CN111188596A - Offshore oil platform riser centralizing hole arrangement method - Google Patents

Offshore oil platform riser centralizing hole arrangement method Download PDF

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CN111188596A
CN111188596A CN201911392253.7A CN201911392253A CN111188596A CN 111188596 A CN111188596 A CN 111188596A CN 201911392253 A CN201911392253 A CN 201911392253A CN 111188596 A CN111188596 A CN 111188596A
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riser
centralizing
hole
holes
elevation
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CN111188596B (en
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焦金刚
刘书杰
吴怡
谢仁军
徐国贤
李莹莹
仝刚
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China National Offshore Oil Corp CNOOC
Beijing Research Center of CNOOC China Ltd
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China National Offshore Oil Corp CNOOC
Beijing Research Center of CNOOC China Ltd
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    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21BEARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/01Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells specially adapted for obtaining from underwater installations
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21BEARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B17/00Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
    • E21B17/10Wear protectors; Centralising devices, e.g. stabilisers
    • E21B17/1078Stabilisers or centralisers for casing, tubing or drill pipes

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Mining & Mineral Resources (AREA)
  • Physics & Mathematics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Mechanical Engineering (AREA)
  • Earth Drilling (AREA)

Abstract

The invention provides a method for arranging centralizing holes of a riser of an offshore oil platform, which comprises the following steps: determining the length of a riser pipe to be arranged on a target platform; determining a reference span of a riser centralizing hole according to the size of the riser; determining the number of riser centralizing holes based on the length of the riser in the step 1) and the riser centralizing hole reference span in the step 2); and determining the position of the lowermost guide hole and determining the positions of the other centralizing holes to obtain the arrangement scheme of the centralizing holes of the riser of the offshore oil platform. The arrangement method improves the stability of the riser under the condition of the same number of centralizing holes; on the deepwater jacket platform, the designed righting hole elevation is more reasonable, and the construction on the engineering site is facilitated.

