GAS PIPING IN PETROLEUM INDUSTRIES

Presented By

Mohammad Saied

Hesham Ali

Mohammad Amin

Kareem Mohammad

Mohammad Farrag

I- INTRODUCTION

II- CONSTRUCTION, INSTALLATION & TESTING

III- PIPELINE OBSTACLES

IV- CONTROL OF PIPELINES

V- MAINTENANCE

INTRODUCTION

Why gas pipelines?

Toxic gases. Transportation of gaseous fluid is more

practical and has lower cost than liquefying it. Least hazard.

Example For Major Pipelines:

West African Gas Pipeline: The west African gas pipeline is 678 Km Long pipeline

from Nigeria's ‘Escraves ‘ region to Benin, Togo and Ghana.

South Stream: It is a proposed gas pipeline to transport Russian

natural gas to black sea to Bulgaria and further to Italy and Austria.

Alaska gas pipeline :

The Alaska gas pipeline is a proposal to transport natural gas from the Alaska North Slope natural gas reserves to the U.S. Midwest.

INTRODUCTION

PLANNING AND CONSTRUCTIONOF PIPELINES

Planning and Construction of any new pipeline system depends on several factors: Material (fluid or solid) to be transported by the

pipeline ( whether it is natural gas, oil, water,…………etc).

Length of the pipeline. Environment ( whether the pipeline is in urban

or countryside, setting on land or offshore, worm or cold climate ).

Procedures used for long-distance steel gas pipe lines: Step 1: Preliminary Planning. Step 2: Route Selection. Step 3: Acquisition of right of way. Step 4: Testing Soil. Step 5: Pipeline Design. Step 6: Start Construction.

Way preparation. Strings. Ditching and Trenching. Tunneling. Welding, Coating and wrapping. Pipe laying. Backfill and restoration of land.

PLANNING AND CONSTRUCTIONOF PIPELINES

Expansion in pipeline : Building Zigzagged instead of straight pipeline to

provide allowance for thermal expansion. Zigzag move freely either outward (During

Expansion ) or inward (During Shrinkage). For pipelines above ground, sometimes an

inverted U or loop is used instead. Special joints are available for expansion, such

as: a)Bell and spigot joints. b) Slip joints.For small diameter pipes, using a joint made of

flexible pipe (hose) will allow expansion.

PLANNING AND CONSTRUCTIONOF PIPELINES

Installation and Connecting Pipes: Pipes available in sections of 20-ft length. For steel pipes, the maximum section length is

usually 40-ft. Segments transported to the construction site. Before being laid in ditches,

sections joined (connected) together to form a long pipeline.

Joining can be done in several ways including: a) Flanged joints. b) Other mechanical joints. c) Welding.

PLANNING AND CONSTRUCTIONOF PIPELINES

Pipeline Welding Defects: a) Under cutting due to technique mistakes. b) Accumulation of discontinuity. c) Cracks. d) Porosity or gas pockets. e) Slag inclusion. f) Burn through. g) Incomplete fusion.

PLANNING AND CONSTRUCTIONOF PIPELINES

Testing a) Welding Inspection and Testing: 

There are two inspection methods.  I) Non-destructive test NDT:

Visual/Optical Testing VT/OT. Radiographic (x-ray and gamma ray) RT. Ultrasonic Testing UT. Penetrant Testing PT. Magnetic Testing MT.

II) Destructive test DT: This could be done by taking a sample of the welding

part and testing it in the lab. Location of the sample should be according to API

standard. The test could be tension, bending and impact.

PLANNING AND CONSTRUCTIONOF PIPELINES

Testing b)Hydro-testing:

Hydro-testing of pipe, pipelines and vessels is done to expose defective materials that have missed prior detection, ensure that any remaining defects are insignificant enough to allow operation at design pressures, expose possible leaks and serve as a final validation of the integrity of the constructed system. ASME B31.3 requires this testing to ensure tightness and strength. ASME B31.3 p345.

