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1.
Turkey has been divided into eight different seismic regions taking into consideration the tectonic environments and epicenters of the earthquakes to examine relationships of the modal values (a/b), the expected maximum magnitudes (Mmax) and the maximum intensities (Imax). For this purpose, the earthquakes for the time period 1900–1992 from the Global Hypocenter Data Base CD-ROM prepared by USGS, and for the time period 1993–2001 from the PDE data and IRIS data are used. Concerning the relationships developed between different magnitude scales and between surface wave magnitudes (MS) and intensity for different source regions in Turkey, we have constructed a uniform catalog of MS. We have estimated the values of Mmax and Imax using the Gumbel III asymptotic distribution. Highest a-values are observed in the Aegean region and the lowest b-values are estimated for the North Anatolian Fault. Maximum values of a/b, Mmax and Imax are related to the eastern and western part of the North Anatolian Fault and the Aegean Arc. The lowest values of all parameters are observed near the Mid Anatolian Fault system. Linear relationships have been calculated between a/b, Mmax and Imax using orthogonal regression. If one of the three parameters is computed, two other parameters can be calculated empirically using these linear relationships. Hazard maps of Mmax and Imax values are produced using these relationships for a grid of equally spaced points at 1°. It is observed that the maps produced empirically may be used as a measure of seismic hazard in Turkey.  相似文献   

2.
The Rock-Eval pyrolysis and TOC analysis have been widely used to evaluate the source rock quality. The atomic H/C ratio of kerogen, however, has been overlooked in source rock evaluation. In this study, coal and carbonaceous samples, including 26 from northwestern Taiwan, 12 from China, and 4 from the United States were analyzed, and integrated with 157 published data, to explore the significance of atomic H/C ratio as a parameter of source rock evaluation. Two different linear trends were observed in the cross-plot of S 1 versus S 2. Field outcropped shale or C-shale exhibits a steeper slope compared to that of coal samples which can be attributed to the compositional difference in their organic material. A rather strong positive correlation for H% versus S 2 illustrates the contribution of H-containing macerals, especially exinite. Organic matters in the samples studied are of type II/III kerogen based on the relationship between HI and T max. The H/C ratio, as well as the HI, S 1, and S 2, generally decreases with the maturity increasing. The H/C ratio decreases slightly from 1.1 to 0.7 with the maturity increasing from R o 0.55 to 0.85%. Samples with H/C ratio in this range show significant change in certain other geochemical parameters (e.g. HI, S 1, S 2, S 1 + S 2, S 1/(S 1 + S 2), S 1/TOC, (S 1 + S 2)/TOC, T max). The (S 1 + S 2)/TOC ratio (defined as QI) was used as an indicator of the hydrocarbon potential. The QI, HI, and H/C ratio show a certain correlation, all increasing accordingly. The QI of the samples analyzed in this study is approximately 100–380 (mgHC/gTOC), similar to that of most humic coals for oil and gas generation. Samples with R o value lower than 0.55% always show significant variation in their HI, ranging from 80 to 520 mgHC/gTOC. It is inferred that hydrocarbon potential started from R o 0.55% and atomic H/C ratio 1.1 in this study.  相似文献   

3.
We conducted a study of the spatial distributions of seismicity and earthquake hazard parameters for Turkey and the adjacent areas, applying the maximum likelihood method. The procedure allows for the use of either historical or instrumental data, or even a combination of the two. By using this method, we can estimate the earthquake hazard parameters, which include the maximum regional magnitude Mˆmax, the activity rate of seismic events and the well-known bˆ value, which is the slope of the frequency-magnitude Gutenberg-Richter relationship. These three parameters are determined simultaneously using an iterative scheme. The uncertainty in the determination of the magnitudes was also taken into consideration. The return periods (RP) of earthquakes with a magnitude M ≥ m are also evaluated. The whole examined area is divided into 24 seismic regions based on their seismotectonic regime. The homogeneity of the magnitudes is an essential factor in such studies. In order to achieve homogeneity of the magnitudes, formulas that convert any magnitude to an MS-surface scale are developed. New completeness cutoffs and their corresponding time intervals are also assessed for each of the 24 seismic regions. Each of the obtained parameters is distributed into its respective seismic region, allowing for an analysis of the localized seismicity parameters and a representation of their regional variation on a map. The earthquake hazard level is also calculated as a function of the form Θ = (Mˆmax,RP6.0), and a relative hazard scale (defined as the index K) is defined for each seismic region. The investigated regions are then classified into five groups using these parameters. This classification is useful for theoretical and practical reasons and provides a picture of quantitative seismicity. An attempt is then made to relate these values to the local tectonics.  相似文献   

