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formation Mechanism and Sedimentary Pattern of Abandoned Channels

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Acta Geologica Sinica(English Edition) 2020年第2期94卷 545-555页

作者： LIU Zongbao SHANG Yunzhi ZHAO Rongsheng LIU Fang XUE Xinyu LIU Yunyan Northeast Petroleum University DaqingHeilongjiang 163318China Daqing Oilfield Limited Liability Company DaqingHeilongjiang 163514China Jilin University Changchun 130061China

Accurately identifying and quantitatively describing abandoned channels in meandering rivers are of great significance for improving hydrocarbon recovery. By using modern deposition analogy, field outcrop analysis, a dense well spacing, core observations and a review of the literature, this paper studied the formation process and space–time amalgamation of abandoned channels in meandering river. The results reveal that formation mechanisms of abandoned channels include chute cutoff patterns(shoal-cutting, ditch-scouring and embayment-eroding patterns) and neck cutoff patterns. The chute cutoff pattern forms a gradually abandoned channel, while the neck cutoff pattern forms a suddenly abandoned channel. From upstream to downstream, the sedimentary pattern of the abandoned channel transforms from a chute cutoff pattern to a neck cutoff pattern, where the main controlling factors transition from the grain size and gradient to the flow and vegetation. An abandoned channel formed by a chute cutoff pattern consists mainly of siltstone, fine sandstone and thin gravel layers, which form a lithological-physical barrier. The abandoned channel formed by a neck cutoff pattern consists mainly of mudstone and argillaceous siltstone, forming a lithological barrier. Based on the amalgamation and structure of the reservoir architectural elements, the abandoned channel can be divided into three planar sedimentary patterns(crescent, semilune and horseshoe) for a single channel and five vertical sedimentary patterns for composite channels.

关键词： abandoned channel cutoff pattern formation mechanism sedimentary pattern meandering river

formation of zirconia polymorphs under hydrothermal conditions

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Science China(Technological Sciences) 2002年第3期45卷 273-281页

作者：郑燕青施尔畏李汶军陈之战仲维卓胡行方 Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai China

Using zirconium oxychloride solution as precursor, monoclinic zirconia crystallites withnarrow distribution of nanosize were obtained in the hydrothermal reaction. However, when thereaction was in weak acidic medium or base medium, whether directly using the colloidal precipi-tate prepared from zirconium salt solutions with base solution as precursor added, or using theprecipitate after filtrating, washing and drying treatments as precursor, the product of the hydro-thermal reaction was the mixture of both monoclinic and tetragonal polymorphs. As the pH of themedium rises, the content of tetragonal phase in the product, the morphologies and size of thecrystallites all change. There are three types of formation mechanisms under hydrothermal condi-tion, which can be called as saturation-precipitation mechanism in homogeneous solution, dissolu-tion-crystallization mechanism and in-situ crystallization mechanism, respectively. The formationmechanism of crystallites varies with different hydrothermal conditions, such as the states of theprecursor and the pH of the medium, which lead to changes in the phases, morphologies andsizes of the resulting crystallites.

关键词： crystal, polymorph, formation mechanism.

formation Mechanism and Numerical Model of Quartz in Fine-Grained Organic-Rich Shales: A Case Study of Wufeng and Longmaxi formations in Western Hubei Province, South China

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Journal of Earth Science 2020年第2期31卷 354-367页

作者： Bao Zhang Detian Yan Hassan Jasmine Drawarh Xiangrong Yang Jin He Liwei Zhang Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education China University of GeosciencesWuhan 430074China

