Analysis of 5,000 km of multi-client long-offset 2-D seismic data has led to the identification of three sedimentary basins, Levantine, Cyprus, and Latakia, located in offshore Syria. Each basin has a unique structural and stratigraphic history. They are separated from each other by the middle to Late Cretaceous aged Latakia Ridge System that initiated as a compressional fold-thrust belt and was re-activated under a sinistral strike-slip regime that developed during the Early Pliocene in response to a re-organisation of the plate-tectonic stresses. There is significant evidence for a working petroleum system in offshore Syria with numerous onshore oil and gas shows, DHIs (direct hydrocarbon indicators) observed on seismic, and oil seeps identified from satellite imagery. Prospective reservoirs range in age from Triassic to Pliocene – Quaternary and include Lower Miocene deep-water turbidite sands as encountered in recent discoveries in the offshore southern Levantine Basin. The complex structural evolution of each of the three sedimentary basins has produced an array of potential structural and stratigraphic trapping mechanisms.
{"title":"Regional seismic interpretation of the hydrocarbon prospectivity of offshore Syria","authors":"S. Bowman","doi":"10.2113/geoarabia160395","DOIUrl":"https://doi.org/10.2113/geoarabia160395","url":null,"abstract":"\u0000 Analysis of 5,000 km of multi-client long-offset 2-D seismic data has led to the identification of three sedimentary basins, Levantine, Cyprus, and Latakia, located in offshore Syria. Each basin has a unique structural and stratigraphic history. They are separated from each other by the middle to Late Cretaceous aged Latakia Ridge System that initiated as a compressional fold-thrust belt and was re-activated under a sinistral strike-slip regime that developed during the Early Pliocene in response to a re-organisation of the plate-tectonic stresses. There is significant evidence for a working petroleum system in offshore Syria with numerous onshore oil and gas shows, DHIs (direct hydrocarbon indicators) observed on seismic, and oil seeps identified from satellite imagery. Prospective reservoirs range in age from Triassic to Pliocene – Quaternary and include Lower Miocene deep-water turbidite sands as encountered in recent discoveries in the offshore southern Levantine Basin. The complex structural evolution of each of the three sedimentary basins has produced an array of potential structural and stratigraphic trapping mechanisms.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2011-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68184045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-07-01DOI: 10.2113/geoarabia1603197
The following abstracts are a selection from those accepted for presentation at GEO 2010, the Ninth Middle East Geosciences Exhibition and Conference that was held in Bahrain on March 7–10, 2010. GEO 2010 was organized by Arabian Exhibition Management (AEM), the American Association of Petroleum Geologists (AAPG) in collaboration with the European Association of Geoscientists and Engineers (EAGE), and was supported by the Society of Exploration Geophysicists (SEG), Dhahran Geoscience Society (DGS), Bahrain Geoscience Society (BGS), Geological Society of Oman (GSO) and Emirates Society of Geoscience (ESG). The abstracts that are published here by permission of the organizers represent the third group that primarily cover Exploration and Basin Analysis in the Middle East. The abstracts have been slightly edited and/or reworded so as to conform to a more common style and format; for example, capitalization of formal names for formations, geological periods and stages, etc. Some abstracts required rewording to clarify the scientific content or were submitted as short papers. Every effort was made to present these as concisely and accurately as possible. GeoArabia sent the pre-press version of all the abstracts to the primary authors for their approval, but regrettably some could not be reached or did not respond. In the next issues of GeoArabia, additional groups of GEO 2010 abstracts will be published so that a permanent record of these important studies is available to GeoArabia’s readers and the international geoscience community.