PLANNING AND CONSTRUCTIONOF PIPELINES

Testing b)Hydro-testing:

Testing procedures: The vessel is filled with a nearly incompressible liquid –

usually water and examined for leaks or permanent changes in shape. Red or fluorescent dyes are usually added to the water to make leaks easier to see. The test pressure is always considerably higher than the operating pressure to give a margin for safety. This margin of safety is typically 150% or 5/3 of the design pressure, depending on the regulations that apply.

Water is commonly used because it is almost incompressible so will only expand by a very small amount should the vessel split.

PLANNING AND CONSTRUCTIONOF PIPELINES

Design data needed for external corrosion control: Operating temperature Water temperature Water movement Depth of water Burial Pipe size and length

PIPELINE OBSTACLES

Design data needed for internal corrosion control: CO2

H2S Moisture Content. Operating temperature and pressure. Condensate. Velocity. Solids, scaling

PIPELINE OBSTACLES

Internal Corrosion Control Requires Monitoring:Chemical injection

Corrosion inhibitors CI Biocides Scale inhibitors Methanol Kinetic Hydrate Inhibitor KHI

Materials selection 13-Cr alloys Duplex Stainless steels

PIPELINE OBSTACLES

Typical Pipeline Coatings For Corrosion Control : External pipeline protective coatings Fusion bond epoxy

With a rough coat Bitumen, asphalt and coal tar coatings

Coal tar epoxies Coal tar urethanes

External concrete coatings weight coatings Polymer concrete

PIPELINE OBSTACLES

Geographical Problems: Onshore

Presence of hills, mountains, cliffs, and valleys affects the pipeline cost.

Offshore Hard to find flat surface to install a pipeline, so,

paving the seabed for a straight or constructing bridges on seabed.

PIPELINE OBSTACLES

Leakage ,it’s Causes and Effects: There are four main categories of pipeline

failures.These are: Pipeline corrosion and wear Operation outside design limits Unintentional third party damage Intentional damage

Gas leakage has bad effects on the environment, and the mankind.

PIPELINE OBSTACLES

CONTROL OF PIPELINES

Most modern pipeline systems are automated and controlled by computers. The degree of sophistication of the automation/computer system depends on the size and complexity of the pipeline and its operation.

They often include three I) SCADA (Supervisory Control And Data

Acquisition). II) The communication media that links the

SCADA to the remote stations. III) RTUs (Remote Terminal Units)

SCADA consists of three parts: (1) A user-friendly console to interface with the

operator (human), (2) A server, which contains the database

needed for operating the pipeline, (3) The MTU (Master Terminal Unit) that

communicates with the RTUs.

CONTROL OF PIPELINES

Leakage detection: Gas leakage is a main source for

economic losses. Methods of leakage detection:

Mass-Balance. Pressure Drop. Visual and Photographic Observation.

CONTROL OF PIPELINES

PIPELINE MAINTENANCE

In order to keep any pipeline in service, it should be repaired and maintained. Routine Maintenance:

Provides smooth operation for the pipeline Maintaining the pipe itself ,

and accompanied equipment. Malfunctioned equipment

repaired or replaced. Pigs

Cleaning and Inspection.

PIPELINE MAINTENANCE

Fracture Repairing: Pipeline Clamps: For minor fracture or small cracks

Fracture Repairing: Ball and Misaligning Flanges

For major fracture or failure of a part of a pipeline.

PIPELINE MAINTENANCE

REVIEW

IMPORTANCE OF GAS PIPELINES

CONSTRUCTION, INSTALLATION & TESTING

CONTROL OF PIPELINES

OBSTACLES

MAINTENANCE

REFERENCES

“Pipeline Engineering” By Henry Liu www.oilstates.com www.oceaneering.com http://en.wikipedia.org www.intecsea.com www.saipem.it www.ndt-ed.org

THANKS FOR YOUR TIME

OUR GREETINGS

SAIED AMIN FARRAG

HESHAM KAREEM