Xu B.,Zhejiang University |
Xu B.,Research Center for Structures in Oil & Gas Bearing Basins |
Xu B.,Geophysical and Geochemical Exploration Institute of Zhejiang |
Xiao A.,Zhejiang University |
And 7 more authors.
Journal of Earth Science | Year: 2014
Compressional region usually forms complex thrust faults system, which is difficult to identify using traditional migration profiles. The successful application of three-dimensional (3D) seismic attributes analysis greatly reduces the difficulty, and improves the accuracy and efficiency of seismic interpretation and structural analysis. In this paper, we took Qiongxi area in the compressional region of western Sichuan as an example, using two 3D seismic attributes, coherence and instantaneous phase, to identify fault assemblages and variations both vertically and laterally. The results show that the study area mainly consists of NS-, NE- and NEE-trending faults. The NS-trending faults are the largest and have a component of sinistral slip controlling the formation of NEE-trending faults, while the NE-trending faults are intermediate in scale, formed earlier and were cut by the NS-trending faults. Our results demonstrate that using seismic attributes for structural analysis have the following advantages: (1) more details of major fault zones, (2) highlighting minor faults which are hardly traced in seismic migration cube, and (3) easier acquisition of accurate fault systems. The application of seismic attributes provides a new idea for deciphering fine and complicated structures, and will significantly contribute to the development of objective and precise geological interpretation in the future. © 2014, China University of Geosciences and Springer-Verlag Berlin Heidelberg.
Mao L.G.,Zhejiang University |
Mao L.G.,Research Center for Structures in Oil & Gas Bearing Basins |
Xiao A.C.,Zhejiang University |
Xiao A.C.,Research Center for Structures in Oil & Gas Bearing Basins |
And 10 more authors.
Science China Earth Sciences | Year: 2014
The Eastern Kunlun Mountains play an important role in the growth and eastward extrusion of the Tibetan Plateau. Tectonic and sedimentary study of the Cenozoic Qaidam Basin, especially the southern part, provides key evidence for understanding their evolution. Here we present evidence including isopach maps, seismic sections and sedimentary analysis of single well to illustrate the sedimentary development of the basin and the structural features of its southern margin. The Qaidam Basin extended across Qiman Tagh-Eastern Kunlun Mountains in the early Cenozoic and withdrew northward at ca. 35.5 Ma, and then buckled as an EW striking elliptical depression since ca. 14.9 Ma, with the main depocenter migrating eastward. Our results support the view that the Kumukol and Hoh Xil basins joined the Qaidam Basin in the early Cenozoic time and we propose the Eastern Kunlun Mountains uplifted in the mid-Miocene. © 2014, Science China Press and Springer-Verlag Berlin Heidelberg.
Mao L.,Zhejiang University |
Mao L.,Research Center for Structures in Oil & Gas Bearing Basins |
Xiao A.,Zhejiang University |
Xiao A.,Research Center for Structures in Oil & Gas Bearing Basins |
And 6 more authors.
Tectonophysics | Year: 2016
The Qaidam Basin is located in the northeastern Tibetan Plateau and provides an excellent field laboratory in understanding the history and mechanism of the plateau growth. It deformed widely over the northwest during the Cenozoic but with little thrust loading along the margins, where no foreland depression is observed. Based on satellite images, seismic and borehole data, we investigated the structural deformation pattern (including the structural style and timing of deformation) and its formation mechanism within the northwestern Qaidam Basin during the Cenozoic era. Mapping of surface geology shows that the modern Qaidam Basin is characterized by five SE-trending anticlinal belts. Each belt consists of several right-step en echelon anticlines with plenty of normal and strike-slip faults crossing the crests. Those anticlines are generally dominated by double fault systems at different depths: an upper thrust fault system, controlling the anticlines identified on the surface and a lower dextral transpressional fault system characterized by typical flower structures. They are separated by weak layers in the upper Xiaganchaigou or the Shangganchaigou formations. The upper system yields shortening strain 2–5 times larger than that of the lower system and the additional strain is interpreted to be accommodated by hinge-parallel elongation in the upper system. Growth strata indicate that deformation within the Qaidam Basin initiated in the middle Miocene (~ 15 Ma) and accelerated in the late Miocene (~ 8 Ma). A simple Riedel-P-Shear model is used to explain the deformation mechanism within the northwestern Qaidam Basin. © 2016 Elsevier B.V.
Xu Z.,Petrochina |
Zhao B.,Zhejiang University |
Zhao B.,Research Center for Structures in Oil & Gas Bearing Basins |
Wang X.,Zhejiang University |
And 4 more authors.
Shiyou Xuebao/Acta Petrolei Sinica | Year: 2016
The hydrocarbon enrichment zone is underlying the gypsum-salt bed of Kuqa depression. Due to the sheltering effect of salt bed, the under-salt seismic reflection information is fuzzy, and a controversy exists on structural interpretation. According to critical wedge theory, the slope angle α of top surface and dip angle β of basal detachment layer in Kelasu and Dina structural belt uner-salt thrust structure wedges were measured, and the linear fitting to the regression straight line of under-salt structure wedge was carried out to solve the rock strength and frictional strength of basal detachment fault. The Eastern Qiulitage structural belt is neighbored with Kelasu and Dina structural belt, presenting consistent structural characteristics and deformation mechanism as well as nearly the same rock strength and strength parameter of bottom detachment layer. The slope angle of top surface in the Eastern Qiulitage structural belt under-salt thrust structure wedge is α =6°, and the dip angle of basal detachment layer is β =7°. It is deduced that low gentle thrust fault was developed in Eastern Qiulitage structural belt under-salt layers, and thrust fault slipped along the bottom of Mesozoic formation. According to the calculation method for the shortening amount of sedimentary wedge structure, Dina structural belt Mesozoic strata were shortened by 6.5 km and completely absorbed by the Dina anticline. The Mesozoic Eastern Qiulitage structural belt was shortened by 9 km, of which 6 km was absorbed by the Eastern Qiulitage anticline, and 3 km was absorbed by faults. It is predicted that there are small thrust faults underlying the Eastern Qiulitage anticline. © 2016, Science Press. All right reserved.