offshore

PRESENTATION ON OFF SHORE PLATFORM DESIGN

April 20 , 2011

Overview

•Offshore platforms are used for exploration of oil and gas from under Seabed and processing.

• The first offshore platform was installed in 1947 off the coast of lousiana in 6M depth of water.

• Today there are thousands of offshore platforms around the world in water depths more than 2000 metres.

Overview

• Platforms size depends on facilities to be installed on top side eg. Oil rig,living quarters,helipad etc.

• Classification of water depths:

- <350M-Shallow water

- <1500M-Deep water

- >1500M-Ultra deep water

ClassificationOffshore platforms can be broadly categorized into two types….

Fixed structures that extend to the seabed

steel jacket

concrete gravity structure

compliant tower

Structures that float near the water surface

Tension leg platforms

Semi submersible

Spar

Ship shaped vessel

The loads generated by environmental conditions plus by onboard equipment must be resisted by the piles at the seabed and below.

The soil investigation is vital to the design of any offshore structure.Geotech report is developed by doing soil borings at the desired location ,and performing in-situ and laboratory tests.

Pile penetrations depends on platform size and loads,and soil characteristics,but normally range from 30 meters to about 100 meters.

Typical slope is 1/6 (statistical analysis)

The angle of bending obtained as 9.46 degrees.

Platform height 630mm.

Base span – square of side 305mm.

Raw materials usedMild steel rod – dia 6mm,10mm,16mm.

Square metal plate (170X170),thickness 3mm.

Ball bearings (Inner dia 15mm)– 2Nos.

Workshop Processes• Welding

• Lathe

• Drilling

• Filing

Top platform dimensions (mm)

Recommended safe load

calculated is

Max 3.0kg

References

W.J.Graff, Introduction to Offshore Structures.

B.C Gerwick : Construction of Offshore Structures.

Patel M.H.Dynamics of Offshore Structures .

Thanks to• Ramji Sir

• Workshop instructors

• Audience

Group Members1. R HARILAL

2. AJMAL HUSSAIN

3. IZAZ NAHA

4. ARAVIND KRISHNAN

5. SHAIK ASIF AHAMMED