable follower is controlled to slide along cable 14, the overall appara~us 16 and the intended way in which it is used may be identical in structure and function to the overall apparatus described in the previously recited Reichman et al patent. Moreover, as will be pointed out hereinafter, the cable follower 20 disclosed herein is similar or may be identical in most respects to the cable follower described in the Reichman et al patent. The primary differences between the two reside in the utilization of an improved cable gripping arrangement comprising part of the present cable follower, as indicated above.
While this particular arrangement will be described in detail ~2~0598 hereinafter, the other components of apparatus 16 including those comprising part of ca~le follower 2a will be only briefly discussed unless more detailed discussions are necessary to an understanding of the improved ca~le gripping arrangement. For a more detailed description of those components only briefly discussed herein reference is specifically made to the Reichman et al patent.
Turning now to Figures 2-4, attention is specifically directed to cable follower 20 and the way the latter operates to slidably move along and ream around cable 14. ~o this end, the cable follower can be separated into three functional components, (i) a main body or drive mechanism 36 which responds to external hydraulic forces to move along cable 14, (ii~ rearward and forward gripping arrangements 38 and 39 for interconnecting the main body or drive mech.anism to the cable such that the entire cable follower slidably moves along the length of the cable in a forward direction from one end of the latter to its other end, and (iii) means 40 in the form of a nozzle bearing front end cap arrangement for receiving a supply of high pressure water or other suitable liquid and for converting the latter to a number of high pressure fluid jets so as to ream or otherwise loosen the soil surrounding the cable.
As seen in Figure 2 in conjunction with.Figures 3 and 4, main body 36 of cable. follo~er 20 takes th.e form of an open ended cylinder which with the aid of arrangements 38 and 39 to be discussed below is concentrically positioned around cable 14.
Main body 36 includes an outer sleeve 42 including a rearward .. ~, ~OS98 -7a-section 44 and a diametrically larger forward section 46. The rearward section includes an outer tuhular segment 44a and a shorter segment 44b concentrically positioned against the inner surface of outer segment 44a a predetermined distance inwardly from the forwardmost end of the latter. In this way, the inner segment defines a radially inwardly directed and forwardly facing annular shoulder 48. The two segments 44a and 44~ are interconnected in any suitable manner, for example by means of circumferentially spaced roll pins, two of which are indicated at 50. The two sections of outer sleeve 36/ that is sections 44 and 46, are interconnected by an adapter barrow 52 which extends partially into the front end of segment 44a to provide a radially inwardly extending and rearwardly ~,.. .
1210~;98 would not be possible for a typical launch vessel to reach that location because there is insufficient draft to float the launch vessel. The main buoy 52 is located at a posi-tion in body of water 30 sufficient to allow a launch ves-r~ sel to approach main buoy 52.
The main launching line 48 is provided with sufficient buoyancy means 56 to hold main launching line 48 above the floor 54 of body of water 30. It will be appreciated by those skilled in the art that the buoyancy means 50 may either be separate detachable elements attached to an other-wise non-buoyant line 48, or the line 48 may be constructed in such a manner and of such materials that the line 48 has an inherent buoyancy.
Also illustrated in FIG. 1 is the high tide mark 58 of body of water 30. The present invention is particularly adapted to launching the pipeline system 10 at high tide, and is adapted for launching at high speeds so that the en-tire laun~hing procedure can be accomplished while the body of water 30 is at or substantially near its high tide mark 58.
Preferably, support means 20 with runners 24 having wooden skids 25 running on tallowed rails 26 and 28 are utilized so that a known friction force is provided between the support means 20 and the rails 26 and 28 to apply a retarding force on pipeline 12 sufficient to hold it in tension and hold it above the ocean floor as the pipeline 12 is towed into the body of water. When that system is used there is no need to initially attach a retarding line to the landward end of the pipeline 12.
If, however, a wheeled support means 86 like that shown in FIG. 9 is used, it may be necessary to attach a retard-ing line 60 (see FIG. 1) to the landward end 18 of pipeline system 10 and to the landward end of the support connecting line 22. Retarding line 60 is mounted upon a retarding winch 62. This retarding line 60 is then used to hold pipe-line system 10 in tension as it is towed into the body of water.
Referring now to FIG. 2, the pipeline system 10 has ~2~5~8 g includes a series of innermost outer surfaces 86, the previously recited annular shoulder 72, 74 and annular opening 80 as well as an outermost outex surface 90.
The two sleeves together, that is, oute.r sleeve 42 and inner sleeve 60, define annular spaces 92 and 94 which, as will be seen hereinafter, respectively correspond in function to the spaces 62 and 6Q in the cable follower disclosed in the above recited Reichman et al patent. More specifically, the annular spaces 92, 94 are adapted to receive hydraulic fluid under pressure in a sequential, controlled manner for causing the overall tubular body 36 to move in a forward direction. To this end, the outer sleeve 42 includes a series of passageways connecting the annular spaces to the remote supply 30 of hydraulic fluid described with respect to Figure 1. For a detailed discussion of these passages and the way they interconnect the annular spaces to the hydraulic fluid supply, reference is made to the previously recited Reichman et al patent. For reasons to be discussed hereinafter, the annular opening 80 is maintained in fluid communication with the annular space 92 by means of a series of circumferentially spaced ports 100.
Before turning to the cable gripping arrangements 38 and 39, attention is briefly directed to means 40 which, as stated previously, serves as a nozzle beari~.g front end cap arrangement for receiving a s.upply of high pressure water or other suitable liquid so as to convert the latter to a number of high pressure fluid jets for reaming or otherwise loosening the soil around the cable. Since this particular arrangement could be identical ~Z~0598 -lQ~
to its counterpart in the previously recited Reichman et al patent and since it does not per se form part o~ the present invention, it will not be described any further herein. Rather reference is made to the Reichman et al patent.
Turning specifically to Figure 3 in conjunction with Figure 2 attention is directed to cable gripping arrangement 38. This arrangement may be identical to the cable gripping arrangement lQ6 in the Reichman et al patent and hence will not be described in detail herein. It suffices to say that this arrangement is connected with and at the rearward end of outer sleeve 42 for continuously engaging cable 14 in a way which allows the outer sleeve to slide along the cable in the forward direction only.
Referring now to Figure 4 in conjunction with Figure 2, attention is directed to ca~le gripping arrangement 39 which is designed in accordance with the present invention and which is provided for engaging and disengaging cable 14 in a controlled fashion to be described below. Arrangement 39 includes three gripping members disposed within and equally circumferentially spaced around the forwardmost section 64 of inner sleeve 60. One of these gripping members is illustrated in Figure 2 at 102. Gripping member 102 includes an elongated arm 104 which ext~nds generally parallel with sleeve section 64 and which is connected at its forwardmost end with the forwardmost end of section 64 by suitable means such as roll pin 105. Arm 104 is spaced radially inwardly from the inner surface 84 of sleeve section 64 to define an axially extend-ing channel lQ6 thereb~tween. At the same time, arm 104 is somewhat flexible so that its rearwardmost, otherwise free end ~%l~g8 -lOa-is radially movable with respect to surface 84. Gripping member lQ2 also includes a gripper lQ8 connected by suitable means such as roll pin 110 and flat head screws 112 to the otherwise free rearward end of arm 104. As seen in Figure 2, this gripper includes radially inwardly extending teeth 114 and, for reasons to be discussed below, an outwardly extending, inclined cam surface 116.
The gripping member just described is one of three such members forming part of overall gripping arrangement 39, as stated above.
