CN103398218A - Construction and protection method for long-distance parallel subsea pipeline - Google Patents

Abstract

The invention relates to a construction and protection method for a long-distance parallel subsea pipeline. The method comprises the steps of comparative analysis on original pipeline design material and a research report, analysis on pipeline parallel laying risk points, analysis on a pipe-laying ship mooring system, analysis on an anchor cable catenary and rendering and filed conduction of a construction anchor settling drawing. By means of research on the anchor cable catenary, with combination of a calculation result, the construction anchor settling drawing is rendered according to the engineering ship anchor settling theory, and the stress situation of each anchor in the anchor settling state of a ship under the extreme working condition is counted through relative software. The method has the advantages of economical, efficient, free of pollution, strong in operability and the like. In addition, the construction requirement is met.

Description

The parallel submerged pipeline construction of a kind of long distance guard method

Technical field

The present invention relates to the technical field of undersea pipe-laying, be specifically related to the parallel submerged pipeline construction of a kind of long distance guard method.

Background technique

Along with the offshore oil and gas field exploitation is constantly expanded to deep layer and frontier, offshore platform process treating flow process is more and more simplified, increasing submerged pipeline is used, inevitably there will be pipeline installation and the existing pipeline phenomenon that walks abreast in the pipe installation process, the present invention's problem for this reason provides simple and practical operating method.

At present, standard does not have corresponding standard to long apart from parallel pipeline pipe laying construction resist technology both at home and abroad, and domestic not long apart from parallel pipeline construction precedent, only engineering ship rear anchor hawser crossover line in place arranges floating drum and do not move the anchor job execution.

For above situation; we are consulting on the basis of data at home and abroad; by large component analysis; develop the method that a cover meets the parallel submerged pipeline construction of long distance protection; the method is based on catenary equation; work out the parallel submerged pipeline cloth anchor method of long distance, realized the control to pipe laying construction cloth anchor, solved the difficult problem of the parallel submerged pipeline protection of long distance.The method has proposed the solution of the parallel submerged pipeline construction of long distance first, has ensured the safety of pipeline during original pipeline operation.Break through first traditional buoy anchoring system mode, will grow the parallel submerged pipeline resist technology successful Application of distance in the branch line submarine pipeline state key project financing of the second west to east gas pipeline project Hong Kong.

The method has the characteristics such as economy, efficient, pollution-free, strong operability, meets construction requirement.

Summary of the invention

For above-mentioned deficiency of the prior art, the object of the invention is based on catenary equation, has worked out the parallel submerged pipeline cloth anchor method of long distance, has realized the control to pipe laying construction cloth anchor, has solved the difficult problem of the parallel submerged pipeline protection of long distance.The method has proposed the solution of the parallel submerged pipeline construction of long distance first, has ensured the safety of pipeline during original pipeline operation.Consider controlled investment, reduction of erection time, facilitate the aspect factor such as site operation, form the technological scheme that is applicable to the parallel submerged pipeline construction of long distance protection.

In order to realize the foregoing invention purpose, the application provides following technological scheme:

(1) original pipeline design data and survey report comparative analysis

, by the pipeline route survey report to original pipeline design data and employing GeoPulse sub-bottom profiler/pipeline instrument, analyze the present routing condition of pipeline, pipe top buried depth and cover the soil property type.

(2) the parallel laying of pipeline risk point analysis

In construction operation, maximum risk sources is in the impact on pipeline of the anchor of operation boats and ships and anchor hawser.Because long distance is parallel, the pipe laying barge construction is a dynamic process, often complete a sea pipe job execution, need to carry out folding and unfolding anchor hawser reach pipe laying barge, and there is an operation of casting anchor of rising of cycle, anchor hawser is crossed over original pipeline, has scraping and sawing risk to original pipeline, works the operation of casting anchor and has equally this risk.

(3) the pipe laying barge mooring system is analyzed

By construction operation pipe laying barge self mooring system is studied, each parameter of clear and definite mooring system.Comprise anchor weight, anchor hawser model, anchor hawser length and windlass maximum pull etc.

Adopt the anchoring analytical technology, check cloth anchor scheme and whether meet the mechanical equilibrium requirement; The mechanics projecting point of clear and definite each cloth anchor scheme, the cloth anchor work of accurate instruction practice of construction, thereby the destruction that the mechanical structure of avoiding wrong cloth anchor scheme to form causes to extra large pipe.

