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71.
塔里木盆地三叠系烃源岩有机岩石学特征与生烃评价 总被引:5,自引:1,他引:5
应用现代有机岩石学方法,配合有机地球化学方法,通过对塔里木盆地三叠系烃源岩的研究,认识了一种较特殊的烃源岩类型,其生烃母质以菌解无定形体为主,不仅其实测镜质组反射率R°具有明显抑制作用,而且其生烃早,“液态窗”范围介于镜质组R°为0.40%-0.95%之间。这类烃源岩生烃潜力较强(相当于ⅡB型干酪根),实际上已进入成熟-成烃峰期阶段,并广泛分布于塔北轮南及其以南地区,预测展布面积达1.0-1.5万 相似文献
72.
In situ seismic attenuationQ−1logs are derived from borehole velocity profiles and reveal sharp boundaries between morphologies of the extrusive volcanic layers in intermediate- and slow-spreading oceanic crust.Q−1logs are calculated from the scattering attenuation associated with vertical velocity heterogeneity in Ocean Drilling Program Holes 504B and 896A and in Hole 395A, located in 5.9–7.3 Ma crust on the Pacific and Atlantic plates, respectively. Our results strongly tie crustal properties to seismic measurables and observed geological structures: we find that the scattering attenuation can be used to identify the extrusive volcanic sequence because it is closely related to changes in the degree of vertical heterogeneity. We interpret a distinct decrease in the Q−1log at the transition below the extrusive volcanic layer to correspond with the seismic layer 2A/2B boundary. The boundary is located at 465 m depth below the sea floor in both Hole 395A and 504B, although this is likely to be a coincidence of the sediment thickness at these sites. Layer 2A is estimated to be approximately 150 m thick in Hole 504B and > 300 m thick in Hole 395A. Cyclic sequences of high-porosity pillows and low-porosity massive units in the uppermost 100 m of volcanics in Hole 395A result in large velocity heterogeneities which cause > 5 times more attenuation in this layer than in Hole 504B. In Hole 896A, by contrast, fewer pillows, more massive flows, and a greater volume of carbonate veins decrease the velocity heterogeneity and attenuation significantly over only 1 km distance from Hole 504B. We conclude that the attenuation in the extrusive volcanics of the ocean crust is largely controlled by variation in local heterogeneity and morphology as well as by subsequent hydrothermal alteration. The observed differences inQ−1profiles and layer 2A thickness at these sites may be attributed to variations in the volume and duration of volcanic activity at mid-ocean spreading centers for these Pacific and Atlantic ridge segments. 相似文献
73.
The hydrocarbon generation mechanism and the three-stage type model of hydrocarbon generation for carbonate source rocks 总被引:1,自引:0,他引:1
The diagenetic mechanism and process of carbonate rocks, which is different to that of clastic rocks, decides the existence
of different existing state organic matters in carbonate rocks. This has been verified by both the microscopic observation
of organic petrology and the analysis of organic geochemistry of many samples. Based on the hydrous pyrolysis simulation experiment
of the low-mature carbonate rocks, the contrasting study on the yield and their geochemistry characteristics of different
existing state soluble organic matters of a series of various maturity samples shows that the different existing state organic
matters make different contributions to hydrocarbon generation during every evolution state. So that, the hydrocarbon generation
process of carbonate rocks can be summarized as the following three stages: the first is the direct degradation of biogenic
bitumen macromolecules during the immature stage, the second is the thermal degradation of a large amount of kerogen at the
mature stage, the last stage is the expulsion or release of inclusion organic matter owing to the increased thermal expansion
pressure during the high evolution stage.
Part of achievements of the Eighth Five-Year National Science-Technology Key-Task Project “85-102-02-07”. 相似文献
74.
Evolution model and formation mechanism of bio-thermocatalytic transitional zone gas 总被引:1,自引:0,他引:1
As a new genetic type of natural gas exploration area, the bio-thermocatalytic transitional zone gas (BTTZG) has been highly
stressed by geologists both at home and abroad. Systematic study on the generation mechanism of hydrocarbon at the transitional
zone is presented. Based on simulating experiments and geochemistry analysis of the source rock with lower evolution, a hydrocarbon-forming
model at the transitional zone has been established. The mechanism is proposed that under the condition of low temperature
and pressure combining with extremely active structural stress and clay mineral catalysis, BTTZG is formed by de-group of
soluble organic matter and polarized compositions through orthocarbon ion as well as by condensation polymerization of aromatic
ring-rich insoluble organic matter. This mechanism controls the formation of BTTZG, and furthermore, BTTZG is the product
of superimposition and interaction of all the factors mentioned above. 相似文献
75.
76.
77.