Description

Offshore oil platform riser centralizing hole arrangement method
Technical Field
The invention relates to an offshore oil platform arrangement technology, in particular to a method for arranging a riser centralizing hole of an offshore platform.
Background
In the development of marine oil and gas, a riser pipe is a first layer of casing pipe inserted into the seabed during marine drilling, can isolate seawater, form a circulation channel and play a role in supporting subsequent casing pipe strings and wellhead equipment. The riser is fixed through setting up rightting hole (also called guiding hole) on the offshore platform jacket, guarantees its straightness that hangs down. With the increase of the water depth, the righting hole plays an important role in the stability of the riser. Simultaneously, the quantity and the standard height of righting the hole will influence the convenience of installation on the engineering. The existing riser centralizing hole arrangement is generally arranged by virtue of engineering experience, and is lack of scientificity, so that the following problems are caused: 1) the subsequent stability calculation needs to be carried out repeatedly, the arrangement position is adjusted, the stability of the riser is ensured, and the design workload is increased; 2) the finally completed riser centralizing hole arrangement cannot give full play to the material performance of the riser, and engineering waste is caused. How to scientifically arrange the centralizing holes becomes a problem to be considered in the design of offshore platforms, particularly deep-level platforms.
Disclosure of Invention
Aiming at the problems, the invention aims to provide a method for arranging the riser centralizing holes of the offshore platform, the quantity and the arrangement of the centralizing holes are scientific and reasonable, and the stability and the engineering installation of the riser are facilitated.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a method for arranging a riser centralizing hole of an offshore oil platform, which comprises the following steps:
1) determining the length of a riser pipe to be arranged on a target platform;
2) determining a reference span of a riser centralizing hole according to the size of the riser;
3) determining the number of riser centralizing holes based on the length of the riser in the step 1) and the riser centralizing hole reference span in the step 2);
4) determining the position of the lowest end guide hole;
5) and determining the positions of the other centralizing holes to obtain the arrangement scheme of the centralizing holes of the marine oil platform riser.
Further, the length of the riser in the step 1) is calculated by formula (1):
L=Hwell+Hwater+6D (1)
wherein L is the calculated length of the riser pipe in m;
Hwellis the distance between the wellhead and the sea level, in m;
Hwateris the depth of the seawater, unit m;
d is the outer diameter of the riser pipe in m.
Further, the reference span of the septal water conduit centralizing hole in the step 2) is calculated by the formula (2):
Figure BDA0002345304160000021
wherein leA riser centralizing hole reference span is set as a riser centralizing hole;
lambda is the slenderness ratio reference value of the riser, and is dimensionless;
i is the radius of gyration of the cross section, in m;
d is the outer diameter of the riser pipe in m;
d is the inner diameter [ m ] of the riser.
Further, the number of the septal water guide pipe righting holes in the step 3) is calculated by a formula (3):
Figure BDA0002345304160000022
wherein n is the number of riser centralizing holes, and is rounded in calculation without dimension;
lea riser centralizing hole reference span is set as a riser centralizing hole;
and L is the calculated length of the riser pipe in m.
Further, in the step 4), the elevation of the rightmost hole at the lowest end is determined by optimizing the reference span of the riser guide hole:
Hn=-Hwater+Kle(4)
k is an optimization coefficient of the rightmost hole of the lowest layer and is dimensionless;
lea riser centralizing hole reference span is set as a riser centralizing hole;
Hwateris the depth of the seawater, unit m;
Hnthe elevation of the righting hole at the lowest layer is in the unit of m.
Further, the position of the righting hole in the step 4) is determined by an elevation, and the elevation of the sea level is 0.
Further, in the step 5), the elevation of each layer of the righting hole is calculated by the formula (5):
Figure BDA0002345304160000023
k is an optimization coefficient of the rightmost hole of the lowest layer and is dimensionless;
lea riser centralizing hole reference span is set as a riser centralizing hole;
Hwateris the depth of the seawater, unit m;
Hn-jthe elevation of the righting hole of the nth-j layer is in unit m;
n is the number of riser centralizing holes and is dimensionless;
d is the outer diameter of the riser pipe in m;
and L is the calculated length of the riser pipe in m.
Further, in the step 5), obtaining an offshore oil platform riser pipe centralizing hole arrangement scheme according to the elevation of each layer of centralizing hole.
The centralizing hole related in the above content is an annular object which is used for sleeving a water-resisting guide pipe, and the outer side of the centralizing hole is connected with the offshore oil platform jacket and used for realizing the connection between the offshore oil platform jacket and the water-resisting guide pipe at a certain distance. The riser is like a vertical pipe, and the centralizing holes are arranged along the length direction of the pipe. Compared with the arrangement method based on experience, the riser pipe with the centralizing hole arranged by the arrangement method is higher in critical load, less prone to instability and higher in stability after calculation.
By adopting the technical scheme, the invention has the following advantages: the arrangement method improves the stability of the riser under the condition of the same number of centralizing holes; on the deepwater jacket platform, the designed righting hole elevation is more reasonable, and the construction on the engineering site is facilitated.
Detailed Description
The principles and features of this invention are described below in conjunction with specific embodiments, which are set forth merely to illustrate the invention and are not intended to limit the scope of the invention.
To further illustrate the technical means and effects of the present invention adopted to achieve the predetermined objects, the following detailed description of the embodiments according to the present invention with reference to the preferred embodiments is provided as follows:
example 1
The invention provides a method for arranging guide holes of a riser of an offshore platform, which comprises the following steps:
the method comprises the following steps:
