Journal of Petroleum Geology最新文献

{"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}

{"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}

{"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}

{"title":"Issue Information","authors":"","doi":"10.1111/jpg.12764","DOIUrl":"https://doi.org/10.1111/jpg.12764","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":"45129663","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":"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}

{"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}

{"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}

{"title":"A NEW REGIONAL PETROLEUM SYSTEMS MODEL FOR CENTRAL ITALY AND THE CENTRAL ADRIATIC SEA SUPPORTED BY BASIN MODELLING AND AN ANALYSIS OF HYDROCARBON OCCURRENCES","authors":"L. Lipparini, A. D’Ambrosio, F. Trippetta, S. Bigi, J. Derks, Victoire Roblet Bambridge, T. Cassola","doi":"10.1111/jpg.12800","DOIUrl":"https://doi.org/10.1111/jpg.12800","url":null,"abstract":"The petroleum system in Central Italy and the Adriatic Sea is of great interest for future hydrocarbon exploration. However, major uncertainties remain about key risk elements such as source rock spatial distribution and maturation history, the timing of hydrocarbon migration, and the nature of migration pathways. This paper presents a new regional‐scale petroleum systems model based on an integrated inter‐disciplinary study which includes public‐domain subsurface data on key petroleum systems elements, heat‐flow and petroleum geochemical data, and an extensive set of 1D basin models.","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":"44596486","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":"GEOCHEMISTRY OF OILS IN THE TEREK-CASPIAN FOREDEEP AND PRIKUMSK SWELL, NE GREATER CAUCASUS, SOUTHERN RUSSIA","authors":"N. Sh. Yandarbiev,&nbsp;R. F. Sachsenhofer,&nbsp;S. Ajuaba,&nbsp;A. Bechtel,&nbsp;D. N. Yandarbieva","doi":"10.1111/jpg.12796","DOIUrl":"10.1111/jpg.12796","url":null,"abstract":"<div>\u0000 <p>Hydrocarbon reserves of the order of 1140 MM brl oe have been identified in the northern foreland of the eastern Greater Caucasus, principally in the Terek-Caspian fold-and-thrust belt and the Prikumsk Swell in the north of the Terek-Caspian foredeep. Despite the great economic significance of these areas and their long exploration history, the origin of the hydrocarbons is still poorly understood. In the present paper, geochemical data from 73 oil samples representing 28 fields are used to investigate the presence of oil families and to correlate the oils with potential source rocks.</p>\u0000 <p>Biomarker composition of oils in Cretaceous and Miocene reservoirs in the Terek-Caspian fold-and-thrust belt is mainly controlled by reservoir depth (100-5700 m) and maturity (0.70-1.15 %R_o), and it is therefore difficult to separate maturity and facies effects. For example, a downward increase in diasterane/sterane ratios may indicate a change in source rock facies or may be attributed to increasing maturity. Some shallow oils are biodegraded. The presence of short-chain n-alkanes in biodegraded oils indicates recent hydrocarbon migration. Biomarker data (e.g. the presence of oleanane) and compound-specific isotope data suggest that the Khadum Formation in the lower part of the Maikop Group is the main source rock. However data from Cretaceous and Paleogene organic-rich rocks, which may also have contributed to the accumulated oils, are urgently needed in order to quantify their possible input.</p>\u0000 <p>In the Prikumsk Swell, at least two oil families, characterized by low and high C₂₈/C₂₉ sterane ratios respectively, can be distinguished in reservoir rocks of Triassic to Cretaceous age. Most oils are characterized by low C₂₈/C₂₉ sterane ratios and the absence of oleanane (“Group B oils”). These characteristics suggest a pre-Upper Cretaceous source for the oils, which is also supported by the geological setting. Hierarchical cluster analysis suggests the presence of four sub-groups (Sub-Groups B1 to B4). Typically, biomarker ratios in oils in Cretaceous reservoirs are more uniform than those in Triassic and Jurassic reservoirs. Potential source rocks include Lower Triassic deep-water clayey limestones and shales as well as Middle Jurassic and Aptian-Albian marine shales. Three oil samples from Triassic and Cretaceous reservoirs form a separate oil family (“Group A”), which is genetically related to oils from the Terek-Caspian fold-and-thrust belt. Group A oils have high C₂₈/C₂₉ sterane ratios and in general contain at least some oleanane. A contribution by Cenozoic source rocks to Group A oils is likely.