Assessment of unconventional oil and gas resources in the Jurassic Sargelu Formation of Iraq, 2014

Fact Sheet 2015-3006
National and Global Petroleum Resource Assessment Project
By: , and 



The U.S. Geological Survey (USGS) quantitatively assessed the potential for unconventional (continuous) oil and gas resources within the Jurassic Sargelu Formation of Iraq. Organic-rich shales of the Jurassic Sargelu Formation are one of the main petroleum source rocks for conventional fields in the Arabian Peninsula. The Sargelu Formation consists of marine shales, with as much as 10 weight percent sulfur-rich Type IIS organic matter, deposited in a relatively deep, anoxic Jurassic depocenter. The potential for volumes of oil retained in the Sargelu Formation source-reservoir rock system following oil migration, cracking, or degradation is the focus of this assessment. Conventional oil and gas resources of Iraq were assessed by the USGS in 2012.

The USGS assessment methodology consists of a well-performance approach that recognizes the geologic variability within assessed reservoirs. For non-U.S. assessments, the USGS assesses shale-gas or shale-oil reservoirs that (1) contain greater than 2 weight percent total organic carbon (TOC), (2) are within the proper thermal maturity window for oil or gas generation, (3) have greater than 15-m thickness of organic-rich shale, and (4) contain Type I or II organic matter. These specific USGS criteria when applied to any given shale-oil or shale-gas reservoir might significantly reduce the potential resource assessment area compared to maps made with greater than 1 weight percent TOC.

Study Area

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Assessment of unconventional oil and gas resources in the Jurassic Sargelu Formation of Iraq, 2014
Series title Fact Sheet
Series number 2015-3006
DOI 10.3133/fs20153006
Year Published 2015
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Central Energy Resources Science Center
Description 2 p.
Country Iraq
Other Geospatial Jurassic Sargelu Formation
Online Only (Y/N) N
Additional Online Files (Y/N) N
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