The other two gripping members may ~e 1~0~98 Cnnected between the landward end 18 of pipeline system 10 and the trailing tow vessel 76.
Then, trailing tow Yessel 76 applies a tensional re-tarding force to trailing tow line 80 to hold pipeline sys-5 tem 10 abo~e the floor 54 of body of water 30, and the sea-going retarding line means 74 is disconnected from the pipe-line system 10.
A leading tow vessel 82 is then connected to seaward end 16 of pipeline system 10 by a leading tow line 84 and I0 the pipeline launch line 64 is then disconnected from the pipeline system 10. At that point, the pipeline system 10 has the appearance shown in FIG~ 6 where it is suspended in a catenary fashion between leading tow vessel 82 and trail-ing tow vessel 76.
FIG. 9 illustrates an alternative manner of construc-tion of the suppoxt means. The support means of FIG. 9 is designated by the numeral 86, and is a floating support means 86. The floating support means 86 includes a struc-tural frame 88 having a saddle member 90 extending upwardly therefrom for engagement with pipeline 12. ~ttached to the frame 88 are a plurality of wheels 92 for engagement with the rails 26 and 28. It will be understood by those skilled in the art that skids or runners such as runners 22 could be substituted for the wheels 92.
Attached to the support means 86 is a float 94. The float 94 is preferably a toroidal shaped inflatable elasto-meric member. The flaat 94 may be an innertube from a pneu-matic tire or the like, and thus is relatively inexpensive.
The float 94 is attached to the frame 88 by an annular :: 30 wooden support piece 96. Float 94 is attached to support piece 96 by a plurality of straps 98. The support piece 96 is itself attached to frame 88 by a plurality of brackets : 100 the lower ends of which are welded to frame 88 and the : upper ends of which are bolted to wooden support piece 96.
:~ 35 As can be seen in FIG. 9, the toroidal float 94 fits around the saddle member 90.
Referring again to FIGS. 7 and 8, it is seen that each of the support means thereshown, supports a portion of the weight of the pipeline 12 and also supports one of the chain weights 14 which is piled up on top of the support means 20.
Similarly, the chain weight 14 is layed on top of the wooden support piece 96 of support means 86.
Each of the Ifloats 94 has a buoyancy greater than a combined weight of the float 94 plus the support means 86 to which it is àttached, and less than a combined weight of the float 94, plus the support means 86 to which it is at-tached, plus the portion of the total weight of pipeline system 10 supported by the support means 86, so that when the portion of the total weight of pipeline system 10 car-ried initially by support means 86 is removed from the sup-port means 86, the support means 86 will float to the sur-face of body of water 30.
As can be understood by viewing FIGS. 7 and 8, once the pipeline system 10 is in the body of water 30, the support means 86 will begin to submerge. As soon as suppor~ means 86 has moved slightly downward away from the pipeline 12, the only portion of pipeline system 10 then being supported by the support means 86 will be the weight of chain weight 14. As the depth of submergence of support means 86 below pipeline 12 increases, the portion of chain weight 14 being supported by the support means 86 will also decrease.
Thus, the float 94 preferably has a buoyancy less than a combined weight of the float 94, plus the support means 86, plus the chain weight 14, so that so long as the sup-port means 86 is supporting a substantial portion of the chain weight 14, the support means 86 will be held under water.
When using an inflatable elastomeric float like the float 94, the overall design of the system must take into account the fact that as the inflatable elastomeric float 94 is submerged to deeper depths within the body of water, the external pressures acting upon the inflatable float in-crease thus decreasing the volume of water displaced by the float and thus decreasing the buoyancy of the float. For any given inflatable elastomeric float attached to a support means having a fixed submerged weight, it is possible to sùbmerge the assembled float and support means to a depth such that the buoyancy of the float is decreased to a value less than the total weight of the float and the support means, so that the float is no longer capable of buoying the support means and at that point the entire assembly will sink to the bottom of the body of water. Thus, the design of the system must be such that the float 94 will not be submerged to this critical depth during the process of launching the pipeline.
An example of such a design is illustrated in FIG. 10, which is a graph plotting the weight supported by float 94, and the buoyancy of the float 94, as a function af the depth to which the float is submerged.
In FIG. 10, the horizontal axis represents the submer-gence depth of the float 94 and the vertical axis is scaledin pounds and both weight and buoyancy are plotted on the vertical axis.
The curve 102 on FIG. 10 represents the buoyancy of float 94 as a function of depth of submergence. The posi-tion of curve 102 may be moved, for example, to the posi-tion shown in dotted lines, by varying the inflation pres-sure of float 94. It can be seen that for the particular example plotted in FIG. 10, the buoyancy of the float at the surface is equal to 334 pounds. A second curve 104 of FIG. 10 is a plot of the total of the weight of the support means 86, the float 94, and the portion of weight chain 14, if any, supported by support means 86 for a given submer-gence depth of float 94.
For a pipeline system 10 like that disclosed in the present application, the chain weight 14 has a length of 6.8 feet and a weight of about 18.4 pounds per foot in salt water, so that the chain weight 14 has a total weight of approximately 125 pounds. The combined weights of the sup-port means 86 and the float 94 attached thereto is approxi-mately 220 pounds. It will be understood that in the embo-diment disclosed herein the weight of the float 94 itself is negligible so it can be said that the support means 86 weighs approximately 220 pounds. It is, however, possible that , 12~0S98 applied to shoulders 48 and 72. Since the outer sleeve cannot move rearwardly, these forces cause the inner sleeve to move forward an increment to the position illustrated in Figure 5E. In this regard, it should be noted that the entire cable gripping arrange-ment 39 moves with the inner sleeve without engaging the cable.
As the inner sleeve moves forward, the space 92 is closed causing any fluid therein to be forced back to its source.
The foregoing has been a description of how the outer sleeve and inner sleeve each moves an increment in the forward direction.
This procedure is repeated in order to move the overall cable follower along cable 14. The precise way in which the hydraulic fluid is applied alternatively into the annular spaces may be the same as in the Reichman et al patent or, in any event, it could be readily provided in view of the teachings in that patent. In this regard, Figure 2 includes a diagrammatic illustration of the cont:rols for accomplishing this. These controls do differ slightly from those in the Reichman et al patent. One difference worth noting resides in the utilization of a time delay between the time pressure is released from spaces 92, 134 and the time hydraulic fluid is applied to space 94. This time delay ~approximately ten seconds) is provided to allow the grippers to move from their cable engaging positions to their non-engaging positions.
Having described cable follower 20 both structurally and opera-tionally, attention is directed to a modified cable follower 20Q
which is designed in accordance with a second, preferred embodiment of the present invention and which is illustrated in ~210~;98 -15~
Figures 6-9. As ~ill he seen helow, cahle follower 200 serves the same purpose as cable follower 2~ in overall system 10 and can be readily su~stituted for the previously described cable follower in this system. As will also be seen, the cable follower 200 is significantly less complicated fr~m a mechanical stand-point than cable follower 20 and, at the same time, it utilizes two cable engaging and disengaging mechanisms rather than just one as in the cable follower 20. In this way, there is never a cable gripping mech.anism in sli.ding engagement with an associated cable as the overall cable follower slides along the latter.
