CN206111103U - Arrange surface texture's buoyancy block - Google Patents
Arrange surface texture's buoyancy block Download PDFInfo
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- CN206111103U CN206111103U CN201620647744.7U CN201620647744U CN206111103U CN 206111103 U CN206111103 U CN 206111103U CN 201620647744 U CN201620647744 U CN 201620647744U CN 206111103 U CN206111103 U CN 206111103U
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- pit
- cylinder
- elementary cell
- buoyant mass
- groove
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Abstract
The utility model discloses an arrange surface texture's buoyancy block, this buoyancy block is established ties in order by a plurality of elementary cells and forms, the elementary cell is by the two halves symmetry, the combination of lightweight plastic semicircular cylinder forms, the surface of semicircular cylinder is wavy cylinder, wavy cylinder comprises periodic sine curve, circumference direction distribution along wavy cylinder has the external diameter of several pit (1) elementary cell roughly suitable with marine riser's external diameter D, the length H of elementary cell is 5D~20D, wavelength L is H4, wave amplitude a=0.002D~0.15D, wavy cylinder curve is periodic sine curve, the wave face function is dz= (Dmin+Dmax) 2+2acos (2 pi z lambda ), the degree of depth h of pit (1) is 0.001D~0.05D, the width s of pit (1) is 0.001D~0.04D, pit (1) level interval e is 0.001D~0.06D. The beneficial effects of the utility model are that: compact structure, do not add any auxiliary equipment and down reduce 15%, can effectively suppress vortex induced vibration with smooth cylindrical looks specific resistance.
Description
Technical field
This utility model is related to marine riser column system mechanical behavior control field, relates generally to layout surface texture and floats
Stressing influence of the power block to water proof tubular column system, belongs to marine oil and gas exploitation security control field, and particularly one kind is disposed with table
The buoyant mass of plane texture.
Background technology
Deep water is the forward position for mainly taking over area and scientific and technical innovation of 21 century World Oil Industry, and over nearly 5 years, the whole world is great
Strategic emphasis is progressively proceeded to deep water by 70% waters from the depth of water more than 1000m in oil and gas discovery, global each major oil companies
Oil And Gas Exploration And Development.China's deep water hydrocarbon resource very abundant, 30,000,000,000 tons of South China Sea petroleum resources total amount, in accounting for
State's total resources 1/3, potentiality to be exploited is very huge, wherein about 70% contains at deep-sea, it is that the strategy of China's petroleum resources is taken over
One of area (Chinese Ministry of Land and Resources).Surrounding countries rob every year 50000000 tons of oil gas equivalents, exploitation south from the line of nine sections of the South Sea
Extra large deep water hydrocarbon resource is to set up ocean power, safeguards the strategic measure of China's maritime rights and interests.The South Sea is marine environment in the world
Most complicated and worst marine site, exploitation deep sea resources face lot of challenges, and water proof tubular column system is in complicated sea situation and spudder
Mechanical behavior control, the reliability of raising drillng operation under the coupling of condition is exactly one of most important of which link.
Riser system is the critical passage for connecting drilling platforms and subsea blow out preventer, and marine riser should bear in the seawater
Deadweight and tension force is pushed up, while the coupling for still suffering from the drilling condition such as stormy waves, current load and internal drill string, drilling fluid is made
With the failure such as easily deform, wear and tear, rupturing.Therefore the performance of water proof tube material has higher requirement, and water proof tube material is
X-80 steel, its external diameter is 21 ", wall thickness has four types, and respectively 1 ", 0.9375 ", 0.875 ", 0.75 ", length is 75ft
(22.86m)；The buoyant mass external diameter of its configuration is 54 ".Choke flow line, kill line, hydraulic tube are usually mounted with marine riser
5 auxiliary lines such as line, drilling fluid supercharging pipeline and chemical agent injection pipeline, its material is also X-80 steel.
