Quantitative prediction of petroleum resources and evaluation of exploration risk     

Zhuoheng Chen  Richard Sinding-Larsen  Richard McCammon 《Natural Resources Research》1997,6(4):243-243

  相似文献   

Upper-lower crust thickness of the Borborema Province,NE Brazil,using Receiver Function     

《Journal of South American Earth Sciences》2013

The thickness estimates of the upper-crust and the V_p/V_s ratios are essential in order to detail the structures and geologic features. They also corroborate the regional tectonic evolution models. The crust study using the Receiver Function is performed with teleseismic P-waves that reaches the interface, under the station, with an almost vertical angle. The Receiver Function is obtained through the deconvolution of the horizontal component from the vertical one. The synthetic seismogram of the Receiver Function has a higher peak of direct P-waves, followed by minor peaks of Psc waves, where P converted into S in the upper-lower crust limit and multiple reflections. It was used the phase weighted slant-stacked method for the estimate of upper-crustal thickness and m_b ratio. The best estimates are correctly stacked. The Normal Moveout correction for the Psc phase was used for the upper-crust thickness, simulating a vertical incidence. A total of 8 stations on the Borborema Province in the Brazilian Northeast was analyzed. The results show that there is an upper-lower crust limit in all the analyzed signs. The thickness estimates showed two thickness regions. The first one in Coast Region, that indicates of the thin upper-crust and the second, continental regions characterized by uniform thicker upper-crust. East station data suggests underplating of mafic bodies.  相似文献   

Non-rigid disk-based DDA with a new contact model     

《Computers and Geotechnics》2013

In this paper, a new disk-based DDA formulation is presented. In the original disk-based DDA, disks are considered to be rigid and the penalty method is used to enforce disk contact constraints. In order to improve the accuracy of the disk-based DDA, new formulations of stiffness and force matrices for non-rigid disks using a new efficient contact model are presented in this paper. Blocks are considered deformable without need to do more computations for contact detection. In the proposed contact model, disk–disk and disk–boundary contacts are transformed into the form of point-to-line contacts and normal spring, shear spring and frictional force sub-matrices are derived by vector analysis. The penalty method is quite simple to implement, but has some major disadvantages. In the presented contact model, not only the simplicity of the penalty method is retained but also the limitations are overcome by using the augmented Lagrangian method. Moreover, unlike the contact model used in the original disk-based DDA, reference line can be obtained directly by using only coordinates of disk centers and their radii, and no more computations are needed. The validity and capability of the new disk-based DDA formulation are demonstrated by several illustrative examples.  相似文献   

Geological evolution of offshore pollution and its long-term potential impacts on marine ecosystems     

《地学前缘(英文版)》2022,13(5):101427

Populations and metropolitan centers are accumulated in coastal areas around the world. In view of the fact that they are geographically adjacent to coasts and intense anthropogenic activities, increasing global offshore pollution has been an important worldwide concern over the past several decades and has become a very serious problem that needs to be addressed urgently. Due to offshore pollution, various geological disasters occur in high frequency, including intensified erosion and salinization of coastal soils, frequent geological collapses and landslides and increasing seismic activities. Moreover, offshore pollution shows increasingly serious impacts on the topography and geomorphology of offshore and coastal areas, including coastal degradation, retreating coastlines and estuary delta erosion. Offshore sedimentation processes are strongly influenced by the pH changes of terrestrial discharges, and sedimentary dynamics have become extremely acute and complex due to offshore pollution. The seabed topography and hydrodynamic environment determine the fate and transport of pollutants entering offshore regions. Coastal estuaries, port basins and lagoons that have relatively moderate ocean currents and winds are more likely to accumulate pollutants. Offshore regions and undersea canyons can be used as conduits for transporting pollutants from the continent to the seabed. It is particularly noteworthy that the spatial/temporal distribution of species, community structures, and ecological functions in offshore areas have undergone unprecedented changes in recent decades. Due to increasing offshore pollution, the stable succession and development trend of marine ecosystems has been broken. It is thus important to identify and regulate the quantity, composition and transportation of pollutants in offshore regions and their behavior in marine ecosystems. In particular, crucial actions for stabilizing marine ecosystems, including increasing species and biodiversity, should be implemented to enhance their anti-interference capabilities. This review provides an overview of the current situation of offshore pollution, as well as major trends of pollutant fate and transportation from continent to marine ecosystems, transformation of pollutants in sediments, and their bioaccumulation and diffusion. This study retrospectively reviews the long-term geological evolution of offshore pollution from the perspective of marine geology, and analyses their long-term potential impacts on marine ecosystems. Due to ecological risks associated with pollutants released from offshore sediments, more research on the influence of global offshore pollution based on marine geology is undoubtedly needed.  相似文献   