{"title":"GEO 2010 Abstracts Part III","authors":"","doi":"10.2113/geoarabia1603197","DOIUrl":"https://doi.org/10.2113/geoarabia1603197","url":null,"abstract":"The following abstracts are a selection from those accepted for presentation at GEO 2010, the Ninth Middle East Geosciences Exhibition and Conference that was held in Bahrain on March 7–10, 2010. GEO 2010 was organized by Arabian Exhibition Management (AEM), the American Association of Petroleum Geologists (AAPG) in collaboration with the European Association of Geoscientists and Engineers (EAGE), and was supported by the Society of Exploration Geophysicists (SEG), Dhahran Geoscience Society (DGS), Bahrain Geoscience Society (BGS), Geological Society of Oman (GSO) and Emirates Society of Geoscience (ESG).\u0000 The abstracts that are published here by permission of the organizers represent the third group that primarily cover Exploration and Basin Analysis in the Middle East. The abstracts have been slightly edited and/or reworded so as to conform to a more common style and format; for example, capitalization of formal names for formations, geological periods and stages, etc. Some abstracts required rewording to clarify the scientific content or were submitted as short papers. Every effort was made to present these as concisely and accurately as possible. GeoArabia sent the pre-press version of all the abstracts to the primary authors for their approval, but regrettably some could not be reached or did not respond.\u0000 In the next issues of GeoArabia, additional groups of GEO 2010 abstracts will be published so that a permanent record of these important studies is available to GeoArabia’s readers and the international geoscience community.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2011-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68184318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Levantine Basin has proven hydrocarbons, yet it is still a frontier basin. There have been significant oil and gas discoveries offshore the Nile Delta, e.g. several Pliocene gas plays and the Mango Well with ca. 10,000 bbls/day in Lower Cretaceous rocks and recently, Noble Energy discovered two gas “giants” (> 5 TCF and one estimated at 16 TFC) one of which is in a pre-Messinian strata in ca. 1,700 m (5,577 ft) water depth. Regional two-dimensional (2-D) petroleum system modeling suggests that source rocks generated hydrocarbons throughout the basin. This paper provides insight into the petroleum systems of the Levantine Basin using well and 2-D seismic data interpretations and PetroMod2D. Tectonics followed the general progression of the opening and closing of the Neo-Tethys Ocean: rift-extension, passive margin, and compression. The stratal package is up to 15 km thick and consists of mixed siliciclastic-carbonate-evaporite facies. Five potential source rock intervals (Triassic – Paleocene) are suggested. Kerogen in the older source rocks is fully transformed, whereas the younger source rocks are less mature. There are several potential reservoir and seal rocks. The model suggests that oil and gas accumulations exist in both structural and stratigraphic traps throughout the basin.
{"title":"2-D Basin modeling study of petroleum systems in the Levantine Basin, Eastern Mediterranean","authors":"L. Marlow, K. Kornpihl, C. Kendall","doi":"10.2113/geoarabia160217","DOIUrl":"https://doi.org/10.2113/geoarabia160217","url":null,"abstract":"\u0000 The Levantine Basin has proven hydrocarbons, yet it is still a frontier basin. There have been significant oil and gas discoveries offshore the Nile Delta, e.g. several Pliocene gas plays and the Mango Well with ca. 10,000 bbls/day in Lower Cretaceous rocks and recently, Noble Energy discovered two gas “giants” (> 5 TCF and one estimated at 16 TFC) one of which is in a pre-Messinian strata in ca. 1,700 m (5,577 ft) water depth. Regional two-dimensional (2-D) petroleum system modeling suggests that source rocks generated hydrocarbons throughout the basin. This paper provides insight into the petroleum systems of the Levantine Basin using well and 2-D seismic data interpretations and PetroMod2D. Tectonics followed the general progression of the opening and closing of the Neo-Tethys Ocean: rift-extension, passive margin, and compression. The stratal package is up to 15 km thick and consists of mixed siliciclastic-carbonate-evaporite facies. Five potential source rock intervals (Triassic – Paleocene) are suggested. Kerogen in the older source rocks is fully transformed, whereas the younger source rocks are less mature. There are several potential reservoir and seal rocks. The model suggests that oil and gas accumulations exist in both structural and stratigraphic traps throughout the basin.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2011-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68184000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-04-01DOI: 10.2113/geoarabia1602153
The following abstracts are a selection from those accepted for presentation at GEO 2010, the Ninth Middle East Geosciences Exhibition and Conference that was held in Bahrain on March 7–10, 2010. GEO 2010 was organized by Arabian Exhibition Management (AEM), the American Association of Petroleum Geologists (AAPG) in collaboration with the European Association of Geoscientists and Engineers (EAGE), and was supported by the Society of Exploration Geophysicists (SEG), Dhahran Geoscience Society (DGS), Bahrain Geoscience Society (BGS), Geological Society of Oman (GSO) and Emirates Society of Geoscience (ESG). The abstracts that are published here by permission of the organizers represent the second group that primarily cover the characterization of Middle East reservoirs. The abstracts have been slightly edited and/or reworded so as to conform to a more common style and format; for example, capitalization of formal names for formations, geological periods and stages, etc. Some abstracts required rewording to clarify the scientific content or were submitted as short papers. Every effort was made to present these as concisely and accurately as possible. GeoArabia sent the pre-press version of all the abstracts to the primary authors for their approval, but regrettably some could not be reached or did not respond. In the next issues of GeoArabia, additional groups of GEO 2010 abstracts will be published so that a permanent record of these important studies is available to GeoArabia’s readers and the international geoscience community.
