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1.
Kerogen plays an important role in shale gas adsorption, desorption and diffusion. Therefore, it is necessary to characterize the molecular structure of kerogen. In this study, four kerogen samples were isolated from the organic-rich shale of the Longmaxi Formation. Raman spectroscopy was used to determine the maturity of these kerogen samples. High-resolution transmission electron microscopy (HRTEM), 13C nuclear magnetic resonance (13C NMR) , X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy were conducted to characterize the molecular structure of the shale samples. The results demonstrate that VReqv of these kerogen samples vary from 2.3% to 2.8%, suggesting that all the kerogen samples are in the dry gas window. The macromolecular carbon skeleton of the Longmaxi Formation kerogen is mainly aromatic (fa’=0.56). In addition, the aromatic structural units are mainly composed of naphthalene (23%), anthracene (23%) and phenanthrene (29%). However, the aliphatic structure of the kerogen macromolecules is relatively low (fal*+falH=0.08), which is presumed to be distributed in the form of methyl and short aliphatic chains at the edge of the aromatic units. The oxygen-containing functional groups in the macromolecules are mainly present in the form of carbonyl groups (fac=0.23) and hydroxyl groups or ether groups (falO=0.13). The crystallite structural parameters of kerogen, including the stacking height (Lc=22.84 ?), average lateral size (La=29.29 ?) and interlayer spacing (d002=3.43 ?), are close to the aromatic structural parameters of anthracite or overmature kerogen. High-resolution transmission electron microscopy reveals that the aromatic structure is well oriented, and more than 65% of the diffractive aromatic layers are concentrated in the main direction. Due to the continuous deep burial, the longer aliphatic chains and oxygen-containing functional groups in the kerogen are substantially depleted. However, the ductility and stacking degree of the aromatic structure increases during thermal evolution. This study provides quantitative information on the molecular structure of kerogen samples based on multiple research methods, which may contribute to an improved understanding of the organic pores in black shale.  相似文献   

2.
We present here for the first time,the Raman and infrared spectroscopic investigation of amphiboles from the World's deepest borehole,the Kola super-deep borehole,at the depth of 11.66 km.The Kola Super-deep borehole(SG-3)(henceforth referred as KSDB) is located in the northwest of the Kola Peninsula in the northern frame of the Pechenga structure,Russia.It was drilled in the north-eastern part of the Baltic Shield(69°5'N,30°44'E) and reached a depth of 12.262 km.It has been drilled in the northern limb of the Pechenga geosyncline composed of rhythmically inter-bedded volcanogenic and tuffaceous-sedimentary strata extending to the NW at 300°–310° and dipping to SW at angles of 30°–50°.The SG-3 geological section is represented by two complexes – Proterozoic and Archaean.Amphibolite facies is dominant in the depth region from 6000 m to 12,000 m to the deepest.The Raman spectra of the sample reveal abundant presence of plagioclase and amphiboles.The most distinct Raman peak in this study indicates the tremolite-ferro-actinolite rich enrichment of the borehole samples at this depth corroborating earlier conventional petrographic studies.  相似文献   

3.
A Calculation Model for Corrosion Cracking in RC Structures   总被引：5，自引：0，他引：5  
A novel calculation model is proposed aiming at the problem of concrete cover cracking induced by reinforcement corrosion. In this article, the relationship between the corrosion depth of the bar and the thickness of the rust layer is established. By deducing the radial displacement expression of concrete, the formula for corrosion depth and corrosion pressure before cracking is proposed. The crack depth of cover in accordance with the maximum corrosion pressure is deduced; furthermore, the corrosion depth and corrosion pressure at the cracking time are obtained. Finally, the theoretical model is validated by several experiments, and the calculated values agree well with the experiment results.  相似文献   