step one, determining the calculated length of the riser: when the riser is installed, the lower end of the riser goes deep into the seabed, and the upper end of the riser is connected with a wellhead. And determining the distance from the position 6 times the outer diameter of the riser pipe below the seabed mud line to the wellhead position of the platform as the calculated length L of the riser pipe. The calculated length L of the riser pipe is equal to the distance H between the wellhead and the sea levelwellDepth H of sea waterwaterAdding 6 times of the outer diameter D of the riser, namely:
L=Hwell+Hwater+6D (1)
wherein L is the calculated length of the riser pipe in m;
Hwellis the distance between the wellhead and the sea level, in m;
Hwateris the depth of the seawater, unit m;
d is the outer diameter of the riser pipe in m.
Step two, calculating the reference span of the riser centralizing hole: the reference span is the span between the two centralizing holes. Radius of gyration of riser cross section
Figure BDA0002345304160000041
Wherein D is riser pipe external diameter, and D is riser pipe internal diameter, multiplies riser pipe's slenderness ratio reference value lambda, and lambda value 120 determines riser pipe centralizing hole's reference span:
Figure BDA0002345304160000042
wherein leA reference span unit m is used for the riser centralizing hole;
lambda is the slenderness ratio reference value of the riser, and 120 is suggested to be taken without dimension;
i is the radius of gyration of the cross section, in m;
d is the outer diameter of the riser pipe in m;
d is the inner diameter of the riser pipe in m.
Step three, determining the number of the righting holes: the number of the righting holes is the number of the righting holes needed to be arranged on the platform.
Figure BDA0002345304160000043
Wherein n is the number of riser centralizing holes, and is rounded in calculation without dimension;
step four, arranging the position of the guide hole at the lowest end: the position of the centralizing hole is determined by the elevation, usually the elevation of the sea level is 0. Determining the elevation H of the bottommost righting hole by optimizing the reference span of the riser guide holen= -Hwater+Kle(4)
K is an optimization coefficient of the rightmost hole of the lowest layer, and 1.35 is suggested and is dimensionless;
step five, determining the positions of the rest centralizing holes: the elevation of other righting holes is continuously arranged from bottom to top
Figure BDA0002345304160000051
From this, the elevation of each layer of n centralizing holes can be obtained: h1,H2,…,Hn
It should be noted that the calculated value of the elevation of each layer of the centralizing hole calculated by the method for arranging the centralizing holes of the riser pipe is not an integer under most conditions, and is not easy to construct, and an integer or other numerical values easy to construct can be taken near the designed elevation according to the principle of the near. If the calculated elevation value is-28.43, the calculated elevation value can be-28 or-28.5.
Example 2
For a certain platform position column, the arrangement scheme of the riser centralizing hole is designed according to the method in the embodiment 1, and relevant parameters are set as follows: depth H of seawater at a certain deepwater jacketwater330m, well head position elevation Hwell9 m. The riser pipe with the diameter of 609.6mm is selected, the outer diameter D of the riser pipe is 0.6096m, and the inner diameter D of the riser pipe is 0.5588 m.
1) According to the distance H between the well head and the sea level of the well positionwellDepth H of sea waterwaterAdding 6 times of the outer diameter D of the riser:
L=Hwell+Hwater+6D=9+330+6*0.6096=342.66m (6)
wherein L is the calculated length of the riser pipe in m;
Hwellis the distance between the wellhead and the sea level, in m;
Hwateris the depth of the seawater, unit m;
d is the outer diameter of the riser pipe in m.
2) Calculating the reference span of the riser centralizing hole according to the size of the selected riser:
Figure BDA0002345304160000052
wherein leReference span [ m ] for centralizing hole of riser];
Lambda is the slenderness ratio reference value of the riser, and 120 is suggested to be taken without dimension;
i is the radius of gyration of the cross section, in m;
d is the outer diameter of the riser pipe in m;
d is the inner diameter of the riser pipe in m;
3) the calculated length L of the riser obtained by the steps 1) and 2) and the riser centralizing hole reference span LeCalculating the number of righting holes required to be arranged on the platform:
Figure BDA0002345304160000061
wherein n is the number of riser centralizing holes, and is rounded in calculation without dimension;
4) from upwards calculating down and right hole elevation, at first calculate the hole elevation of rightting of lower floor:
H14=-Hwater-6D+K*le=-330-6*0.6096+1.35*24.81=-300.16m (9)
k is an optimization coefficient of the rightmost hole of the lowest layer, and 1.35 is suggested and is dimensionless;
the elevation of the righting hole at the lowest layer is designed as follows: hn=-300m;
5) And (3) continuously calculating the elevations of the rest centralizing holes from bottom to top:
Figure BDA0002345304160000062
the elevation calculated according to the equation (10) is designed to have a data design elevation convenient for construction, as shown in table 1.
Table 1. calculated and designed elevations of the centralizing holes:
Figure BDA0002345304160000063
6) according to the elevation H of each layer of righting hole obtained by calculation1,H2,…,H14The position of the righting hole of each layer is arranged.
It should be noted that the elevation calculated value of each layer of the centralizing hole obtained by the method for arranging the centralizing holes of the riser pipe is not an integer or engineering data easy to construct in most cases, and an integer or other numerical values easy to construct can be taken near the designed elevation according to the principle of the near. May be designed as an integer or other value that is easy to construct.
And calculating the elastic critical load of the riser under the arrangement mode of the centralizing holes according to a characteristic value buckling analysis method based on an elastic stability theory to be 8041 KN.
Comparative example, as per conventional methods, 14 centralizing holes were also provided, typically at elevations:
Figure BDA0002345304160000071
at this time, the elastic critical load of the corresponding riser pipe is calculated to be 6503KN according to a characteristic value buckling analysis method based on the elastic stability theory.
Comparing the data, it is obvious that compared with the conventional design method, the elasticity critical load calculated by the arrangement mode of the centralizing hole is 1538KN larger, and the stability is better.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (8)