{"title":"GEO 2010 Abstracts Part II","authors":"","doi":"10.2113/geoarabia1602153","DOIUrl":"https://doi.org/10.2113/geoarabia1602153","url":null,"abstract":"The following abstracts are a selection from those accepted for presentation at GEO 2010, the Ninth Middle East Geosciences Exhibition and Conference that was held in Bahrain on March 7–10, 2010. GEO 2010 was organized by Arabian Exhibition Management (AEM), the American Association of Petroleum Geologists (AAPG) in collaboration with the European Association of Geoscientists and Engineers (EAGE), and was supported by the Society of Exploration Geophysicists (SEG), Dhahran Geoscience Society (DGS), Bahrain Geoscience Society (BGS), Geological Society of Oman (GSO) and Emirates Society of Geoscience (ESG).\u0000 The abstracts that are published here by permission of the organizers represent the second group that primarily cover the characterization of Middle East reservoirs. The abstracts have been slightly edited and/or reworded so as to conform to a more common style and format; for example, capitalization of formal names for formations, geological periods and stages, etc. Some abstracts required rewording to clarify the scientific content or were submitted as short papers. Every effort was made to present these as concisely and accurately as possible. GeoArabia sent the pre-press version of all the abstracts to the primary authors for their approval, but regrettably some could not be reached or did not respond.\u0000 In the next issues of GeoArabia, additional groups of GEO 2010 abstracts will be published so that a permanent record of these important studies is available to GeoArabia’s readers and the international geoscience community.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2011-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68183968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-04-01DOI: 10.2113/geoarabia1602111
L. Breesch, R. Swennen, B. Dewever, F. Roure, B. Vincent
The diagenesis and fluid system evolution of outcrop analogues of potential sub-thrust Cretaceous carbonate reservoirs in the Musandam Peninsula, northern United Arab Emirates, is reconstructed during the successive stages of the Oman Mountains development. Detailed petrographic and geochemical analyses were carried out on fracture cements in limestones and dolomites mostly situated close to the main faults, which were the locations of major fluid fluxes. The main result of this study is a generalised paragenesis subdivided into four diagenetic time periods. Based on analyses of syn-tectonic veins and dolomites a large-scale fluid system is inferred with migration of hot brines with H2O-NaCl-CaCl2 composition along Cenozoic reverse faults. These brines were sourced from deeper formations or even from the basal decollement and infiltrated in the footwall. These results are compared with similar studies, which were carried out in other regions worldwide. Furthermore some implications for reservoir characteristics and hydrocarbon scenarios could be postulated. It must be noted that the majority of the analysed rocks do not have sufficiently high porosities to be regarded as reservoir rocks. However, some diagenetic processes that can improve the reservoir quality were observed. For example dolomite recrystallisation occurred in patches at the carbonate platform border, which created poorly connected reservoirs. Other possible exploration targets could be the footwall blocks of the Cenozoic reverse fault zones. When the migration of hot brines along these faults and into the footwall would be combined with petroleum migration, the footwall block could act as a potential hycrocarbon trap sealed by the fault. The fluid system evolution is incorporated in a schematic model of the geodynamic framework of the region in order to summarise the different diagenetic and fluid events, which took place during the northern Oman Mountains evolution up to now.
