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Niu Y.-B.,Henan Polytechnic University | Niu Y.-B.,Key Laboratory of Biogenic Traces and Sedimentary Minerals of Henan Province | Zhong J.-H.,China University of Petroleum - East China | Wang P.-J.,Petrochina | And 2 more authors.
Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of China University of Petroleum (Edition of Natural Science) | Year: 2010

By using the methods of core observation, thin-section analysis, cathode ray, the characteristics of diagenesis and its effect on accumulate capability of Ordovician carbonate rock in block 2 of Tahe Oilfield were studied. The results show that compaction-presolution, cementation, dissolution, dolomization, recrystallization and siliconization mainly ocurred in Ordovician of the research area. Cementation and dissolution occured on the same time and throughout the whole diagenetic stages, which was the most important for the reservoir space of research area and determined the final form of reservoir space. The burial dolomitization mainly occurred in deep burial diagenetic stage. Lots of sandy gobbets formed in Yijianfang formation and Yingshan formation. Owing to plenty of intergranular pore formed in the sandy gobbet, it is a kind of important reservoir space for oil-gas accumulation. On account of the limited actions, the impact of compaction-presolution, recrystallization and siliconization is relatively small. Lower Ordovician is in the late stage of diagenesis, and Middle-Upper Ordovician is in the late-middle stage of diagenesis. Source

Jin Y.,Henan Polytechnic University | Jin Y.,Key Laboratory of Biogenic Traces and Sedimentary Minerals of Henan Province | Dong J.B.,Henan Polytechnic University | Li X.,Henan Polytechnic University | Wu Y.,Henan Polytechnic University
International Journal of Modern Physics C | Year: 2015

It is hard to experimentally or analytically derive the hydraulic tortuosity (τ) of porous media flow because of their complex microstructures. In this work, we propose a kinematical measurement method for τ by introducing the concept of local tortuosity, which is defined as the ratio of fluid particle velocity to its component along the macro flow. And then, the calculation model of τ is analytically deduced in terms of that τ is the mean value of the local tortuosity. To avoid the impact from the singularity of local tortuosity, the velocity is normalized, and τ is then approximated by the ratio of the mean normalized velocity to the average value of its component along the macro-flow direction. The new estimation method is verified by flow through different types of porous media via the lattice Boltzmann method, and the relationships between permeabilities and tortuosities obtained by different methods are examined. The numerical results show that tortuosity by the novel approach is in good agreement with the existing theory, and the kinematic definition of hydraulic tortuosity is also proven. © 2015 World Scientific Publishing Company. Source

Wang C.-Z.,Henan Polytechnic University | Wang J.,Henan Polytechnic University | Wang J.,Key Laboratory of Biogenic Traces and Sedimentary Minerals of Henan Province | Hu B.,Key Laboratory of Biogenic Traces and Sedimentary Minerals of Henan Province | Lu X.-H.,Henan Polytechnic University
Geodinamica Acta | Year: 2016

The Upper Cretaceous Gaogou, Majiachun and Sigou formations in the Xixia Basin are composed of terrestrial clastic deposits, which are dominated by red-violet mudstones, muddy siltstones, siltstones, grayish fine-grained sandstones, intercalated with grayish, off-white medium-and coarse-grained sandstones or conglomerates. They contain 10 ichnogenera and 22 ichnospecies and Rhizoliths, including Arenicolites isp., Archaeonassa isp., Beaconites antarcticus, B. capronus, B. coronus, Cylindricum isp., Gastruichnus xixiaensis, Palaeophycus megas, P. tubularis, P. heberti, P. sulcatus, P. cf. sulcatus, P. striatus, Planolites beverleyensis, P. isp., Scoyenia gracilis, Skolithos verticalis, S. linearis, S. isp., Taenidium irregularis, T. serpentinum and T. barretti. From north to south across the basin, alluvial fan, braided and meandering fluvial and fluvio-lacustrine systems are recognised on the basis of sedimentary features. In reference to them, four ichnoassemblages are recognised: (1) Skolithos-Gastruichnus ichnoassemblage in the channel environment of braided and meandering river, (2) Beaconites-Taenidium ichnoassemblage in the natural levee and crevasse splays, (3) Beaconites-Palaeophycus ichnoassemblage in the flood plain and (4) Taenidium-Scoyenia ichnoassemblage in the periodically exposed fluvio-lacustrine (pond or very shallow lacustrine) sedimentary environments. The present work not only enrich the trace fossils database of terrestrial origin but also offer new data to complete further continental ichnofacies mode and also provide the constraints on palaeoenvironments of the Xixia Basin. © 2015 Taylor and Francis. Source