4.
Eighty-four to ninety-eight percent of land subsidence in Shanghai City is caused by the visco-elastic–plastic deformation of sediments. Numerical experiments are done on the sediments with visco-elastic–plastic deformation in Shanghai to verify the modified Merchant model (MM model) and land subsidence model based on the modified Merchant (LS-MM) model. There are two advantages of the MM model and the LS-MM model. One is that only a few parameters are involved. There are three parameters in the MM model and four parameters in the LS-MM model. The other one is that both models can describe elastic, elastic–plastic and visco-elastic deformation in addition to visco-elastic–plastic deformation. The corresponding models are developed by setting proper values of the three parameters of μ, α 1 and α 2. The two advantages make the LS-MM model flexible and applicable to the simulation of the large regional land subsidence with visco-elastic–plastic deformation and other different kinds of deformation. The results can be improved by variable parameters, especially specific storage.  相似文献   

5.
一种页岩含气性热演化规律研究的模拟实验方法   总被引：2，自引：1，他引：1  
目前针对页岩气赋存规律研究的热模拟实验主要是沿袭常规油气热模拟方法,以粉末态样品开展模拟,研究对象为岩石生成并排出的烃类气体,这种模拟方式未明确页岩气的实质为"滞留气",并且模拟后样品无法开展扫描电镜分析,不能确定岩石孔隙结构变化规律。本文通过石英玻璃管封装块状样开展页岩生烃热模拟实验,并结合一套数据处理方法,尝试建立了一种适合页岩气研究的热模拟实验方法,研究泥页岩在不同演化阶段(Ro范围为0.596%~2.143%)不同赋存状态气体的含量以及岩石微观孔隙特征的变化情况。结果表明,泥岩及油页岩样品的排出气及解析气含量在高成熟度阶段(400℃以后)有明显增加的趋势,结合扫描电镜微观结构分析显示这是由于有机质生气量以及无机孔隙均有增加。本方法可以研究页岩热演化过程中不同赋存状态气体含量及微观孔隙结构的变化,为页岩气勘探开发提供了一种可参考的方法。  相似文献   

6.
In situ stress measurements by hydraulic fracturing were carried out in the 617 m deep borehole specially drilled in the epicentral zone of the 1993 Latur earthquake for the purpose of research. The stress measurements carried out at 592 m depth in this borehole are the deepest of all such measurements made so far in the Indian shield. The maximum and minimum principal horizontal stresses (S H max andS h min) have been derived from the hydrofracture data using the classical method. TheS H max andS h min are found to be 16.5 and 9.6 MPa at 373 m depth, and 25.0 and 14.1 MPa at 592 m depth, indicating that the vertical gradients ofS hmax andS hmin in the epicentral zone are 39 MPa/km and 21 MPa/km respectively. The principal horizontal stresses in the epicentral zone are comparable with those at Hyderabad and 30% higher than in most other comparable intra-continental regions. Analysis of the results indicate that the stresses in the focal region of the 1993 Latur earthquake have not undergone any significant change following its occurrence and this is in agreement with a similar inference drawn from the seismic data analysis. It appears that the Latur earthquake was caused due to rupturing of the overpressured fault segment at the base of the seismogenic zone.  相似文献   

7.
Comprehensive quantitative evaluation of shale gas content and the controlling factors in different occurrence states is of great significance for accurately assessing gas-bearing capacity and providing effective well-production strategies. A total of 122 core samples from well JY-A in the Fuling shale gas field were studied to reveal the characteristics of S_1 l shale,15 of which were selected to further predict the shale gas content in different occurrence states, which are dependent on geological factors in the thermal evolution process. Geological parameters were researched by a number of laboratory programs, and the factors influential in controlling shale gas content were extracted by both PCA and GRA methods and prediction models were confirmed by the BE method using SPSS software. Results reveal that the adsorbed gas content is mainly controlled by TOC, Ro, SSA, PD and pyrite content, and the free gas content is mainly controlled by S_2, quartz content, gas saturation and formation pressure for S_1 l in well JY-A. Three methods, including the on-site gas desorption method, the empirical formula method, and the multiple regression analysis method were used in combination to evaluate the shale gas capacity of well JY-A, all of which show that the overall shale gas content of well JY-A is in the range of 2.0–5.0 m~3/t and that the free gas ratio is about 50%, lower than that of well JY-1. Cause analysis further confirms the tectonics and preservation conditions of S_1 l in the geological processes, especially the influence of eastern boundary faults on well JY-A, as the fundamental reasons for the differences in shale gas enrichment in the Jiaoshiba area.  相似文献   