{"title":"Diagenesis and fluid system evolution in the northern Oman Mountains, United Arab Emirates: Implications for petroleum exploration","authors":"L. Breesch, R. Swennen, B. Dewever, F. Roure, B. Vincent","doi":"10.2113/geoarabia1602111","DOIUrl":"https://doi.org/10.2113/geoarabia1602111","url":null,"abstract":"\u0000 The diagenesis and fluid system evolution of outcrop analogues of potential sub-thrust Cretaceous carbonate reservoirs in the Musandam Peninsula, northern United Arab Emirates, is reconstructed during the successive stages of the Oman Mountains development. Detailed petrographic and geochemical analyses were carried out on fracture cements in limestones and dolomites mostly situated close to the main faults, which were the locations of major fluid fluxes. The main result of this study is a generalised paragenesis subdivided into four diagenetic time periods. Based on analyses of syn-tectonic veins and dolomites a large-scale fluid system is inferred with migration of hot brines with H2O-NaCl-CaCl2 composition along Cenozoic reverse faults. These brines were sourced from deeper formations or even from the basal decollement and infiltrated in the footwall. These results are compared with similar studies, which were carried out in other regions worldwide.\u0000 Furthermore some implications for reservoir characteristics and hydrocarbon scenarios could be postulated. It must be noted that the majority of the analysed rocks do not have sufficiently high porosities to be regarded as reservoir rocks. However, some diagenetic processes that can improve the reservoir quality were observed. For example dolomite recrystallisation occurred in patches at the carbonate platform border, which created poorly connected reservoirs. Other possible exploration targets could be the footwall blocks of the Cenozoic reverse fault zones. When the migration of hot brines along these faults and into the footwall would be combined with petroleum migration, the footwall block could act as a potential hycrocarbon trap sealed by the fault. The fluid system evolution is incorporated in a schematic model of the geodynamic framework of the region in order to summarise the different diagenetic and fluid events, which took place during the northern Oman Mountains evolution up to now.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2011-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68183956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Geologists have commonly argued that the deposition of the excellent carbonate source rock (up to 13.7% total organic carbon) in the Upper Cretaceous Natih-B Member intrashelf basin (water depth circa 50 m) was mainly controlled by the presence of bottom-water “anoxia” in the basin centre. Some authors have even linked the formation of the Natih-B organic-carbon-rich sediments to the global development of “oceanic anoxia” that occurred a number of times during the Late Cretaceous. Recent research, however, suggests that the mechanisms that underpin organic-carbon enrichment in intrashelf-basinal settings are complicated and, instead, controlled by the complex interplay of variations in primary production of organic carbon, clastic dilution, bottom-water anoxia, early diagenesis and optimising rates of sediment accumulation, and are not necessarily related to global-forcing mechanisms. In this study, the requirement for persistent bottom-water anoxic conditions for the preservation of organic matter in this setting is assessed, evidence for oxic/dysoxic bottom-water conditions during deposition of the Natih-B organic-carbon-rich sediments is presented, and alternative models to explain organic-matter enrichment are considered. Natih-B sediments (collected both spatially and temporally from both core and exposures in North Oman) have been investigated using a combination of optical and electron-optical (backscattered electron imagery) techniques, which provide additional data to those gathered by traditional field and geochemical methods. Natih-B lithofacies alternate between two main types: organic-carbon-rich carbonate mudstones and calcite-cement-rich wackestones. The organic-rich mudstones are typically fine grained, dark grey, exhibit remnant parallel lamina, and are partially burrowed. These units commonly contain planktonic foraminifera, coccoliths and organic matter (average about 5.4%, up to 13.7% total organic carbon). In addition, in-place bivalves (including thick-shelled oysters and flattened pectens) are present. The calcite-cement-rich wackestones are lighter in colour and extensively bioturbated (in most cases < 1.5% total organic carbon). This lithofacies comprises a mix of reworked skeletal fragments (including bivalves, gastropods, echinoderms, brachiopods and corals), ostracods, calcispheres, and both benthic and planktonic foraminifera that are pervasively cemented by calcite. Given the above observations, bottom waters during deposition of the Natih-B intrashelf-basinal sediments must have contained at least some oxygen, and it is unlikely that they were persistently “anoxic”. Instead, it is likely that short-term enhanced organic productivity, rapid delivery of organic components to the sediment/water interface, optimal rates of sediment accumulation and episodic burial were the fundamental parameters that controlled organic-carbon production and preservation. Organic-matter enrichment was, therefore, not restricted to an