Song H.-B.,Henan Polytechnic University | Song H.-B.,Key Laboratory of Biogenic Traces and Sedimentary Minerals of Henan Province | Wang H.,Henan Polytechnic University | Wang F.,Henan Polytechnic University | And 2 more authors.
Geodinamica Acta | Year: 2016

Thirteen ichnogenera and seventeen ichnospecies were recognised in carbonate rocks from the Lower Permian Taiyuan Formation in North China Basin. Based on the composition, occurrence and diversity of ichnofossils, intensity of bioturbation, lithologic characteristics, especially on the variation of individual size and the filling colour diversities of the Zoophycos burrows, four types of ichnofabrics were recognised, that is (1) epigenic tiering ichnofabric-mainly appeared on or near the bedding plane and formed in restricted bay or lagoon sedimentary environments; (2) shallow tiering ichnofabric-developed less than 15 cm under the bedding plane and occurred in the upper shallow-marine environment; (3) medium tiering ichnofabric-mainly distributed from 15 to 20 cm under the bedding plane and generated in the mid-upper shallow sea (restricted-open platform); (4) deep tiering ichnofabric-distributed from 25 to 30 cm under the bedding plane and occurred in lower shallow sea (open platform) far from shore. Based on ichnological and sedimentological analyses above four types of ichnofabrics, the sedimentary environment model of the ichnofabrics in carbonate rocks from the Taiyuan Formation in North China Basin is proposed in this paper. © 2015 Taylor and Francis. Source

Jin Y.,Henan Polytechnic University | Jin Y.,Key Laboratory of Biogenic Traces and Sedimentary Minerals of Henan Province | Song H.B.,Henan Polytechnic University | Song H.B.,Key Laboratory of Biogenic Traces and Sedimentary Minerals of Henan Province | And 4 more authors.
Science China Earth Sciences | Year: 2013

The influences of fractal pore structure in coal reservoir on coalbed methane (CBM) migration were analyzed in detail by coupling theoretical models and numerical methods. Different types of fractals were generated based on the construction thought of the standard Menger Sponge to model the 3D nonlinear coal pore structures. Then a correlation model between the permeability of fractal porous medium and its pore-size-distribution characteristics was derived using the parallel and serial modes and verified by Lattice Boltzmann Method (LBM). Based on the coupled method, porosity (φ), fractal dimension of pore structure (Db), pore size range (rmin, rmax) and other parameters were systematically analyzed for their influences on the permeability (κ) of fractal porous medium. The results indicate that: {circled digit one} the channels connected by pores with the maximum size (rmax) dominate the permeability κ, approximating in the quadratic law; {circled digit two} the greater the ratio of rmax and rmin is, the higher κ is; {circled digit three} the relationship between Db and κ follows a negative power law model, and breaks into two segments at the position where Db{all equal to}2.5. Based on the results above, a predicting model of fractal porous medium permeability was proposed, formulated as κ=Cfrmax n, where C and n (approximately equal to 2) are constants and f is an expression only containing parameters of fractal pore structure. In addition, the equivalence of the new proposed model for porous medium and the Kozeny-Carman model κ=Crn was verified at Db=2.0. © 2013 Science China Press and Springer-Verlag Berlin Heidelberg. Source

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