4.
Thirty-seven Kupferschiefer samples from southwestern Poland were analyzed by microscopy, Rock-Eval approach and instrumental neutron activation analysis to understand the geochemical and morphological characteristics of kerogen present in the samples. The analytical results indicate that there are two different types of kerogens. One type was only subjected to thermal alteration processes, and the other was further oxidized after deposition of the sediment.In the oxidized samples migrabitumen was transformed into pyrobitumen. Rock-Eval analyses show a significant decrease in HI values in the oxidized samples and an increase in OI values in relation to the samples that were not influenced by oxidation. Variations in S2 versus Corg contents indicate a change in kerogen from Type II to Type III with progressing oxidation. The presence of pyrobitumen and the depletion of hydrogen in the altered kerogen allow one to conclude that the kerogen was used as hydrogen donor for thermochemical sulfate reduction(TSR).  相似文献   

5.
The characteristic structures of the Precambrian cherts from the Gusui section, Guangdong ,Chi-na, include bedded structure ,laminated structure ,massive structure and pseudobrecciated structure.The chert is characterized by consistently low abundance of TiO2,Al2O3 and most trace elements.Howevver ,it is enriched in Ba,As,Sb,Hg and Se.In Al-Fe-Mn ternary diagrams,it falls into the “hydrothermal field“ .Correspondence analysis and factor analysis show that many elements show up in the factor that represents the leaching of country rocks by hydrothermal solutions,and are the very characteristic element association fo the geochemically anomalous South China basement.Petrologic and geochemical evidence suggests a hydrothermal origin for the chert.The chert may have been formed in a Precambrian fift or an extension zone developed within the Yunkai marginal geosyncline, with a fault system linking it to an unknown heat source at depth.  相似文献   

6.
Kerogen is an important organic matter fraction widely spread in soils and sediments. It plays a major role in the sorption and sequestration of hydrophobic organic contaminants （HOCs） such as trichlorobenzene （TCB）. It is known that kerogen is geochemically heterogeneous due to the differences in source materials and diagenesis history. We hypothesized that kerogen derived from different source materials and diagenetic history exhibits different sorption properties for TCB. We employed two different kerogen materials （coals） as the original materials and two series of kerogen for a given series with an identical source material but different alteration history were yielded through thermal treatment at temperature ranging from 200 to 500℃. The original and treated materials were characterized for their physicochemical properties. Sorption experiments were conducted with batch reactor systems using 1, 3, 5-TCB as the HOCs sorbates and the original and treated materials as the sorbents.  相似文献   

7.
Sourthern China referred to in this paper embraces all the provinces to the south of latitude 32° N within the territory of China, exclusive of Tibet and Taiwan.The paper is based on the data obtained from temperature measurements of 680 boreholes drilled for petroleum, coal and hydrogeology. The depth of these boreholes ranges between 1,000 and 2,000m in most cases, being generally not less than 400m and reaching 7,000m in maximum.Through the elaboration and analysis of the temperature data, isotherm maps showing the temperatures at depths of 1,000m, 2,000m and 3,000m respectively and a geothermal gradient map of southern China have been compiled. These maps indicate that the earth's temperature distribution in southern China is characterized by a elatively low value in areas of its central part and those to the west of the Anning River valley of the western part(30℃, 40℃ and 70℃ at depths of 1,000m, 2,000m and 3,000m respectively), and a comparatively high value in the southeastern coastal areas and western Yunnan(60℃, 80℃ and over 120℃ respectively), and that the geothermal gradient also increases from less than 1.5℃/100 m in the central part towards both the east and the west to 2.0-3.0℃/100m or even over 4.0℃/100m.The earth's temperature distribution is strictly controlled by the deep structure of the earth's crust and is very closely related to the character of the regional geological structure, The stable central areas remarkably differ in the earth's temperature distribution from the tectonicalty active areas such as the southeastern coastal areas and the Jinggu-Tengchong area in western Yunnan, the former being lower than the latter. Meanwhile, due to the well-developed karst features in southern China, the strong groundwater flow may exert certain cooling effect on the temperature down to a depth of about 1,500m.According to the regularity of the earth's temperature distribution, regional deep structure of the earth's crust, regional geological structure and hydrogeological conditions, the following four models are proposed to explain the mechanism of formation and distribution of the earth's temperature fields in southern China: 1) onduction type; 2) convection type; 3) deep heat-source conduction-convection type; and 4) precipitation infiltration cooling type.  相似文献   