{"title":"Sedimentological evidence for bottom-water oxygenation during deposition of the Natih-B Member intrashelf-basinal sediments: Upper Cretaceous carbonate source rock, Natih Formation, North Sultanate of Oman","authors":"S. A. Balushi, J. Macquaker","doi":"10.2113/geoarabia160247","DOIUrl":"https://doi.org/10.2113/geoarabia160247","url":null,"abstract":"\u0000 Geologists have commonly argued that the deposition of the excellent carbonate source rock (up to 13.7% total organic carbon) in the Upper Cretaceous Natih-B Member intrashelf basin (water depth circa 50 m) was mainly controlled by the presence of bottom-water “anoxia” in the basin centre. Some authors have even linked the formation of the Natih-B organic-carbon-rich sediments to the global development of “oceanic anoxia” that occurred a number of times during the Late Cretaceous. Recent research, however, suggests that the mechanisms that underpin organic-carbon enrichment in intrashelf-basinal settings are complicated and, instead, controlled by the complex interplay of variations in primary production of organic carbon, clastic dilution, bottom-water anoxia, early diagenesis and optimising rates of sediment accumulation, and are not necessarily related to global-forcing mechanisms. In this study, the requirement for persistent bottom-water anoxic conditions for the preservation of organic matter in this setting is assessed, evidence for oxic/dysoxic bottom-water conditions during deposition of the Natih-B organic-carbon-rich sediments is presented, and alternative models to explain organic-matter enrichment are considered.\u0000 Natih-B sediments (collected both spatially and temporally from both core and exposures in North Oman) have been investigated using a combination of optical and electron-optical (backscattered electron imagery) techniques, which provide additional data to those gathered by traditional field and geochemical methods. Natih-B lithofacies alternate between two main types: organic-carbon-rich carbonate mudstones and calcite-cement-rich wackestones. The organic-rich mudstones are typically fine grained, dark grey, exhibit remnant parallel lamina, and are partially burrowed. These units commonly contain planktonic foraminifera, coccoliths and organic matter (average about 5.4%, up to 13.7% total organic carbon). In addition, in-place bivalves (including thick-shelled oysters and flattened pectens) are present. The calcite-cement-rich wackestones are lighter in colour and extensively bioturbated (in most cases < 1.5% total organic carbon). This lithofacies comprises a mix of reworked skeletal fragments (including bivalves, gastropods, echinoderms, brachiopods and corals), ostracods, calcispheres, and both benthic and planktonic foraminifera that are pervasively cemented by calcite.\u0000 Given the above observations, bottom waters during deposition of the Natih-B intrashelf-basinal sediments must have contained at least some oxygen, and it is unlikely that they were persistently “anoxic”. Instead, it is likely that short-term enhanced organic productivity, rapid delivery of organic components to the sediment/water interface, optimal rates of sediment accumulation and episodic burial were the fundamental parameters that controlled organic-carbon production and preservation. Organic-matter enrichment was, therefore, not restricted to an","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"101 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2011-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68184019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The problem of identifying and quantifying the brittle deformation of carbonate reservoirs both in the United Arab Emirates (UAE) and elsewhere is addressed. Naturally occurring fractures may substantially increase or decrease the permeability and porosity of reservoirs, and therefore knowledge of location, orientation, density and connectivity of fractures is required to optimise hydrocarbon production. A rock containing parallel fractures can be seismically anisotropic, provided the vertical and horizontal extent and spacing of the fractures is small compared to the seismic wavelength. Seismic anisotropy may be detectable from attributes of pre-stack 3-D seismic data including reflection amplitude variation with offset and azimuth (AVOA). However, in carbonates seismic-velocity anisotropy can result from many different factors, including present-day horizontal stress anisotropy, sedimentological features such as clinoforms, and geological structure. We present a methodology for determining whether a proposed reservoir-fracture model is consistent with the observed seismic data. The approach includes modelling the seismic anisotropy where an essential input parameter is the compliance of the fractures. Since so little is known about this key parameter, we determine an upper bound to fracture compliance from well data and existing laboratory and field data and consequently obtain an upper bound to the seismic anisotropy that might be detected. We apply our method to data from an onshore carbonate oilfield in Abu Dhabi, United Arab Emirates, where analysis of core, log and 3-D post-stack seismic data indicates that open or partially open fractures may be pervasive and could have a dominant influence on reservoir production. Due to poor AVOA data quality our results are inconclusive. However, this case study is a demonstration of the methodology that could be applied elsewhere.