Riser system method for designing：Be followed successively by from platform to subsea wellheads separator, top flexible coupling, be adapted to it is short
Section, telescopic joint, marine riser, adapter, LMRP, lower flex joint, subsea blow out preventer.Riser system is under different depth
Configuration plate, as shown in Figure 1, its configuration feature is as follows：(1) top and bottom marine riser do not install buoyant mass, using naked
It is single；(2) wall thickness is gradually lowered from sea to seabed；(3) mid portion marine riser is all configured with buoyant mass；(4) marine riser
Sea level lower section is configured with filling-valve.
Vortex-induced vibration mechanism：When fluid particle flows through the leading edge of cylinder, periphery meeting convection cell produces obstruction,
High pressure near leading edge fluid promotes the boundary-layer for being formed gradually to develop in the both sides of cylinder.But in high reynolds number feelings
Under condition, the power produced by pressure is not enough to boundary-layer to shift onto and surrounds the cylinder back side, will be in cylinder section width maximum
Produce burble point.Fluid is extended backward by burble point and forms shear layer, in the range of shear layer, due to being close to the outer of area is freely flowed
Side portion flow rate is more than inboard portion, and fluid has the trend for rotating and being dispersed into several whirlpools, whirlpool be alternatively formed and
Come off, the fluctuation pressure that now cylinder can be subject to laterally and flow to.Marine riser can be reduced to elongated resilient support rod member, pulsation
Fluid force causes the vibration of water proof tube vibration, marine riser to change its wake structure again in turn, and this phenomenon is referred to as " swashing in whirlpool
Vibration ".When whirlpool release frequency and riser system natural frequency it is close when, marine riser shakes there is strong fluid structurecoupling
It is dynamic, and whirlpool is released into frequency lock on frequency of vibration, phenomenon referred to as " is locked ", cause marine riser fatigue failure even accident
Generation.
Utility model content
The purpose of this utility model is the shortcoming for overcoming prior art, there is provided a kind of simple structure, without any
Auxiliary equipment lower horizontal plane internal resistance reduces 15% and can effectively suppress the buoyant mass for being disposed with surface texture of vortex-induced vibration.
The purpose of this utility model is achieved through the following technical solutions：A kind of buoyant mass for being disposed with surface texture, institute
The buoyant mass stated is formed by multiple elementary cells are in sequential series, elementary cell combined by two hemihedrism, light plastic semicircular cylinder and
Into the outer surface of semicircular cylinder is wavy cylinder, and wavy cylinder is made up of periodic sine curve, and corrugated function is Dz=(Dmin
+Dmax)/2+2acos(2πz/λ)；Several pits are distributed with along the circumferential direction of wavy cylinder, the external diameter of described elementary cell
Suitable with the outer diameter D of marine riser, length H of elementary cell is 5D～20D, and wavelength L is H/4, the amplitude a=0.002D of ripple～
0.15D, depth h of pit is 0.001D～0.05D, and the width s of pit is 0.001D～0.04D, and pit level interval e is
0.001D～0.06D.
Multiple trapezoidal grooves are set on the axial direction of described buoyant mass, and trapezoidal groove is uniformly distributed circumferentially, buoyancy
Block outer diameter D is 0.9～1.5m, and groove width d of trapezoidal groove is 0.001D～0.1D, the separation s of trapezoidal groove be 0.001D～
0.04D, groove depth h of trapezoidal groove is 0.001D～0.05D.
Pit is provided with the both sides waist of described trapezoidal groove, described pit depth h is 0.001D～0.01D, wide
Degree d is 0.001D～0.01D, and pit row is 0.001D～0.01D away from s.
Described trapezoidal groove also can be replaced by U-type groove.
