The Upper Triassic deep-lacustrine sedimentary gravity flow sandstones (Yanchang Formation, Southern Ordos Basin) form an important oil reservoir, however, it is considered as a low permeability to ...tight reservoir. This study combines petrographic, mineralogical and geochemical data in order to better constrain the controls on reservoir quality. Two major lithofacies types (lithofacies 1 - sandy debrite; lithofacies 2 - turbidite) were identified and their origin relating to deep-lacustrine gravity flows have been addressed. The gravity flow sandstones are significantly diagenetically altered, including mechanical compaction, authigenic clay formation, carbonate and quartz cementation and dissolution. In addition, volcanic tuffaceous dust alteration is one of the important processes during burial, which provided silica for quartz cementation and that easily transformed to authigenic smectite. It also formed poorly crystallised kaolinite and random mixed-layer I/S clays. The relatively negative δ13C (with an average of −2.3‰) and δ18O values (with an average of −17.0‰) of carbonate cements in the gravity flow sandstones reflect decarboxylation of organic matter as one of the important carbonate sources.
The factors controlling reservoir quality relate to depositional and diagenetic processes. Depositional factors (e.g. grain size, grain sorting) had a stronger influence on lithofacies 2 sandstones compared to lithofacies 1, which made lithofacies 2 sandstones more easily compact and lose most of its primary porosity. Samples with less intergranular volume (IGV) indicate that mechanical compaction plays an important role in reducing reservoir quality. However, cementation (clay minerals and carbonate cementation) affected sandstones of lithofacies 1 to a stronger degree, heavily destroying reservoir quality while in this lithofacies dissolution (e.g. feldspar, volcanic fragments and minor quartz) significantly improved reservoir characteristics in contrast to lithofacies 2 sandstones. Quartz cements could stabilize the framework and preserve the open porosity, however, they are present with relatively low contents and have limited effect in influencing the reservoir quality. In summary, lithofacies 1 sandstones possess a slightly better reservoir potential in the study area. All these factors have great implications for tight oil exploration and production of the Yanchang Formation in the Southern Ordos Basin which can serve as an example for other tight sandstone gravity flow reservoirs elsewhere in the world.
•Sandy debrite and turbidite were identified and their origin relating to lacustrine gravity flows have been addressed.•Volcanic tuffaceous dust was easily transformed to authigenic smectite, also providing silica for quartz cementation.•Decarboxylation of organic matter as one of the important carbonate sources.•The factors controlling reservoir quality relate to depositional and diagenetic processes.•Sandy debrites form the slightly better reservoirs.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Real-time fault diagnostic system is very important to maintain the operation of the gas turbine generator system (GTGS) in power plants, where any abnormal situation will interrupt the electricity ...supply. The GTGS is complicated and has many types of component faults. To prevent from interruption of electricity supply, a reliable and quick response framework for real-time fault diagnosis of the GTGS is necessary. As the architecture and the learning algorithm of extreme learning machine (ELM) are simple and effective respectively, ELM can identify faults quickly and precisely as compared with traditional identification techniques such as support vector machines (SVM). This paper therefore proposes a new application of ELM for building a real-time fault diagnostic system in which data pre-processing techniques are integrated. In terms of data pre-processing, wavelet packet transform and time-domain statistical features are proposed for extraction of vibration signal features. Kernel principal component analysis is then applied to further reduce the redundant features in order to shorten the fault identification time and improve accuracy. To evaluate the system performance, a comparison between ELM and the prevailing SVM on the fault detection was conducted. Experimental results show that the proposed diagnostic framework can detect component faults much faster than SVM, while ELM is competitive with SVM in accuracy. This paper is also the first in the literature that explores the superiority of the fault identification time of ELM.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
