Organic geochemical characteristics of the Lower Cretaceous Abu Gabra Formation in the Great Moga oilfield, Muglad Basin, Sudan: Implications for depositional environment and oil-generation potential

Makeen, Yousif M.; Abdullah, Wan Hasiah; Hakimi, Mohammed Hail; Elhassan, Osman M.A.

doi:10.1016/j.jafrearsci.2014.12.006

Cited by 30 publications

(18 citation statements)

References 24 publications

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“…Because of the low maturity of all the oil shale samples studied, the influence of maturity can be excluded. In addition, the relationship between the ratio of Pr/n-C 17 and Ph/n-C 18 has been widely used in the classification and correlation of oil source rocks and the study of oil-generating environments [49,50]. Pr/n-C 17 and Ph/n-C 18 diagrams further demonstrate the algal/microbial source of the organic matter deposited in a reducing environment [51] (Figure 7; Table 2).…”

Section: Molecular Composition Of Hydrocarbonsmentioning

confidence: 99%

Organic Geochemical Characteristics of the Upper Cretaceous Qingshankou Formation Oil Shales in the Fuyu Oilfield, Songliao Basin, China: Implications for Oil-Generation Potential and Depositional Environment

Sun

Guo

et al. 2019

Energies

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The Cretaceous Era has always been a focus of geologic and palaeoenvironmental studies. Previous researchers believed that the impact of the global carbon cycle represents significant short-term global biogeochemical fluctuations, leading to the formation of a large number of organic rich sediments in the marine environment. During the Turonian, a large number of organic-rich oil shales were deposited in the lakes of the Songliao Basin in the Qingshankou Formation. How the depositional environment affected the formation of oil shales in continental lakes and the characteristics of these oil shales remain controversial. In this paper, through sampling of Qingshankou Formation strata, various testing methods are used to provide a variety of new data to study the characteristics of oil shales and palaeoenvironment evolution history in the Songliao Basin. The research of the sediments in the Qingshankou Formation in the Fuyu oilfield, Songliao Basin, via result analysis revealed that the oil shales possess an excellent oil-generation potential with moderate-high total organic carbon (TOC) levels (0.58–9.43%), high hydrogen index (HI) values (265–959 mg hydrocarbons (HC)/g TOC), high extractable organic matter (EOM) levels (2.50–6.96 mg/g TOC) and high hydrocarbon fractions (48–89%). The sources of the organic matter were mainly zooplankton, red algae and higher plants (including marine organisms). The aqueous palaeoenvironment of the Qingshankou Formation was a saline water environment with a high sulfate concentration, which promoted an increase in nutrients and stratification of the water density in the lake basin. Oxygen consumption in the bottom water layer promoted the accumulation and burial of high-abundance organic matter, thus forming the high-quality oil shales in the Qingshankou Formation. The global carbon cycle, warm-humid palaeoclimate, dynamic local biogeochemical cycling and relative passive tectonism were the most likely reasons for the TOC increase and negative δ13Corg deviation.

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Section: Molecular Composition Of Hydrocarbonsmentioning

confidence: 99%

Organic Geochemical Characteristics of the Upper Cretaceous Qingshankou Formation Oil Shales in the Fuyu Oilfield, Songliao Basin, China: Implications for Oil-Generation Potential and Depositional Environment

Sun

Guo

et al. 2019

Energies

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“…2 , 3 ) are widely distributed within the interior Muglad Basin, serving as source rock and reservoir respectively 4 , 5 . Source rock characteristics and hydrocarbon generation potentials of the Abu Gabra Formation have been studied by 1 , 2 , 6 – 8 . Like other Cretaceous source rocks around the world, especially Persian Gulf in the Middle East, Mediterranean, Gulf Coast of the USA and China, that have been suggested to have relatively good hydrocarbon prospects with Type I to III kerogens 1 – 4 .…”

Section: Introductionmentioning

confidence: 99%

“…Like other Cretaceous source rocks around the world, especially Persian Gulf in the Middle East, Mediterranean, Gulf Coast of the USA and China, that have been suggested to have relatively good hydrocarbon prospects with Type I to III kerogens 1 – 4 . Authors 1 , 6 – 8 reported that, the Lower Cretaceous shales and claystones of the Abu Gabra Formations represent the primary source rocks within the Muglad Basin. These are mainly characterized by Type I kerogen with very good to excellent hydrocarbon generation potentials.…”