Referring now to Figures 6-9, and specifically Figure 7, cable follower 200 is shown including an outermost support tube or body segment 202 which is closed at its back end ~y means of a rear flange 204 and associated pilot spacer 2Q6. The front end of support tube 202 carries a nozzle bearing front end cap arrange-ment generally indicated at 208 which is similar in function to means 40 forming part of the cable follower 20. Arrangement 2Q8 is shown best in Figures 7 and 8 including a forwardmost nozzle guard 210 containing a plurality of spray nozzles 212, some of which may be of the deflected type such as the bottom one illustrated in Figure 8. Arrangement 208 also includes a manifold 214 connecting nozzle guard 210 to a front flange 216 and associa-ted front pilot spacer 218 which close the front end of support tube 2a2. Suitable cap screws 22a and 222 are utilized to connect these various components making up arrangement 208 together. As stated above, this overall nozzle. bearing front end cap arrange-ment serves th.e same purpos.e as means 4n in cable follower 20 and the corresponding means in the previously recited Reichman ~2~0S~8 -15a-et al patent. Thus, a suitable arrangement of conduit generally indicated at 24 serves to carry the source of fluid spray, e.g., water, to the nozzles from an appropriate source, for example one on truck 34 shown in Figure 1.
As best seen in Figure 7, a front cable guiding tube 226 is disposed partially within tube 2G2 and partially outside the front end of the latter in a fixed position relative to and connected with front flange 216, around a cable 227. For reasons to be discussed below, the cable guiding tube 226 is disposed at the bottom end of tube 202 and includes an ~-2~0s98 and engaging the lower end of the chain weight, the float 94 attached to support means 86 has a buoyancy greater than the combined weight of the float 94 and the support means 86. This eliminates any possibility of the float 94 being submerged into the second negative buoyancy zone 118.
Referring now to FIG. 11, several methods are there schematically illustrated for retrieving the floating sup-port means 86 after the pipeline system 10 has been launched.
As previously described, one of the final steps in the launching of the pipeline system 10 is the disconnection of pipeline launch line 64 from the seaward end of pipeline system 10. At the same time the support means launch line 68 is disconnected from support connecting line 22. If a non-floating type of support means such as support means 20 is utilized, then when it is disconnected from barge 42, the support connecting line 22 and all of the attached sup-port means 20 will sink to the ocean floor. If, however, floating support means such as support means 86 are utilized, then the support connecting line 22 and all of the support means 86 will float to the surface of the body of water 30.
The floating support means 86 and support connecting line 22 may then be retrieved in any one of several manners.
FIG. 11 simultaneously illustrates these various methods.
A first manner of retrieving the floating support means 86 is to connect the support connecting line 22 to a retrieving winch 120 located on shore. Then the support connecting line 22 may be reeled into shore by the winch 120 thus also pulling the floating support means 86 onto shore.
A second method of retrieving the floating support 30 means 86 is to connect small boats, such as boats 122 and 124, to the support connecting line 22 and the floating sup-port means 86 and to tow the support connecting line 22 and floating support means 86 to shore.
A third method of retrieving is illustrated on the up-35 per portion of FIG. 11 wherein a boat 126 is anchored in the body of water 30 by anchor lines 128 and the support con-necting line 22 is connected to a retrieving winch 130 on ~, ~, . ..
~210S~8 the boat 126. Then the support connecting line 22 is reeled into the boat 126 by means of winch 130 thus pulling the support connecting line 22 and floating support means 86 into the boat 126.
Thus it is seen that the present invention readily achieves the ends and advantages mentioned as well as those inherent therein. While certain specific arrangements of parts and steps have been illustrated for the purposes of the present disclosure, numerous changes in the construc-tion and arrangement of steps and parts may be made by those skilled in the art, which changes are encompassed within the scope and spirit of the present invention as defined by the appended claims.
FIG. 8 is a front elevation view of the system of FIG.
7 taken along line 8-8 of FIG. 7.
FIG. 9 is an exploded view of an alternative fcrm of ground engaging support means which includes a floatatian means so that the support means will float once it is dis-engaged from the pipeline.
FIG. 10 is a graph describing the buoyancy of the sys-tem of FIG. 9 in relation to the depth of submergence of the float.
FIG. 11 i5 a schematic plan view illustrating several alternative methods of retrieving the floating support means ~210S98 \
of FIG. 9 after they are disengaged from the pipeline.
Detailed Descri tion of the Preferred Embodiment .. . P . ._ ..
The methods of the present invention are particularly adapted for use with a pipeline system and for use with subsequent methods of towing such a pipeline.
Referring now to FIGS. 7 and 8, a pipeline system 10 n,ncludes a pipeline 12 having a plurality of chain weights 14 attached thereto. As can be seen in ~IG. 6, the pipeline system 10 also includes a leading pipeline sled assembly 16 defining a seaward end of pipeline 12 t and includes a trailing pipeline sled assembly 18 defining a landward end of pipeline 12. Pipeline 12 itself has a positive buoyancy. ~Chain weight 14 givesthe entire system 10 a negative buoyancy, so that in the absence of any lifting forces from outside sourcespipeline system 10 will assume a position with pipeline 12 floating off bottom and chain weight 14 engaging the bottom of body of water ~0 .
As shown in FIGS. 7 and 8, the pipeline system 10 is supported at an on-shore construction site by a plurality of ground engaging support means 20 which are spaced along a length of the pipeline system 10. The support means 20 are connected together by a support connecting line 22 which may be a steel cable. The connecting line 22 may be a continuous cable being attached at intermediate points to the various support means 20, or it may be comprised of a plurality of cable segments having their ends attached to adjacent support means 20.
The support means 20 are movable relative to the ground surface so that when the pipeline system 10 is towed into the ocean, support means 20 will move with the pipeline system 10.
~2~0S98 that the soil initially surrounding the cable is usually relatively free of rocks ~ince the cable as originally installed was most likely placed in an open trench back-filled with soil. This, of course, makes it easier to ream around the cable by means of water jets or the lïke. Both the water under pressure and the hydraulic fluid, preferably oil, can be portably ~rought to station 10. As illustrated in Figure 1, overall apparatus 16 includes a source of high pressure water, that is, a water tank generally indicated at 24 and an electrically powered water pump 26 for providing water jets for reaming around the soil.
The apparatus also includes a hydraulic pump 28 along with a supply of hydraulic fluid 30 and suitable control valves generally indicated at 32 in Figure 1, all of which are provided for powering the cable follower. All of these components, that is, the source of high pressure water and the hydraulic compon-ents can be carried to the site on a truck 34.
With the exception of cable follo~er 20 and the specific way in which the cable follower is controlled to slide along cable 14, the overall appara~us 16 and the intended way in which it is used may be identical in structure and function to the overall apparatus described in the previously recited Reichman et al patent. Moreover, as will be pointed out hereinafter, the cable follower 20 disclosed herein is similar or may be identical in most respects to the cable follower described in the Reichman et al patent. The primary differences between the two reside in the utilization of an improved cable gripping arrangement comprising part of the present cable follower, as indicated above.
While this particular arrangement will be described in detail ~2~0598 hereinafter, the other components of apparatus 16 including those comprising part of ca~le follower 2a will be only briefly discussed unless more detailed discussions are necessary to an understanding of the improved ca~le gripping arrangement. For a more detailed description of those components only briefly discussed herein reference is specifically made to the Reichman et al patent.
Turning now to Figures 2-4, attention is specifically directed to cable follower 20 and the way the latter operates to slidably move along and ream around cable 14. ~o this end, the cable follower can be separated into three functional components, (i) a main body or drive mechanism 36 which responds to external hydraulic forces to move along cable 14, (ii~ rearward and forward gripping arrangements 38 and 39 for interconnecting the main body or drive mech.anism to the cable such that the entire cable follower slidably moves along the length of the cable in a forward direction from one end of the latter to its other end, and (iii) means 40 in the form of a nozzle bearing front end cap arrangement for receiving a supply of high pressure water or other suitable liquid and for converting the latter to a number of high pressure fluid jets so as to ream or otherwise loosen the soil surrounding the cable.
