{"title":"BIOMARKER GEOCHEMISTRY OF PALEOGENE CRUDE OILS AND SOURCE ROCKS FROM THE RAOYANG SAG, BOHAI BAY BASIN, NE CHINA: AN OIL – SOURCE ROCK CORRELATION STUDY","authors":"S.-H. Su, Youlu Jiang","doi":"10.1111/jpg.12807","DOIUrl":"https://doi.org/10.1111/jpg.12807","url":null,"abstract":"This study presents a systematic geochemical analysis of Paleogene crude oils and source rocks from the Raoyang Sag in the Jizhong sub‐basin of the Bohai Bay Basin (NE China). The geochemical characteristics of fifty‐three oil samples from wells in four sub‐sags were analysed using gas chromatography (GC) and gas chromatography – mass spectrometry (GC‐MS). Twenty core samples of mudstones from Members 1 and 3 of the Eocene‐Oligocene Shahejie Formation were investigated for total organic carbon (TOC) content and by Rock‐Eval pyrolysis and GC‐MS to study their geochemistry and hydrocarbon generation potential. The oils were tentatively correlated to the source rocks.","PeriodicalId":16748,"journal":{"name":"Journal of Petroleum Geology","volume":"45 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2021-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42252778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"GEOCHEMICAL COMPOSITION OF ORDOVICIAN OILS FROM THE TUOPUTAI REGION, NORTHERN TARIM BASIN, NW CHINA: SOURCE ROCK CORRELATION","authors":"B. Cheng, Hua Liu, Xian Wu, Shen Wang, Zepeng Wu","doi":"10.1111/jpg.12809","DOIUrl":"https://doi.org/10.1111/jpg.12809","url":null,"abstract":"Molecular and stable carbon isotope compositions of 46 Ordovician crude oil samples from wells in the Tuoputai region of the northern Tarim Basin were investigated using GC–MS, MRM GC–MS and IRMS to determine their genetic relationships and to identify possible source rocks. Thirty‐three source rock samples from outcrops and cores were also investigated. The oil samples varied from light to heavy crudes and showed very narrow δ13C value ranges for the whole oil, saturated and aromatic fractions. The majority of the oils displayed very similar molecular compositions with relatively high concentrations of n‐alkanes and isoprenoids and low concentrations of terpenoids and steroids. Comparison of the compositions of these crude oils strongly suggested their genetic affinity, while maturity parameters indicated maturity variations from the peak to the late oil generation stages. The samples also showed the characteristics of mixtures of biodegraded and fresh oil charges.","PeriodicalId":16748,"journal":{"name":"Journal of Petroleum Geology","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2021-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48037124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Mohialdeen, Sardar S. Fatah, Rzger Abdula, M. Hakimi, W. Abdullah, P. Khanaqa, G. Lunn
{"title":"STRATIGRAPHIC CORRELATION AND SOURCE ROCK CHARACTERISTICS OF THE BALUTI FORMATION FROM SELECTED WELLS IN THE ZAGROS FOLD BELT, KURDISTAN REGION, NORTHERN IRAQ","authors":"I. Mohialdeen, Sardar S. Fatah, Rzger Abdula, M. Hakimi, W. Abdullah, P. Khanaqa, G. Lunn","doi":"10.1111/jpg.12806","DOIUrl":"https://doi.org/10.1111/jpg.12806","url":null,"abstract":"The Upper Triassic Baluti Formation has been identified and mapped based on its log response in selected wells from the Zagros foldbelt in the Kurdistan Region of northern Iraq. A preliminary evaluation of the formation's source rock potential was made by Rock‐Eval screening analysis in four wells along a NW‐SE profile (Atrush‐1, Shaikan‐5B, Taq Taq‐22 and Miran‐2) with maturity determined from reflectance measurements in samples from well Taq Taq‐22. The Baluti Formation consists of thinly interbedded shales, carbonates and anhydrite ranging in thickness from 48 m in well Atrush‐1 to 118 m in well Miran‐2. The Rock‐Eval screening was conducted primarily on bulk cuttings samples plus selected picked cuttings. The TOC content is low to moderate (0.23 to 1.14 wt%). However, the shale content in many of the analysed bulk samples was relatively low, making assessment of the source potential problematic. The highest TOCs are recorded from the thickest analysed sections from wells Miran‐2 and Taq Taq‐22, where high‐gamma bituminous shales are present. Rock‐Eval Tmax values ranging from 295 to 438°C are not consistent with estimates of pre‐Zagros burial to depths of between 4600 m (Atrush‐1) and 