非线性AVO反演方法研究   总被引：2，自引：0，他引：2       下载免费PDF全文

魏超  郑晓东  李劲松 《地球物理学报》2011,54(8):2110-2116

与叠后地震数据相比,叠前地震数据包含有更多的反映地下地层特征的信息,利用AVO( Amplitude Versus Offset,振幅随偏移距的变化)信息通过求解Zoeppritz方程的近似公式,叠前反演可直接得到反映地下岩石特征的弹性参数——密度、纵波速度和横波速度.从本质上讲,叠前地震反演是非线性的,但目前多采用线...  相似文献   

Cover deformation above steep, basement normal faults: Insights from 2D discrete element modeling     

Stuart Hardy 《Marine and Petroleum Geology》2011,28(5):966-972

A discrete element model is used to investigate progressive cover deformation above a steep (70°), basement normal fault. The cover materials are homogenous with frictional material behavior. In the model shown here both normal and reverse faults in the cover accommodate displacement on the underlying basement fault. The earliest faults are curved, reverse faults which propagate upwards from the basement fault tip into the proto hanging wall. These are replaced, progressively towards the footwall, by subvertical to steep normal faults and finally by a normal fault which dips at an angle predicted by Mohr-Coulomb theory. Thus, most early, secondary structures are located in the hanging-wall of the final, through-going, fault. This structural evolution produces an asymmetric, triangular zone of deformation above the basement fault tip which superficially resembles that associated with trishear; however, its progressive development is quite different. Results also emphasize that the occurrence of reverse faults in extensional settings is not diagnostic of inversion.  相似文献   

Fluid flow reconstruction in hanging and footwall carbonates: Compartmentalization by Cenozoic reverse faulting in the Northern Oman Mountains (UAE)     

Liesbeth Breesch  Rudy Swennen  Benoit Vincent 《Marine and Petroleum Geology》2009

In this paper, the diagenesis from either side of a major Cenozoic reverse fault in the Northern Oman Mountains is documented. Detailed petrographical and geochemical analysis of calcite-filled fractures in carbonate strata of Late Triassic and Early Cretaceous age in the hanging wall and footwall in Wadi Ghalilah reflect a different diagenetic history. In both hanging wall and footwall most of the fractures are pre-burial, extensional in origin, formed by a crack-seal mechanism, and the calcite vein infill has a host-rock buffered signature. In the hanging wall, the fluid responsible for calcite precipitation of these extensional fractures was a marine fluid at 60 °C. These veins predate deep burial and contractional tectonic deformation and consequently do not provide any information about syntectonic fluid flow. Neither do the pre-burial extension fractures in the footwall which are also host-rock buffered. The fractures post-dating the tectonic stylolitization in the footwall, by contrast, show evidence of syntectonic migration of saline formation waters at temperatures between 80 and 160 °C during contractional deformation. These fluids probably were sourced from the subsurface via the reverse fault, which acted as a fluid conduit. At the same time, however, this fault functioned as a permeability barrier towards the hanging wall, since no evidence of syntectonic fluid flow is present here. In this way compartmentalization of the hanging wall and footwall block was realized.  相似文献   

Membrane effects during filtering investigation of membrane effects during filtering of natural surface waters in Missouri     

Rosanna Saindon  T. M. Whitworth 《Aquatic Geochemistry》2006,12(4):365-374

Previous work has demonstrated that suspended clay accumulating on filter paper can act as a membrane and affect chemical concentrations in the filtered water. For this reason, we looked at the possibility of membrane effects altering water chemistry during filtering for Missouri Rivers. Membrane effects during filtering could cause an initial decrease in sample concentrations as the filter cake began acting as a membrane, with a corresponding increase of concentration as the concentration polarization layer was formed behind the filter cake. Samples from five Missouri rivers were tested: the Mississippi River at St. Louis, the Missouri River at Kansas City, the Gasconade River at Jerome, the Osage River at the junction of Highway 63 and 50, and the Meramec River one mile downstream from springs. Three 1-l samples were filtered from each river using a 0.45 m filter. An unfiltered sample from each river underwent dialysis to determine the actual ion concentrations of the overall sample. None of the filtered samples demonstrated a statistically significant alteration of water chemistry using current filtering techniques in this preliminary study, suggesting that membrane effects due to accumulation of clay particles on filter paper may not be a common problem in Missouri and similar regions.  相似文献   

海拉尔盆地乌尔逊凹陷中的三角形断块：演化及对油气的控制作用   总被引：2，自引：0，他引：2       下载免费PDF全文

陈均亮  蒋鸿亮  李宏伟  林春华 《地质科学》2009,44(2):657-668

在乌尔逊凹陷中部发育一个三角形断块,因边界断裂的同沉积活动而使断块沉陷深,沉积厚度大.晚期的构造反转使整个三角形断块向上冲断,尤以北界断裂的冲断活动表现强烈.三角形断块为各时期的沉积中心,控制着深湖相和湖底扇沉积的发育;烃源岩的类型也与三角形断块有关,块内为Ⅰ型和Ⅱ型干酪根,边部和外部为Ⅱ型和Ⅲ型十酪根.南屯组的有效烃源岩在乌尔逊断陷分布范围较大,主力烃源岩只局限于三角形断块内.晚期反转时北界断裂有利于构造圈闭的形成,反转断层也为油气的运移提供了通道.因此,三角形断块在生储盖层的发育和油气生成、运移与聚集的空间配置关系上可谓得天独厚,是最有利的油气聚集区.  相似文献   

Salt tectonics and tear faulting in the central part of the Zagros Fold-Thrust Belt,Iran     