1. A marine oil platform riser centralizing hole arrangement method is characterized by comprising the following steps:
1) determining the length of a riser pipe to be arranged on a target platform;
2) determining a reference span of a riser centralizing hole according to the size of the riser;
3) determining the number of riser centralizing holes based on the length of the riser in the step 1) and the riser centralizing hole reference span in the step 2);
4) determining the position of the lowest end guide hole;
5) and determining the positions of the other centralizing holes to obtain the arrangement scheme of the centralizing holes of the marine oil platform riser.
2. The offshore oil platform riser centralizing hole arrangement method according to claim 1, wherein the length of the riser in the step 1) is calculated by formula (1):
L=Hwell+Hwater+6D (1)
wherein L is the calculated length of the riser pipe in m;
Hwellis the distance between the wellhead and the sea level, in m;
Hwateris the depth of the seawater, unit m;
d is the outer diameter of the riser pipe in m.
3. The offshore oil platform riser centralizing hole arrangement method according to claim 1, wherein the reference span of the riser centralizing hole in step 2) is calculated by formula (2):
Figure FDA0002345304150000011
wherein leA riser centralizing hole reference span is set as a riser centralizing hole;
lambda is the slenderness ratio reference value of the riser, and is dimensionless;
i is the radius of gyration of the cross section, in m;
d is the outer diameter of the riser pipe in m;
d is the inner diameter [ m ] of the riser.
4. The offshore oil platform riser centralizing hole arrangement method according to claim 1, wherein the number of riser centralizing holes in step 3) is calculated by formula (3):
Figure FDA0002345304150000012
wherein n is the number of riser centralizing holes, and is rounded in calculation without dimension;
lea riser centralizing hole reference span is set as a riser centralizing hole;
and L is the calculated length of the riser pipe in m.
5. The offshore oil platform riser centralizing hole arrangement method according to claim 3, characterized in that in step 4), the elevation of the lowermost centralizing hole is determined by optimizing the reference span of the riser guide hole:
Hn=-Hwater+Kle(4)
k is an optimization coefficient of the rightmost hole of the lowest layer and is dimensionless;
lea riser centralizing hole reference span is set as a riser centralizing hole;
Hwateris the depth of the seawater, unit m;
Hnthe elevation of the righting hole at the lowest layer is in the unit of m.
6. The offshore oil platform riser centralizing hole arrangement method according to claim 5, wherein the position of the centralizing hole in the step 4) is determined by an elevation, and the elevation of the sea level is 0.
7. The offshore oil platform riser centralizing hole arrangement method according to claim 1, characterized in that in the step 5), the elevation of each layer of centralizing hole is calculated by the formula (5):
Figure FDA0002345304150000021
k is an optimization coefficient of the rightmost hole of the lowest layer and is dimensionless;
lea riser centralizing hole reference span is set as a riser centralizing hole;
Hwateris the depth of the seawater, unit m;
Hn-jthe elevation of the righting hole of the nth-j layer is in unit m;
n is the number of riser centralizing holes and is dimensionless;
d is the outer diameter of the riser pipe in m;
and L is the calculated length of the riser pipe in m.
8. The offshore oil platform riser centralizing hole arrangement method according to claim 1, wherein in the step 5), the offshore oil platform riser centralizing hole arrangement scheme is obtained according to the elevation of each layer of centralizing hole.
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Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3687204A (en) * 1970-09-08 1972-08-29 Shell Oil Co Curved offshore well conductors
US4279542A (en) * 1979-12-17 1981-07-21 Standard Oil Company (Indiana) Subsea well flow lines tie-in using conductors
CN85106164A (en) * 1985-08-15 1987-03-04 麦克德莫特国际公司 The conduit guide system of offshore drilling platform
CN2911009Y (en) * 2006-01-23 2007-06-13 中国海洋石油总公司 One-leg three-pile simple platform suitable for developing medium-small oil fields in sea
CN201043269Y (en) * 2006-12-11 2008-04-02 中国海洋石油总公司 Vertical protection pipe underwater pile type simple platform
CN202787206U (en) * 2012-08-07 2013-03-13 天津市海王星海上工程技术有限公司 Reusable shoal water pitshaft structure
CN103032046A (en) * 2011-10-10 2013-04-10 天津市海王星海上工程技术有限公司 Novel self-installing four-cylindrical-foundation two-upright wellhead platform
CN103711459A (en) * 2012-09-29 2014-04-09 天津市海王星海上工程技术股份有限公司 Basement-type water surface connecting cylinder type underwater dry oil production device
CN105339584A (en) * 2013-04-16 2016-02-17 Gva咨询股份公司 Conduit balcony
CN207620753U (en) * 2017-12-15 2018-07-17 深圳市惠尔凯博海洋工程有限公司 A kind of wellhead frame structure

