Offshore Platform Selection Criteria

The assessment that would be done before choosing a development system for oil and gas
production includes:

Water depth

The realities of the laws of physics and the limited strength and flexibility of materials make
water depths the first cut in choosing a development system. Below is the water depth for 
each options;-

            Fixed platforms…………………<1500ft
            Gravity platforms………………1000ft
            CTs ………………………………3000ft
            TLPs……………………………..5000ft
            Spars…………………………… 7500ft
            FPSs…………………………….unlimited
            Subsea systems……………….unlimited

Oil Transportation

With the cost of laying new pipelines exorbitant  calls for floating production systems with oil
storage onboard or floating nearby. So that’s why in remote West Africa, the complete lack 
of oil pipeline infrastructure calls for FPSOs, or at minimum, FSOs.

Gas Disposition

Deepwater gas can provide good news or bad in the selection of development systems. If 
the prospect has associated gas dissolved in the oil, something besides flaring has to be
done with the gas as it is produced. Gas is good news when a gas pipeline infrastructure
presents itself in some proximity. The good news is then compounded when the reservoir is
predominantly gas , with just some associated liquids.

Reservoir Proximity


Development opportunity can include more than one reservoir. The proximity of the various 
reservoir can dictate the scheme selected. If they are relatively close to each other (2 miles)
, that arrangement favours a fixed platform, a TLP, a spar, or a compliant tower, but doesn’t 
exclude development with subsea wet trees. If the reservoirs range over many miles, 
subsea wells connected via flowlines to a fixed or floating station makes more sense.