8.
Probability integral method is an official prediction method for mining subsidence in China. However, how to obtain the probability integral method parameters based on the measured data is the premise of realizing the accurate prediction of the probability integral method. Simulated annealing (SA) is an effective nonlinear optimization algorithm that has recently been introduced into the mining subsidence field to obtain the parameters of the probability integration method. To solve the problems of slow convergence speed and easily falling into the local optimal solution in the method of parameters inversion in probability integral method based on SA (MPIPIMSA), the method of parameters inversion in probability integral method based on quantum annealing (MPIPIMQA) is proposed by combining the quantum fluctuation mechanism and simulated annealing theory. The simulation experimental results show that MPIPIMQA is superior to MPIPIMSA in the accuracy and stability of parameters, and MPIPIMQA has a stronger anti-interference ability for local losing observation points, random errors and gross errors in observation data. Finally, the parameters of probability integral method for the 1414(1) working face of the Guqiao Coal Mine in Huainan mining area were obtained by using MPIPIMQA, namely, q?=?0.9916, tanβ?=?1.9277, b?=?0.4190, θ?=?84.3381, Su = ??7.3715, Sd = ??14.7126, Sl = 59.0695, and Sr = 32.6381, and the fitting error is 106.8863 mm. The research results have important reference values for accurate inversion of probability integral parameters.  相似文献   

9.
Raman spectroscopy was used as a supplementary method to characterise the thermal maturity of Ediacaran organic matter (OM) from the East European Craton. Because this method is based on organic particles measurement, it appears to be a good supplementary method in addition to the acquisition of biomarker data, which is based on extractable organic matter and may be affected by potential contamination. Raman spectroscopy seems to be particularly useful for lower Palaeozoic rocks, which do not contain vitrinite. Here, we compared C31 22S/(S + R) homohopane ratio results (obtained using gas chromatography – mass spectrometry), with various Raman parameters including: G_STA, Gmax position, Dmax/Gmax, FWHMG, RAR, D_STA, and PDmax. Close correlations were observed between C31 22S/(S + R) and G_STA, Gmax position, Dmax/Gmax, and FWHMG, reaching values of R2 = 0.5‒0.6, whereas no correlation existed between homohopane ratio and the RAR, D_STA, and PDmax parameters. Raman spectroscopy results divided Ediacaran samples into two distinctive groups: (i) immature (Russian, Lithuanian, and Belarusian), characterised by relatively higher values of G_STA, Dmax/Gmax, and FWHMG and relatively lower values of PGmax, and (ii) mature (Polish and Ukrainian), with relatively lower values of G_STA, Dmax/Gmax, and FWHMG and relatively higher values of PGmax. Within each group no statistically confirmed differences were found. However, significant discrepancies were observed between the hopane ratio and Raman parameters in Lithuanian samples, in relation to other samples from the group (i). Values of the C31 22S/(S + R) ratio for Lithuanian samples are close to those for the group (ii) and significantly higher than those for the group (i). However, all Raman parameters are the same as those of the rest samples from the group (i), indicating the immature character of OM from Lithuanian rocks. We interpret this discrepancy as representing contamination of the cores with drilling fluids, resulting in increased values for the C31 22S/(S + R) ratio. In this case, Raman spectroscopy is a useful tool for detecting extract contamination and appears to be an effective and decisive method in the case of rocks suspected of contamination.  相似文献   