8.
河北衡水地区钻孔岩芯的古地磁研究   总被引：6，自引：0，他引：6  
Paleomagnetic measurements were carried out on 134 vertically oriented spccimens taken from a Cenozoic drilling core in the Hengshui area, North China Plain.An alternating magnetic field with a peak value of 160 Oe, was adopted for oppositedirection-magnetic cleaning to eliminate secondary viscous and rotated remanent magnetization. The results proved greatly successful. It is evident from the paleomagnetic studies that geomagnetic polarity epochs and events were recorded in this set of loose sediments during the last 3 m.y. with the boundary between the Brunhes normal epoch and the Matuyama reversed epoch (ca. 0.7m.y.) at a depth of 140m and the Matuyama-Gauss boundary (ca. 2.43m.y.) at 489 m depth with respect to the drilling cores. At present, it is acceptable that the beginning of the Quarternary should be dated back at 1.8--2 m.y., rightly corresponding to the basal limit of the Olduvia event at the depth of 360m. The area is characterized by a high and constant rate of sedimentation (ca. 200mm per 1,000 years).  相似文献   

9.
Based on the data of field measurement and drilling in the Tongling area, a series of numerical simulations are carried out by using the "Surplus Space Method" (SSM), which is first put forward in this paper and applied to predict the shallow-seated magmatic bodies. The results of the numerical simulations show the existence and the 3-D shape of a conical magmatic structure at a depth of-1000 m beneath the center of the area: its top offsets southwards and bifurcates to several branches, while its lower part stretches northeastwards and contracts rapidly to a point at about -1000 m depth. This point is reckoned to be a "sink" of magma system, transferring ore materials and heat energy from the deep magma chamber to the sub-surface apophyses. The preliminary application of the SSM proves that it may be developed as a new detection means for determining the existence of shallow-seated magmatic bodies and analyzing their three-dimensional features.  相似文献   

10.
洛川黄土剖面的古地磁研究   总被引：28，自引：1，他引：28  
Paleomagnetic measurements were conducted on 96 ariented loess specimens collected from the Lochuan section in Shanxi Prov., the total thickness of which is up to 130 m and more. The results have provided evidence that the deposition of Late Pleistocene Malan Loess and Middle Pleistocene Lishih Loess in the Lochuan section took place during the Brunhes normal epoch. The lower limit of the Lishih Loess which represents the boundary between the Brunhes epoch and the Matuyama epoch is located at the top of the lower silt bed, corresponding to a depth of 75 m. The Wucheng Loess, which recorded the Jalomillo normal polarity event, deposited during the middle-late period of the Matuyama reversed epoch. The upper limit of the Jalamillo is set at a depth of 100 m. and the lower limit at 110 m. Experiments have shown that rotated remanent magnetization of the specimen resulted from AF demagnetization Can be effectively eliminated by means of magnetic cleaning in opposite directions,despite of the differences in magnetic stability and ages of various strata (loess, silt bed, buried soil and weathered beds) in the Lochuan section.  相似文献   

