CN102354323B - Method for integrally analyzing steel catenary riser and floating platform - Google Patents

Abstract

The invention relates to a method for integrally analyzing a steel catenary riser and a floating platform, which is implemented by taking the floating platform as a rigid body through the step of connecting the floating platform and the steel catenary riser to be an integral structure by using a rigid arm unit in a finite element method, so that the rigid body motion of the floating platform is converted into the motion of the top end of the steel catenary riser, thereby achieving an effect of carrying out integral analysis on the steel catenary riser and the floating platform. By using the method provided by the invention, a coupling analysis method implemented by taking a steel catenary riser and a floating platform as two independent structures in the prior art is improved, and the inertia force and bending moment transmission between the steel catenary riser and the floating platform is realized.

Description

The holistic approach method of a kind of steel catenary suspension type continuous vulcanization standpipe and floating platform

Technical field

The present invention relates to a kind of analytical approach, especially relate to the holistic approach method of a kind of steel catenary suspension type continuous vulcanization standpipe and floating platform.

Background technology

The steel catenary riser is the novel riser systems of deep-sea oil gas exploitation, compares with compliant riser, and the cost of steel catenary riser is low; Compare with top tension force standpipe, it need not the compensation of top tension force and buoyancy aid heaving, is considered to the effective standpipe solution of a cost of deep-sea oil gas development of resources.Steel catenary suspension type continuous vulcanization standpipe has not only replaced compliant riser and has been successfully applied to tension leg platform (TLP) and semisubmersible platform, and becomes the standpipe pattern of floating production system and Floating Production storing and transporting system first-selection, also is considered to the economical standpipe of fixed platform simultaneously.Its collection subsea pipeline and standpipe are all over the body, and the stress joint or the flexible joint that need not the seabed connect, and greatly reduce quantities and the difficulty of construction of underwater construction.Its top free suspension is in the platform outside simultaneously, need not hydropneumatic tensioning system and jumper hose, saved larger platform space, and the drift motion of buoyancy aid there is larger content, be more suitable in the high-temperature high-pressure medium environment, obtain the favor of ocean petroleum developing, become the first-selected riser systems of deep-sea oil gas development of resources.

Steel catenary suspension type continuous vulcanization standpipe is a steel pipe that freely dangles that is suspended on the floating platform, and as shown in Figure 1, its axis is the catenary shape.Because it directly extends on the sea bed, have point of the tactile end 2 at sea bed, with subsea pipeline be the steel pipe of an integral body.The pipe string that contacts with sea bed is called streamline section 3, and one section pipeline that dangles from the seabed to floating platform is called the section of dangling 1.The section of dangling 1 interacts with seawater, be called the solid coupling of stream, and streamline Duan Ze is subject to the effect of contraction of seabed soil.Because the top of steel catenary suspension type continuous vulcanization standpipe is connected with floating platform, therefore, it will move along with the motion of floating platform.Steel catenary suspension type continuous vulcanization standpipe comprises displacement, speed and the acceleration of hitch point with the motion of floating platform, displacement has determined the current location of steel catenary suspension type continuous vulcanization standpipe, and speed and acceleration have then determined motion state and the inertia of steel catenary suspension type continuous vulcanization standpipe.

At present, there is following problem in the analytical approach of steel catenary suspension type continuous vulcanization standpipe:

1) top of steel catenary suspension type continuous vulcanization standpipe is suspended on the floating platform, and it is similar to effect of contraction and the mooring system of floating platform, and its constraining force changes with the motion of floating platform.But existing steel catenary suspension type continuous vulcanization standpipe method of dynamic analysis adopts coupling analytical method, is about to floating platform and steel catenary suspension type continuous vulcanization standpipe and analyzes respectively as two structural systems.When analyzing floating platform, do not consider that steel catenary suspension type continuous vulcanization standpipe is to the effect of contraction of floating platform.Therefore, the real motion state of result of calculation and floating platform has larger difference.Because the effect of contraction of steel catenary suspension type continuous vulcanization standpipe is suitable with the gravity type anchor chain, therefore, the effect of contraction of ignoring steel catenary suspension type continuous vulcanization standpipe is equivalent to floating platform and lacks an anchor chain.