{"title":"Seismic modelling of a fractured carbonate reservoir in Abu Dhabi, United Arab Emirates","authors":"Mohammed Y. Ali, M. Worthington","doi":"10.2113/geoarabia160289","DOIUrl":"https://doi.org/10.2113/geoarabia160289","url":null,"abstract":"\u0000 The problem of identifying and quantifying the brittle deformation of carbonate reservoirs both in the United Arab Emirates (UAE) and elsewhere is addressed. Naturally occurring fractures may substantially increase or decrease the permeability and porosity of reservoirs, and therefore knowledge of location, orientation, density and connectivity of fractures is required to optimise hydrocarbon production. A rock containing parallel fractures can be seismically anisotropic, provided the vertical and horizontal extent and spacing of the fractures is small compared to the seismic wavelength. Seismic anisotropy may be detectable from attributes of pre-stack 3-D seismic data including reflection amplitude variation with offset and azimuth (AVOA). However, in carbonates seismic-velocity anisotropy can result from many different factors, including present-day horizontal stress anisotropy, sedimentological features such as clinoforms, and geological structure. We present a methodology for determining whether a proposed reservoir-fracture model is consistent with the observed seismic data. The approach includes modelling the seismic anisotropy where an essential input parameter is the compliance of the fractures. Since so little is known about this key parameter, we determine an upper bound to fracture compliance from well data and existing laboratory and field data and consequently obtain an upper bound to the seismic anisotropy that might be detected. We apply our method to data from an onshore carbonate oilfield in Abu Dhabi, United Arab Emirates, where analysis of core, log and 3-D post-stack seismic data indicates that open or partially open fractures may be pervasive and could have a dominant influence on reservoir production. Due to poor AVOA data quality our results are inconclusive. However, this case study is a demonstration of the methodology that could be applied elsewhere.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2011-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68184050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-01-01DOI: 10.2113/geoarabia1601113
A. Youssef
The analyses of thirteen planktonic and benthonic biozones, paleobathymetry and electric log data were used to interpret the sequence stratigraphy of the Early to early Middle Miocene syn-rift section in the Gulf of Suez. The study area is located in the central province of the Gulf and includes six boreholes located in two half grabens and the October Field. The new framework proposes the Suez Supersequence and Suez Depositional Sequence DS 50 instead of the five paleontological sequences commonly cited in the literature (S10 to S50). The Supersequence starts above the regional unconformity that separates the pre-and syn-rift rocks, commonly referred to as Terrace T00. The shallow-marine deposits of the Aquitanian Nukhul Formation form the lowstand systems tract. The Burdigalian Mheiherrat Formation starts with the Uvigerina costata flooding event and forms the transgressive systems tract deposited in outer-neritic to upper-bathyal settings. The overlying Langhian Hawara Formation was deposited in upper to middle bathyal settings and represents the maximum flooding interval. The Langhian Asl Formation (early falling stage systems tract, upper bathyal to outer neritic) and overlying Langhian Lagia Member of the Ayun Musa Formation (late falling stage systems tract) closed the Supersequence. Suez Depositional Sequence DS 50 lies unconformably on the Supersequence, and represents a major transgression starting with the Praeorbulina glomerosa s.l. flooding event. DS 50 corresponds to the Ras Budran Member of the Ayun Musa Formation (paleontological sequence S50). Its setting is outer neritic and its upper sequence boundary is an unconformable with the Belayim Formation. The Suez Supersequence is interpreted in terms of 35 genetic parasequences and DS 50 by 10 more. The parasequences are interpreted by the coincidence of quantitative paleontological faunal and paleobathymetric breaks with the electric log shifts. The sequences and parasequences are correlated between the six wells to show the evolution of the half-grabens and October Field at different times.