11.
The studies on configuration, character/property of the basement of Qiangtang basin is helpful for evaluating petroleum and nature gas resources as well as understanding the basin evolvement. Recently a moderate to high-grade metamorphic gneiss rock was found underlying beneath very low metamorphic Ordovician strata in Mayer Kangri to the north of the central uplift. That fact actually proved existence of the crystalline basement just the distribution and structures of pre-Paleozoic crystalline basement still remain puzzle. In recent years a number of active sources deep seismic profiling, to aim at lithospheric structure of northern Tibet and petroleum resources of the Qiangtang basin, had been conducted that make it possible to image the structure of the basement of the Qiangtang. Near vertical reflection profiles, included those acquired previously and those during 2004 to 2008, have been utilized in this study. By through the interaction process and interpretation between the reflection profiles and the wide-angle profile, a model with the detailed structure and velocity distribution from surface to the depth of 20 km of Qiangtang basin has been imaged.Based on the results and discussions of this study, the preliminary conclusions are as follows: (1) The velocity structure section (~20 km) that is interactively constrained by the refraction and reflection seismic data reveals that the sedimentary stratum gently lie until 10 km in the south Qiangtang basin. (2) The basement consists of fold basement (the upper) and crystalline basement (the lower).The fold basement buried at the average depth of 6 km with a velocity of 5.2–5.8 km/s. The shallowest appear at range of the central uplift. The crystalline basement is underlying beneath the fold basement at the average depth of 10 km with a velocity of 5.9–6.0 km/s except near Bangong-Nujiang suture. (3) The high-velocity body at the depth range of 3–6 km of the central uplift is considered as a fragment of the crystalline basement that perhaps was raised by Thermal or deformation. (4) The lower-consolidated fold basement show more affinity of Yangtze block but the crystalline basement seems more approximate to Lhasa terrene in geophysical nature. We have attempted to improve the resolution and reliability by interaction of the active seismic data and prove it effective to image complex basement structure. It will be a potential to process the piggy-back acquisition data and has wide prospects.  相似文献   

12.
顺5孔的磁性地层学和早松山世的北京海侵   总被引：16，自引：0，他引：16  
Vertically oriented samples collected from the care S-5 in the county of Shunyi,Beijing Plain, were measured on an astatic magnetometer, after demagnetized with a peak value of 150 or 200 Oe. The results have shown that the loose sediments up to a thickness of 640 m have recorded the Brunhes-Matuyama boundary at the depth of 160m, the Matuyama-Gauss boundary at the. depth of 468 m, and the short events corresponding to the polarity events during each epoch. 28 species of foraminiferal fossils were isolated from the sample at the depth of 428 m, 31% of this fauna is composed of planktonic foraminifera. Such an assemblage in dicates the warm, shallow-water, open-sea palaeoecological environments.According to the ages of magnetostratigraphic sequences, this marina bed composed of silts and sands with foraminiferal fossils marked by classical HyaliNea baltica,has been dated to be about 2.26 re.y, B.P., approximating the age of FAD of Hyalinea baltica in the section at Santa Maria in Italy (about 2.1 m.y.B. P). Its equivalent is also found in the other coree from the Beijing Plain. From these facts, it is postulatsd that during the early Matuyama epoch, an extensive transgression took place on the Beijing Plain. A new datum level of benthonic and planktonic foraminifera marked by the appearance of Hyalinea baltica has been found in Early Matuyama strata in the Beijing Plain. The first appearance of cold forms in the Vrica Section in Italy has been dated to be about 2:4 m.y.B.P. Based upon the up-to-date reports on calcareous nannoplankton, the interval of 2.3--1.6 m.y. is a distinet alternating stage in their evolution history. The climate in the Northern Hemisphere began to become obviously colder at about 2.5 m.y. ago. From the foregoing discussion, it is reasonable to set the Pliocene-Pleistoecne boundary in the Beijing Plain at the basal limit of the Matuyama epoch (2.43 m.y.).  相似文献   

13.
The geochemistry data show that the total organic carbon （TOC） contents are high in the surface sediments in the eastern part of the Moknine＇ s Sebkha. Low decreasing of organic matter （ OM ） with increasing depth indicates the good preservation of OM in modern sediments. ＂Lignite levels＂ inserted in the sand sequence and deposited at the edge and in the intermediate zone are considered as lithologic and organic markers. It is characterized by high TOC and poor hydrogen index （HI） , indicating a higher plant origin and good preservation of OM in thin beds under anoxic condition. In all samples low values of HI are typical for strong terrigenous input in the Sebkha. Gas chromatography （GC） of saturate fraction showed that OM in the border zone is provided from plants but in the central zone OM is a mixture of terrestrial fraction and little fraction from microalgae. The study of free lipids indicated that this environment was influenced by intense bacterial and microbial activities, as evidenced by the abundance of n-alkanes and nC18-nC22.  相似文献   

