PIPELINE SPANNING ANALYSIS

Introduction

Assessment of pipeline where determining the acceptability of pipeline freespan without effected the structural integrity, which was measure the allowable span of pipeline with respect to certain criteria as per below:


-Static stress cross flow vortex shedding for the maximum design wave data combined with steady current.
-In-line vortex shedding using steady current only (no wave induce current)


A lot of factor that contribute the pipeline span like


-Uneven seabed
-Pipeline crossing
-Coral


Static Spanning



To maintain the consistency with other features in pipeline, span length based on static stress considerations are governed by:


-Selfweight and coatings
-Environmental factor
-Operational Factor
-Hydrotest Factor


All method of pipeline spanning analysis is according to DnV 81 as follow:

Dynamic Spanning


Dynamic span is to check the allowable span for installation, hydrotest and operation under the steady state current conditions.

Analysis is according to DnV 81 which fluid flow passing a free span that cause unsteady flow patterns due to vortex shedding, which may lead to oscillations of the pipe. vortex shedding frequency may coincide with, or be a multiple of, the natural frequency of the pipe. Harmonic or sub-harmonic excitation of the free span may then result.

SYMETRIC VORTEX SHEDDING

WEAK ALTERNATE VORTEX SHEDDING

STRONG ALTERNATE VORTEX SHEDDING

Swiber to lay Myanmar gas lines (Ref : http://www.offshore-mag.com)

Published: Nov 25, 2009


Offshore staff

SINGAPORE -- Swiber Holdings has won its first pipeline installation contract offshore Myanmar. An unnamed oil and gas company has issued a Letter of Award valued at $77 million for laying of 150 km (93 mi) of subsea gas pipelines.

Preparation for the project should get under way next month, with the installation program due to be completed in 2Q 2010.

Swiber is expanding its vessel pool, in anticipation of increased demand for offshore construction work. The fleet currently comprises 34 offshore vessels and 10 construction vessels, and Swiber expects to own and operate a total of 52 vessels by 2011.

11/25/2009

ARTICLES - NEW METHOD OF CONSTRUCTION PIPELINE

NOTE : Please click at the articles for zoom in

CATHODIC PROTECTION DESIGN

-External Corrosion Coating is a combination of both coating and anode.

ANODE
-In the event of coating damage or deterioration, a secondary anode system is also provided, typically in the form of zinc or aluminum alloy sacrificial bracelet anodes.
-Cathodic Protect design is based on DNV-RP-F103.
-The minimum required anode length corresponding to the selected anode bracelet thickness to meet both minimum weight and surface area requirement which is the thickness of anode must to be same as thickness of concrete coating
-Cathodic Protection design calculation as per below :

EXTERNAL CORROSION COATING
-List of external corrosion coatings and the maximum temperature limit as per below:

NEW OGA PIPELINE LOGO

After a years started, OGA PIPELINE officially launch a new logo. Start from today, any other bussiness that involve by OGA PIPELINE will using these logo. Thanks for all your support and stay tuned for more info in OGA PIPELINE.

From now on, OGA PIPELINE has been registered as:

OGA PIPELINE ENTERPRISE

(Reg. No. : 001903538-H)

No. 401 Block A-12, Section 1 Wangsa Maju,

Setapak,

53300 Kuala Lumpur

PIPELINE ENGINEERING SCOPE OF WORK

These are the details of Pipeline Engineering scope of work which are the stage from design until construction/installation. OGA PIPELINE will discuss further every point as stated in the table and as of now, only Wall Thickness and On Bottom Stability have been discussed.

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5. OR YOU CAN MAKE A PAYMENT VIA CREDIT CARD/DEBIT CARD : SEE AT SIDE PAGE- (PACKAGE A-JOBSEEKERS AND PACKAGE B-COMPANY SEARCH). SEE THIS LOGO