{"title":"Early – Middle Miocene Suez Syn-rift-Basin, Egypt: A sequence stratigraphy framework","authors":"A. Youssef","doi":"10.2113/geoarabia1601113","DOIUrl":"https://doi.org/10.2113/geoarabia1601113","url":null,"abstract":"\u0000 The analyses of thirteen planktonic and benthonic biozones, paleobathymetry and electric log data were used to interpret the sequence stratigraphy of the Early to early Middle Miocene syn-rift section in the Gulf of Suez. The study area is located in the central province of the Gulf and includes six boreholes located in two half grabens and the October Field. The new framework proposes the Suez Supersequence and Suez Depositional Sequence DS 50 instead of the five paleontological sequences commonly cited in the literature (S10 to S50). The Supersequence starts above the regional unconformity that separates the pre-and syn-rift rocks, commonly referred to as Terrace T00. The shallow-marine deposits of the Aquitanian Nukhul Formation form the lowstand systems tract. The Burdigalian Mheiherrat Formation starts with the Uvigerina costata flooding event and forms the transgressive systems tract deposited in outer-neritic to upper-bathyal settings. The overlying Langhian Hawara Formation was deposited in upper to middle bathyal settings and represents the maximum flooding interval. The Langhian Asl Formation (early falling stage systems tract, upper bathyal to outer neritic) and overlying Langhian Lagia Member of the Ayun Musa Formation (late falling stage systems tract) closed the Supersequence. Suez Depositional Sequence DS 50 lies unconformably on the Supersequence, and represents a major transgression starting with the Praeorbulina glomerosa s.l. flooding event. DS 50 corresponds to the Ras Budran Member of the Ayun Musa Formation (paleontological sequence S50). Its setting is outer neritic and its upper sequence boundary is an unconformable with the Belayim Formation. The Suez Supersequence is interpreted in terms of 35 genetic parasequences and DS 50 by 10 more. The parasequences are interpreted by the coincidence of quantitative paleontological faunal and paleobathymetric breaks with the electric log shifts. The sequences and parasequences are correlated between the six wells to show the evolution of the half-grabens and October Field at different times.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68183597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, organic matter content, type and maturity as well as some petrographic characteristics of the Jurassic shales exposed in the Masila Basin were evaluated and their depositional environments were interpreted using organic geochemical and organic petrological studies. The total organic carbon (TOC) contents of shales in the Sunah, Wadi Taribah, and Kharir fields vary between 2.4% and 4.7% with high Hydrogen Index (HI) values. All shale samples display very low Oxygen Index (OI) values. The Sunah and Wadi Taribah shales contain Type II organic matter, while the Kharir shales contain Type II, with minor contributions from Type I organic matter. Tmax values for the shales range from 428 °C to 438 °C and vitrinite reflectance values (%Ro) range from 0.52% to 0.80%. These values reveal that the Sunah and Kharir shales are at peak mature stage while the Wadi Taribah shales are early mature. This is supported by their biomarker maturity parameters. The pristane/phytane (Pr/Ph) ratios range from 1.8 to 2.3. In addition, all shales show a homohopane distribution which is dominated by low carbon numbers, and C35 homohopane index is very low for all shale samples. All these features may indicate that these shales were deposited in a suboxic environment. Sterane distribution was calculated as C27>C29>C28 from the m/z 217 mass chromatogram for all shale samples. The Sunah, Wadi Taribah and Kharir shales are believed to have good oil generating potential. This is supported by high total organic carbon content, hydrogen indices up to 400 mg HC/g TOC and early to peak mature oil window range.