柴达木盆地北缘断裂构造分形特征与油气分布关系研究   总被引：15，自引：5，他引：15  

曾联波  金之钧  李京昌  汤良杰  由福报  雷兵足 《地质科学》2001,36(2):241-247

本文应用分形几何理论对柴达木盆地北缘断裂体系的分布进行了定量研究,在研究标定尺度范围内,该区断裂体系的平面分布具有良好的统计自相似性和分形特征,在双对数坐标系中,用最小二乘法进行直线拟合的相关系数平方(R²)均在0.97以上。该区4个已知油气田断裂构造的分维数D值均大于1.3,明显高于整个区域内4个反射层的断层分维数(平均D=1.218)。可以认为断裂构造的分维值大于1.3的部位是该区油气聚集分布的有利区。断裂体系分数维值越大的地区,有利于油气藏的分布,其单位面积内的油气地质储量越高。  相似文献   

准噶尔盆地阜东斜坡区侏罗系层序地层格架的建立   总被引：6，自引：0，他引：6  

张琴  朱筱敏  张满郎  况军  张年富 《沉积学报》2001,19(4):575-580

综合阜东斜坡区侏罗系钻测井及地震资料,将侏罗系划分为六套层序。层序边界识别标志包括不整合面、古生物化石突变面、底砾岩及冲刷面等标志。体系域划分的关键是确定首次湖泛面和最大湖泛面的位置。研究区侏罗系沉积时期存在较为明显的地形坡折带,因此能够确定首次湖泛面的位置,建立起具有地形坡折带的层序地层模型。研究了侏罗系层序形成的主要控制因素,即构造沉降、物质供应速率、气候和基准面升降等。  相似文献   

板桥凹陷沙三段沉积体系与物源分析   总被引：30，自引：5，他引：30       下载免费PDF全文

陈纯芳  郑浚茂  王德发 《古地理学报》2001,3(1):55-62

板桥凹陷位于黄骅坳陷中北部，沙三段是区内的主要生储油岩系。根据沉积环境、沉积特征及重矿物组合分布特征分析，板桥凹陷沙三段沉积期在湖盆的陡岸发育冲积扇-扇三角洲-深水浊积扇-深湖沉积体系以及近岸水下扇-深湖沉积体系，不同的物源区通过边界断层的运动控制着沉积体系的发育。在盆地的裂陷兴盛期，北部燕山褶皱带物源经过北唐凹陷和海河断层，于长芦一带形成扇三角洲，并进一步向板桥凹陷中央推进，形成板桥深水浊积扇沉积体；西北部的沧县隆起物源则沿着不同的入口，在沧东大断裂下降盘形成近岸水下扇和扇三角洲，它们也可进一步向凹陷深处推进而形成深水浊积体。应用沉积体系分布与油气聚集的规律，处于沉积体系的中间相带的扇三角洲和深水浊积扇，具有良好的油气生储组合，是断陷湖盆中有利的勘探目标。  相似文献   