By applying the weight functions, the idea of introducing parameters and the technique of real analysis, a new multiple Hilbert-type integral inequality involving the upper limit functions is given. ...The constant factor related to the gamma function is proved to be the best possible in a condition. A corollary about the case of the nonhomogeneous kernel and some particular inequalities are obtained.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Recently, 15.1 billion tons of shale oil geological resources were discovered in the Qingshankou Formation of Gulong Sag, Songliao Basin, and this discovery has attracted considerable attention. Thus ...far, the sedimentary environment and diagenetic process of the Qingshankou Formation in Gulong Sag, particularly the reservoir space and accumulation mechanism of the shale oil, are unclear, which has seriously affected the exploration and development of shale oil. Based on detailed core and thin section observation, thin section analysis, mineral analysis, and geochemical analysis, thin layers and concretions of dolostone in Qingshankou Formation shale in Gulong Sag are studied. Three types of layers and nodules can be seen in the core and thin sections: the first is composed of very pure micrite, powdery calcite, or dolomite (dolomite greater than 90%); the second are argillaceous dolomite thin layers or nodules (dolomite content of approximately 75–90%); and the third is a highly impure dolomite thin layer (dolomite content between 50–75%). The chemical composition of three kinds of dolomite thin layers and nodules is different: the contents of CaO and MgO of the pure dolomite thin layer and nodules are more than 40%. The contents of CaO and MgO in the thin layer and nodules of argillaceous dolomite are between 30 and 40%. The content of CaO and MgO in the impure dolomite thin layers and nodules is less than 30%. The reservoir space is developed at the micron or nanometer scale in the thin dolomite layers and nodules, although most of these layers are filled with asphalt. The development of thin layers and nodules of dolomites is related to a dry and hot depositional climate and influenced by hydrothermal fluids. The findings presented here provide important information for exploiting the newly discovered shale oil resources. Many dolostone thin layers and nodules have curved silt veins, and the bending coefficient is 1.48, indicating that the dolostone thin layers and nodules have undergone compaction after formation.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Shale oil has become a global hotspot of unconventional exploration and development. In this study, the latest drill core and experiment analyses of the Qingshankou Formation in the northern Songliao ...Basin were used to evaluate its lithofacies classification, sedimentary environment, pore types, pore-throat structure characterization, and shale oil potential. Lithofacies classification was determined according to the total organic carbon (TOC) content, sedimentary structure, and rock mineral content. Laminae genesis and micro-sedimentary structures indicate the deposition of fine-grained sedimentary rocks (FGSRs) in a semi-deep to deep lacustrine environment; however, evidence also suggests partial reworking by storm events and bottom current flows. FGSRs mostly comprise type I kerogen, with small amounts of type II1. The average vitrinite reflectance of the FGSRs was 1.37%, indicating middle to high stages of thermal maturation within the oil generation window. The N2 adsorption experiment indicated that silty mudstone (SM), silty fine mixed sedimentary rock (SFMR), and argillaceous fine mixed sedimentary rock (AFMR) had ink-bottle-shaped and slit-shaped pores, and the lithofacies were dominated by mesopores, accounting for 77.4%, 71.9%, and 80.8% of the total pore volume, respectively. Mercury injection capillary pressure analysis indicated that SM and SFMR had an average pore-throat radius of 0.01–0.04 μm, whereas AFMR and CM were dominated by nanopores, mainly distributed in the range of 0.004–0.0063 μm. Based on the comprehensive studies of TOC content, pore development, and brittleness, we concluded that organic-rich laminated SM and SFMR should be the focus of shale oil exploration of the Qingshankou Formation in the northern Songliao Basin, followed by organic-rich or organic-moderate laminated and layered AFMR, as well as calcareous fine mixed sedimentary rocks.