As seen in Figure 2 in conjunction with.Figures 3 and 4, main body 36 of cable. follo~er 20 takes th.e form of an open ended cylinder which with the aid of arrangements 38 and 39 to be discussed below is concentrically positioned around cable 14.
Main body 36 includes an outer sleeve 42 including a rearward .. ~, ~OS98 -7a-section 44 and a diametrically larger forward section 46. The rearward section includes an outer tuhular segment 44a and a shorter segment 44b concentrically positioned against the inner surface of outer segment 44a a predetermined distance inwardly from the forwardmost end of the latter. In this way, the inner segment defines a radially inwardly directed and forwardly facing annular shoulder 48. The two segments 44a and 44~ are interconnected in any suitable manner, for example by means of circumferentially spaced roll pins, two of which are indicated at 50. The two sections of outer sleeve 36/ that is sections 44 and 46, are interconnected by an adapter barrow 52 which extends partially into the front end of segment 44a to provide a radially inwardly extending and rearwardly ~,.. .
1210~;98 would not be possible for a typical launch vessel to reach that location because there is insufficient draft to float the launch vessel. The main buoy 52 is located at a posi-tion in body of water 30 sufficient to allow a launch ves-r~ sel to approach main buoy 52.
The main launching line 48 is provided with sufficient buoyancy means 56 to hold main launching line 48 above the floor 54 of body of water 30. It will be appreciated by those skilled in the art that the buoyancy means 50 may either be separate detachable elements attached to an other-wise non-buoyant line 48, or the line 48 may be constructed in such a manner and of such materials that the line 48 has an inherent buoyancy.
Also illustrated in FIG. 1 is the high tide mark 58 of body of water 30. The present invention is particularly adapted to launching the pipeline system 10 at high tide, and is adapted for launching at high speeds so that the en-tire laun~hing procedure can be accomplished while the body of water 30 is at or substantially near its high tide mark 58.
Preferably, support means 20 with runners 24 having wooden skids 25 running on tallowed rails 26 and 28 are utilized so that a known friction force is provided between the support means 20 and the rails 26 and 28 to apply a retarding force on pipeline 12 sufficient to hold it in tension and hold it above the ocean floor as the pipeline 12 is towed into the body of water. When that system is used there is no need to initially attach a retarding line to the landward end of the pipeline 12.
If, however, a wheeled support means 86 like that shown in FIG. 9 is used, it may be necessary to attach a retard-ing line 60 (see FIG. 1) to the landward end 18 of pipeline system 10 and to the landward end of the support connecting line 22. Retarding line 60 is mounted upon a retarding winch 62. This retarding line 60 is then used to hold pipe-line system 10 in tension as it is towed into the body of water.
Referring now to FIG. 2, the pipeline system 10 has ~2~5~8 g includes a series of innermost outer surfaces 86, the previously recited annular shoulder 72, 74 and annular opening 80 as well as an outermost outex surface 90.
The two sleeves together, that is, oute.r sleeve 42 and inner sleeve 60, define annular spaces 92 and 94 which, as will be seen hereinafter, respectively correspond in function to the spaces 62 and 6Q in the cable follower disclosed in the above recited Reichman et al patent. More specifically, the annular spaces 92, 94 are adapted to receive hydraulic fluid under pressure in a sequential, controlled manner for causing the overall tubular body 36 to move in a forward direction. To this end, the outer sleeve 42 includes a series of passageways connecting the annular spaces to the remote supply 30 of hydraulic fluid described with respect to Figure 1. For a detailed discussion of these passages and the way they interconnect the annular spaces to the hydraulic fluid supply, reference is made to the previously recited Reichman et al patent. For reasons to be discussed hereinafter, the annular opening 80 is maintained in fluid communication with the annular space 92 by means of a series of circumferentially spaced ports 100.
Before turning to the cable gripping arrangements 38 and 39, attention is briefly directed to means 40 which, as stated previously, serves as a nozzle beari~.g front end cap arrangement for receiving a s.upply of high pressure water or other suitable liquid so as to convert the latter to a number of high pressure fluid jets for reaming or otherwise loosening the soil around the cable. Since this particular arrangement could be identical ~Z~0598 -lQ~
to its counterpart in the previously recited Reichman et al patent and since it does not per se form part o~ the present invention, it will not be described any further herein. Rather reference is made to the Reichman et al patent.
Turning specifically to Figure 3 in conjunction with Figure 2 attention is directed to cable gripping arrangement 38. This arrangement may be identical to the cable gripping arrangement lQ6 in the Reichman et al patent and hence will not be described in detail herein. It suffices to say that this arrangement is connected with and at the rearward end of outer sleeve 42 for continuously engaging cable 14 in a way which allows the outer sleeve to slide along the cable in the forward direction only.
Referring now to Figure 4 in conjunction with Figure 2, attention is directed to ca~le gripping arrangement 39 which is designed in accordance with the present invention and which is provided for engaging and disengaging cable 14 in a controlled fashion to be described below. Arrangement 39 includes three gripping members disposed within and equally circumferentially spaced around the forwardmost section 64 of inner sleeve 60. One of these gripping members is illustrated in Figure 2 at 102. Gripping member 102 includes an elongated arm 104 which ext~nds generally parallel with sleeve section 64 and which is connected at its forwardmost end with the forwardmost end of section 64 by suitable means such as roll pin 105. Arm 104 is spaced radially inwardly from the inner surface 84 of sleeve section 64 to define an axially extend-ing channel lQ6 thereb~tween. At the same time, arm 104 is somewhat flexible so that its rearwardmost, otherwise free end ~%l~g8 -lOa-is radially movable with respect to surface 84. Gripping member lQ2 also includes a gripper lQ8 connected by suitable means such as roll pin 110 and flat head screws 112 to the otherwise free rearward end of arm 104. As seen in Figure 2, this gripper includes radially inwardly extending teeth 114 and, for reasons to be discussed below, an outwardly extending, inclined cam surface 116.
The gripping member just described is one of three such members forming part of overall gripping arrangement 39, as stated above.
The other two gripping members may ~e 1~0~98 Cnnected between the landward end 18 of pipeline system 10 and the trailing tow vessel 76.
Then, trailing tow Yessel 76 applies a tensional re-tarding force to trailing tow line 80 to hold pipeline sys-5 tem 10 abo~e the floor 54 of body of water 30, and the sea-going retarding line means 74 is disconnected from the pipe-line system 10.
A leading tow vessel 82 is then connected to seaward end 16 of pipeline system 10 by a leading tow line 84 and I0 the pipeline launch line 64 is then disconnected from the pipeline system 10. At that point, the pipeline system 10 has the appearance shown in FIG~ 6 where it is suspended in a catenary fashion between leading tow vessel 82 and trail-ing tow vessel 76.
FIG. 9 illustrates an alternative manner of construc-tion of the suppoxt means. The support means of FIG. 9 is designated by the numeral 86, and is a floating support means 86. The floating support means 86 includes a struc-tural frame 88 having a saddle member 90 extending upwardly therefrom for engagement with pipeline 12. ~ttached to the frame 88 are a plurality of wheels 92 for engagement with the rails 26 and 28. It will be understood by those skilled in the art that skids or runners such as runners 22 could be substituted for the wheels 92.
Attached to the support means 86 is a float 94. The float 94 is preferably a toroidal shaped inflatable elasto-meric member. The flaat 94 may be an innertube from a pneu-matic tire or the like, and thus is relatively inexpensive.
