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1.
正Objective The Songliao Basin is located in northeastern China. The Upper Cretaceous Qingshankou Formation(Fm.)(K2 qn), Yaojia Fm.(K2 y), and Nenjiang Fm.(K2 n) were deposited in its depression. The sediments are mainly continental clastic rocks. The first member of the Qingshankou Fm.(K2 qn1) in the southern Songliao Basin mainly comprises semi-deep to deep lacustrine shale of large thickness, generally 30,100 m, with wide distribution; the thickness of the shale has an average thickness of 70 m.  相似文献   

2.
<正>Objective The Huoshiling Formation is the earliest volcanic stratum in the Songliao Basin,composed mainly of intermediate-basic volcanic rocks,with rare fossils.The geological age of this formation has been controversial for long.The accurate dating is not only the basis of  相似文献   

3.
Micropores of shale are significant to the gas content and production potential of shale, which has been verified in the research of marine shale gas; while, few studies have been conducted on lacustrine shales. This study collected 42 samples from three wells in the Late Cretaceous Qingshankou Formation of the southern Songliao Basin, NE China, and investigated these samples by the focused ion beam-scanning electron microscope (FIB–SEM) and nitrogen adsorption analysis techniques. Four types of micropores were identified in the samples, i.e., intergranular pore, intracellular pore, organic matter pore and microfracture. The pore structure type is characterized by open slit pores and “ink type” pores which are mainly 1.5–5 nm in diameter with mesopores as the main pores. The mesopores account for 74.01% of the pore volume and 54.68% of the pore surface area. Compared with the lacustrine shales from the Triassic Yanchang Formation in the Ordos Basin and Xujiahe Formation in the Sichuan Basin, the intergranular clay mineral interlayer pores are considered to be the main reservoir space for shale gas storage in the study area, followed by intraparticle pores, organic matter pores and microfractures. Maturity and micropore are the key controlling factors which affect the shale gas content of the Qingshankou Formation in southern Songliao Basin.  相似文献   

4.
正Objective The Dayangshu Basin located in eastern Inner Mongolia,is one of the key areas for oil and gas exploration in the periphery of Songliao Basin.So far,this basin has been poorly explored,and the basic geological research is still weak,due to the lack of high-quality paleontologic and stratigraphic data.The previous oil and gas investigations were mainly focused on the Early Cretaceous strata.However,the Late Cretaceous Nenjiang Formation in the basin also has hydrocarbon potential according to the latest research.In recent oil and gas geological survey,palynological fossils have been discovered from the Nenjiang Formation in the Dayangshu Basin,providing new evidence for biostratigraphic division and correlation.  相似文献   

5.
Abstract: Cretaceous phytoplankton from the newly completed core hole (SK-1, N&S) in the central Songliao Basin was studied. The target interval is from the upper Quantou Formation of Upper Cretaceous to Mingshui Formation. Twelve genera of dinoflagellates, six of acritarcha and three of chlorophyta were identified in 588 samples from the 2300-m deep core. Ten phytoplankton assemblages have been classified: Tetranguladinium-Subtilisphaera-Botryococcus, Botryococcus-Pediastrum, Pediastrum, Dinogymniopsis-Chlamydophrella-Vesperopsis bifurcate, Dinogymniopsis minor-Balmula, Pediastrum-Botryococcus, Schizosporis-Campenia, Kiokansium-Dinogymniopsis-Botryococcus, Dinogymniopsis-Granodiscus-Filisphaeridium and Granodiscus. According to the findings mentioned above, the age of the upper Qantou Formation is Cenomanian, the Qingshankou Formation belongs to upper Cenomanian-Turonian, the Yaojia Formation to Coniancian-Santonian age, the Nenjiang Formation is of Campanian age, and Sifangtai-Mingshui formations are referred to Maastrichtian stage. The ecology of phytoplankton is closely related to water salinity. Each type of phytoplankton is within a certain living water mass whose evolution type reflects salinity change of the Songliao Lake. The assemblages from the SK-1 indicate that water salinity changes with the cycle of freshwater–slight brackish water–brackish water–slight brackish water–freshwater in the lake.  相似文献   