The difference in quartz types in shales not only affects the porosity and permeability of the rocks,but also reflects the difference in the sedimentary *** established the formation mechanism and numerical model of quartz in shales of Wufeng and Longmaxi formations in the Wangjiawan Section,South China,based on thin-section studies using SEM(scanning electron microscope),SEM-CL(cathodoluminescence),XRD(X-ray diffraction)and geochemical *** are two types of quartz in the shales:detrital quartz and authigenic *** quartz is mostly silt-size,typically ranging from 10 to 60μm in size and subangular to angular monocrystal in shape,and brighter than authigenic quartz by CL intensity;authigenic quartz is present in two phases in shape:grain overgrowths and crystallite *** surfaces are *** grains are typically less than 10μm in size,euhedral or subhedral monocrystal in *** quartz can be subdivided into biogenic quartz and clay mineral transformed quartz according to the source of *** the numerical model,the content of detrital quartz is relatively consistent(20%);the content of biogenic quartz ranges from 40%to 70%,with a sharp fall(0–30%)in the Guanyinqiao *** the Katian,a lower anoxic and dense water column make the dissolution of biogenic silica well *** quartz is the major contributor to the *** the early Hirnantian interval,due to the drop of sea level and the oxygenation of seafloor,the sediment is mainly composed of clay transformed quartz and detrital *** the latest Hirnatian and Rhuddanian,rapid sea level rise and anoxic ocean enhance the preservation of the biogenic silica,thereby biogenic quartz re-emerges as the major contributors to the *** crystallite grains and grain overgrowths have filled in primary pore space and have decreased the interparticle porosity,however,as a rigid framework,they can suppress compac

关键词： brittle mineral quartz Wufeng and Longmaxi formations formation mechanism numerical simulation

formation process and fractal growth model of HCFC-141b refrigerant gas hydrate

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Science China Chemistry 2002年第2期45卷 216-224页

作者：赵永利樊栓狮葛新石刘勇郭开华刘晓聪梁栋舒碧芬 Guangzhou Institute of Energy Conversion Chinese Academy of Sciences Guangzhou China University of Science and Technology of China Hefei China

The microscopic visualization experiment on the formation process of HCFC-141b refrigerant gas hydrate has been investigated, and the morphological photos of hydrate formation process have been obtained. The results show that gas hydrate originally nucleated on the interface of refrigerant HCFC-141b and water under the condition of supercooling, then the hydrate grows continually due to the inducement of formed nucleation and diffusion of refrigerant. The formation of gas hydrate presents an arboreous phenomenon. The fractal dimension of the hydrate formation morphology on different stages was calculated. The calculating results indicate that the initial stage of the hydrate formation belongs to fractal growth, and the dimension is about 1.52. Based on the fractal theory, an RIN-DLA (random inducement nucleation-diffusion limited aggregation) model for the HCFC-141b hydrate growth was developed. The hydrate growth process was simulated with the developed model, and the fractal dimension for the simulated morphology is well compared with that from the experiment.

关键词： refrigerant gas hydrate, formation process, fractal growth, dimension, RIN-DLA model.

formation mechanisms of heavy oils in the Liaohe Western Depression,Bohai Gulf Basin

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Science China Earth Sciences 2008年第S2期51卷 156-169页

作者： LI SuMei1,2,PANG XiongQi1,2,LIU KeYu3,GAO XianZhi1,2,LI XiaoGuang4,CHEN ZhenYan4 & LIU BaoHong41 State Key Laboratory of Petroleum Resource and Prospecting,China University of Petroleam,Beijing 102249,China 2 Basin and Reservoir Research Center,China University of Petroleum,Beijing 102249,China 3 CSIRO Petroleum,P.O. Box 1130,Bentley WA 6102,Australia 4 Liaohe Oilfield Co. Ltd,PetroChina,Panjin 124010,China State Key Laboratory of Petroleum Resource and Prospecting China University of Petroleam Beijing China Basin and Reservoir Research Center China University of Petroleum Beijing China CSIRO Petroleum Bentley Australia Liaohe Oilfield Co. Ltd PetroChina Panjin China