This utility model has advantages below：(1) this utility model uses imitative shagreen surface texture drag principle,
Shagreen texture after simplification is arranged in buoyant mass, such as trapezoidal groove, U-type groove, pit etc. texture, with smooth, cylindrical peripheral surface
Compare its resistance and reduce up to 15%.(2) this utility model is by setting up the mechanical model of water proof tubing string, top tension force,
The increase that horizontal plane internal resistance load has considerable influence, tensile force to marine riser dynamic behavior can make each intersegmental company of marine riser
Connect effect to decline, increase marine riser natural frequency, when frequency is let out in whirlpool and marine riser natural frequency is close resonance is also easy to produce；Otherwise
Drag loads in horizontal plane reduce, and the tensile force for contributing to riser system reduces, on the premise of safety, to water proof tubing string
System is optimized configuration, improves the security performance of system.(3) this utility model leads in buoyant mass surface layout difference texture
Many experiments are crossed, bionical texture surface is demonstrated and be there is preferable drag-reduction effect really, and by having built up water proof tubing string
Mechanics of system model analysiss understand that marine riser flexural deformation reduction and vortex-induced vibration are suppressed, the tensioning that simultaneity factor needs
Power reduces, and improves the distribution of force of marine riser, improves security of system.(4) this utility model establishes water proof tubing string power
Model is learned, analyzing affects the principal element of marine riser mechanical property, by the different texture of arrangement in buoyant mass, reduce marine riser
Vortex-induced vibration, takes into account service behaviour and economic benefit, and riser system mitigates quality using becoming by the way of wall thickness, improves water proof
Guard system mechanical property.(5) the features such as this utility model has ease for operation, systematicness, science, control high efficiency.
Description of the drawings
Fig. 1 is riser system configuration plate under different depth；
Fig. 2 is the structural representation of this utility model embodiment one；
Fig. 3 is the front view of Fig. 2；
Fig. 4 is the structural representation of the pits of this utility model embodiment one；
Fig. 5 is the structural representation of this utility model embodiment two；
Fig. 6 is the sectional view of Fig. 5；
Fig. 7 is the I portions partial enlarged view of Fig. 6；
Fig. 8 is the mathematical model figure set up；
Fig. 9 is the structural representation of elementary cell；
In figure, 1- pits, 2- trapezoidal grooves.
Specific embodiment
This utility model is further described below in conjunction with the accompanying drawings, protection domain of the present utility model be not limited to
It is lower described：
Embodiment one, as shown in figs. 2 to 4, a kind of buoyant mass for being disposed with surface texture, described buoyant mass is by multiple bases
This unit is in sequential series to be formed, and elementary cell is combined by two hemihedrism, light plastic semicircular cylinder, is illustrated in figure 9 basic
The structural representation of unit, the outer surface of semicircular cylinder is wavy cylinder, and wavy cylinder is made up of periodic sine curve, corrugated
Function is Dz=(Dmin+Dmax)/2+2acos(2πz/λ).Several pits 1 are distributed with along the circumferential direction of wavy cylinder, it is described
The external diameter of elementary cell is suitable with the outer diameter D of marine riser, and length H of elementary cell is 5D～20D, wavelength L is H/4, and ripple shakes
Width a=0.002D～0.15D, depth h of pit 1 is 0.001D～0.05D, and the width s of pit 1 is 0.001D～0.04D, recessed
1 level interval e is cheated for 0.001D～0.06D.
Under normal circumstances because wave is near sea, the region marine riser receives concentration pressure effect, and bears
The weight of bottom marine riser, belongs to weakness zone, when carrying out marine riser design and mechanics evaluation, it is necessary to consider wave power to every
The effect of water pipe.Again because the external diameter co-wavelength of marine riser is compared little many, the calculating of wave force is had using Morison equations
Preferable precision, is thought of as viscosity effect and virtual masseffect causes effect of the wave to cylinder, and a part is acceleration
The inertia item f that degree is directly proportionalI, another part is square resistance items f being directly proportional of same speedD, wherein
Wherein CD
Resistance coefficient suffered by buoyant mass surface；CMInertia force coefficient；ρ densities of sea water；D buoyant mass external diameters；F (x, t) horizontal plane is inside and outside to be carried
The time dependent function of lotus.