(4) mooring line catenary analysis

Boats and ships are when casting anchor mooring, and anchor cable is the stretched wire state.The anchor hawser wire rope has good flexibility and uniform quality, and therefore single anchor chain or the anchor cable of wire rope can be regarded the simple cautionary suspension line as, are below the catenary formula.

$y=a[\sec \mathrm{\α}\left(\mathrm{ch}\frac{x}{a}\right)-1]+\mathrm{tg\α}\·\mathrm{sh}\frac{x}{a}=\frac{R}{w}[\frac{1}{\cos \mathrm{\α}}(\frac{e^{\frac{x\·w}{R}}+e^{\frac{-x\·w}{R}}}{2}-1)+\mathrm{tg}\·\frac{e^{\frac{x\·w}{R}}+e^{\frac{-x\·w}{R}}}{2}]---\left(1\right)$

The y depth of water in formula, m;

R effect external force aboard ship, t;

The x anchoring point is to the horizontal equivalent of chaining point, m;

The a angle of weighing anchor, °;

Every meter chain weight of w, t/m

Suppose that the anchor cable that hitches boats and ships is that an intensity is very large, and do not have ponderable anchor cable.The pulling force H that acts on boats and ships is substantially horizontal, and this power acts on anchor by anchor cable.When anchor cable is strained and is not dragged of anchor, the horizontal pull H0 of anchor and environmental forces H balance, i.e. H0=H.Equilibrium of forces as shown in Figure 1.If the angle theta of the horizontal force H0 at anchor point O place, vertical force V0, tension force T0 and tension force and horizontal force ₀, the vertical force V of hawse pipe outlet port A, tension force T, and the angle theta of tension force and horizontal force.According to equilibrium of forces, following equation is arranged:

V ₀=H ₀tanθ ₀=Htanθ ₀ (2)

$T_0=\sqrt{{H_0}^2+{V_0}^2}=H\sec {\mathrm{\θ}}_0---\left(3\right)$

If anchor cable is ponderable, the linear mass load of anchor cable in seawater is w, and the length of anchor cable (catenary) is s, and the horizontal equivalent of A to O is x, and vertical distance (depth of water) is z.

$\frac{w}{H}s=\tan \mathrm{\θ}-\tan {\mathrm{\θ}}_0---\left(4\right)$

$\frac{w}{H}z=\sec \mathrm{\θ}-\sec {\mathrm{\θ}}_0---\left(5\right)$

$\frac{w}{H}x=\ln \left(\frac{\sec \mathrm{\θ}+\tan \mathrm{\θ}}{\sec {\mathrm{\θ}}_0+\tan {\mathrm{\θ}}_0}\right)---\left(6\right)$

Have the characteristics such as friendly interface, computational speed be fast based on the simulated program of VB programming, and be easy to grasp.The program that adopts is that VB writes.

The program solution step:

Determine initial catenary parameter a (each anchor cable is the same).

Set up the newton iteration formula of each anchor cable about a value.

Carry out iteration.

Determine whether requirement, meet, finish to calculate; Otherwise, increase iterations, until full

Till the foot condition.

(5) construction cloth anchor figure draws and field conduct

According to cloth anchor principle, draw cloth anchor figure, crossover line one side, anchor point and pipeline safety, apart from considering to slip the anchor distance, guarantee greater than more than 100 meters.Original pipeline top is every 200 meters indication buoys of arranging 30 meters of three color different interval.Need the tension force of pre-imputation during site operation cloth anchor, guarantee while casting anchor operation that anchor is placed on safely on the anchor boat deck and fixing, avoid from landing on anchor boat.Work the shape cast anchor between operational period by special messenger's charge of overseeing anchor hawser stressing conditions and anchor hawser.

Beneficial effect:

1, be first domestic.Parallel submerged pipeline construction, the pipeline standard is without clear and recommend way, and the parallel submerged pipeline construction of long distance, at home and abroad all beyond example;

2, economic, efficient, strong operability can solve effectively that engineering place marine area function zoning complexity, boats and ships frequent activity, project investment are controlled sternly, the tight requirement of implementing plan duration.

3, the parallel submerged pipeline construction of long distance protection, construction forms danger to the primary tube line, moves the anchor Job Operations in construction improper, very easily original pipeline is worked the mischief, and produces immeasurable consequence.This scheme can meet this project project investment and control tight, tight characteristics of implementing plan duration, meets the field engineering requirement.