10.
Diagenetic effects upon the hydraulic parameters of dolomite aquifers were examined. Results indicate that dolomites affected only by late (burial) diagenesis are economically more interesting to exploit than those formed first by early and then also affected by late diagenesis, as the values of most studied hydraulic parameters (transmissivity, specific capacity, linearized specific capacity and maximum yields) are higher in the former group. Data were collected from the hydrogeological reports of 298 wells in dolomites from Permian to Cretaceous age in Slovenia, classified in a relational hydrogeological database and analyzed by statistical methods. The studied parameters are hydraulic conductivity K, transmissivity T, specific capacity q (=Q/s), linearized specific capacity Ql (=q/d) and maximum yields Q max. Values of the studied parameters are distributed log-normally according to most normality tests and span several orders of magnitude. Statistical tests show significant differences between the “late” and “early + late” groups for parameters q, Ql and T, and non-significant differences for K and Q max.  相似文献   

11.
依据烃源岩地球化学实验手段和油气地化理论,对辽东湾地区辽中凹陷东营组东二下段(Ed2-1)和东三段(Ed3)地层进行了有机地化分析。在实验获取总有机碳(TOC)、生烃潜量(S1+S2)、氢指数(IH)、氢碳比(H/C)、氧碳比(O/C)、最大热解峰温(Tmax)、镜质体反射率(Ro)等有机地化参数的基础上,对有机质丰度、类型、成熟度等进行了系统分析,同时对东营组烃源岩进行了综合评价。研究表明,东二下段S1+S2集中在0~3 mg/g,TOC集中在0%~1.5%;东三段S1+S2集中分布在4~9 mg/g之间,TOC集中分布在1%~1.25%。东二下段有机质类型主要是III型,东三段有机质类型为II1、II2型。东二下段Ro0.5,东三段Ro0.5,并且随着深度的增加东三段烃源岩Ro相应的增加。Tmax随着深度的增加呈现出先增加后减少的异常现象,该种异常现象出现的原因与烃源岩有机质类型和有机质丰度之间存在很大关联。  相似文献   

12.
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13.
A simple method for application in source potential mapping is used to assess the original oil and gas potentials in source rock horizons based upon Rock-Eval potential (S2) and total organic carbon (TOC) values. The method assumes that kerogens consist of mixtures of end-members with assigned hydrogen index values. Based on suggested algorithms, the average amounts of oil-prone, gas-prone and inert organic material over source rock intervals are determined in TOC units. The method uses regression lines from plots of remaining hydrocarbon potentials (S2) versus total organic carbon (TOC), and “quick-look” transparent overlays are used to read the appropriate kerogen mixture.Mineral matrix effects during pyrolysis, when strong, can cause erroneous results. This effect which occurs for oil-prone kerogens and adsorptive minerals can cause problems particularly for lean samples (S2 = 0–3 mg HC/g rock) whilst the errors for richer samples are less.The method is applied on three sections of Upper Jurassic organic-rich rocks from the Danish North Sea sector, which are at different maturity stages. One of these sections is dominated by gas-prone material, one is dominated by oil-prone material and the third section contains a mixture of oil- and gas-prone material.The method has been compared with other methods that split kerogens in oil and gas generating potential and has given reasonable results.Experience using the method and a presented example suggest that sedimentological, system tract information may be derived from S2 to TOC cross-plots. A constructed modelling example suggests that the end-member concept used in this approach may be used in forward type source rock prediction models when combined with sedimentological models. The resulting S2–TOC plots can be used in order to check the forward modelling results against observed values.  相似文献   

14.
Magnitude conversion problem for the Turkish earthquake data   总被引：1，自引：0，他引：1  
Earthquake catalogues which form the main input in seismic hazard analysis generally report earthquake magnitudes in different scales. Magnitudes reported in different scales have to be converted to a common scale while compiling a seismic data base to be utilized in seismic hazard analysis. This study aims at developing empirical relationships to convert earthquake magnitudes reported in different scales, namely, surface wave magnitude, M S, local magnitude, M L, body wave magnitude, m b and duration magnitude, M d, to the moment magnitude (M w). For this purpose, an earthquake data catalogue is compiled from domestic and international data bases for the earthquakes occurred in Turkey. The earthquake reporting differences of various data sources are assessed. Conversion relationships are established between the same earthquake magnitude scale of different data sources and different earthquake magnitude scales. Appropriate statistical methods are employed iteratively, considering the random errors both in the independent and dependent variables. The results are found to be sensitive to the choice of the analysis methods.  相似文献   