The float 94 is attached to the frame 88 by an annular :: 30 wooden support piece 96. Float 94 is attached to support piece 96 by a plurality of straps 98. The support piece 96 is itself attached to frame 88 by a plurality of brackets : 100 the lower ends of which are welded to frame 88 and the : upper ends of which are bolted to wooden support piece 96.
:~ 35 As can be seen in FIG. 9, the toroidal float 94 fits around the saddle member 90.
Referring again to FIGS. 7 and 8, it is seen that each of the support means thereshown, supports a portion of the weight of the pipeline 12 and also supports one of the chain weights 14 which is piled up on top of the support means 20.
Similarly, the chain weight 14 is layed on top of the wooden support piece 96 of support means 86.
Each of the Ifloats 94 has a buoyancy greater than a combined weight of the float 94 plus the support means 86 to which it is àttached, and less than a combined weight of the float 94, plus the support means 86 to which it is at-tached, plus the portion of the total weight of pipeline system 10 supported by the support means 86, so that when the portion of the total weight of pipeline system 10 car-ried initially by support means 86 is removed from the sup-port means 86, the support means 86 will float to the sur-face of body of water 30.
As can be understood by viewing FIGS. 7 and 8, once the pipeline system 10 is in the body of water 30, the support means 86 will begin to submerge. As soon as suppor~ means 86 has moved slightly downward away from the pipeline 12, the only portion of pipeline system 10 then being supported by the support means 86 will be the weight of chain weight 14. As the depth of submergence of support means 86 below pipeline 12 increases, the portion of chain weight 14 being supported by the support means 86 will also decrease.
Thus, the float 94 preferably has a buoyancy less than a combined weight of the float 94, plus the support means 86, plus the chain weight 14, so that so long as the sup-port means 86 is supporting a substantial portion of the chain weight 14, the support means 86 will be held under water.
When using an inflatable elastomeric float like the float 94, the overall design of the system must take into account the fact that as the inflatable elastomeric float 94 is submerged to deeper depths within the body of water, the external pressures acting upon the inflatable float in-crease thus decreasing the volume of water displaced by the float and thus decreasing the buoyancy of the float. For any given inflatable elastomeric float attached to a support means having a fixed submerged weight, it is possible to sùbmerge the assembled float and support means to a depth such that the buoyancy of the float is decreased to a value less than the total weight of the float and the support means, so that the float is no longer capable of buoying the support means and at that point the entire assembly will sink to the bottom of the body of water. Thus, the design of the system must be such that the float 94 will not be submerged to this critical depth during the process of launching the pipeline.
An example of such a design is illustrated in FIG. 10, which is a graph plotting the weight supported by float 94, and the buoyancy of the float 94, as a function af the depth to which the float is submerged.
In FIG. 10, the horizontal axis represents the submer-gence depth of the float 94 and the vertical axis is scaledin pounds and both weight and buoyancy are plotted on the vertical axis.
The curve 102 on FIG. 10 represents the buoyancy of float 94 as a function of depth of submergence. The posi-tion of curve 102 may be moved, for example, to the posi-tion shown in dotted lines, by varying the inflation pres-sure of float 94. It can be seen that for the particular example plotted in FIG. 10, the buoyancy of the float at the surface is equal to 334 pounds. A second curve 104 of FIG. 10 is a plot of the total of the weight of the support means 86, the float 94, and the portion of weight chain 14, if any, supported by support means 86 for a given submer-gence depth of float 94.
For a pipeline system 10 like that disclosed in the present application, the chain weight 14 has a length of 6.8 feet and a weight of about 18.4 pounds per foot in salt water, so that the chain weight 14 has a total weight of approximately 125 pounds. The combined weights of the sup-port means 86 and the float 94 attached thereto is approxi-mately 220 pounds. It will be understood that in the embo-diment disclosed herein the weight of the float 94 itself is negligible so it can be said that the support means 86 weighs approximately 220 pounds. It is, however, possible that , 12~0S98 applied to shoulders 48 and 72. Since the outer sleeve cannot move rearwardly, these forces cause the inner sleeve to move forward an increment to the position illustrated in Figure 5E. In this regard, it should be noted that the entire cable gripping arrange-ment 39 moves with the inner sleeve without engaging the cable.
As the inner sleeve moves forward, the space 92 is closed causing any fluid therein to be forced back to its source.
The foregoing has been a description of how the outer sleeve and inner sleeve each moves an increment in the forward direction.
This procedure is repeated in order to move the overall cable follower along cable 14. The precise way in which the hydraulic fluid is applied alternatively into the annular spaces may be the same as in the Reichman et al patent or, in any event, it could be readily provided in view of the teachings in that patent. In this regard, Figure 2 includes a diagrammatic illustration of the cont:rols for accomplishing this. These controls do differ slightly from those in the Reichman et al patent. One difference worth noting resides in the utilization of a time delay between the time pressure is released from spaces 92, 134 and the time hydraulic fluid is applied to space 94. This time delay ~approximately ten seconds) is provided to allow the grippers to move from their cable engaging positions to their non-engaging positions.
Having described cable follower 20 both structurally and opera-tionally, attention is directed to a modified cable follower 20Q
which is designed in accordance with a second, preferred embodiment of the present invention and which is illustrated in ~210~;98 -15~
Figures 6-9. As ~ill he seen helow, cahle follower 200 serves the same purpose as cable follower 2~ in overall system 10 and can be readily su~stituted for the previously described cable follower in this system. As will also be seen, the cable follower 200 is significantly less complicated fr~m a mechanical stand-point than cable follower 20 and, at the same time, it utilizes two cable engaging and disengaging mechanisms rather than just one as in the cable follower 20. In this way, there is never a cable gripping mech.anism in sli.ding engagement with an associated cable as the overall cable follower slides along the latter.
Referring now to Figures 6-9, and specifically Figure 7, cable follower 200 is shown including an outermost support tube or body segment 202 which is closed at its back end ~y means of a rear flange 204 and associated pilot spacer 2Q6. The front end of support tube 202 carries a nozzle bearing front end cap arrange-ment generally indicated at 208 which is similar in function to means 40 forming part of the cable follower 20. Arrangement 2Q8 is shown best in Figures 7 and 8 including a forwardmost nozzle guard 210 containing a plurality of spray nozzles 212, some of which may be of the deflected type such as the bottom one illustrated in Figure 8. Arrangement 208 also includes a manifold 214 connecting nozzle guard 210 to a front flange 216 and associa-ted front pilot spacer 218 which close the front end of support tube 2a2. Suitable cap screws 22a and 222 are utilized to connect these various components making up arrangement 208 together. As stated above, this overall nozzle. bearing front end cap arrange-ment serves th.e same purpos.e as means 4n in cable follower 20 and the corresponding means in the previously recited Reichman ~2~0S~8 -15a-et al patent. Thus, a suitable arrangement of conduit generally indicated at 24 serves to carry the source of fluid spray, e.g., water, to the nozzles from an appropriate source, for example one on truck 34 shown in Figure 1.
As best seen in Figure 7, a front cable guiding tube 226 is disposed partially within tube 2G2 and partially outside the front end of the latter in a fixed position relative to and connected with front flange 216, around a cable 227. For reasons to be discussed below, the cable guiding tube 226 is disposed at the bottom end of tube 202 and includes an ~-2~0s98 and engaging the lower end of the chain weight, the float 94 attached to support means 86 has a buoyancy greater than the combined weight of the float 94 and the support means 86. This eliminates any possibility of the float 94 being submerged into the second negative buoyancy zone 118.