4, the parallel submerged pipeline construction of long distance guard method, can obtain good effect in engineering, can solve long actual conditions apart from parallel pipeline construction and duration anxiety.Compare conventional scheme, reduce investment outlay, produce obvious economic benefit.

5, the parallel submerged pipeline construction of long distance guard method, at home and abroad all beyond example, apply first in the branch line submarine pipeline engineering of the second west to east gas pipeline project Hong Kong, successfully solved the difficult problem with parallel 6.11 kilometers of precipice municipal administration line.Therefore, the breakthrough of this technology, have great importance to the technical barrier that fills the domestic gaps, solve China parallel pipeline construction protection etc.For the construction of submarine pipeline of the same trade provides strong reference reference value.

Description of drawings

Fig. 1 basis cloth anchor figure

The phase diagram of Fig. 2 anchor hawser stretched wire

Fig. 3 anchor hawser stretched wire state free-body diagram

Fig. 4 program is calculated interface

Fig. 5 indication buoy schematic diagram

The parallel section of Fig. 6 straight line cloth anchor figure

The parallel section of Fig. 7 camber line cloth anchor figure

Progressive section cloth anchor figure of Fig. 8

Embodiment

The parallel submerged pipeline arrangement and method for construction of long distance:

By presetting pretensioning, calculate the different water depth anchor hawser according to the catenary program and touch the mud point horizontal length that dangles, guarantee that anchor hawser touches the mud point in original pipeline outside, to guarantee that anchor hawser does not contact with pipeline.

Catenary equation programming calculated data

Three kinds of operating modes for the parallel existence of pipeline:

The parallel section of pipeline straight line;

The parallel section of pipeline curve;

Progressive section of pipeline.

(1) the parallel section construction of pipeline straight line

Calculate the distance of crossing over the tactile original pipeline of mud point of anchor hawser according to program.By controlling the pipe laying barge pretensioning, while guaranteeing that pipe laying barge moves, anchor hawser touches mud point in the precipice municipal administration line outside, guarantees that anchor hawser above pipeline, does not contact with pipeline., at anchor point reasonable Arrangement anchor point monitoring ship, monitor the position, anchor hawser length, each anchor of the anchor point angle with respect to pipe laying barge constantly.

(2) the parallel section construction of pipeline curve.

Calculate and cross over anchor hawser and touch mud point distance by the catenary program, rationally the cloth anchor, control pipe laying barge anchor hawser tension variation and realize that anchor hawser touches the mud point outside original pipeline, avoids contacting of anchor hawser and pipeline., at anchor point reasonable Arrangement anchor point monitoring ship, monitor the position, anchor hawser length, each anchor of the anchor point angle with respect to pipe laying barge constantly.

(3) progressive section construction of pipeline.

Calculate and cross over anchor hawser and touch mud point distance by the catenary program, rationally the cloth anchor, control pipe laying barge anchor hawser tension variation and realize that anchor hawser touches the mud point outside original pipeline, avoids contacting of anchor hawser and pipeline., at anchor point reasonable Arrangement anchor point monitoring ship, monitor the position, anchor hawser length, each anchor of the anchor point angle with respect to pipe laying barge constantly.

It should be noted that finally: obviously, above-described embodiment is only for example of the present invention clearly is described, and is not the restriction to mode of execution.For those of ordinary skill in the field, can also make other changes in different forms on the basis of the above description.Here need not also can't give all mode of executions exhaustive.And the apparent variation of being amplified out thus or change still are among protection scope of the present invention.

Claims (5)

1. the parallel submerged pipeline construction of a long distance guard method, is characterized in that, comprises the steps

The original pipeline design data of step 1 and survey report comparative analysis

, by the pipeline route survey report to original pipeline design data and employing GeoPulse sub-bottom profiler or pipeline instrument, analyze the present routing condition of pipeline, pipe top buried depth and cover the soil property type;

The analysis of the parallel laying of step 2 pipeline risk point

In construction operation, maximum risk sources is in the impact on pipeline of the anchor of operation boats and ships and anchor hawser;

Step 3 pipe laying barge mooring system is analyzed

By construction operation pipe laying barge self mooring system is studied, each parameter of clear and definite mooring system, comprise anchor weight, anchor hawser model, anchor hawser length and windlass maximum pull;

The step 4 mooring line catenary is analyzed

Boats and ships are after casting anchor, and anchor cable is the stretched wire state, and anchor chain or wire rope have good flexibility and uniform quality, and single anchor chain or the anchor cable of wire rope are regarded the simple cautionary suspension line as;

Step 5 construction cloth anchor figure draws and field conduct

, by to mooring line catenary research,, in conjunction with result of calculation,, according to engineering ship cloth anchor point theory, draw construction cloth anchor figure, and by the related software module, adjust this cloth anchor state of boats and ships each anchor hawser stressing conditions under extreme operating condition.

