NO821203L

NO821203L - LINEFOERINGSINNRETNING

Info

Publication number: NO821203L
Application number: NO821203A
Authority: NO
Inventors: Donald A Hayes; Lyle D Finn; Carl R Brinkmann
Original assignee: Exxon Production Research Co
Priority date: 1980-08-21
Filing date: 1982-04-13
Publication date: 1982-04-13
Also published as: BR8009101A; IT8149132A1; NO155059B; IT8149132A0; CA1162752A; JPS57501292A; EP0058159B1; ES8307961A1; WO1982000675A1; EP0058159A4; EP0058159A1; ES504851A0; MY8600687A; IT1171474B

Description

De foranstående problemer overvinnes ved å utforme lineavbøyningen i to deler: 1) en fast avbøyning i en retning som tilfredsstiller: klaringskravene i tårnet, og 2) en variabel avbøyning som opptrer ved omkretsen av tårnet for å fullføre den krevede totale avbøyning. Slike problemer fore-ligger ved føring av liner til bardunavstivede offshore olje-borings- og produksjonstårn fra deres vertikale orientering ved klem- og strekk- (spenn-) innretningene opp til toppen av tårnet og til sjøbunnforankringsfestene som omslutter tårnet i en stor avstand. Retningen for avstivningslinene er ikke nøyaktig kjent på grunn av uunngåelige tårnfeilinnrettinger ved installasjonen og forskyvning av sjøbunnfestene. Videre vil tårnbevegelse som kan opptre under storm kunne variere retningen for avstivningskablene om' flere grader. Til slutt-vi-1- en overfylling i tårnkonstruksjonen, brønnene og tilbe-hør nødvendiggjøre føring av avstivningskablene gjennom visse konstruksjonselementer fra en første indre avbøyning til en andre avbøyning ved omkretsen av tårnkonstruksjonen. The above problems are overcome by designing the line deflection in two parts: 1) a fixed deflection in a direction which satisfies: the clearance requirements in the tower, and 2) a variable deflection which occurs at the circumference of the tower to complete the required total deflection. Such problems exist when guiding liners to bardun-stiffened offshore oil drilling and production towers from their vertical orientation at the clamping and stretching (tensioning) devices up to the top of the tower and to the seabed anchorages that enclose the tower for a large distance. The direction of the bracing lines is not precisely known due to inevitable tower misalignments during installation and displacement of the seabed anchorages. Furthermore, tower movement that can occur during storms could vary the direction of the bracing cables by several degrees. Finally-we-1- an overflow in the tower structure, the wells and accessories necessitates routing the bracing cables through certain structural elements from a first internal deflection to a second deflection at the perimeter of the tower structure.

Innretningen ifølge foreliggende oppfinnelse løser dette problem på følgende måte. En første del som er festet på plass i tårnet bøyer linen i et første plan i en forutbe-stemt grad. En andre del som også er festet på plass på omkretsen av tårnet bøyer linen i det første plan hvis nødven-dig, og 'ogsåyavbøyer,.'".linen i en retning ut av det første plan. De faste relative stillinger for første og andre del bibeholder en stilling for linen som unngår enhver hindring i tårnet, og den andre del fullfører avbøyningen av linen ut av tårnet. The device according to the present invention solves this problem in the following way. A first part fixed in place in the tower bends the line in a first plane to a predetermined degree. A second part which is also fixed in place on the circumference of the tower bends the line in the first plane if necessary, and 'also deflects,'" the line in a direction out of the first plane. The fixed relative positions of the first and second part maintains a position for the line that avoids any obstruction in the tower, and the other part completes the deflection of the line out of the tower.

Den første del er en sko med en sporforsynt, krummet linekontaktflate og en hylse. Den andre del innbefatter en ytre fast husdel og en indre roterbar husdel. Den indre husdel inneholder linen og er utstyrt med en sporforsynt linekontaktflate og andre kontaktflater for tilpasning for alle lineretninger og krefter som er ventet. Lagerinnretnin-ger mellom husene tillater at det indre hus kan dreie seg og således øke størrelsen og variasjonen av potensielle lineav-bøyninger. Den indre flate til det indre hus kan ha en tre- The first part is a shoe with a grooved, curved line contact surface and a sleeve. The second part includes an outer fixed housing part and an inner rotatable housing part. The inner housing part contains the line and is equipped with a grooved line contact surface and other contact surfaces for adaptation for all line directions and expected forces. Bearing arrangements between the housings allow the inner housing to rotate and thus increase the size and variation of potential line deflections. The inner surface of the inner housing can have a wooden

Foreliggende oppfinnelse vedrører lineføringsinn-retninger, og spesielt lineføringsinnretninger som er anvend-bare for føring av liner som benyttes til å forankre marine bore- og produksjonskonstruksjoner. The present invention relates to line guiding devices, and in particular line guiding devices which are applicable for guiding lines which are used to anchor marine drilling and production structures.

