查看“API比重”的源代码

API是[[美国石油学会]]的缩写，同时它用来表示石油流体相对于水的比重，定义为<math>API=\frac {141.5}{\bar{\gamma_{o}}}-131.5</math>，其中<math>\bar{\gamma_{o}}</math>是<math>60^\circ/60^\circ</math>时油的<math>\bar{\gamma}</math>值。

[[液体]]的<math>\bar{\gamma}</math>值，定义为同一[[温度]]和[[压力]]下液体密度<math>\rho</math>与水的密度<math>\rho_{w}</math>之比。

若API大于10，石油液体密度小于水。正常情况下大多数石油流体API值介于10到70之间。
==参考文献==
{{reflist}}
==外部链接==
*[http://www.koehlerinstrument.com/products/hydrometer.html Link to hydrometer]
*[https://web.archive.org/web/20140728125404/http://dnr.louisiana.gov/assets/docs/oilgas/productiondata/comments_1989_rev.pdf Comments on API gravity adjustment scale]
*[http://www.globalsecurity.org/military/library/policy/army/fm/10-67-1/APPI.HTML Instructions for using a glass hydrometer measured in API gravity]
*[http://www.sizes.com/units/hydrometer_api.htm API Degree history]
[[Category:物理量]]
[[Category:石油地质学]]
[[Category:石油生產]]