In this study, the source rock potantial of the Organic-rich Eocene-age Suzak Formation was investgated. This Formation belongs is located in Afghan-Tajik basin in the northern Afghanistan.
Suzak Formation conformably overlies the Bukhara Formations. In Tajikestan and Ozbekistan this formation has proven to be petroleums source rock, but in Afghanistan geologists have been investingating the Organic-rich Eocene-age Suzak (also called Givar) mudstone for many years in other to prove its potential of the bed rock. To understand the capacity of this formation organic petographic and organic geochemical analyzes of the bed rock was carried.
During the organic petrographic and organic geochemical analysis many samples of crude oil, natural gas, and source rock were collected from wells, fields, and outcrops in northern Afghanistan to correlate with crude oil and natural gas of postulated source rocks.
The Total Organic Carbon (TOC) content of Suzak mudstone outcrop samples is generally low, averaging approximately 0.4 weight percent. Only two outcrop samples contain total organic carbon greater than 1 weight percent, both approximately 1.3 weight percent. Two Suzak mudstone core samples have total organic matter contents of 13.9 and 19.7 weight percent, indicating that these rocks are capable of generating petroleum.
Results from pyrolysis analysis (Rock-Eval) indicate that Tmax is between 435-465 degrees C, in which organic mattter shows it takes place between immature-post mature.
Pyrolysis analysis of the Suzak mudstone also indicates that most of the samples of the outcrop contain natural gas-prone type III kerogen. But core samples and a few outcrop samples contain crude oil-prone type II kerogen.
Most of the samples have mean vitrinite reflectance values between 0.9 and 1.5 percent, indicating that the organic matter is thermally mature and within the realm of crude oil generation. Two samples have vitrinite reflectance values of approximately 2%, capable of natural gas generation. One aberrant sample probably contains reworked (recycled) vitrinite with a reflectance value of 5.6 percent. |