To estimate the volume of oil and gas in the hydrocarbon reservoirs, the rock-typing must be considered. The volume and type of available space in the reservoir rocks (porosity) and the ease of hydrocarbons flow (perm...To estimate the volume of oil and gas in the hydrocarbon reservoirs, the rock-typing must be considered. The volume and type of available space in the reservoir rocks (porosity) and the ease of hydrocarbons flow (permeability) are important in the classification of rock-types. In the field study, touching-vug Porosities (intergranular, intercrystalline and brecciate) increase the total porosity and form high quality rock-types, on the other side, separated-vug porosities (such as moldic, intraparticle and vuggy) increase the total porosity but do not play a large role in the production of hydrocarbon. In this paper, based on the SCAL data (Special Core Analysis) and according to amount of irreducible water saturation (Swir) and capillary pressure, the reservoir rocks are divided into 4 classes including Reservoir Rock-Types 1 to Reservoir Rock-Types 4 (RRTs-1 to RRTs-4). By study of the prepared thin sections, we investigated the role of porosity in the rock-typing. Among the rock-types, category 1 is the best type-reservoir and category 4 is non-reservoir. Probably, the latest diagenetic process determines the quality rocks, not sedimentary environments.展开更多
Introduction The East Kunlun Orogenic Belt is located in the northeastern part of the Qinghai–Tibet Plateau(Li et al.,2007),stretching from the East Kunlun to the Elashan area in an east–west direction(Guo et al.,20...Introduction The East Kunlun Orogenic Belt is located in the northeastern part of the Qinghai–Tibet Plateau(Li et al.,2007),stretching from the East Kunlun to the Elashan area in an east–west direction(Guo et al.,2018).It is an important part of the Central Orogenic Belt(Xiong et al.,2023).It is considered one of the important gold mineralization regions in the Tethys tectonic domain(Norbu et al.,2023)and an essential potential base for mineral resources in China.Wulonggou and Gouli gold mines have been discovered successively,earning the reputation of the"Golden Belt of Qinghai Province"(Feng et al.,2004;He et al.,2023).展开更多
Offshore Nile Delta in Egypt represents an enormous hydrocarbon province with recent projected gas and condensate discoveries of more than 50 trillion cubic feet“TCF”.Most of these occur in the post-salt hydrocarbon...Offshore Nile Delta in Egypt represents an enormous hydrocarbon province with recent projected gas and condensate discoveries of more than 50 trillion cubic feet“TCF”.Most of these occur in the post-salt hydrocarbon plays where biogenic gases are dominant.This study integrates organic geochemistry,seismic geomorphology and petrophysics in order to decipher the origin,and accumulation conditions of the wet gas/condensate blend in the Upper Miocene sub-salt Wakar Formation sandstones in Port Fouad Marine“PFM”Field,offshore Nile Delta.Hydrocarbon pay zones are scattered thin(<10 m)sandstones deposited in as turbiditic channel/levee complex facies.Spatial distribution of vertical gas chimneys(~2 km wide)rooting-down to the Messinian Rosetta salt is associated with the lateral pinching-out of the turbiditic sandstones.Organically-rich(total organic carbon“TOC”>1 w.t.%,hydrogen index“HI”>200 mgHC/gTOC)and mature(Tmax>430℃,vitrinite reflectance“VR”>0.6%R_(o)),source rocks are restricted to Upper Miocene Wakar and Oligo-Miocene Tineh formations.The latter contains more mature organofacies(up to 1.2%R_(o))and type Ⅱ/Ⅲ kerogen,thereby demonstrating a good capability to generate wet gases.The studied gas is wet and has thermogenic origin with signs of secondary microbial alteration,whereas the condensate contains a mixture of marine and terrestrial input.Molecular bio-markers of the condensate,isotopic and molecular composition of the gas reveals a generation of condensate prior to gas expulsion from the source.The Wakar sandstones have a heterogeneous pore system where three reservoir rock types(RRTⅠ,RRTⅡ and RRTⅢ).RRTI rocks present the bulk compo-sition of the Wakar pay zones.Spatial distribution of RRTⅠ facies likely control the accumulation of the sub-salt hydrocarbons.Our results provide a new evidence on an active petroleum system in the sub-salt Paleogene successions in the offshore Nile Delta where concomitant generation of gas/condensate blend has been outlined.展开更多
Gold deposits occurring in the Liaodong rift are located in interlayered carbonate rocks and fine-clastic rocks, belonging to the middle and upper parts of the lower Proterozoic. Compared with the Carlin-type Au depos...Gold deposits occurring in the Liaodong rift are located in interlayered carbonate rocks and fine-clastic rocks, belonging to the middle and upper parts of the lower Proterozoic. Compared with the Carlin-type Au deposits abroad and gold deposits in Yunnan-Guizhou-Guangxi, Qinling and western Sichuan Province, they are similar in many respects. This paper discusses the geological features of ore-bearing formations and ore-filling structures and metallogenetic characteristics. Through the discussion on the sources of ores, heat and water, it points out that the Au deposits belong to vadose reworked hydrothermal deposits. This conforms to the principle of “mineralization in the neighbouring areas”, i.e., the deposits are formed in nearby ore-bearing layers, and the latest hydrothermal event was the main factor in forming the Au deposits.展开更多
文摘To estimate the volume of oil and gas in the hydrocarbon reservoirs, the rock-typing must be considered. The volume and type of available space in the reservoir rocks (porosity) and the ease of hydrocarbons flow (permeability) are important in the classification of rock-types. In the field study, touching-vug Porosities (intergranular, intercrystalline and brecciate) increase the total porosity and form high quality rock-types, on the other side, separated-vug porosities (such as moldic, intraparticle and vuggy) increase the total porosity but do not play a large role in the production of hydrocarbon. In this paper, based on the SCAL data (Special Core Analysis) and according to amount of irreducible water saturation (Swir) and capillary pressure, the reservoir rocks are divided into 4 classes including Reservoir Rock-Types 1 to Reservoir Rock-Types 4 (RRTs-1 to RRTs-4). By study of the prepared thin sections, we investigated the role of porosity in the rock-typing. Among the rock-types, category 1 is the best type-reservoir and category 4 is non-reservoir. Probably, the latest diagenetic process determines the quality rocks, not sedimentary environments.
