Anticline
an upfold in rock strata producing an arch or dome structure that closes in four directions. One of the most common hydrocarbon traps
API
American Petroleum Institute. API gravity is a standard method of measuring density of crude oils and is expressed in degrees
Appraisal Well or Appraisal Drilling
a well that is being drilled into a discovered hydrocarbon accumulation to further understand the extent and size of the accumulation – usually denoted by “name-2”, “name-3” etc. appraisal wells can be drilled either before or after an accumulation has been developed. an appraisal well usually has a chance of success greater than an exploration well but less than a development well.
Aromatics
Group of hydrocarbons of which benzene is the parent. They are called "aromatics" because many of their derivatives have sweet or aromatic odors.