6900 m (Miran‐2). The relatively low Tmax values suggest that the S2 response does not reflect kerogen pyrolysis in these samples and may be due to the presence of solid bitumen, which is observed in the Baluti Formation in at least three of the study wells (Taq Taq‐22, Miran‐2 and Shaikan‐5B). Little pyrolysable organic matter remains in the formation due to the interpreted deep pre‐Zagros burial and the consequent high maturity in Taq Taq‐22 (VR = 1.51%Ro) and Miran‐2 (estimated VR >2%Ro), and the poor source character in Atrush‐1 and Shaikan‐5B. Organic petrography suggests the presence of vestiges of Types I and II kerogen in Taq Taq‐22, with bitumen observed as stains in the matrix of the shales and also in the pores and fractures of interbedded dolostones. However, bitumen reflectance determinations for Taq Taq‐22 indicate an equivalent vitrinite reflectance maturity of no more than 0.93%Ro, which is significantly less than that of the indigenous vitrinite, implying the solid bitumen in this well is derived primarily from migrated hydrocarbons. Further detailed analysis is required, but the results suggest that the Baluti Formation may have sourced hydrocarbons in its depocentre which is identified in this study as covering a NW‐SE trending area between Bekhme and Sangaw.","PeriodicalId":16748,"journal":{"name":"Journal of Petroleum Geology","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2021-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42585324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Liliana López, Jesús A. Romero, Salvador Lo Mónaco
{"title":"SEVERE BIODEGRADATION OF CRUDE OILS FROM THE QUIRIQUIRE FIELD, EASTERN VENEZUELAN BASIN","authors":"Liliana López, Jesús A. Romero, Salvador Lo Mónaco","doi":"10.1111/jpg.12808","DOIUrl":"https://doi.org/10.1111/jpg.12808","url":null,"abstract":"Five crude oil samples from the Quiriquire field (Maturin sub‐basin, Eastern Venezuelan Basin) were analysed to evaluate their levels of biodegradation. The oils were obtained from coarse sandstones and conglomerates of the Pliocene Quiriquire Formation at depths <1000 m. Analyses of the samples’ bulk physicochemical parameters indicate variations in API gravity and in the content of saturated hydrocarbons and NSO+asphaltenes, and also in the saturate/aromatic ratio which increases in more biodegraded oils. n‐Alkane distributions are characterized by a dominant unresolved complex mixture (UCM) or hump under an envelope of peaks which lack the acyclic isoprenoids pristane and phytane. The alteration of steranes and terpanes together with the presence of 25‐norhopanes and 17‐nor‐tricyclic terpanes, and the alteration of low molecular‐weight (C20‐C21) triaromatic steroids, phenanthrene, methyl‐phenanthrene, dibenzothiophene and methyl‐dibenzothiophene, indicate that the oils have undergone severe biodegradation.","PeriodicalId":16748,"journal":{"name":"Journal of Petroleum Geology","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2021-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48841109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Zeinalzadeh, M. Sharafi, M. Mirshahani, A. Shirzadi
{"title":"SOURCE ROCK EVALUATION AND BASIN MODELLING IN THE GORGAN PLAIN, SE SOUTH CASPIAN BASIN, NORTHERN IRAN","authors":"A. Zeinalzadeh, M. Sharafi, M. Mirshahani, A. Shirzadi","doi":"10.1111/jpg.12802","DOIUrl":"https://doi.org/10.1111/jpg.12802","url":null,"abstract":"Hydrocarbon exploration in the Gorgan Plain to the SE of the South Caspian Basin (northern Iran) has taken place since the 1960s but no economic resources of petroleum have yet been discovered in this area and few studies of potential source rocks have been carried out. In this study, the generation potential and thermal maturity of potential Cenozoic source rocks are investigated on the basis of Rock‐Eval analyses of core and cuttings samples and organic petrographic observations. Hydrocarbon generation, migration and entrapment are evaluated from 2D basin modelling along two seismically‐derived profiles, oriented east‐west and north‐south across the Gorgan Plain area. The models used input data from ten wells.","PeriodicalId":16748,"journal":{"name":"Journal of Petroleum Geology","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2021-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45746311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Bojesen‐Koefoed, M. Fyhn, H. Nytoft, L. Nielsen, N. Schovsbo, I. Abatzis