</p>\u0000 </div>","PeriodicalId":16748,"journal":{"name":"Journal of Petroleum Geology","volume":"44 3","pages":"317-348"},"PeriodicalIF":1.8,"publicationDate":"2021-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/jpg.12796","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47671896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"NEW GEOCHEMICAL INSIGHTS INTO CENOZOIC SOURCE ROCKS IN AZERBAIJAN: IMPLICATIONS FOR PETROLEUM SYSTEMS IN THE SOUTH CASPIAN REGION","authors":"V. Aghayeva,&nbsp;R. F. Sachsenhofer,&nbsp;C.G.C. van Baak,&nbsp;A. Bechtel,&nbsp;T. M. Hoyle,&nbsp;D. Selby,&nbsp;N. Shiyanova,&nbsp;S. J. Vincent","doi":"10.1111/jpg.12797","DOIUrl":"10.1111/jpg.12797","url":null,"abstract":"<div>\u0000 <p>The Maikop Group and the Diatom Formation constitute the two main source rocks in the South Caspian Basin and onshore Azerbaijan where large-scale oil production began more than 150 years ago. However, the stratigraphic distribution of the source rocks and the vertical variation of source-rock parameters are still poorly understood. The aim of the present paper is therefore to investigate in high resolution the source-rock distribution in the Perekishkyul and Islamdag outcrop sections, located 25 km NW of Baku, which provide nearly complete middle Eocene and lower Oligocene to upper Miocene successions. Bulk geochemical parameters of 376 samples together with maceral, biomarker and isotope data were analysed. In addition, new Re/Os data provide independent age dating for the base of the Upper Maikop Formation (30.0 ± 1.0 Ma) and the paper shale within the Diatom Formation (7.2 ± 2.6 Ma). The presence of steradienes in high concentrations demonstrates the thermal immaturity of the studied successions, limiting the application of some biomarker ratios.</p>\u0000 <p>Intervals with high TOC contents and containing kerogen Type II occur near the top of the middle Eocene succession. However, because of the low net thickness, these sediments are not considered to constitute significant hydrocarbon (HC) source rocks. The Maikop Group in the Islamdag section is 364 m thick and represents lower Oligocene (upper Solenovian) to middle Miocene (Kozakhurian) levels. Samples are characterized by moderately high TOC contents (∼1.8 wt.%) but low hydrogen index (HI) values (average ∼120 mgHC/gTOC) despite a dominance of aquatic organic matter (diatoms, methanotrophic archaea and sulphate-reducing bacteria). Rhenium-osmium chronology suggests low sedimentation rates (∼25 m/Ma), which may have had a negative impact on organic matter preservation. Terrigenous organic matter occurs in variable but typically low amounts. If mature, the Maikop Group sediments at Islamdag could generate about 2.5 tHC/m².</p>\u0000 <p>The Diatom Formation includes a 60 m thick paper shale interval with high TOC contents (average 4.35 wt.%) of kerogen Type II-I (HI up to 770 mgHC/gTOC). The source potential is higher (∼3 tHC/m²) than that of the Maikop Group. The organic matter is dominated by algal material including diatoms. High TOC/S ratios suggest deposition under reduced salinity conditions. Strictly anoxic conditions are indicated by the presence of biomarkers for archaea involved in methane cycling.</p>\u0000 <p>For oil-source correlations and a better understanding of the petroleum system, it will be necessary to distinguish oil generated by the Maikop Group from that generated by the Diatom Formation. This study shows that these oils can be distinguished based on the distribution of specific biomarkers e.g. C₃₀ steranes, C₂₅ highly branched isoprenoids (HBIs), and the C₂₅ isoprenoid pent","PeriodicalId":16748,"journal":{"name":"Journal of Petroleum Geology","volume":"44 3","pages":"349-384"},"PeriodicalIF":1.8,"publicationDate":"2021-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/jpg.12797","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47468069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}