Det er foreslått mange forskjellige utforminger for offshore plattformer for bruk som bore- og produksjonsplatt-former i dypt vann. Noen av disse plattformutforminger er oppbygget for å tillate plattformen å beveges som reaksjon på bølgekrefter. En slik utforming er bardunavstivede tårn. I avstivningssystemer for et bardunavstivet tårn blir avstiv-ningsbarduner eller liner ført fra plattformen til forankringssystemet på sjøbunnen. Avstivningslinene blir festet til plattformdekket ved kabelgripeinnretninger i en linestrekkinn-retning og passerer rundt avbøyningsinnretninger eller lede-ruller plassert under vannflaten. Avstivningslinene føres så utover i en vinkel fra vertikalretningen til forankringssystemet. Many different designs have been proposed for offshore platforms for use as drilling and production platform forms in deep water. Some of these platform designs are built to allow the platform to move in response to wave forces. One such design is bardun braced towers. In bracing systems for a bar dune-braced tower, bracing bar dunes or lines are led from the platform to the anchoring system on the seabed. The bracing lines are attached to the platform deck by cable gripping devices in a line stretching direction and pass around deflection devices or guide rollers placed below the water surface. The bracing lines are then led outwards at an angle from the vertical direction to the anchoring system.

I den senere tid er såvel skivetypen som skotypen av lineavbøyningsinnretninger blitt foreslått for bruk ved en tårnavstivningslinetilslutning. Hver type må imidlertid kunne tilpasses for feilinnrettinger av tårnet og forankrings-pelene for å minimalisere slitasje og tretthet for avstivningslinene. Avbøyningsinnretninger av sviveltypen er blitt foreslått til dette formål. I de tilfeller hvor strekkinn-retninger er plassert i det indre av tårnkonstruksjonen bør en avbøyningsinnretning bli plassert i det indre av tårnet direkte under strekkinnretningen. Bruken av en avøyningsinn-retning av sviveltypen ville resultere i en interferens mellom line og indre konstruksjonselementer. Problemet vil så være å avbøye en stram line fra det indre av tårnet i retning av forankringssystemet uten interferens fra konstruksjonselementer i tårnet. Retningen for forankringssystemene mot av-bøyningsinnretningen behøver ikke være helt eksakt kjent, og videre kan denne variere med tiden da tårnet kan rotere. En In recent times, both the disc type and the shoe type of line deflection devices have been proposed for use with a tower bracing line connection. However, each type must be able to accommodate misalignments of the tower and anchor piles to minimize wear and fatigue of the bracing lines. Deflection devices of the swivel type have been proposed for this purpose. In cases where tensioning devices are placed in the interior of the tower structure, a deflection device should be placed in the interior of the tower directly below the tensioning device. The use of a swivel-type de-eyeing device would result in interference between the line and internal structural members. The problem will then be to deflect a tight line from the interior of the tower in the direction of the anchoring system without interference from structural elements in the tower. The direction of the anchoring systems towards the deflection device does not need to be known exactly, and furthermore this can vary with the time when the tower can rotate. One

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slik avbøyning må ikke ødelegge linenvpå grunn}av utstrakt statisk eller syklisk belastning eller ved slitasje, og klaringskravene i selve tårnet må imøtekommes. such deflection must not destroy the line due to extensive static or cyclic loading or wear and tear, and the clearance requirements in the tower itself must be met.

Claims

1. Device for use with line guidance, characterized in that it comprises a part fixed in place for bending the line in a selected plane and in addition for deflecting the line in a direction out of said selected plane.

2. Device according to claim 1, characterized in that the part comprises an outer housing and an inner housing which is rotatable in relation to the outer housing, which inner housing has a grooved line contact surface.

3. Device according to claim 2, characterized in that the inner surface of the inner housing forms a three-sided pyramidal shape, where one of the corners of the pyramid forms said track surface, which side opposite to the track is curved for cooperation with slack line.

4. Device for use when guiding a line, characterized in that it comprises a first part which is fixed in place for bending the line in a first selected plane, and a second part which is fixed in place by bending said line in said first plane and also for deflection of said line in a direction out of the first selected plane to a second plane.

5. Device according to claim 4, characterized in that the mentioned first part comprises a shoe with a grooved, curved line contact surface and a curved sleeve, and that the second part comprises an outer housing which is fixed in place and an inner housing which is rotatable in relation to to said outer housing, which inner housing has a line contact groove on its inner surface.

6. Device according to claim 5, characterized in that the inner surface of said inner housing forms a three-sided pyramidal shape, where one of the corners of the pyramid forms said groove and where the side opposite to the groove is curved for cooperation with slack line.

7. Device according to claim 6, characterized in that said first part is attached to an offshore structure below the water surface and in the interior of said structure vertically under a tension device on the offshore structure, and that the second part is placed under said first part and on the circumference for the offshore construction.

8. Device for use when guiding stretch anchoring lines from an anchor system on the seabed to the tensioning device on an offshore structure, characterized in that it comprises: a first part fixed in place on said offshore structure below the water surface for bending the line from a direction to another direction in a selected plane, and a second part fixed in place on the circumference of said offshore structure for bending said line in a selected plane and also for deflecting said line in a direction out of said selected plane to another plane in the direction of said forward anchoring device.

9. Device according to claim 8, characterized in that said first part is placed vertically under said clamping device and comprises a grooved, curved line contact surface and a curved sleeve, and that said second part is placed on the circumference of said construction and comprises an outer housing part which is attached in place below and spaced from said first part and an inner housing part which is rotatable relative to and in said outer housing part, which inner housing part has a line contact groove formed on its inner surface.

10. Device according to claim 9, characterized in that the inner surface of said inner housing part which contains said groove forms a three-sided pyramidal shape, where one of the corners of the pyramid forms said groove, and that the side opposite to the groove is curved inwards to cooperate with said line.

11. Device according to claim 10, characterized in that said inner and outer housing parts are initially attached to each other to prevent rotation of said inner housing part.