{"title":"PETROLEUM GEOCHEMISTRY OF OILS FROM MYANMAR – A PRELIMINARY ASSESSMENT","authors":"J. Bojesen‐Koefoed, M. Fyhn, H. Nytoft, L. Nielsen, N. Schovsbo, I. Abatzis","doi":"10.1111/jpg.12799","DOIUrl":"https://doi.org/10.1111/jpg.12799","url":null,"abstract":"Myanmar has a long history of petroleum production, but little information has so far been published pertaining to the detailed composition of the country's oils. The present paper reports the results of the analysis of a total of 28 Cenozoic oil samples collected from producing fields/wells or natural seepages in the onshore Salin and Chindwin Basins of the Central Myanmar Depression and from Ramree Island in the Rakhine Coastal Belt. In addition, a set of 68 mudstones and coals from four Oligocene – Paleocene formations were collected along the western margin of the Central Myanmar Depression and were analysed for petroleum generation potential. Data on five oil samples from the Assam Province of India, situated to the north of the Central Myanmar Depression, were also included in the study for comparison purposes.","PeriodicalId":16748,"journal":{"name":"Journal of Petroleum Geology","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2021-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44997256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
W. Siedl, M. Drews, B. Liu, J. Klaver, M. Pupp, J. Howard, S. J. Vincent, A. Al-Hadidy, B. Thusu, J. Borgomano, Y. Guglielmi, G. Massonnat, J. Rolando, L. Marie
{"title":"Index of editorial contents, JPG vol. 44, 2021","authors":"W. Siedl, M. Drews, B. Liu, J. Klaver, M. Pupp, J. Howard, S. J. Vincent, A. Al-Hadidy, B. Thusu, J. Borgomano, Y. Guglielmi, G. Massonnat, J. Rolando, L. Marie","doi":"10.1111/jpg.12803","DOIUrl":"https://doi.org/10.1111/jpg.12803","url":null,"abstract":"","PeriodicalId":16748,"journal":{"name":"Journal of Petroleum Geology","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2021-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48396308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hanene Matoussi Kort, Ahmed Abd Elmola, Néjia Laridhi Ouazaa, Dalel Sgheir, Asma Ben Saleh
{"title":"MATURITY OF POTENTIAL CRETACEOUS SOURCE ROCKS AT THE ISIS FIELD, OFFSHORE EASTERN TUNISIA: INFLUENCE OF HYDROTHERMAL FLUIDS","authors":"Hanene Matoussi Kort, Ahmed Abd Elmola, Néjia Laridhi Ouazaa, Dalel Sgheir, Asma Ben Saleh","doi":"10.1111/jpg.12801","DOIUrl":"https://doi.org/10.1111/jpg.12801","url":null,"abstract":"An increase in source rock thermal maturity is in general linked to burial‐related heating according to the regional geothermal gradient, but maturities may also locally be influenced by high‐temperature hydrothermal fluids or igneous intrusions. In the present study of the Isis field located in the Gulf of Gabes (offshore Tunisia), we combine an analysis of organic matter maturity indicators and clay mineral signatures to constrain possible fluid/rock interactions and to define controls on the maturity of potential source rocks. Cuttings samples were collected from source rock intervals in the Cretaceous Bahloul (Cenomanian – Turonian) and underlying Fahdene (Albian – Cenomanian) Formations at the PM borehole, and detailed organic geochemical and clay mineralogical analyses of source rock samples and extracts were carried out. Samples from the Bahloul Formation (2381 m to 2400 m) consist of black to dark grey claystones and globigerinid limestones. Those from the Fahdene Formation (2400 m to 2700 m) comprise alternating claystones and chalky limestones containing globigerinids including Ticinella primula. Both source rock intervals have similar mineralogical compositions consisting of calcite, quartz, albite, anorthite, minor anatase, pyroxene and pyrite. The clay mineralogy of the formations is composed of abundant smectite (two generations), subordinate kaolinite and minor illite and/or mica. The Fahdene source rock contains organic matter consisting of mixed kerogen Types II/III; Type II OM is present in the Bahloul Formation.","PeriodicalId":16748,"journal":{"name":"Journal of Petroleum Geology","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2021-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46678249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}