塔里木盆地志留系层序地层特征   总被引：20，自引：7，他引：20  

朱筱敏  王贵文  谢庆宾 《古地理学报》2001,3(2):64-71

通过对塔里木盆地西缘露头、盆内钻井、测井和地震资料以及大量室内分析化验资料的层序地层综合分析，可将志留系划分成五个三级层序，志留系沉积层序厚度40--155m。层序界面多为分布范围较广的区域性或局部不整合。层序叠置样式可用具陆棚坡折的I型层序地层样式来描述。每个沉积层序可由完整的低位、海侵和高位体系域组成或由其中的一个、两个体系域组成。体系域边界主要依据滨岸上超点位置、岩性组合及准层序叠置样式变化来确定。低位体系域由向上粒度变细、砂岩厚度向上减薄的准层序组成；海侵体系域表现为向上泥岩厚度加大、砂岩厚度减薄的叠置特点；高位体系域表现为加积--进积沉积特征。志留纪，研究区接受了滨外陆棚及滨岸、海湾潮坪沉积，发育典型的海相沉积构造，表现出明显的旋回特征。  相似文献   

准噶尔盆地西北缘车排子地区侏罗系物源及古水流分析   总被引：16，自引：8，他引：16  

胡宗全  朱筱敏  彭勇民 《古地理学报》2001,3(3):49-54

通过岩石岩屑组分分析、重矿物组分分析、倾角测井、地层厚度分析等方法，对准噶尔盆地西北缘车排子地区侏罗系进行物源及古水流方向分析。岩屑组分分析指示着大致的物源前进方向，重矿物分析明确了物源泄入的主要通道，倾角测井在单井点处对古流向有相当高的表现精度，但这三种方法均存在数据平面覆盖率较低和分布密度差异大的缺陷，而运用地震层位解释所得的地层等厚度图则可以在较大尺度上的二维平面内推测沉积时期的古地形，进而可以推测古流向，但它仅是一种间接预测方法，存在局部古流向预测精度较低的不足。文中综合各种方法，将直接预测方法的高精度和间接方法的高覆盖能力结合起来，对古流向作出较高精度的预测。在古流向研究的基础上建立了冲积扇－辫状河－河泛平原沉积体系的沉积相模式。该模式认为对于水流能量保持能力差的冲积扇，其古流向应该沿短轴陡坡降方向，即大致为SEE方向，而对于水流能量保持能力较强的辫状河来说，其古流向应该沿长轴缓坡降方向，即为SE甚至SSE方向。该模式的提出对于提高地震相－沉积相的转相精度具有一定的指导意义。  相似文献   

广西百色盆地州景矿第三系褐煤有机地球化学与煤岩学研究　Ⅳ．单化合物碳稳定同位素推断生物标志物起源     

Schoe.  M 王铁冠 《沉积学报》1995,13(4):73-81

一个未成熟褐煤抽提物中，高等植物生源化合物的同位素值在全煤碳同位素组成（δ１３Ｃ值－２７．０‰）的±２‰范围内，表明相似成煤植物对这些化合物的贡献，或者其成煤植物经历过相似的生物合成分馏效应。所检测的萜烃类按同位素差异分为两组:二萜类（δ１３Ｃ值－２５．０±１．４‰）和倍半萜类（δ１３Ｃ值－２５．９±１．５‰）平均较全煤样富集１～２％。１３Ｃ，而奥利烷－乌散烷－羽扇烷型衍生物（δ１３Ｃ值－２９．０±０．８‰）平均比全煤样减少１～２‰１３Ｃ。Ｃ₁₅～Ｃ₃₅正烷烃δ１３Ｃ平均值－３２．４±０．６‰，据此表明Ｃ₁₇～Ｃ₂₂和Ｃ₂₂～Ｃ₃₃正烷烃的同位素值与上述平均值没有明显差异。与全煤样相比较，该煤样抽提物的藿烷衍生物１３Ｃ值则减少８～３４‰，标志在成煤过程中甲烷的细菌循环起着作用。  相似文献