Changes

Figures for the world's production of NGL are not consistently reported and are, therefore, not easy to obtain. The total amounts of NGL, or of the lease condensate production, or both, are commonly reported as part of the crude oil production, and while production volumes of natural-gas plant liquids are sometimes reported, separate figures for lease condensate production can seldom be obtained.  

Figures for the world's production of NGL are not consistently reported and are, therefore, not easy to obtain. The total amounts of NGL, or of the lease condensate production, or both, are commonly reported as part of the crude oil production, and while production volumes of natural-gas plant liquids are sometimes reported, separate figures for lease condensate production can seldom be obtained.  

[[file:St54Ch3Figure21.jpg|thumb|300px|{{figure number|1}}World natural-gas liquids production. From Salvador.<ref name=Salvador_2005>Salvador, Amos, 2005, Energy-A historical perspective and 21st century forecast: AAPG Studies in Geology 54, 208 p.</ref>]]

[[file:St54Ch3Figure21.jpg|thumb|300px|{{figure number|1}}World natural-gas liquids production. From Salvador.<ref name=Salvador_2005>Salvador, A., 2005, Energy-A historical perspective and 21st century forecast: AAPG Studies in Geology 54, 208 p.</ref>]]

Because of the difficulty for obtaining figures for NGL production, the volumes of the world's total NGL production shown in [[:file:St54Ch3Figure21.jpg|Figure 1]] had to be estimated, assuming an average liquids-to-gas ratio of 22.5 bbl of NGL per mmcf of gas. In the United States, where better information is available, the average NGL yield of natural gas is higher: 35-40 bbl per mmcf. The ratio, of course, varies from petroleum field to petroleum field and from country to country, and the overall world average can only be calculated based on reliable statistics for gas and NGL, statistics that are not always readily available.

Because of the difficulty for obtaining figures for NGL production, the volumes of the world's total NGL production shown in [[:file:St54Ch3Figure21.jpg|Figure 1]] had to be estimated, assuming an average liquids-to-gas ratio of 22.5 bbl of NGL per mmcf of gas. In the United States, where better information is available, the average NGL yield of natural gas is higher: 35-40 bbl per mmcf. The ratio, of course, varies from petroleum field to petroleum field and from country to country, and the overall world average can only be calculated based on reliable statistics for gas and NGL, statistics that are not always readily available.