2) displacement coupling analytical approach, prior art adopts the analytical approach of steel catenary suspension type continuous vulcanization standpipe and floating platform displacement coupling, is about to steel catenary suspension type continuous vulcanization standpipe and floating platform and analyzes respectively as two structural systems.When analyzing steel catenary suspension type continuous vulcanization standpipe, the moving displacement of floating platform and steel catenary suspension type continuous vulcanization standpipe tie point is inputted as the boundary condition of steel catenary suspension type continuous vulcanization riser top ends.And other coupling between the two comprises power, speed and acceleration, all is left in the basket.

3) ignore turning effect, the top of steel catenary suspension type continuous vulcanization standpipe is connected with floating platform by flexible joint, and therefore, the pitching of floating platform and rolling motion will produce flecition to the steel catenary riser.But the coupling analytical method of prior art can only be input to the line motion of floating platform and steel catenary suspension type continuous vulcanization standpipe tie point in the top margin condition of steel catenary suspension type continuous vulcanization standpipe, is left in the basket and rotate.Therefore, the rotary action of floating platform to steel catenary suspension type continuous vulcanization standpipe namely ignored on the top that the flecition that floating platform produces steel catenary suspension type continuous vulcanization standpipe can't be coupled to steel catenary suspension type continuous vulcanization standpipe.

If correctly analyze steel catenary suspension type continuous vulcanization standpipe, must adopt the method for steel catenary suspension type continuous vulcanization standpipe and floating platform holistic approach.If adopt the coupling analytical method of prior art, then can only carry out the displacement coupling analysis, and ignore speed and the acceleration coupling of tie point.Because, coupling analytical method with steel catenary suspension type continuous vulcanization riser top ends as the border, motion by independent calculating floating platform, obtain first the displacement of floating platform, again with the displacement of floating platform and the steel catenary suspension type continuous vulcanization standpipe tie point top margin condition entry as steel catenary suspension type continuous vulcanization standpipe, thereby calculate the motion of tapping catenary suspension type continuous vulcanization standpipe, this has just ignored floating platform movement velocity and acceleration to the impact of steel catenary suspension type continuous vulcanization standpipe motion.Be directed to the problem that exists in the present analytical approach, need to find out a kind of rational method and be solved.

Summary of the invention

The present invention proposes the method for a kind of steel catenary suspension type continuous vulcanization standpipe and floating platform holistic approach, thereby can realize the holistic approach problem of steel catenary suspension type continuous vulcanization standpipe and floating platform.

One of purpose of the present invention is to set up the holistic approach method of steel catenary suspension type continuous vulcanization standpipe and floating platform, improves prior art with steel catenary suspension type continuous vulcanization standpipe and the floating platform coupling analytical method as two absolute construction systems.

One of purpose of the present invention be consider floating platform vertical/rolling is to the turning effect of steel catenary suspension type continuous vulcanization standpipe, realizes moment of flexure transmission between steel catenary suspension type continuous vulcanization standpipe and the floating platform by holistic approach.

One of purpose of the present invention is to consider that floating platform movement velocity and acceleration are on the motion of steel catenary suspension type continuous vulcanization standpipe and stressed impact, by the inertial force transmission between holistic approach realization steel catenary suspension type continuous vulcanization standpipe and the floating platform.

One of purpose of the present invention is to consider steel catenary suspension type continuous vulcanization standpipe to the effect of contraction of floating platform, by the constraining force transmission between holistic approach realization steel catenary suspension type continuous vulcanization standpipe and the floating platform.

The present invention relates to the holistic approach method of a kind of steel catenary suspension type continuous vulcanization standpipe and floating platform, wherein, with floating platform as a rigid body, adopt the firm arm unit in the Finite Element Method that floating platform and steel catenary suspension type continuous vulcanization standpipe are connected to an one-piece construction, thereby the rigid motion of floating platform is converted to the motion on steel catenary suspension type continuous vulcanization standpipe summit, realizes the holistic approach to steel catenary suspension type continuous vulcanization standpipe and floating platform.

Wherein, be connected in the motion of point with steel catenary suspension type continuous vulcanization standpipe at the calculating floating platform, parameter line/angular displacement, line/angular velocity, line/angular acceleration, force and moment carried out coupling calculated.

Wherein, the center of mass motion of floating platform comprises the translation of barycenter and around the rotation of barycenter.

