Total Petroleum System Study Of Nahr Umr Oil field Southern Iraq
Abdullah Abdulhasan Ali, Abdulhussein N. Alattabi, Murtadha D. Abdullah · 2022 International Symposium on Multidisciplinary Studies and Innovative Technologies (ISMSIT) · 2022
The Nahr Umar field is in the Basrah Governorate in the southeastern part of Iraq, about 30 km north to northwest of the city of Basrah. The Shatt aI-Arab passes through it and divides it into two parts. The research included studying the oil-producing formations and knowing their chemical properties, as well as the source rocks and linking the relationship of the oil system to this field. Rock samples were collected by 41 rock samples (including 19 reservoir samples and 22 source rock samples from Yamama Formation and Sulaiy Formation). In addition to collecting 39 oil samples from wells NR-7,NR-9, NR-18 &NR-23. They represent four crude oil samples and 35 oil samples extracted from Lower Fars Zubair and Yamama reservoirs. These samples were subjected to analyzes using different techniques that included the Gas-chromatography,SRA technique,Liqiud chromotography (HPLC), Gas Chromatography- Mass spectrometry GC Mass, Method of isolating asphalt from oils. The study showed that the total organic matter TOC in the formations of Zubair, Yamamah and Sulaiy in varying proportions, but the Sulaiy Formation recorded the highest percentage, reaching 4.9%, so this formation is very rich in organic matter and is considered an excellent source rock of the type II & III. And it has a high ability to generate hydrocarbons. As for the maturation of the organic matter, depending on the maximum temperature T max, which ranges between (442–446), and the reflectivity of Vetrenite R0 % ranging from(0.8-0.86), it is considered mature rocks and has the ability to generate oil only. The reservoir oils under study were classified into two groups depending on the geochemical characteristics. The first group includes the Mishrif and The lower Fars reservoirs, while the second group includes Nahr Umar, Yamamah and Zubair reservoirs. The study indicated that the sulfur content of the first group ranges from (2.2 - 2.3), where these oils have a high sulfur content. These percentages of sulfur decrease with increasing API. We note the low maturity in the reservoirs of the first group, and also, the data of the study, which included the sulfur content Pr/Ph, CPI, showed that the oils of the first group originated from limestone rocks. The study also showed that the oils of the second group contain a lower percentage of asphalt than the first group, and this is evidence that the oils of the second group are sourced from muddy carbonate rocks, deeper than the carbonate rocks generating the oils of the first group. The results also indicated that the sections of asphalt and resins do not exceed 26% in the oils of the second group. While it reached 39.64% in the first group, and this is evidence that the second group has greater mobility and migration than the first group. (Abstract)