2. method according to claim 1, it is characterized in that: the pipe laying barge mooring system in described step 3 is analyzed, pipe laying barge anchor, anchoring cable and displacement winch are studied, and clear and definite pipe laying barge anchor weight, anchor hawser model and winch performance parameter, determine the anchoring ability of pipe laying barge.

3. method according to claim 1 is characterized in that: the mooring line catenary analysis in described step 4, and boats and ships are after the cloth anchor, anchor hawser is the stretched wire state, single anchor hawser is considered as simple catenary,, according to the catenary formula, passes through method of iteration, according to construction depth of water situation, default different tension forces, calculate engineering ship in the same depth of water situation, goes out the chain hole and touch the horizontal equivalent of mud point to anchor hawser, distance between selection level distance is parallel greater than pipeline, determine the pretensioning size.

4. method according to claim 1, it is characterized in that: in step 4, the catenary formula is

$y=a[\sec \mathrm{\α}\left(\mathrm{ch}\frac{x}{a}\right)-1]+\mathrm{tg\α}\·\mathrm{sh}\frac{x}{a}=\frac{R}{w}[\frac{1}{\cos \mathrm{\α}}(\frac{e^{\frac{x\·w}{R}}+e^{\frac{-x\·w}{R}}}{2}-1)+\mathrm{tg}\·\frac{e^{\frac{x\·w}{R}}+e^{\frac{-x\·w}{R}}}{2}]$

In formula

The y depth of water, m;

R effect external force aboard ship, t;

The x anchoring point is to the horizontal equivalent of chaining point, m;

The a angle of weighing anchor, °;

Every meter chain weight of w, t/m

When the anchor cable that hitches boats and ships is that an intensity is very large, and while not having ponderable anchor cable, the pulling force H that acts on boats and ships is substantially horizontal, and this power acts on anchor by anchor cable, when the anchor cable tension and while not dragging of anchor, and the horizontal pull H of anchor ₀With environmental forces H balance, i.e. H ₀=H, the horizontal force H at anchor point O place ₀, vertical force V ₀, tension force T ₀And the angle theta of tension force and horizontal force ₀, the vertical force V of hawse pipe outlet port A, tension force T, and the angle theta of tension force and horizontal force have following equation according to equilibrium of forces:

V ₀＝H ₀tanθ ₀＝Htanθ ₀

$T_0=\sqrt{{H_0}^2+{V_0}^2}=H\sec {\mathrm{\θ}}_0$

When anchor cable is ponderable, the linear mass load of anchor cable in seawater is w, and the length of anchor cable is s, and the horizontal equivalent of A to O is x, and vertical distance (depth of water) is z,

$\frac{w}{H}s=\tan \mathrm{\θ}-\tan {\mathrm{\θ}}_0$

$\frac{w}{H}z=\sec \mathrm{\θ}-\sec {\mathrm{\θ}}_0$

$\frac{w}{H}x=\ln \left(\frac{\sec \mathrm{\θ}+\tan \mathrm{\θ}}{\sec {\mathrm{\θ}}_0+\tan {\mathrm{\θ}}_0}\right)\·$

5. method according to claim 1, it is characterized in that: construct in described step 5 cloth anchor figure and field conduct, according to cloth anchor principle, draw cloth anchor figure, crossover line one side, anchor point and pipeline safety are apart from considering to slip the anchor distance, assurance is greater than more than 100 meters, adjust this cloth anchor state of boats and ships each anchor hawser stressing conditions under extreme operating condition by the related software module, original pipeline top is every 200 meters indication buoys of arranging 30 meters of three color different interval, need preset according to the tension force that calculates in step 4 during site operation cloth anchor, guarantee while casting anchor operation that anchor is placed on safely on the anchor boat deck and fixes, avoid from landing on anchor boat, work the shape cast anchor between operational period by special messenger's charge of overseeing anchor hawser stressing conditions and anchor hawser.

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