Wherein, the rigidity of steel catenary suspension type continuous vulcanization standpipe is far smaller than floating platform.

Wherein, it is characterized in that: steel catenary suspension type continuous vulcanization standpipe and floating platform mass motion equation be,

$\left[\stackrel{\‾}{M}\right]\left\{{\stackrel{\·\·}{u}}_s\right\}+\left[\stackrel{\‾}{C}\right]\left\{{\stackrel{\·}{u}}_s\right\}+\left[\stackrel{\‾}{K}\right]\left\{u_s\right\}=\left\{\stackrel{\‾}{F}\right\}$

Wherein,

$\left\{\stackrel{\‾}{F}\right\}=\left\{\begin{array}{c}\left\{F_1\right\}+\left\{{\stackrel{\‾}{F}}_b\right\}\\ \left\{F_2\right\}\\ .\\ .\\ .\\ .\\ .\\ .\end{array}\right\}.$

Wherein,

Be followed successively by acceleration, speed and the displacement vector of steel catenary suspension type continuous vulcanization standpipe

Wherein, above-mentioned equation is found the solution, requirement according to API RP 2RD standard is divided into several unit with steel catenary suspension type continuous vulcanization standpipe, adopts mass matrix, damping matrix and the stiffness matrix of beam element interpolating function computing unit, forms corresponding overall system matrix.

Wherein, to the mass motion equation of steel catenary suspension type continuous vulcanization standpipe and floating platform, adopt time history analysis method to find the solution, obtain the dynamic response of node acceleration, speed and the displacement of steel catenary suspension type continuous vulcanization standpipe.

Description of drawings

Fig. 1, steel catenary suspension type continuous vulcanization standpipe schematic diagram

Embodiment

For the purposes of the present invention, technical scheme and advantage be clearer, referring to accompanying drawing and in conjunction with practical embodiments, the present invention is described in more detail.

The present invention with floating platform as a rigid body, adopt the firm arm unit in the Finite Element Method that floating platform and steel catenary suspension type continuous vulcanization standpipe are connected to an one-piece construction, thereby the rigid motion of floating platform is converted to the motion of steel catenary suspension type continuous vulcanization riser top ends, has realized steel catenary suspension type continuous vulcanization standpipe and the floating platform holistic approach of considering that simultaneously line/angular displacement, line/angular velocity, line/angular acceleration, force and moment transmit.

Key of the present invention is how to calculate floating platform is connected motion of point with steel catenary suspension type continuous vulcanization standpipe, comprises translation and rotation.Because the motion of floating platform is to measure with the motion of barycenter, comprise the translation of barycenter and around the rotation of barycenter, and the rigidity of steel catenary suspension type continuous vulcanization standpipe is far smaller than floating platform, therefore, if process as elastic component equally, then certainly will cause the unusual of stiffness matrix and can't find the solution.Therefore, the present invention has adopted firm arm unit to solve the motion conversion of floating platform center of mass motion and steel catenary suspension type continuous vulcanization riser top ends.

At first, adopt firm arm unit to set up the annexation of floating platform and steel catenary suspension type continuous vulcanization riser top ends, namely according to formula (1) floating platform barycenter and steel catenary suspension type continuous vulcanization standpipe hitch point carried out conversion:

Wherein: the displacement vector of u}---floating platform and steel catenary suspension type continuous vulcanization standpipe tie point,

{u}＝[u，v，w，α _x，α _y，α _z] ^T

Wherein, u, v, w, α _x, α _y, α _zFor the surging of floating platform and steel catenary suspension type continuous vulcanization standpipe tie point, swaying, hang down swing, rolling, pitching and yawing displacement;

U}---the displacement vector of floating platform barycenter,

Wherein, U, V, W,

For the surging of floating platform barycenter, swaying, hang down swing, rolling, pitching and yawing displacement;

The air line distance of l---floating platform barycenter and steel catenary suspension type continuous vulcanization standpipe hitch point;

θ _z---in l and z-axle (Z-axis) plane, the angle of l and z-axle.