Referring now to FIG. 11, several methods are there schematically illustrated for retrieving the floating sup-port means 86 after the pipeline system 10 has been launched.
As previously described, one of the final steps in the launching of the pipeline system 10 is the disconnection of pipeline launch line 64 from the seaward end of pipeline system 10. At the same time the support means launch line 68 is disconnected from support connecting line 22. If a non-floating type of support means such as support means 20 is utilized, then when it is disconnected from barge 42, the support connecting line 22 and all of the attached sup-port means 20 will sink to the ocean floor. If, however, floating support means such as support means 86 are utilized, then the support connecting line 22 and all of the support means 86 will float to the surface of the body of water 30.
The floating support means 86 and support connecting line 22 may then be retrieved in any one of several manners.
FIG. 11 simultaneously illustrates these various methods.
A first manner of retrieving the floating support means 86 is to connect the support connecting line 22 to a retrieving winch 120 located on shore. Then the support connecting line 22 may be reeled into shore by the winch 120 thus also pulling the floating support means 86 onto shore.
A second method of retrieving the floating support 30 means 86 is to connect small boats, such as boats 122 and 124, to the support connecting line 22 and the floating sup-port means 86 and to tow the support connecting line 22 and floating support means 86 to shore.
A third method of retrieving is illustrated on the up-35 per portion of FIG. 11 wherein a boat 126 is anchored in the body of water 30 by anchor lines 128 and the support con-necting line 22 is connected to a retrieving winch 130 on ~, ~, . ..
~210S~8 the boat 126. Then the support connecting line 22 is reeled into the boat 126 by means of winch 130 thus pulling the support connecting line 22 and floating support means 86 into the boat 126.
Thus it is seen that the present invention readily achieves the ends and advantages mentioned as well as those inherent therein. While certain specific arrangements of parts and steps have been illustrated for the purposes of the present disclosure, numerous changes in the construc-tion and arrangement of steps and parts may be made by those skilled in the art, which changes are encompassed within the scope and spirit of the present invention as defined by the appended claims.
Claims (24)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of launching a pipeline from an on-shore site into a body of water, said method comprising the steps of:
connecting a launch vessel to a seaward end of said pipeline;
moving said launch vessel seaward and thereby tow-ing said pipeline into said body of water; and applying a retarding force to said pipeline and thereby maintaining a tension force in said pipeline, as said pipeline is towed into said body of water, sufficient to hold said pipeline above a floor of said body of water.
connecting a launch vessel to a seaward end of said pipeline;
moving said launch vessel seaward and thereby tow-ing said pipeline into said body of water; and applying a retarding force to said pipeline and thereby maintaining a tension force in said pipeline, as said pipeline is towed into said body of water, sufficient to hold said pipeline above a floor of said body of water.
2. The method of claim 1, further comprising:
prior to said connecting step, supporting said pipeline at said on-shore site with a plurality of ground engaging movable support means spaced along a length of said pipeline, said support means of said plurality of sup-port means being connected together by a support connecting line;
wherein said connecting step is further charac-terized as connecting said launch vessel also to a seaward end of said support connecting line; and wherein said moving and towing step is further characterized as also towing said support connecting line into said body of water.
prior to said connecting step, supporting said pipeline at said on-shore site with a plurality of ground engaging movable support means spaced along a length of said pipeline, said support means of said plurality of sup-port means being connected together by a support connecting line;
wherein said connecting step is further charac-terized as connecting said launch vessel also to a seaward end of said support connecting line; and wherein said moving and towing step is further characterized as also towing said support connecting line into said body of water.
3. The method of claim 2, wherein:
said supporting step is further characterized as supporting said pipeline at said on-shore site with a plu-of sleds having runners slidably engaging a pair of parallel rails extending into said body of water, said sleds being said ground engaging support means.
said supporting step is further characterized as supporting said pipeline at said on-shore site with a plu-of sleds having runners slidably engaging a pair of parallel rails extending into said body of water, said sleds being said ground engaging support means.
4. The method of claim 2, further comprising:
prior to said connecting step, positioning an intermediate floating vessel off-shore from said site, de-ploying a main launching line seaward from a seaward end of said intermediate floating vessel, and providing suffi-cient buoyancy means to hold said main launching line above said floor of said body of water;
wherein said connecting step includes the steps of:
connecting a pipeline launch line between a laundered end of said intermediate floating vessel and said seaward end of said pipeline;
connecting a support means launch line be-tween said landward end of said intermediate floating vessel and said seaward end of said support connecting line; and connecting a seaward end of said main launch-ing line to said launch vessel.
prior to said connecting step, positioning an intermediate floating vessel off-shore from said site, de-ploying a main launching line seaward from a seaward end of said intermediate floating vessel, and providing suffi-cient buoyancy means to hold said main launching line above said floor of said body of water;
wherein said connecting step includes the steps of:
connecting a pipeline launch line between a laundered end of said intermediate floating vessel and said seaward end of said pipeline;
connecting a support means launch line be-tween said landward end of said intermediate floating vessel and said seaward end of said support connecting line; and connecting a seaward end of said main launch-ing line to said launch vessel.
5. The method of claim 4, wherein:
said step of applying a retarding force to said pipeline includes a step of providing a predetermined fric-tional force between said support means and the ground suf-ficient to maintain said tension force in said pipeline.
said step of applying a retarding force to said pipeline includes a step of providing a predetermined fric-tional force between said support means and the ground suf-ficient to maintain said tension force in said pipeline.
6. The method of claim 5, wherein:
said step of applying a retarding force to said pipeline further includes the steps of:
connecting a retarding line means to a land-ward end of said pipeline before said landward end of said pipeline enters said body of water; and applying a retarding force to said retarding line means, thereby maintaining said tension force in said pipeline.
said step of applying a retarding force to said pipeline further includes the steps of:
connecting a retarding line means to a land-ward end of said pipeline before said landward end of said pipeline enters said body of water; and applying a retarding force to said retarding line means, thereby maintaining said tension force in said pipeline.
7. The method of claim 4, wherein:
said step of applying a retarding force to said pipeline includes the steps of:
connecting a retarding line means to landward ends of said pipeline and said support connecting line;
and applying a retarding force to said retarding line, thereby maintaining a tension force in said pipe-line and said support connecting line as said pipeline and support connecting line are towed into said body of water.
said step of applying a retarding force to said pipeline includes the steps of:
connecting a retarding line means to landward ends of said pipeline and said support connecting line;
and applying a retarding force to said retarding line, thereby maintaining a tension force in said pipe-line and said support connecting line as said pipeline and support connecting line are towed into said body of water.
8. The method of claim 4, further comprising:
connecting a trailing tow line between a trailing tow vessel and a landward end of said pipeline after said landward end of said pipeline is towed into said body of water; and applying a tensional retarding force to said trailing tow line and said pipeline by means of said trail-ing tow vessel to hold said pipeline above said floor of said body of water.
connecting a trailing tow line between a trailing tow vessel and a landward end of said pipeline after said landward end of said pipeline is towed into said body of water; and applying a tensional retarding force to said trailing tow line and said pipeline by means of said trail-ing tow vessel to hold said pipeline above said floor of said body of water.
9. The method of claim 8, further comprising:
connecting a leading tow line between a leading tow vessel and said seaward end of said pipeline after said is towed into said body of water; and disconnecting said pipeline launch line from said pipeline.
connecting a leading tow line between a leading tow vessel and said seaward end of said pipeline after said is towed into said body of water; and disconnecting said pipeline launch line from said pipeline.