《Marine and Petroleum Geology》2017

The central part of the Zagros Fold-Thrust Belt is characterized by a series of right-lateral and left-lateral transverse tear fault systems, some of them being ornamented by salt diapirs of the Late Precambrian–Early Cambrian Hormuz evaporitic series. Many deep-seated extensional faults, mainly along N–S and few along NW–SE and NE–SW, were formed or reactivated during the Late Precambrian–Early Cambrian and generated horsts and grabens. The extensional faults controlled deposition, distribution and thickness of the Hormuz series. Salt walls and diapirs initiated by the Early Paleozoic especially along the extensional faults. Long-term halokinesis gave rise to thin sedimentary cover above the salt diapirs and aggregated considerable volume of salt into the salt stocks. They created weak zones in the sedimentary cover, located approximately above the former and inactive deep-seated extensional faults. The N–S to NNE–SSW direction of tectonic shortening during the Neogene Zagros folding was sub-parallel with the strikes of the salt walls and rows of diapirs. Variations in thickness of the Hormuz series prepared differences in the basal friction on both sides of the Precambrian–Cambrian extensional faults, which facilitated the Zagros deformation front to advance faster wherever the salt layer was thicker. Consequently, a series of tear fault systems developed along the rows of salt diapirs approximately above the Precambrian–Cambrian extensional faults. Therefore, the present surface expressions of the tear fault systems developed within the sedimentary cover during the Zagros orogeny. Although the direction of the Zagros shortening could also potentially reactivate the basement faults as strike-slip structures, subsurface data and majority of the moderate-large earthquakes do not support basement involvement. This suggests that the tear fault systems are detached on top of the Hormuz series from the deep-seated Precambrian–Cambrian extensional faults in the basement.  相似文献   

逆序断裂的发育特征与地震反射识别   总被引：2，自引：1，他引：1  

陶涛  季建清  周立宏  王金铎  付立新  袁淑琴  包项 《地质科学》2010,45(2):380-394

在具有盆地基底和未固结盖层的双层结构的盆地里,由于松散盖层对基底断裂应变的吸收,晚期发育的基底断裂在进入盖层后,应变会逐渐减小甚至消失,形成下部错动大、上部错动小的特点,本文把这样的后期断裂称之为逆序断裂。当基底断裂为走滑断裂时,逆序断裂具有双层空间构造样式,即在盆地基底发育主干走滑断裂、而在盖层优先发育另外走向的次级雁行断裂。逆序断裂在渤海湾盆地普遍发育,本文以歧口凹陷的张北断裂带和白水头断裂带为例(这两处断裂带都在下构造层发育北东向基底走滑断裂、而在上构造层发育近东西向盖层次级正断裂),运用三维地震资料,结合沿层属性和垂直剖面,阐述了逆序断裂的发育特征和对地震反射剖面的识别。由于之前晚期的逆序断裂一般被当作早期同沉积生长断裂对待,本文希望能帮助重新认识渤海湾地区的区域断裂期次和构造发育演化过程。  相似文献   

反浮选-冷结晶法生产氯化钾相图分析          下载免费PDF全文

保英莲 《盐湖研究》2006,14(3):39-42

察尔汗盐湖是我国最大的可溶性钾镁盐矿床,以相图理论为依据,介绍了反浮选—冷结晶法从含钠光卤石制取氯化钾的相图分析。  相似文献   

Increased correlation range of seismicity before large events manifested by earthquake chains   总被引：1，自引：0，他引：1  

P. Shebalin   《Tectonophysics》2006,424(3-4):335

“Earthquake chains” are clusters of moderate-size earthquakes which extend over large distances and are formed by statistically rare pairs of events that are close in space and time (“neighbors”). Earthquake chains are supposed to be precursors of large earthquakes with lead times of a few months. Here we substantiate this hypothesis by mass testing it using a random earthquake catalog. Also, we study stability under variation of parameters and some properties of the chains. We found two invariant parameters: they characterize the spatial and energy scales of earthquake correlation. Both parameters of the chains show good correlation with the magnitudes of the earthquakes they precede. Earthquake chains are known as the first stage of the earthquake prediction algorithm reverse tracing of precursors (RTP) now tested in forward prediction. A discussion of the complete RTP algorithm is outside the scope of this paper, but the results presented here are important to substantiate the RTP approach.  相似文献   

丽江-小金河断裂第四纪以来的左旋逆推运动及其构造地质意义——陆内活动地块横向构造的屏蔽作用   总被引：34，自引：9，他引：25       下载免费PDF全文

向宏发  徐锡伟  虢顺民  张晚霞  李洪武  于贵华 《地震地质》2002,24(2):188-198

通过卫、航片解释、野外活断层调查实测与年龄测试分析发现 :斜切中国西南“川滇菱块”的横向构造———丽江 -小金河断裂为一断面高角度倾向NW的逆左旋走滑型活动断裂。通过盆地复位和同沉积盆地的位错分析 ,确定了该断裂第四纪以来的水平位错量为 7 4～ 7 6km。断裂两侧差异隆升及相应堆积物的分析表明 ,中更新世以来 ,断裂垂直位错量达 5 0 0～ 70 0m以上。由此计算得到丽江 -小金河断裂第四纪和中更新世以来的水平与垂直位错速率分别为 3 7～ 3 8mm/a和 1 0～1 5mm/a。水平位错及相关年龄测试资料表明 ,该断裂晚更新世以来的平均位错速率在 2 6～4 0mm/a之间 ,中值为 3 3mm/a ;全新世以来的平均位错速率在 2 5～ 5 0mm/a之间 ,中值为3 5mm/a。第四纪各时段以来滑动速率的较好相似性表明 ,长期以来 ,该断裂的活动具相对稳定性和活动地块边界的持久性  相似文献