The Liaohe Oilfield in the Liaohe Western Depression of the Bohai Gulf Basin is the third-largest oil producing province and the largest heavy oil producing oilfield in China. A total of 65 oil samples,35 rock samples and 36 reservoir sandstone samples were collected and analyzed utilizing conventional geochemical and biogeochemical approaches to unravel the mechanisms of the formation of the heavy oils. Investigation of the oils with the lowest maturity compared with the oils in the Gaosheng and Niuxintuo oilfields indicates no apparent relation between the maturity and physical properties of the heavy oils. It is suggested that the heavy oil with primary origin is not likely the main mechanism re-sponsible for the majority of the heavy oils in the Liaohe Western Slope. The absence and/or depletion of n-alkanes etc.,with relatively low molecular weight and the occurrence of 25-norhopane series in the heavy oils as well as the relatively high acidity of the oils all suggest that the majority of the heavy oils once experienced secondary alteration. The fingerprints of the total scanning fluorescence (TSF) of the inner adsorbed hydrocarbons on the reservoir grains and the included hydrocarbons in fluid inclusions are similar to that of the normal oils in the area but are different from the outer adsorbed and reser-voired free oils at present,further indicating that most of the heavy oils are secondary in origin. Analyses of bacteria (microbes) in 7 oil samples indicate that anaerobic and hyperthermophilic Ar-chaeoglobus sp. are the dominant microbes relevant to oil biodegradation,which coincides with the shallow commercial gas reservoirs containing anaerobic bacteria derived gas in the Gaosheng and Leijia teotonic belts. The biodegradation most likely occurs at the water/oil interface,where the forma-tion water is essential for microbe removal and nutrient transportation. We think that biodegradation,water washing and oxidization are interrelated and are the main mech

关键词： heavy oil Liaohe Western Depression biodegradation water washing formation mechanism

formation control for nonholonomic agents using passivity techniques

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Applied Mathematics and Mechanics(English Edition) 2010年第1期31卷 27-36页

作者：吴凡耿志勇 State Key Laboratory for Turbulence and Complex Systems Department of Mechanics and Aerospace EngineeringPeking University

This paper studies the problem of the formation control for the multiple nonholonomic agents on a plane. A dynamic feedback linearization method is used to transform the dynamical model of each agent into two third-order integrator chains. A decentralized formation control law with the inter-agent damping .injection is derived. The asymptotical stability of the overall system is proven using the Lyapunov method. The simulation of the formation maneuver of a planar vehicle shows the effectiveness of the proposed method.

关键词： nonholonomic agents formation full-state linearization passivity

formation mechanism of carbonate cemented zones adjacent to the top overpressured surface in the central Junggar Basin,NW China

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Science China Earth Sciences 2010年第4期53卷 529-540页

作者： YANG Zhi1,2,ZOU CaiNeng1,3,HE Sheng2,LI QiYan1,HE ZhiLiang3,WU HengZhi5,CAO Feng1,MENG XianLong4,WANG FuRong2 & XIAO Qilin21 State Key Laboratory of EOR,Research Institute of Petroleum Exploration & Development,PetroChina,Beijing 100083,China 2 Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education,China University of Geosciences,Wuhan 430074,China 3 State Key Laboratory of EOR,Research Institute of Petroleum Exploration & Development,Petrochina,Beijing 100083,China 4 Research Institute of Petroleum Exploration and Production,SINOPEC,Beijing 100083,China 5 Southwest Branch Company,SINOPEC,Chengdu 610051,China State Key Laboratory of EOR Research Institute of Petroleum Exploration & Development PetroChina Beijing China Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education China University of Geosciences Wuhan China State Key Laboratory of EOR Research Institute of Petroleum Exploration & Development Petrochina Beijing China Southwest Branch Company SINOPEC Chengdu China Research Institute of Petroleum Exploration and Production SINOPEC Beijing China

Carbonate cemented zones are normally adjacent to the top overpressured surface in the central Junggar Basin,NW *** carbon and oxygen isotopic compositions and petrological investigations of carbonate cements in the carbonate cemented zones indicate that:(1) carbonate cements are composed dominantly of ferrocalcite,ferroan dolomite,and ankerite;(2) carbonate cements are formed under a high temperature circumstance in the subsurface,and organic fluid migration has an important effect on the formation of them;and(3) carbon and oxygen ions in the carbonate cements migrate from the underlying overpressured *** suggests that the occurrence of carbonate cemented zones in this region results from multiple phases of organic fluid expulsion out of the overpressure compartment through geological *** study provides a plausible mechanism of the formation of carbonate cemented zones adjacent to the top overpressured surface in the clastic sedimentary basins,and has an important implication for understanding the internal correlation between the formation of carbonate cemented zones adjacent to top overpressured surface and geofluids expulsion out of overpressured system.

