Quality and chemistry of crude oils

Physico-chemical characteristics such as API (American Petroleum Institute gravity) specific gravity, pour point, Calorific value, Kinematic viscosities, Reid vapour pressure, Copper corrosion, Water and sediments, Total Sulphur, Distillation range (I.B.P.F.B.P., Total recovery), residue and hydrocarbon contents (saturates, aromatics and polar) of crude oils collected from different oil fields of North (Punjab) and South (Sindh) regions of Pakistan have been evaluated using standard ASTM (American Society for Testing and Material) procedures. The results of North Region (Punjab) and South Region (Sindh) crude oils have been compared with each other. Punjab crude oils are better than Sindh crude oils because these have low specific gravity, low sulphur contents, low viscosity and low pour point. All the tested samples are of sweet type on the basis of total sulfur contents except three (L, N, O) samples of south (Sindh) region which are of sour type. All the tested samples belongs to the class light crude oil on the basis of API gravity except one (N) sample which belongs to the medium class.   Key words: Classification, quality, sweet, sour, saturates, aromatics, polars, light, medium, heavy, crude oil