WHAT'S IN A NAME NO.1

Hydrocarbon liquids removed from associated and non-associated gas have many names. Some of them are:

CONDENSATE / LIGHT OIL / NGL / CHPS / LIGHT NAPHTA / NATURAL GASOLINE / PENTANES AND HEAVIER / C5+ / LPG / LNG? There are differences between some, but others are equal. My personal use of these terms is as follows:

A CONDENSATE is produced by a non-associated gas/condensate reservoir (with or without free liquid in the reservoir) as long as the initial condensate/gas ratio after stabilising the liquid is not more than 1000 m3 liquid per million m3 gas ( say 180 bbl/MMscf). It is straw coloured to water white. The condensate is in principle recovered from the gas at the first stage separator and is often reported as a quantity after stabilisation. Please be aware that the unstabilised quantity separated at the first stage separator is considerably more as there may be as much as 50 mol % methane in the liquid at high pressure.

LIGHT OIL may be similar to condensate, as far as composition is concerned, but has been or still is associated with an oil reservoir. Often the liquid/gas ratio of the reservoir fluid produced from a depletion type oil field decreases. It may have come from an initial, say 20 000 m3 liquid per million m3 gas (say 3600 bbl/scf) to a number under 1000 m3/m3. Or for those thinking in gas/oil ratio the GOR has increased from 50 to 1000 m3/m3 (say 300 to over 6000 scf/bbl). Then one often talks about producing from the gas-cap. The colour of the liquid will be dark. Also the light oil is recovered at the first stage sep

NGL's or Natural Gas Liquids are those heavier liquid hydrocarbons that drop out in compressor plants and dewpoint treating plants in inter-stage or cold-separators. They are a mixture of light hydrocarbons (methane, ethane, propane) and most of the heavier components (butane, pentane and heavier) that were present in the gas that was separated from crude at the separators of a crude/gas separation station.When talking about NGLs I always think of an unstabilised liquid.

CHPS or Casing Head Petroleum Spirit is a name given to a mixture of condensate and NGLs produced in some countries

LIGHT NAPHTA is a mixture of liquid hydrocarbons in the pentane to octane range recovered by distillation from crude oil in refineries. A large part of this light naphta stream may have been called condensate in the field where it was injected (spiked) into the crude stream.

Liquefied Petroleum Gas (LPG) plant. It is the bottom stream of the de-butaniser and will contain, apart from the pentanes and heavier hydrocarbons, small quantities of butane, propane and even ethane.

PENTANES AND HEAVIER or C5+ is mainly used when we want to indicate the pentanes and heavier CONTENT of a gas. The C5+ is often expressed as a mol % but also in say t/a.

LPG or LIQUEFIED PETROLEUM GAS is the name for a mixture of Propane and Normal- and Iso-Butane that is produced by NGL fractionating plants. The LPG can be sold as separate Propane and Butane streams but also as mixtures. Very small quantities of Ethane and Pentanes will be present.

LNG or LIQUEFIED NATURAL GAS is the name of a liquid gas mainly consisting of Methane and Ethane with sometimes also Propane and Butane present. Transport takes place at a temperature of approximately -160 °C and atmospheric pressure.