10. The method of claim 1, wherein:
said connecting step is further characterized as connecting a main launching line between said launch vessel and said seaward end of said pipeline; and said method further comprises a step of providing sufficient buoyancy means attached to said main launching line to hold said main launching line above said floor of said body of water.
said connecting step is further characterized as connecting a main launching line between said launch vessel and said seaward end of said pipeline; and said method further comprises a step of providing sufficient buoyancy means attached to said main launching line to hold said main launching line above said floor of said body of water.
11. The method of claim 10, said method further com-prising:
prior to said connecting step, positioning an in-termediate floating vessel off-shore from said site and de-ploying said main launching line seaward from a seaward end of said intermediate floating vessel; and wherein said connecting step is further charac-terized as connecting a seaward end of said main launching line to said launch vessel and connecting a pipeline launch line between a landward end of said intermediate floating vessel and said seaward end of said pipeline.
prior to said connecting step, positioning an in-termediate floating vessel off-shore from said site and de-ploying said main launching line seaward from a seaward end of said intermediate floating vessel; and wherein said connecting step is further charac-terized as connecting a seaward end of said main launching line to said launch vessel and connecting a pipeline launch line between a landward end of said intermediate floating vessel and said seaward end of said pipeline.
12. The method of claim 11, wherein:
said step of moving said launch vessel seaward is further characterized as moving said launch vessel seaward, when said body of water is at substantially its high tide mark, with a speed sufficient to tow said pipeline entirely into said body of water while said body of water is at substantially its high tide mark.
said step of moving said launch vessel seaward is further characterized as moving said launch vessel seaward, when said body of water is at substantially its high tide mark, with a speed sufficient to tow said pipeline entirely into said body of water while said body of water is at substantially its high tide mark.
13. The method of claim 1, wherein:
said step of applying a retarding force to said pipeline includes a step of providing a predetermined frictional factor between said support means and the ground which creates a retarding force dividing said step of moving said launched vessel.
said step of applying a retarding force to said pipeline includes a step of providing a predetermined frictional factor between said support means and the ground which creates a retarding force dividing said step of moving said launched vessel.
14. The method of claim 13, wherein:
said supporting step is further characterized as supporting said pipeline at said on-shore site with a plurality of sleds having runners slidably engaging a pair of parallel rails extending into said body of water, said sleds being said ground engaging support means.
said supporting step is further characterized as supporting said pipeline at said on-shore site with a plurality of sleds having runners slidably engaging a pair of parallel rails extending into said body of water, said sleds being said ground engaging support means.
15. The method of claim 14, wherein:
said step of providing a predetermined frictional force includes steps of providing wooden skids said runners for engagement with said rails and applying tallow on said rails so that a wood on tallowed steel friction factor is provided between said runners and said rails.
said step of providing a predetermined frictional force includes steps of providing wooden skids said runners for engagement with said rails and applying tallow on said rails so that a wood on tallowed steel friction factor is provided between said runners and said rails.
16. The method of claim 13, wherein:
said step of applying a retarding force to said pipeline further includes the steps of:
connecting a retarding line means to a land-ward end of said pipeline before said landward end of said pipeline enters said body of water; and applying a retarding force to said retarding line means, thereby maintaining said tension force in said pipeline.
said step of applying a retarding force to said pipeline further includes the steps of:
connecting a retarding line means to a land-ward end of said pipeline before said landward end of said pipeline enters said body of water; and applying a retarding force to said retarding line means, thereby maintaining said tension force in said pipeline.
17. The method of claim 1, wherein:
said step of applying a retarding force to said pipeline includes the steps of:
connecting a retarding line means to a land-ward end of said pipeline; and applying a retarding force to said retarding line, thereby maintaining a tension force in said pipe-line as said pipeline is towed into said body of water.
said step of applying a retarding force to said pipeline includes the steps of:
connecting a retarding line means to a land-ward end of said pipeline; and applying a retarding force to said retarding line, thereby maintaining a tension force in said pipe-line as said pipeline is towed into said body of water.
18. The method of claim 17, further comprising:
connecting a trailing tow line between a trailing tow vessel and said landward end of said pipeline after said landward end of said pipeline is towed into said body of water;
applying a tensional retarding force to said trailing tow line and said pipeline by means of said trail-ing tow vessel to hold said pipeline above said floor of said body of water; and disconnecting said retarding line means from said pipeline.
connecting a trailing tow line between a trailing tow vessel and said landward end of said pipeline after said landward end of said pipeline is towed into said body of water;
applying a tensional retarding force to said trailing tow line and said pipeline by means of said trail-ing tow vessel to hold said pipeline above said floor of said body of water; and disconnecting said retarding line means from said pipeline.
19. The method of claim 1, wherein:
said step of moving said launch vessel seaward is further characterized as moving said launch vessel seaward, when said body of water is at substantially its high tide mark, with a speed sufficient to tow said pipeline entirely into said body of water while said body of water is at sub-stantially its high tide mark.
said step of moving said launch vessel seaward is further characterized as moving said launch vessel seaward, when said body of water is at substantially its high tide mark, with a speed sufficient to tow said pipeline entirely into said body of water while said body of water is at sub-stantially its high tide mark.
20. A method of launching a pipeline from an on-shore site into a body of water, said method comprising the steps of:
supporting said pipeline at said on-shore site with a plurality of ground engaging movable support means spaced along a length of said pipeline, said means of said plurality of support means being connected together by a support connecting line;
attaching a retarding line to a landward end of each of said pipeline and said support connecting line;
positioning a shallow draft barge off-shore from said site;
deploying a main launching line seaward from a seaward end of said barge to a main buoy located at a posi-tion in said body of water where said body of water has a depth sufficient to allow a launch vessel to approach said main buoy, said main launching line being provided with suf-ficient buoyancy means to hold said main launching line above a floor of said body of water;
connecting a pipeline launch line between a land-ward end of said barge and a seaward end of said pipeline;
connecting a support means launch line between said landward end of said barge and a seaward end of said support connecting line;
connecting a seaward end of said main launching line to said launch vessel;
moving said launch vessel seaward and thereby tow-ing said pipeline and said support connecting line into said body of water;
applying a retarding force to said retarding line and thereby maintaining a tension force on said pipeline, as said pipeline is towed, sufficient to hold said pipeline above said floor of said body of water;
connecting a trailing tow line between a trailing tow vessel and said landward end of said pipeline after said landward end of said pipeline is towed into said body of water a distance such that said landward end of said pipe-line is at a position on said body of water having a depth sufficient to float said trailing tow vessel;
applying a tensional retarding force to said trailing tow line and said pipeline by means of said trail-ing tow vessel to hold said pipeline above said floor of said body of water;
disconnecting said retarding line means from said pipeline;
connecting a leading tow line between a leading tow vessel and said seaward end of said pipeline; and disconnecting said pipeline launch line from said pipeline.
supporting said pipeline at said on-shore site with a plurality of ground engaging movable support means spaced along a length of said pipeline, said means of said plurality of support means being connected together by a support connecting line;
attaching a retarding line to a landward end of each of said pipeline and said support connecting line;
positioning a shallow draft barge off-shore from said site;
deploying a main launching line seaward from a seaward end of said barge to a main buoy located at a posi-tion in said body of water where said body of water has a depth sufficient to allow a launch vessel to approach said main buoy, said main launching line being provided with suf-ficient buoyancy means to hold said main launching line above a floor of said body of water;
connecting a pipeline launch line between a land-ward end of said barge and a seaward end of said pipeline;
connecting a support means launch line between said landward end of said barge and a seaward end of said support connecting line;
connecting a seaward end of said main launching line to said launch vessel;
moving said launch vessel seaward and thereby tow-ing said pipeline and said support connecting line into said body of water;
applying a retarding force to said retarding line and thereby maintaining a tension force on said pipeline, as said pipeline is towed, sufficient to hold said pipeline above said floor of said body of water;
connecting a trailing tow line between a trailing tow vessel and said landward end of said pipeline after said landward end of said pipeline is towed into said body of water a distance such that said landward end of said pipe-line is at a position on said body of water having a depth sufficient to float said trailing tow vessel;
applying a tensional retarding force to said trailing tow line and said pipeline by means of said trail-ing tow vessel to hold said pipeline above said floor of said body of water;
disconnecting said retarding line means from said pipeline;
connecting a leading tow line between a leading tow vessel and said seaward end of said pipeline; and disconnecting said pipeline launch line from said pipeline.