Section: Introductionmentioning

confidence: 99%

“…These are mainly characterized by Type I kerogen with very good to excellent hydrocarbon generation potentials. Thermal maturity assessment determined using vitrinite reflectance, biomarker parameters, pyrolysis gas chromatography and production index (PI) data indicated that the source rocks have reached the oil generation window 1 , 2 , 8 , 9 . Furthermore, an integrated trace/major elements and biomarkers study revealed suboxic to anoxic depositional conditions which favored preservation of organic matter in the Abu Gabra Formation 8 , 9 .…”

Section: Introductionmentioning

confidence: 99%

“…Thermal maturity assessment determined using vitrinite reflectance, biomarker parameters, pyrolysis gas chromatography and production index (PI) data indicated that the source rocks have reached the oil generation window 1 , 2 , 8 , 9 . Furthermore, an integrated trace/major elements and biomarkers study revealed suboxic to anoxic depositional conditions which favored preservation of organic matter in the Abu Gabra Formation 8 , 9 . Apart from the aforementioned studies, burial histories as well as petroleum generation modeling of the Abu Gabra Formations have been carried out 10 .…”

Section: Introductionmentioning

confidence: 99%

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Reservoir quality and its controlling diagenetic factors in the Bentiu Formation, Northeastern Muglad Basin, Sudan

Makeen

Shan

Lawal

et al. 2021

Sci Rep

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The Abu Gabra and Bentiu formations are widely distributed within the interior Muglad Basin. Recently, much attention has been paid to study, evaluate and characterize the Abu Gabra Formation as a proven reservoir in Muglad Basin. However, few studies have been documented on the Bentiu Formation which is the main oil/gas reservoir within the basin. Therefore, 33 core samples of the Great Moga and Keyi oilfields (NE Muglad Basin) were selected to characterize the Bentiu Formation reservoir using sedimentological and petrophysical analyses. The aim of the study is to de-risk exploration activities and improve success rate. Compositional and textural analyses revealed two main facies groups: coarse to-medium grained sandstone (braided channel deposits) and fine grained sandstone (floodplain and crevasse splay channel deposits). The coarse to-medium grained sandstone has porosity and permeability values within the range of 19.6% to 32.0% and 1825.6 mD to 8358.0 mD respectively. On the other hand, the fine grained clay-rich facies displays poor reservoir quality as indicated by porosity and permeability ranging from 1.0 to 6.0% and 2.5 to 10.0 mD respectively. A number of varied processes were identified controlling the reservoir quality of the studies samples. Porosity and permeability were enhanced by the dissolution of feldspars and micas, while presence of detrital clays, kaolinite precipitation, iron oxides precipitation, siderite, quartz overgrowths and pyrite cement played negative role on the reservoir quality. Intensity of the observed quartz overgrowth increases with burial depth. At great depths, a variability in grain contact types are recorded suggesting conditions of moderate to-high compactions. Furthermore, scanning electron microscopy revealed presence of micropores which have the tendency of affecting the fluid flow properties in the Bentiu Formation sandstone. These evidences indicate that the Bentiu Formation petroleum reservoir quality is primarily inhibited by grain size, total clay content, compaction and cementation. Thus, special attention should be paid to these inhibiting factors to reduce risk in petroleum exploration within the area.

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Geochemical Characteristics of Oil from Oligocene Lower Ganchaigou Formation Oil Sand in Northern Qaidam Basin, China

et al. 2019

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Organic geochemical characteristics of the Lower Cretaceous Abu Gabra Formation in the Great Moga oilfield, Muglad Basin, Sudan: Implications for depositional environment and oil-generation potential

Cited by 30 publications

References 24 publications

Organic Geochemical Characteristics of the Upper Cretaceous Qingshankou Formation Oil Shales in the Fuyu Oilfield, Songliao Basin, China: Implications for Oil-Generation Potential and Depositional Environment

Organic Geochemical Characteristics of the Upper Cretaceous Qingshankou Formation Oil Shales in the Fuyu Oilfield, Songliao Basin, China: Implications for Oil-Generation Potential and Depositional Environment

Reservoir quality and its controlling diagenetic factors in the Bentiu Formation, Northeastern Muglad Basin, Sudan

Geochemical Characteristics of Oil from Oligocene Lower Ganchaigou Formation Oil Sand in Northern Qaidam Basin, China

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