鄂尔多斯盆地奥陶系海相碳酸盐岩生烃性能与中部长庆气田气源成因研究 总被引:15,自引:0,他引:15
用激光 -荧光显微镜等有机岩石学方法 ,挑选样品中有明显生、排烃现象的碳酸盐岩 ,再以测定的这类碳酸盐岩的有机碳含量为依据 ,确定本区高成熟碳酸盐气源岩残余有机碳的下限指标用 0 .13%~ 0 .14 %比较合理。根据碳酸盐岩储层孔隙中充填沥青和皮膜状残余沥青的分布和含量 ,论证了陕参 1井等奥陶系碳酸盐岩地层在地质历史中 ,存在若干油气有效储层。采用连续升温 ,步进取样的热模拟实验方法 ,揭示了本区煤与碳酸盐岩干酪根随热演化作用增强 ,烃类气体产物的干燥系数增大 ,δ1 3C1 、δ1 3C2 明显变重的规律 ,并根据样品实验结果推算 ,本区石炭系—二叠系煤最大生气阶段的δ1 3C1 应为 - 2 7‰~ - 2 8‰ ,碳酸盐岩最大生气阶段的δ1 3C1 应为- 31.7‰~ - 33‰。在气源成因判识中 ,根据主生气期阶段对天然气成藏储聚的贡献最大、甲烷碳同位素较重以及长庆气田风化壳气藏天然气δ1 3C1 重值区并不与石炭系—二叠系煤的镜质组反射率高值区匹配的现象等进行气源判识 ,认为长庆奥陶系风化壳气藏 ,具有下古生界海相碳酸盐岩气与上古生界石炭系—二叠系煤成气的混源成因 相似文献
78.
This article has two purposes. Firstly, a validation exercise of the modal summation technique for the computation of synthetic
strong-motion records is performed for two regions of Europe (Umbria-Marche and south Iceland), using a variety of region
specific crustal structure models, by comparing the predicted ground motion amplitudes with observed motions. It is found
that the rate of decay of ground motions is well predicted by the theoretical decay curves but that the absolute size of the
ground motions is underpredicted by the synthetic time-histories. This is thought to be due to the presence of low-velocity
surface layers that amplify the ground motions but are not included in the crustal structure models used to compute the synthetic
time-histories.
Secondly, a new distance metric based on the computed theoretical decay curves is introduced which should have the ability
to model the complex decay of strong ground motions. The ability of this new distance metric to reduce the associated scatter
in empirically derived equations for the estimation of strong ground motions is tested. It is found that it does not lead
to a reduction in the scatter but this is thought to be due to the use of crustal structure models that are not accurate or
detailed enough for the regions studied.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
79.
HAO Fang JIANG Jianqun ZOU Huayao FANG Yong & ZENG Zhiping . Key Lab for Hydrocarbon Accumulation Mechanism in the Ministry of Education Petroleum University Beijing China . Department of Petroleum Geology China University of Geosciences Wuhan China 《中国科学D辑(英文版)》2004,47(9)
Thetraditionalhydrocarbongenerationmodeldoesnottakeintoaccounttheeffectofpressure[1].Astotheroleofpressureinorganicmattermaturationandpetroleumgeneration,threeconflictingopinionshaveeverbeenproposed:(1)Increasingpressurehasnodetectableeffectonorganic-mattermaturation[1,2];(2)increasingpressureenhanceshydrocarbon-thermaldestruction[3];(3)increasingpressuresignificantlyretardsorganic-mattermaturationandhydrocarbongeneration[4,5].Therearemorethan180overpressuredbasinsintheworld.Theroleofoverpress… 相似文献
80.
Gürcan Büyüksalih Güven Koçak Murat Oruç Hakan Akçin Karsten Jacobsen 《The Photogrammetric Record》2004,19(107):200-218
TK-350 stereo-scenes of the Zonguldak testfield in the north-west of Turkey have been analysed. The imagery had a base-to-height ratio of 0·52 and covered an area of 200 km × 300 km, with each pixel representing 10 m on the ground. Control points digitised from 1:25 000 scale topographic maps were used in the test. A bundle orientation was executed using the University of Hanover program BLUH and PCI Geomatica OrthoEngine AE software packages. Tests revealed that TK-350 stereo-images can yield 3D geopositioning to an accuracy of about 10 m in planimetry and 17 m in height. A 40 m resolution digital elevation model (DEM) was generated by the PCI system and compared against a reference DEM, which was derived from digitised contour lines provided by 1:25 000 scale topographic maps. This comparison showed that accuracy depends mainly on the surface structure and the slope of the local terrain. Root mean square errors in height were found to be about 27 and 39 m outside and inside forested areas, respectively. The matched DEM demonstrated a systematic shift against the reference DEM visible as an asymmetric shift in the frequency distribution. This is perhaps caused by the presence of vegetation and buildings. 相似文献