Then the displacement of floating platform barycenter can be expressed as:

{U}＝[T]{u} (2)

Wherein:

$\left[T\right]={\left[\begin{array}{cccccc}1& 0& 0& 0& -l\cos {\mathrm{\θ}}_z& 0\\ 0& 1& 0& l\cos {\mathrm{\θ}}_z& 0& l\sin {\mathrm{\θ}}_z\\ 0& 0& 1& 0& -l\sin {\mathrm{\θ}}_z& 0\\ 0& 0& 0& 1& 0& 0\\ 0& 0& 0& 0& 1& 0\\ 0& 0& 0& 0& 0& 1\end{array}\right]}^{-1}$

In addition, for floating platform, need to consider its kinematic relation, set up its equation of motion, shown in the formula specific as follows:

$\left[M_b\right]\left\{\stackrel{\·\·}{U}\right\}+\left[C_b\right]\left\{\stackrel{\·}{U}\right\}+\left[K_b\right]\left\{U\right\}=\left\{F_b\right\}---\left(3\right)$

Wherein: [M _b], [C _b], [K _b]---be respectively mass matrix, hydrodynamic damping matrix and the restoring force matrix of coefficients of floating platform;

---acceleration, speed and the displacement vector of floating platform barycenter;

{ F _b---the hydrodynamic load of floating platform;

For steel catenary suspension type continuous vulcanization standpipe, consider its kinematic relation, set up its equation of motion, shown in the formula specific as follows:

$\left[M_s\right]\left\{{\stackrel{\·\·}{u}}_s\right\}+\left[C_s\right]\left\{{\stackrel{\·}{u}}_s\right\}+\left[K_s\right]\left\{u_s\right\}=\left\{F_s\right\}---\left(4\right)$

In the formula (4): [M _s]---be the mass matrix of steel catenary suspension type continuous vulcanization standpipe, it comprises architecture quality and hydrodynamic force additional mass, and its partitioned matrix can be expressed as:

Wherein: n is the nodes after the steel catenary suspension type continuous vulcanization standpipe dividing elements

[C _s]---be the damping matrix of steel catenary suspension type continuous vulcanization standpipe, comprise structural damping and hydrodynamic damping, its partitioned matrix can be expressed as:

[K _s]---the stiffness matrix of steel catenary suspension type continuous vulcanization standpipe, its partitioned matrix can be expressed as:

---acceleration, speed and the displacement vector of steel catenary suspension type continuous vulcanization standpipe, with above-mentioned minute

The form that block matrix is corresponding is:

$\left\{u_s\right\}=\left\{\begin{array}{c}\left\{u_1\right\}\\ \left\{u_2\right\}\\ \left\{u_3\right\}\\ .\\ .\\ .\\ \left\{u_{i-1}\right\}\\ \left\{u_i\right\}\\ \left\{u_{i+1}\right\}\\ .\\ .\\ .\\ \left\{u_{n-2}\right\}\\ \left\{u_{n-1}\right\}\\ \left\{u_n\right\}\end{array}\right\}$

{ F _s---the hydrodynamic load of steel catenary suspension type continuous vulcanization standpipe, the form corresponding with above-mentioned vector is:

The transposition of formula (2) substitution formula (3) and premultiplication transformation matrix is got:

$\left[{\stackrel{\‾}{M}}_b\right]\left\{\stackrel{\·\·}{u}\right\}+\left[{\stackrel{\‾}{C}}_b\right]\left\{\stackrel{\·}{u}\right\}+\left[{\stackrel{\‾}{K}}_b\right]\left\{u\right\}=\left\{{\stackrel{\‾}{F}}_b\right\}---\left(5\right)$

In the formula (5):

$\left[{\stackrel{\‾}{M}}_b\right]={\left[T\right]}^T\left[M_b\right]\left[T\right]$

$\left[{\stackrel{\‾}{C}}_b\right]={\left[T\right]}^T\left[C_b\right]\left[T\right]$

$\left[{\stackrel{\‾}{K}}_b\right]={\left[T\right]}^T\left[K_b\right]\left[T\right]$

$\left\{{\stackrel{\‾}{F}}_b\right\}={\left[T\right]}^T\left\{F_b\right\}$

The motion vector of floating platform and steel catenary suspension type continuous vulcanization standpipe tie point in the formula (5)

With the motion vector of steel catenary suspension type continuous vulcanization riser top ends be same motion of point parameter, therefore, can be with the combination of formula (5) and formula (4), thereby obtain steel catenary suspension type continuous vulcanization standpipe and floating platform mass motion equation:

$\left[\stackrel{\‾}{M}\right]\left\{{\stackrel{\·\·}{u}}_s\right\}+\left[\stackrel{\‾}{C}\right]\left\{{\stackrel{\·}{u}}_s\right\}+\left[\stackrel{\‾}{K}\right]\left\{u_s\right\}=\left\{\stackrel{\‾}{F}\right\}---\left(6\right)$

In the formula (6):

$\left\{\stackrel{\‾}{F}\right\}=\left\{\begin{array}{c}\left\{F_1\right\}+\left\{{\stackrel{\‾}{F}}_b\right\}\\ \left\{F_2\right\}\\ .\\ .\\ .\\ .\\ .\\ .\end{array}\right\}---\left(10\right)$

Top equation is found the solution, at first the requirement according to API RP 2RD standard is divided into several unit with steel catenary suspension type continuous vulcanization standpipe, wherein, the number of unit depends on length and the element length of steel catenary suspension type continuous vulcanization standpipe, the length of steel catenary suspension type continuous vulcanization standpipe is determined by concrete engineering, because different working environment, cause the length of steel catenary suspension type continuous vulcanization standpipe different, element length is to calculate according to the diameter of steel catenary suspension type continuous vulcanization standpipe and the material formula by API RP 2RD specification recommends, then adopt the mass matrix of beam element interpolating function computing unit, damping matrix and stiffness matrix, and form corresponding overall system matrix.

The system matrix of steel catenary suspension type continuous vulcanization standpipe and corresponding matrix substitution formula (7)～(10) of floating platform are formed the mass motion equation of steel catenary suspension type continuous vulcanization standpipe and floating platform, and adopt time history analysis method.Find the solution the dynamic response (node acceleration, speed and displacement) that can obtain steel catenary suspension type continuous vulcanization standpipe.

The dynamic response substitution formula (2) of steel catenary suspension type continuous vulcanization standpipe summit (with the floating platform tie point) can also be calculated the motion response of floating platform.

Although the present invention illustrates and describes with reference to its preferred embodiment, but will be understood by those skilled in the art that, in the situation that does not break away from the spirit and scope of the present invention that the appended claims limit, can carry out the various changes of form and details.

Claims (3)

1. the holistic approach method of a steel catenary suspension type continuous vulcanization standpipe and floating platform, it is characterized in that: with floating platform as a rigid body, adopt the firm arm unit in the Finite Element Method that floating platform and steel catenary suspension type continuous vulcanization standpipe are connected to an one-piece construction, thereby the rigid motion of floating platform is converted to the motion of steel catenary suspension type continuous vulcanization riser top ends, realizes the holistic approach to steel catenary suspension type continuous vulcanization standpipe and floating platform; Steel catenary suspension type continuous vulcanization standpipe and floating platform mass motion equation be,

Wherein,

，

Wherein, { u _sBe followed successively by acceleration, speed and the displacement vector of steel catenary suspension type continuous vulcanization standpipe,

[M _b], [C _b], [K _b]---be respectively mass matrix, hydrodynamic damping matrix and the restoring force matrix of coefficients of floating platform,

{ F _b---the hydrodynamic load of floating platform;

Wherein,

Above-mentioned equation is found the solution, requirement according to API RP 2RD standard is divided into several unit with steel catenary suspension type continuous vulcanization standpipe, adopt the beam element interpolating function to calculate mass matrix, damping matrix and the stiffness matrix of described some unit, form corresponding overall system matrix; To the mass motion equation of steel catenary suspension type continuous vulcanization standpipe and floating platform, adopt time history analysis method to find the solution, obtain node acceleration, node speed and the nodal displacement vector of steel catenary suspension type continuous vulcanization standpipe.

2. the holistic approach method of steel catenary suspension type continuous vulcanization standpipe as claimed in claim 1 and floating platform, it is characterized in that: in the motion of calculating floating platform and steel catenary suspension type continuous vulcanization standpipe, to the force and motion parameter of floating platform and steel catenary suspension type continuous vulcanization standpipe tie point: line/angular displacement, line/angular velocity, line/angular acceleration, force and moment have carried out the calculating that is coupled.

3. the holistic approach method of steel catenary suspension type continuous vulcanization standpipe as claimed in claim 2 and floating platform is characterized in that: the center of mass motion of floating platform comprises the translation of barycenter and around the rotation of barycenter.

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