14.
To determine the effect of thermal maturity on the methane sorption in shale gas system, two different thermal maturity kerogens of type II isolated from Barnett shale of Fort Worth Basin were used to measure the methane adsorption amount under the pressure ranging from 0 to 14 MPa at constant temperatures. One kerogen was called Lee C-5-1 with 0.58% of vitrinite reflectance; the other was called Blakely#1 kerogen with 2.01% of vitrinite reflectance. The results suggested that the methane sorption capacity of kerogen Blakely#1 was higher than the immature kerogen Lee C-5-1, and its Langmuir constant and Langmuir maximum sorption amount, which were reached by fitting the measured data for at least square method, greater than the immature kerogen Lee C-5-1. This may be associated with that nanopores opened up during the degradation of organic matter, and which increased the specific surface area of kerogen. Therefore, the over mature kerogen has greater methane adsorption capacity.  相似文献   

15.
Microbes were cultured and identified from the saples collected at various depths in 4 weathering profiles of REE-bearing granites in Gonghe,Guangdong,The microbes were found existing at the depth of 0-5m in all the profiles.The main microbes include coccus (Staphylococcus,Streptococcus),bacillus(Bacillus,Clostridium and Escherichia Coli),actinmyces and fungi(Saccharomycete,Penicillium,Fusarium,Aspergillus Aiger and Mucor),The number of colonies decreases downwards in the profiles.Experimental studies show that all the microbes used in the experiment can accelerate downward migation of REE in the experimental tubes.,The ability to accelerate the migration of REE decreases in a sequence of fungi→actinomyces→acillus→coccus.The microbes can change the modes of occurrence of REE in the weathering crust.The coccus,bacillus and actinomyces can increase the amounts of REE in ion state,whereas the fungi have a stronger ability to from organic compounding REE and accumulate REE than the bacteria do.  相似文献   

16.
Deep-seated cracked gas exploration was achieved great breakthrough in Es4L of the Minfeng area on the northern slope of the Dongying Sag. Carbon isotopic and molecular compositions studies revealed the characteristics of wet gas and a normal trend of carbon isotopic composition. Empirical cutoff points of δ13C2 and δ13C3 and light hydrocarbon compositions distinguished the cracking gas as sapropelic gas. Variations in i/nC5, i/nC4 and δ13C2 fur-ther confirmed that the gas was cracked from residual kerogen. Source characteristics indicated that the gas was de-rived from mature-highly mature source rocks of Es4 with kerogen type II being dominant mixed with some oil-cracking gas. Burial history modeling indicated that there were two hydrocarbon charging periods in Es4L reser-voirs. The first period refers to the Guantao-Minghuazhen stage dominated by oil charging, while the second period refers to the Minghuazhen stage and has been dominated by cracked gas charging till now.  相似文献   

17.
Laser Pyrolysis Gas Chromatography (LFGC) can provide important information on organic geochemistry, which can, in return, reflect rapidly and simply the tendency of thermal alteration of organic matter with increasing depth in oil-generating rocks and the percentage production of hydrocarbons as well as permit one to differemtiate the types and properties of kerogen in oil-bearing rocks. Experimental data can also show the variation of organic and effective carbon in oil-bearing rocks. - Aecordingly, new geochemical indexes for oil-generating rocks are expected.  相似文献   