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3687204A (en) * 1970-09-08 1972-08-29 Shell Oil Co Curved offshore well conductors
US4279542A (en) * 1979-12-17 1981-07-21 Standard Oil Company (Indiana) Subsea well flow lines tie-in using conductors
CN85106164A (en) * 1985-08-15 1987-03-04 麦克德莫特国际公司 The conduit guide system of offshore drilling platform
CN2911009Y (en) * 2006-01-23 2007-06-13 中国海洋石油总公司 One-leg three-pile simple platform suitable for developing medium-small oil fields in sea
CN201043269Y (en) * 2006-12-11 2008-04-02 中国海洋石油总公司 Vertical protection pipe underwater pile type simple platform
CN103032046A (en) * 2011-10-10 2013-04-10 天津市海王星海上工程技术有限公司 Novel self-installing four-cylindrical-foundation two-upright wellhead platform
CN202787206U (en) * 2012-08-07 2013-03-13 天津市海王星海上工程技术有限公司 Reusable shoal water pitshaft structure
CN103711459A (en) * 2012-09-29 2014-04-09 天津市海王星海上工程技术股份有限公司 Basement-type water surface connecting cylinder type underwater dry oil production device
CN105339584A (en) * 2013-04-16 2016-02-17 Gva咨询股份公司 Conduit balcony
CN207620753U (en) * 2017-12-15 2018-07-17 深圳市惠尔凯博海洋工程有限公司 A kind of wellhead frame structure

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