Bidvertiser

Loading...

CRUDE OIL FORMATION


Crude oil is a dark viscous substance formed beneath the earth crust.There are actually three stages of crude oil formation: Diagenesis stage,Catagenesis and Metagenesis.

DIAGENESIS STAGE OF CRUDE OIL FORMATION

This is a gradual degradation of organic matter at the bottom of the sea.Organic substance,being more unstable than mineral compound undergo reasonable form of transformation immediately after their deposition below water interface.This continues for a while before being buried completely by shale formation at the bottom of the seabed.As a result of the burial the organic organism transforms to kerogen under anaerobic action at a temperature below 50 degree Celsius. This is regarded as bacteria degradation.


CATAGENESIS STAGE OF CRUDE OIL FORMATION

As the rock or the sediments containing kerogen is progressively buried in a subsiding basin, the kerogen is subjected to increasing temperature and pressure.The temperature may vary from about 50 degrees to 60 degrees even to as high as 75 degrees in the major part of the sedimentary basin.Pressure can range from 1200psi to over 10000psi in same part of the sedimentary section.The increase temperature represents an increase of of energy available for chemical reactions on the kerogen.

Hence, at subsurface temperature of between 50 degrees to 75 degree celsius, the kerogen begins to break up and produce hydrocarbon.The breaking up of kerogen is caused by the cracking and reformation of kerogen molecules which is reflected in an increase in bitumen content of rock or sediment.

The bitumen molecules are intermediate and are inturn broken down into smaller molecules and these along with side chain hydrocarbon form the kerogen molecules from the chain alkanes,napthalene and aromatic hydrocarbon which area all components of hydrocarbon.

With further increase in temperature the reaction becomes more intense and the peak or main stage of petroleum generation is reached and this is know as oil window.At this stage oil and gas are generated with further increament of temperature advance catagenesis stage is reached which produces more and more gas.

METAGENESIS STAGE OF CRUDE OIL FORMATION

At the end of the wet gas stage the capacity of the kerogen to produce anything more than a limited quantity of methane is exhausted and carbonisation or metagenesis stage is reached.At this stage the kerogen has been converted to a carbon residue and the produced petroleum into methane and pyro bitumen.(110 degrees-200 degrees celsius).Beyond 200 degree celsius is a great change with is not a process of oil generation.
ENGINEERING 886091279234406600

Post a Comment

emo-but-icon

Home item

Bidvertiser

MOST RECENT POSTS