18.
This article is to review results from scientific drilling and fault-zone trapped waves(FZTWs) at the south Longman-Shan fault(LSF) zone that ruptured in the 2008 May 12 M8 Wenchuan earthquake in Sichuan, China. Immediately after the mainshock, two Wenchuan Fault Scientific Drilling(WFSD) boreholes were drilled at WFSD-1 and WFSD-2 sites approximately 400 m and 1 km west of the surface rupture along the Yinxiu-Beichuan fault(YBF), the middle fault strand of the south LSF zone. Two boreholes met the principal slip of Wenchuan earthquake along the YBF at depths of 589-m and 1230-m, respectively. The slip is accompanied with a 100-200-m-wide zone consisting of fault gouge, breccia, cataclasite and fractures. Close to WFSD-1 site, the nearly-vertical slip of ~4.3-m with a 190-m wide zone of highly fractured rocks restricted to the hanging wall of the YBF was found at the ground surface after the Wenchuan earthquake. A dense linear seismic array was deployed across the surface rupture at this venue to record FZTWs generated by aftershocks. Observations and 3-D finite-difference simulations of FZTWs recorded at this cross-fault array and network stations close to the YBF show a distinct low-velocity zone composed by severely damaged rocks along the south LSF at seismogenic depths. The zone is several hundred meters wide along the principal slip, within which seismic velocities are reduced by ~30–55% from wall-rock velocities and with the maximum velocity reduction in the ~200-m-wide rupture core zone at shallow depth. The FZTW-inferred geometry and physical properties of the south LSF rupture zone at shallow depth are in general consistent with the results from petrological and structural analyses of cores and well log at WFSD boreholes. We interpret this remarkable low-velocity zone as being a break-down zone during dynamic rupture in the 2008 M8 earthquake. We examined the FZTWS generated by similar earthquakes before and after the 2008 mainshock and observed that seismic velocities within fault core zone was reduced by ~10% due to severe damage of fault rocks during the M8 mainshock. Scientific drilling and locations of aftershocks generating prominent FZTWs also indicate rupture bifurcation along the YBF and the Anxian-Guangxian fault(AGF), two strands of the south LSF at shallow depth. A combination of seismic, petrologic and geologic study at the south LSF leads to further understand the relationship between the fault-zone structure and rupture dynamics, and the amplification of ground shaking strength along the low-velocity fault zone due to its waveguide effect.  相似文献   

19.
In order to study the deep geoelectrical structure and the regional geological structure and detect potential oil and gas areas in Qiangtang basin in northern Xizang (Tibet), 222 MT soundings were conducted along three N - S MT profiles across the basin .The MT results indicate that the south and north parts of the Qiangtang basin have a good contrast in the deep electrical structure . In the south Qiangtang , there are generally two high conductivity layers in the crust . The first is at a depth of about 10-25 km and possesses a resistivity of about 10-80 Ωm . The second, the high conductivity layer in the lower crust, is at a depth of about 40-70 km with 3- 50 Ωm . In the north Qiangtang , there is generally one high conductivity layer . It is at a depth of about 10-30 km and the resistivity is about 1-60 Ωm . The thickness of the second high conductivity layer in both the south Qiangtang and the Bangong-Nujiang suture is much greater than that of the first . The thickness of the lithosphere is abou  相似文献   

20.
This paper addresses the characterization of the Continental Intercalaire aquifer(CI) in the Tinrhert-East area of Illizi Basin on the Algerian-Libyan border, which belongs to the SASS1 system, one of the biggest transboundary aquifers in the world. This study concerns a superficies of 4 300 km~2. On the basis of Mud Logging borehole data conducted in this part of the aquifer, a realistic characterization of the aquifer was done. The thickness of the CI aquifer varies from 300 m in the south to 700 m in the north, and the depth ranges from 180 m to 320 m. The interpretation of the logs showed that the aquifer is characterized by a maximum net thickness in its southwestern part(more than 600 m), the porosity is very high, ranging from 30% in the west to 24% at the Libyan borders, the permeability is low to medium around 10~(-5) m/s, and the maximum transmissivity values of about 8× 10~(-3) m~2/s were recorded at the center of the study area. The depth of water varies from 235 m to 312 m, and the water flows from south to north, in accordance with the general direction observed in the CI aquifer in the Northern Sahara Aquifer System(SASS). The porosity values obtained from the interpretation of the sonic and density logs permit to estimate the water reserves of this aquifer considered fossil, at thresholds much higher than what was considered until now.  相似文献   

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