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CEKLJ, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The detailed characteristics and formation mechanisms of organic-rich clasts (ORCs) in the Upper Paleozoic tight sandstone in the northeastern margin of the Ordos Basin were analyzed through ...818-m-long drilling cores and logging data from 28 wells. In general, compared with soft-sediment clasts documented in other sedimentary environments, organic-rich clasts in coal-bearing tight sandstone have not been adequately investigated in the literature. ORCs are widely developed in various sedimentary environments of coal-bearing sandstone, including fluvial channels, crevasse splays, tidal channels, sand flats, and subaqueous debris flow deposits. In addition to being controlled by the water flow energy and transportation processes, the fragmentation degree and morphology of ORCs are also related to their content of higher plants organic matter. The change in water flow energy during transportation makes the ORCs show obvious mechanical depositional differentiation. Four main types of ORC can be recognized in the deposits: diamictic organic-rich clasts, floating organic-rich clasts, loaded lamellar organic-rich clasts, and thin interlayer organic-rich clasts. The relationship between energy variation and ORCs deposition continuity is rarely studied so far. Based on the different handling processes under the control of water flow energy changes, we propose two ORCs formation mechanisms: the long-term altering of continuous water flow and the short-term water flow acting triggered by sudden events.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Tumor necrosis factor is pivotal in the pathogenesis of psoriasis. Adalimumab is a fully human monoclonal immunoglobulin G
1 antibody that neutralizes tumor necrosis factor.
We sought to assess the ...efficacy and safety of adalimumab in patients with moderate to severe plaque psoriasis.
In this multicenter, randomized, double-blind, placebo-controlled study, 147 patients received adalimumab (40 mg every other week or 40 mg/wk) or placebo. After 12 weeks of blinded therapy, patients taking adalimumab could continue their assigned dosages in a 48-week extension trial; patients taking placebo were switched to adalimumab (40 mg every other week).
At week 12, 53% of patients taking adalimumab every other week, 80% of patients taking adalimumab weekly, and 4% of patients taking placebo achieved 75% improvement in Psoriasis Area and Severity Index score (
P < .001). Responses were sustained for 60 weeks. No new safety signals were noted compared with the existing adalimumab clinical safety database.
The study was insufficiently powered to detect rare adverse events associated with adalimumab.
Adalimumab significantly improved psoriasis and was well tolerated for 60 weeks.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The Qingshankou Formation in the Gulong Sag has attracted significant attention due to its rich shale oil reserves. However, several fundamental geological problems associated with shale from the ...Qingshankou Formation remain unresolved. The Qingshankou Formation in the Gulong Sag is a set of deep-lake and semi-deep-lake fine-grained deposits primarily composed of mudstone and shale. Recent studies have shown that tempestites and storm deposits commonly occur in the Qingshankou Formation. Fine liquefaction veins often occur at the bottom of the tempestite, indicating that storm-shaking liquefaction is expected in the swale structure. Meanwhile, the mudstone and shales primarily have a sand structure with fine grain size, indicating that the environment is exposed to an undercurrent activity, with a water flow velocity of 20–55 cm s
−1
. Unlike previous studies, we posit that the ancient water depth was only 20–30 m or shallower. These phenomena have significance for understanding the formation environment and diagenetic process of shale in the first member of the Qingshankou Formation, which provides a reference for oil and gas exploration and development.
Incipient damages of wind turbine rolling bearing are very difficult to be detected because of the interference of multi-frequency components and strong ambient noise. To solve this problem, this ...paper proposes a new detected method named VMD-AMCKD, combining complementary advantages of variational mode decomposition (VMD) and adaptive maximum correlated kurtosis deconvolution (AMCKD). A novel index is proposed to screen out the most sensitive mode containing fault information after VMD decomposition. The mode also can determine a suspectable range for the fault frequency, based on which the optimized range of devolution period <inline-formula> <tex-math notation="LaTeX">T </tex-math></inline-formula> in MCKD can be pre-determined. The Grasshopper optimization algorithm (GOA) is adapted to adaptively select the key parameters in MCKD. The proposed method can successfully diagnose the simulated signal mixed with strong white Gaussian noise. Its robustness is further proven by the diagnosis for three different types of experimental signal from CWRU bearing data center. Finally, the VMD-AMCKD is applied to detect incipient damages of rolling bearings in a laboratory wind turbine.
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