The method of controlling security of the described buoyant mass for being disposed with surface texture, it is comprised the following steps：
S1, hypothesis marine riser are homogenizing flexible pipe, belong to small strain-large deformation problem；Regulation direction of flow becomes with marine riser
Morpheme is in same vertical plane xoz, and ox axles are positive consistent with direction of flow, take marine riser infinitesimal length ds, set up mathematics
Model, as shown in Figure 8；
S2, according to Mathematical Models vertical direction equilibrium equation, horizontal direction equilibrium equation and to marine riser central point S
Square is taken, wherein vertical direction equilibrium equation is：
Horizontal direction equilibrium equation is：
Square is taken to marine riser central point S：
Wherein FwFor marine riser weight；FIsInertia force；FxsExternal applied load in horizontal plane；The horizontal edge shear stresses of V；
S3, according to small strain assume and pure bending beam theorize formula (1) (2) (3) abbreviation in step S2 and be：Vertically
Direction：T=Tc+∫fwdz-∫fzsDz, vertical tensile force T are gravity and the algebraical sum of axial flow of fluid power distribution function, level side
To：Equal sign left side is followed successively by from left to right marine riser and resists in the formula
The horizontal load that horizontal load that curved rigidity is born, axial tensile force T, the inertia of marine riser horizontal direction are born；
S4, to variable cross-section marine riser, its section parameter EI for z function, the standing balance of marine riser horizontal direction can
It is rewritten as：
Wherein EZIZThe bending rigidity of infinitesimal, for uiform section marine riser EZIZ=EI；The elastic modelling quantity of E materials, Pa；
I cross sectional moment of inertias, unit m4；The buoyant weight that W unit length marine risers are subject to, unit N/m；F (z, t) acts on unit
Fluid force on length pipeline section, unit N/m, from formula (1)～(4)：In the mechanical behavior and horizontal plane of marine riser
Resistance F, vertical direction tensile force T, pipe stiffness EI is relevant for water proof, additionally, the stress of marine riser, strain can be with wave flow velocity, wind
Speed and ocean current flow through the increase of the resistance of marine riser front and rear surfaces generation and increase；
S5, the buoyant mass for being disposed with surface texture is fixed on marine riser, different texture can reduce streams resistance, drop
Low marine riser vortex-induced vibration and tensile force, improve riser system safety, extend the service life of marine riser.
Embodiment two：As shown in Fig. 5～7, the present embodiment is with the difference of embodiment one：The axial direction of described buoyant mass
Side set up multiple trapezoidal grooves 2, trapezoidal groove 2 is uniformly distributed circumferentially, buoyant mass outer diameter D be 0.9～1.5m, trapezoid-shaped trench
Groove width d of groove 2 is 0.001D～0.1D, and the separation s of trapezoidal groove 2 is 0.001D～0.04D, and groove depth h of trapezoidal groove 2 is
0.001D～0.05D, is in step s 5 fixed on the buoyant mass for being disposed with trapezoidal groove texture on marine riser, can reduce around
Flow resistance power, reduces marine riser vortex-induced vibration and tensile force, improves riser system safety, and drag-reduction effect is projected.
Drawn by experimentation：Depth h and groove pitch s of trapezoidal groove is respectively in s+≤30,h+In the range of≤25
With drag-reduction effect, wherein：
According to test result indicate that, when trapezoidal groove height h and width meetWhen, trapezoidal groove drag reduction effect
Fruit is substantially
Embodiment three：The present embodiment is with the difference of embodiment one：It is provided with the both sides waist of described trapezoidal groove 2
Pit 1, described depth h of pit 1 is 0.001D～0.01D, and width d is 0.001D～0.01D, and the line-spacing s of pit 1 is 0.001D
～0.01D.
