Crude Oil Classification Based On Age And Provenance From The Southern Iraq: A Review

Abstract

A collection of 165 crude oils, 12 oil seeps, and 24 extracts and recovered samples from 25 oil exploratory wells and 6 oil seeps in the Southern Mesopotamian Basin were studied. Biomarker configurations and other organic geochemistry parameters were used to discover the depositional environments and to classify the oil samples as provenance groups. Petroleum liquids were geochemically classified into four groups. The first group of oils, Middle Jurassic Zagros Fold Belt, is located in the Maysan, Basra, and Thi qar provinces of the basin that has pristane/phytane (Pr/Ph) proportions ≤0.97 and contains sufficient gammacerane. Methylphenanthrene index 1 (MPI 1) values show that the first group of oils is mature. Oils from Group 2, Upper Jurassic–Lower Cretaceous Sulaiy/Yamama, by disparity have Pr/Ph proportions between 0.72 and 1.12 and relatively moderate C28/C29 steranes, 0.52-0.88. Ts/Tm ratios indicate thermal maturity for Group 2 oils. Unlike oils from other groups, the oils from Group 3, Cretaceous to Tertiary oils, in Subba Field hold the highest canonical variable (CV) values that range between 0.43 and –2.30. The fourth group, Late Triassic-Middle Jurassic oil seeps, is the oldest among all groups. This group holds an average carbon isotope ratio –28.25‰ and –28.10‰ for saturates and aromatics respectively, which are the lowest values among all oils in the studied region. The Tithonian-Berriasian Sulaiy/Yamama oils further divided into three subgroups. The first subgroup, A, has carbon preference index (CPI) values of ≤1.08 (average 0.86) and C28/C29 sterane of 0.56-1.13 with an average of 0.65. Second subgroup, B, holds CPI ≤1.18 (average 0.99) and C28/C29 sterane 0.55-0.82 with an average of 0.63. The last subgroup, C, has CPI values ≤0.93 (average 0.85) and high C27 and C29 steranes (average 46.5% and 39.61%, respectively). In the same way, the Group 3 can be further subdivided into two subgroups based on values of carbon isotopes for saturates and aromatics. The oils from this group are heterogeneous and can be further divided into Tertiary Subgroup and Cretaceous Subgroup.

study of sulfur content in crude oil, gasoline and kerosene in some Iraqi oil fields and refineries

“…The sulfur content of crude oil at the site of the tenth study (Baiji Refinery, 1.7214 wt%) and the results of our study were consistent with the findings of the researcher's mechanism. (Abdula, 2020). The high concentration of sulfur content in crude oil makes it of poor quality and its use in industrial activities causes emissions of sulphur compounds, affecting air quality (Alkhalili, Yahya, Ibrahim, Ganapathy, & Thwaini, 2020).…”

The geologic history of marine dissolved organic carbon from iron oxides

“…100 and supplemented with data from Refs. 78,86,[101][102][103][104][105][106][107][108][109][110][111][112] . Unlike for kerogen, more care must be taken when reporting crude oil ages since depositional age can differ from host-rock age due to oil migration.…”

Investigation of the Geochemical Properties and Origin of the Crude Oils Accumulated in the Mishrif Reservoirs in the Zubair, Halfaya, and Buzurgan Oilfields, Southern Iraq

“…In comparison, there have been limited organic geochemical studies of the oil reserves in the Mishrif Formation. The first geochemical study published was (Al-Ameri et al, 2009), which was followed by subsequent studies such as: Al-Khafaji (2015); Al-Ameri and Al-Zaidi (2014); Awadh et al (2018);Al-Khafaji et al (2018;2019a;2020 and2021a); Al-Mimar et al, 2018;Abdula, (2020); Boschetti et al, 2020;and Alsultan et al (2021).…”