21. The method of claim 20, wherein:
said step of moving said launch vessel seaward is further characterized as moving said launch vessel seaward, when said body of water is at substantially its high tide mark, with a speed sufficient to tow said pipeline and said support connecting line entirely into said body of water while said body of water is at substantially its high tide mark.
said step of moving said launch vessel seaward is further characterized as moving said launch vessel seaward, when said body of water is at substantially its high tide mark, with a speed sufficient to tow said pipeline and said support connecting line entirely into said body of water while said body of water is at substantially its high tide mark.
22. A method of launching a pipeline from an on-shore site into a body of water, said method comprising the steps of:
supporting said pipeline at said on-shore site with a plurality of sleds having runners with wooden skids slidably engaging a pair of parallel rails extending into said body of water, said sleds being spaced along a length of said pipeline and being connected together by a support connecting line;
positioning a shallow draft barge off-shore from said site;
deploying a main launching line seaward from a seaward end of said barge to a main buoy located at a posi-tion in said body of water where said body of water has a depth sufficient to allow a launch vessel to approach said main buoy, said main launching line being provided with suf-ficient buoyancy means to hold said main launching line above a floor of said body of water;
connecting a pipeline launch line between a land-ward end of said barge and a seaward end of said pipeline;
connecting a support means launch line between said landward end of said barge and a seaward end of said support connecting line;
connecting a seaward end of said main launching line to said launch vessel;
moving said launch vessel seaward and thereby towing said pipeline and said support connecting line into said body of water;
applying a retarding force to said pipeline as said pipeline is towed by providing a predetermined fric-tional force between said skids and said rails sufficient to maintain a tension force on said pipeline and to hold said pipeline above said floor of said body of water;
connecting a retarding line means to a landward end of said pipeline before said landward end of said pipe-line enters said body of water, and applying a retarding force to said retarding line means as said landward end of said pipeline is towed into said body of water thereby main-taining said tension force in said pipeline;
connecting a trailing tow line between a trailing tow vessel and said landward end of said pipeline after said landward end of said pipeline is towed into said body of water a distance such that said landward end of said pipe-line is at a position on said body of water having a depth sufficient to float said trailing tow vessel;
applying a tensional retarding force to said trailing tow line and said pipeline by means of said trail-ing tow vessel to hold said pipeline above said floor of said body of water;
disconnecting said retarding line means from said pipeline;
connecting a leading tow line between a leading tow vessel and said seaward end of said pipeline; and disconnecting said pipeline launch line from said pipeline.
supporting said pipeline at said on-shore site with a plurality of sleds having runners with wooden skids slidably engaging a pair of parallel rails extending into said body of water, said sleds being spaced along a length of said pipeline and being connected together by a support connecting line;
positioning a shallow draft barge off-shore from said site;
deploying a main launching line seaward from a seaward end of said barge to a main buoy located at a posi-tion in said body of water where said body of water has a depth sufficient to allow a launch vessel to approach said main buoy, said main launching line being provided with suf-ficient buoyancy means to hold said main launching line above a floor of said body of water;
connecting a pipeline launch line between a land-ward end of said barge and a seaward end of said pipeline;
connecting a support means launch line between said landward end of said barge and a seaward end of said support connecting line;
connecting a seaward end of said main launching line to said launch vessel;
moving said launch vessel seaward and thereby towing said pipeline and said support connecting line into said body of water;
applying a retarding force to said pipeline as said pipeline is towed by providing a predetermined fric-tional force between said skids and said rails sufficient to maintain a tension force on said pipeline and to hold said pipeline above said floor of said body of water;
connecting a retarding line means to a landward end of said pipeline before said landward end of said pipe-line enters said body of water, and applying a retarding force to said retarding line means as said landward end of said pipeline is towed into said body of water thereby main-taining said tension force in said pipeline;
connecting a trailing tow line between a trailing tow vessel and said landward end of said pipeline after said landward end of said pipeline is towed into said body of water a distance such that said landward end of said pipe-line is at a position on said body of water having a depth sufficient to float said trailing tow vessel;
applying a tensional retarding force to said trailing tow line and said pipeline by means of said trail-ing tow vessel to hold said pipeline above said floor of said body of water;
disconnecting said retarding line means from said pipeline;
connecting a leading tow line between a leading tow vessel and said seaward end of said pipeline; and disconnecting said pipeline launch line from said pipeline.
23. The method of claim 22, wherein:
said step of moving said launch vessel seaward is further characterized as moving said launch vessel seaward when said body of water is at substantially its high tide mark, with a speed sufficient to tow said pipeline and said support connecting line entirely into said body of water while said body of water is at substantially its high tide mark.
said step of moving said launch vessel seaward is further characterized as moving said launch vessel seaward when said body of water is at substantially its high tide mark, with a speed sufficient to tow said pipeline and said support connecting line entirely into said body of water while said body of water is at substantially its high tide mark.
24. The method of claim 22, wherein:
said step of moving said launch vessel seaward is further characterized as moving said launch vessel seaward at a substantially constant speed.
said step of moving said launch vessel seaward is further characterized as moving said launch vessel seaward at a substantially constant speed.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US31387381A | 1981-10-22 | 1981-10-22 | |
| US313,873 | 1981-10-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1210598A true CA1210598A (en) | 1986-09-02 |
Family
ID=23217526
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000408480A Expired CA1210598A (en) | 1981-10-22 | 1982-07-30 | Method of launching long pipelines |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS5877987A (en) |
| CA (1) | CA1210598A (en) |
| DK (1) | DK463082A (en) |
| NO (1) | NO823483L (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7862891B2 (en) | 2001-04-27 | 2011-01-04 | Conocophillips Company | Composite tether and methods for manufacturing, transporting, and installing same |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2602300A (en) * | 1950-07-13 | 1952-07-08 | Samuel V Collins | Apparatus for laying and retrieving pipe lines |
| JPS5470606A (en) * | 1977-11-16 | 1979-06-06 | Aoki Construction | Method of laying pipe on sea water and centering apparatus |
-
1982
- 1982-07-30 CA CA000408480A patent/CA1210598A/en not_active Expired
- 1982-10-19 DK DK463082A patent/DK463082A/en unknown
- 1982-10-19 NO NO823483A patent/NO823483L/en unknown
- 1982-10-20 JP JP57184417A patent/JPS5877987A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7862891B2 (en) | 2001-04-27 | 2011-01-04 | Conocophillips Company | Composite tether and methods for manufacturing, transporting, and installing same |
Also Published As
| Publication number | Publication date |
|---|---|
| DK463082A (en) | 1983-04-23 |
| JPS5877987A (en) | 1983-05-11 |
| NO823483L (en) | 1983-04-25 |
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| MKEX | Expiry |