6.
Spectrogram analysis of seven natural gamma-ray logging of Member 1 of the Qingshankou Formation (K2qn1) and Member 1 and 2 of the Nenjiang Formation (K2n1-2) of Late Cretaceous age in the Songliao Basin reveals sedimentary cyclicities controlled by Milankovitch climate periodicities. The recognition of Milankovitch cycles allows estimation of an average accumulation rate of ~7.55–8.62 cm/ka for the K2qn1 sections, and ~6.69–10.16 cm/ka for the K2n1-2 sections. Two marine transgression events occurred during the deposition of K2qn1 and K2n1-2 and their ages are at ~0.74–1.10 Ma and ~2.38–4.84 Ma, respectively. Identification of Milankovitch cycles from fine-grained deep lake sedimentary rocks in the Songliao Basin may provide great potential for high-resolution stratigraphic subdivisions and correlations.  相似文献   

7.
<正>The Lower Cretaceous Yingcheng Formation continental organic-rich shale from Lishu Depression(LSD)of the southern Songliao Basin located in northeast China has significant shale gas potential by geochemistry and petrology.The organic-rich shale contains kerogen type II and III,and has a total organic carbon(TOC)content of 1.5wt.%.The random vitrinite reflectance(Ro,m2.0%)is in  相似文献   

8.
9.
The western part of the Tarim Basin in Xinjiang is one of the main areas in China where the marineCretaceous is well developed. The Upper Cretaceous Yingjisha Group represented mainly by sediments of lit-toral, near-shore neritic and estuarine facies is divided in ascending order into the Kukebai Formation, theOytak Formation, the Ygezya Formation and the Tuylouk Formation. For about thirty years, the basal beds of the Kukebai Formation had been considered to be the lowermostmarine horizon of the Cretaceous in the western part of the Tarim Basin, which represents the earliest trans-gression of the Cretaceous Sea into this region. Recently. marine trace fossils, Ophiomorpha nodosa, O.tuberosa and Thalassinoides? spp. were found in abundance and fine preservation from the upper subcycle andupper part of the lower subcycle of the Kezlesu Group underlying the Kukebai Formation. The fact indicatesthat the marine transgression there took place earlier than the Kukebaian. Process of transgression and regression and change of environment in the West Tarim Basin during the pe-riod from the late Early Cretaceous to the end of the Cretaceous is also discussed in this paper.  相似文献   

10.
The Triassic Jialingjiang Formation and Leikoupo Formation are characterized by thick salt layers. Three tectono-stratigraphic sequences can be identified according to detachment layers of Lower-Middle Triassic salt beds in the northern Sichuan Basin, i.e. the sub-salt sequence composed of Sinian to the Lower Triassic Feixianguan Formation, the salt sequence of the Lower Triassic Jialingjiang Formation and Mid-Triassic Leikoupou Formation, and the supra-salt sequence composed of continental clastics of the Upper-Triassic Xujiahe Formation, Jurassic and Cretaceous. A series of specific structural styles, such as intensively deformed belt of basement-involved imbricated thrust belt, basement-involved and salt-detached superimposed deformed belt, buried salt-related detached belt, duplex, piling triangle zone and pop-up, developed in the northern Sichuan Basin. The relatively thin salt beds, associated with the structural deformation of the northern Sichuan Basin, might act as a large decollement layer. The deformation mechanisms in the northern Sichuan Basin included regional compression and shortening, plastic flow and detachment, tectonic upwelling and erosion, gravitational sliding and spreading. The source rocks in the northern Sichuan Basin are strata underlying the salt layer, such as the Cambrian, Silurian and Permian. The structural deformation related to the Triassic salt controlled the styles of traps for hydrocarbon. The formation and development of hydrocarbon traps in the northern Sichuan Basin might have a bearing upon the Lower-Middle Triassic salt sequences which were favorable to the hydrocarbon accumulation and preservation. The salt layers in the Lower-Middle Triassic formed the main cap rocks and are favorable for the accumulation and preservation of hydrocarbon.  相似文献   

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