15.
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16.
In this paper, white Portland cement was used as an experimental material. Prismatic specimens with pre-existing flaws at different angles of inclination (α) varying through 0°, 30°, 45°, 60°, 75° to 90° and cylindrical specimens with different numbers of pre-existing flaws (n) varying through 0, 1, 2 to 3 were tested under uni-axial compression tests. Crack initiation, propagation, coalescence, and failure were observed. The corresponding analytical expression for the stress intensity factor under uni-axial compression was derived, the coefficient of friction and the stress intensity factor of the specimens on the surfaces of the crack were analysed, and the corrective coefficient for the stress intensity factor was introduced. Fatigue tests with a loading frequency of f = 100 Hz were carried out on cylindrical specimens with constant amplitude of the cyclic load which is a proportion of the compressive load at failure (F f) obtained from the uni-axial compression tests. The fatigue property of the specimens was analysed and the relationship (S max − lg N f) between the maximum stress and the number of loading cycles at failure for specimens with pre-existing flaws was proposed. The effect of pre-existing flaws on the fatigue life (N f) and dynamic load (S D) which can be applied was investigated.  相似文献   

17.
孔喉分布是控制低渗-致密砂岩储层物性的关键因素,其评价依托于各种储层微观特征测试方法,需要综合多方法各自优势进行孔喉分布定量表征。本文提出基于核磁共振标定的高压压汞孔喉分布定量评价的方法,即通过核磁共振离心前后横向弛豫时间T_2谱图对比,依据流体赋存状态重新划分三孔隙度组分百分比法的T_2值界限T_(21)和T_(22),对应将孔喉划分为束缚流体孔喉、过渡流体孔喉和可动流体孔喉,再结合T_2值与孔喉半径的关系将T_2值界限转化为孔喉半径界限r_1和r_2,最终依据高压压汞统计的不同流体赋存状态的孔喉含量S_1、S_2和S_3进行孔喉分布定量评价。该方法综合了核磁共振有效表征孔喉流体赋存状态和高压压汞有效表征孔喉大小的优势。将此方法应用于西湖凹陷花港组低渗-致密砂岩储层孔喉分布评价,建立了T_2值与孔喉半径平均转化系数C为0.0079,求取r_1和r_2为60 nm和160 nm,依据各类孔喉含量及其相互关系将孔喉分布划分为四类,从而为储层评价提供新的参数和思路。  相似文献   

18.
Particle flow code (PFC2D) software was adopted to investigate the anchorage behaviour and the characteristics of crack initiation, propagation and coalescence of reinforced specimens containing a single fissure (RSCSF). The microscopic parameters of the specimens in the numerical simulation were first validated by experimental outcomes of intact specimens, while the microscopic parameters of the rock bolts were validated based on the results of the RSCSF tests. Then, the mechanical parameters as well as the failure modes in the physical experiments were compared with those derived by the numerical simulation; the results showed good agreement between the simulated macroscopic mechanical properties and failure modes and those obtained in the laboratory experiments. The peak strength, number of cracks and the failure mode varied considerably as the anchorage angle α and fissure angle β increased. Three types of stress–strain curves, types I to III, were obtained from the RSCSF. Shear cracks were observed for all three categories of curves, but the tensile cracks were dominant. The number of cracks and the rate of bond failures decreased as the curve changed from type II to type I to type III. RSCSF failure can be classified into three failure modes: (1) tip crack propagation mode, (2) midpoint crack propagation mode and (3) rock bolt crack propagation mode. These failure modes are primarily differentiated by relations between α and β, and the ratio UCSS/UCSI between the uniaxial compressive strength (UCS, σ max) of the RSCSF (UCSS) and the uniaxial compressive strength of the intact specimen (UCSI).  相似文献   

19.
We review published methods of testing for randomness in 3D axial orientation data. We then propose a new test based on eigenvalue analysis. The test statistic is S1/S3, the ratio of the largest to smallest eigenvalues of the orientation tensor. Critical values of this statistic are tabulated and graphed for sample sizes between 5 and 1000, for four confidence levels. The calibrations of S1/S3 were performed by a Monte-Carlo sampling method. The same random samples have been assessed using other tests, as have some natural orientation data samples. We conclude that the S1/S3 test is easier to use and more generally applicable than previous tests, particularly for the common type of data in structural geology.  相似文献   

20.
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