基金supported by Qinghai Provincial Association for Science and Technology Youth Science and Technology Talent Support Project(Grant No.2023QHSKXRCTJ47)Exploration Foundation of Qinghai Province(Grant No.2023085029ky004)。
文摘Introduction The East Kunlun Orogenic Belt is located in the northeastern part of the Qinghai–Tibet Plateau(Li et al.,2007),stretching from the East Kunlun to the Elashan area in an east–west direction(Guo et al.,2018).It is an important part of the Central Orogenic Belt(Xiong et al.,2023).It is considered one of the important gold mineralization regions in the Tethys tectonic domain(Norbu et al.,2023)and an essential potential base for mineral resources in China.Wulonggou and Gouli gold mines have been discovered successively,earning the reputation of the"Golden Belt of Qinghai Province"(Feng et al.,2004;He et al.,2023).
文摘Offshore Nile Delta in Egypt represents an enormous hydrocarbon province with recent projected gas and condensate discoveries of more than 50 trillion cubic feet“TCF”.Most of these occur in the post-salt hydrocarbon plays where biogenic gases are dominant.This study integrates organic geochemistry,seismic geomorphology and petrophysics in order to decipher the origin,and accumulation conditions of the wet gas/condensate blend in the Upper Miocene sub-salt Wakar Formation sandstones in Port Fouad Marine“PFM”Field,offshore Nile Delta.Hydrocarbon pay zones are scattered thin(<10 m)sandstones deposited in as turbiditic channel/levee complex facies.Spatial distribution of vertical gas chimneys(~2 km wide)rooting-down to the Messinian Rosetta salt is associated with the lateral pinching-out of the turbiditic sandstones.Organically-rich(total organic carbon“TOC”>1 w.t.%,hydrogen index“HI”>200 mgHC/gTOC)and mature(Tmax>430℃,vitrinite reflectance“VR”>0.6%R_(o)),source rocks are restricted to Upper Miocene Wakar and Oligo-Miocene Tineh formations.The latter contains more mature organofacies(up to 1.2%R_(o))and type Ⅱ/Ⅲ kerogen,thereby demonstrating a good capability to generate wet gases.The studied gas is wet and has thermogenic origin with signs of secondary microbial alteration,whereas the condensate contains a mixture of marine and terrestrial input.Molecular bio-markers of the condensate,isotopic and molecular composition of the gas reveals a generation of condensate prior to gas expulsion from the source.The Wakar sandstones have a heterogeneous pore system where three reservoir rock types(RRTⅠ,RRTⅡ and RRTⅢ).RRTI rocks present the bulk compo-sition of the Wakar pay zones.Spatial distribution of RRTⅠ facies likely control the accumulation of the sub-salt hydrocarbons.Our results provide a new evidence on an active petroleum system in the sub-salt Paleogene successions in the offshore Nile Delta where concomitant generation of gas/condensate blend has been outlined.
文摘Gold deposits occurring in the Liaodong rift are located in interlayered carbonate rocks and fine-clastic rocks, belonging to the middle and upper parts of the lower Proterozoic. Compared with the Carlin-type Au deposits abroad and gold deposits in Yunnan-Guizhou-Guangxi, Qinling and western Sichuan Province, they are similar in many respects. This paper discusses the geological features of ore-bearing formations and ore-filling structures and metallogenetic characteristics. Through the discussion on the sources of ores, heat and water, it points out that the Au deposits belong to vadose reworked hydrothermal deposits. This conforms to the principle of “mineralization in the neighbouring areas”, i.e., the deposits are formed in nearby ore-bearing layers, and the latest hydrothermal event was the main factor in forming the Au deposits.