{"title":"Organic geochemical characteristics and depositional environments of the Jurassic shales in the Masila Basin of Eastern Yemen","authors":"M. Hakimi, W. Abdullah, M. Shalaby","doi":"10.2113/geoarabia160147","DOIUrl":"https://doi.org/10.2113/geoarabia160147","url":null,"abstract":"\u0000 In this paper, organic matter content, type and maturity as well as some petrographic characteristics of the Jurassic shales exposed in the Masila Basin were evaluated and their depositional environments were interpreted using organic geochemical and organic petrological studies. The total organic carbon (TOC) contents of shales in the Sunah, Wadi Taribah, and Kharir fields vary between 2.4% and 4.7% with high Hydrogen Index (HI) values. All shale samples display very low Oxygen Index (OI) values. The Sunah and Wadi Taribah shales contain Type II organic matter, while the Kharir shales contain Type II, with minor contributions from Type I organic matter.\u0000 Tmax values for the shales range from 428 °C to 438 °C and vitrinite reflectance values (%Ro) range from 0.52% to 0.80%. These values reveal that the Sunah and Kharir shales are at peak mature stage while the Wadi Taribah shales are early mature. This is supported by their biomarker maturity parameters.\u0000 The pristane/phytane (Pr/Ph) ratios range from 1.8 to 2.3. In addition, all shales show a homohopane distribution which is dominated by low carbon numbers, and C35 homohopane index is very low for all shale samples. All these features may indicate that these shales were deposited in a suboxic environment. Sterane distribution was calculated as C27>C29>C28 from the m/z 217 mass chromatogram for all shale samples.\u0000 The Sunah, Wadi Taribah and Kharir shales are believed to have good oil generating potential. This is supported by high total organic carbon content, hydrogen indices up to 400 mg HC/g TOC and early to peak mature oil window range.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68183887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-01-01DOI: 10.2113/geoarabia1601151
The following abstracts are a selection from those accepted for presentation at GEO 2010, the Ninth Middle East Geosciences Exhibition and Conference that was held in Bahrain on March 7-10, 2010. GEO 2010 was organized by Arabian Exhibition Management (AEM), the American Association of Petroleum Geologists (AAPG) in collaboration with the European Association of Geoscientists and Engineers (EAGE), and was supported by the Society of Exploration Geophysicists (SEG), Dhahran Geoscience Society (DGS), Bahrain Geoscience Society (BGS), Geological Society of Oman (GSO) and Emirates Society of Geoscience (ESG). The abstracts that are published here by permission of the organizers represent the first group that primarily cover the stratigraphy of the Middle East. The abstracts have been slightly edited and/or reworded so as to conform to a more common style and format; for example, capitalization of formal names for formations, geological periods and stages, etc. Some abstracts required rewording to clarify the scientific content or were submitted as short papers. Every effort was made to present these as concisely and accurately as possible. GeoArabia sent the pre-press version of all the abstracts to the primary authors for their approval, but regretably some could not be reached or did not respond. In the next issues of GeoArabia, additional groups of GEO 2010 abstracts will be published so that a permanent record of these important studies is available to GeoArabia’s readers and the international geoscience community.
{"title":"GEO 2010 Abstracts Part I","authors":"","doi":"10.2113/geoarabia1601151","DOIUrl":"https://doi.org/10.2113/geoarabia1601151","url":null,"abstract":"The following abstracts are a selection from those accepted for presentation at GEO 2010, the Ninth Middle East Geosciences Exhibition and Conference that was held in Bahrain on March 7-10, 2010. GEO 2010 was organized by Arabian Exhibition Management (AEM), the American Association of Petroleum Geologists (AAPG) in collaboration with the European Association of Geoscientists and Engineers (EAGE), and was supported by the Society of Exploration Geophysicists (SEG), Dhahran Geoscience Society (DGS), Bahrain Geoscience Society (BGS), Geological Society of Oman (GSO) and Emirates Society of Geoscience (ESG).\u0000 The abstracts that are published here by permission of the organizers represent the first group that primarily cover the stratigraphy of the Middle East. The abstracts have been slightly edited and/or reworded so as to conform to a more common style and format; for example, capitalization of formal names for formations, geological periods and stages, etc. Some abstracts required rewording to clarify the scientific content or were submitted as short papers. Every effort was made to present these as concisely and accurately as possible. GeoArabia sent the pre-press version of all the abstracts to the primary authors for their approval, but regretably some could not be reached or did not respond.\u0000 In the next issues of GeoArabia, additional groups of GEO 2010 abstracts will be published so that a permanent record of these important studies is available to GeoArabia’s readers and the international geoscience community.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68183791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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