Example IV：Described trapezoidal groove 2 also can be replaced by U-type groove.
Claims (4)
1. a kind of buoyant mass for being disposed with surface texture, it is characterised in that：Described buoyant mass is sequentially gone here and there by multiple elementary cells
Connection is formed, and elementary cell is combined by two hemihedrism, light plastic semicircular cylinder, and the outer surface of semicircular cylinder is wavy cylinder, ripple
Shape cylinder is made up of periodic sine curve, and several pits (1) are distributed with along the circumferential direction of wavy cylinder, and described is basic
The external diameter of unit is suitable with the outer diameter D of marine riser, and length H of elementary cell is 5D～20D, and wavelength L is H/4, the amplitude a=of ripple
0.002D～0.15D, wavy cylindrical curve is periodic sine curve, and corrugated function is Dz=(Dmin+Dmax)/2+2acos
(2 π z/ λ), wherein DmaxFor the maximum gauge of elementary cell, DminFor the minimum diameter of elementary cell, λ is the ripple of elementary cell
It is long, z be in elementary cell any point to the distance of its end face, depth h of pit (1) is 0.001D～0.05D, pit (1)
Width s be 0.001D～0.04D, pit (1) level interval e be 0.001D～0.06D.
2. a kind of buoyant mass for being disposed with surface texture according to claim 1, it is characterised in that：Described buoyant mass
Multiple trapezoidal grooves (2) are set on axial direction, and trapezoidal groove (2) is uniformly distributed circumferentially, buoyant mass outer diameter D be 0.9～
1.5m, groove width d of trapezoidal groove (2) is 0.001D～0.1D, and the separation s of trapezoidal groove (2) is 0.001D～0.04D, terraced
Groove depth h of shape groove (2) is 0.001D～0.05D.
3. a kind of buoyant mass for being disposed with surface texture according to claim 2, it is characterised in that：Described trapezoidal groove
(2) pit is provided with both sides waist, described pit depth h is 0.001D～0.01D, and width d is 0.001D～0.01D,
Pit row is 0.001D～0.01D away from s.
4. a kind of buoyant mass for being disposed with surface texture according to claim 2, it is characterised in that：Described trapezoidal groove
(2) also can be replaced by U-type groove.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620647744.7U CN206111103U (en) | 2016-06-24 | 2016-06-24 | Arrange surface texture's buoyancy block |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620647744.7U CN206111103U (en) | 2016-06-24 | 2016-06-24 | Arrange surface texture's buoyancy block |
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| Publication Number | Publication Date |
|---|---|
| CN206111103U true CN206111103U (en) | 2017-04-19 |
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ID=58509758
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| Application Number | Title | Priority Date | Filing Date |
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| CN201620647744.7U Withdrawn - After Issue CN206111103U (en) | 2016-06-24 | 2016-06-24 | Arrange surface texture's buoyancy block |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105952389A (en) * | 2016-06-24 | 2016-09-21 | 西南石油大学 | Buoyancy block configured with surface texture and safe control method thereof |
| CN113514224A (en) * | 2021-05-26 | 2021-10-19 | 浙江大学 | Device and method for measuring hydrodynamic coefficient of high-voltage submarine cable |
-
2016
- 2016-06-24 CN CN201620647744.7U patent/CN206111103U/en not_active Withdrawn - After Issue
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105952389A (en) * | 2016-06-24 | 2016-09-21 | 西南石油大学 | Buoyancy block configured with surface texture and safe control method thereof |
| CN113514224A (en) * | 2021-05-26 | 2021-10-19 | 浙江大学 | Device and method for measuring hydrodynamic coefficient of high-voltage submarine cable |
| CN113514224B (en) * | 2021-05-26 | 2022-10-04 | 浙江大学 | Device and method for measuring hydrodynamic coefficient of high-voltage submarine cable |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20170419 Effective date of abandoning: 20180615 |
|
| AV01 | Patent right actively abandoned |