关键词： carbonate cemented zones formation mechanism stable carbon and oxygen isotopic top overpressured surface central Junggar Basin coal-bearing strata

formation OF NECROTIC CORES IN THE GROWTH OF TUMORS: ANALYTIC RESULTS

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Acta Mathematica Scientia 2006年第4期26卷 781-796页

作者：崔尚斌 Department of Mathematics Zhongshan University Guangdong 510275China

In this article, the author studies the mechanism of formation of necrotic cores in the growth of tumors by using rigorous analysis of a mathematical model. The model modifies a corresponding tumor growth model proposed by Byrne and Chaplain in 1996, in the case where no inhibitors exist. The modification is made such that both necrotic tumors and nonnecrotic tumors can be considered in a joint way. It is proved that if the nutrient supply is below a threshold value, then there is not dormant tumor, and all evolutionary tumors will finally vanish. If instead the nutrient supply is above this threshold value then there is a unique dormant tumor which can either be necrotic or nonnecrotic, depending on the level of the nutrient supply and the level of dead-cell dissolution rate, and all evolutionary tumors will converge to this dormant tumor. It is also proved that, in the *** case, if the dormant tumor is necrotic then an evolutionary tumor will form a necrotic core at a finite time, and if the dormant tumor is nonnecrotic then an evolutionary tumor will also be nonnecrotic from a finite time.

关键词： Tumor growth necrotic core formation asymptotic behavior stability

formation and evolution of the tertiary carbonate reefs in the Madura Strait Basin of Indonesia

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Journal of Oceanology and Limnology 2019年第1期37卷 47-61页

作者： RAN Weimin LUAN Xiwu LU Yintao LIU Hong YANG Jiajia ZHAO Yang HE Wenchang YAN Zhonghui College of Marine Geosciences Ocean University of China Evaluation and Detection Technology Laboratory of Marine Mineral Resources Qingdao National Laboratory for Marine Science and Technology Qingdao Institute of Marine Geology Petro China Hangzhou Research Institute of Geology China Petroleum Pipeline Engineering Co. Ltd. (Engineering) China University of Petroleum

Analysis of 2 D seismic data over 4 500 km in length from the Madura Strait Basin in the East Java Sea reveals seismic re?ection characteristics of reefs and associated sedimentary bodies, including asymmetrical or symmetrical dome re?ections, slope progradational re?ections, chaotic re?ections and discontinuous strong re?ections inside the reef, which onlap the ?ank of the reef. It is concluded that the developmental paleo-environment of most reefs is mainly conducive to shallow marine carbonate platform facies and platform margin facies, based on well core data, variations in seismic facies and strata *** formation and evolution of all reefs are primarily in?uenced by the tectonic framework of the Madura Strait Basin. Platform margin reefs are principally controlled by two types of structures: one is a series of E-W trending Paleogene normal faults, and the other is an E-W trending Neogene inversion structures. In addition, wave actions, tidal currents and other ocean currents play an accelerated role in sorting, rounding and redeposition for the accumulation and evolution of reefs. Tertiary reefs in the MSB can be divided into four types: 1) an open platform coral reef of Late Oligocene to Early Miocene, 2) a platform margin coral reef controlled by normal faults in Late Oligocene to Early Miocene, 3) a platform margin Globigerina moundreef controlled by a "hidden" inversion structure in Early Pliocene, and 4) a platform margin Globigerina mound-reef controlled by thrust faults in the early Pliocene. Patterns of the formation and evolution of reefs are also suggested.

关键词： reef seismic reflection characteristics formation and evolution Tertiary Madura Strait Basin,Indonesia