| Yingen-Ejinaqi basin located in western area of Mongolia, on the Alashan plateau,encircled by mountains. The hydrocarbon generation condition upper Palaeozoic condition is superior, but due to the limitation of natural geography, range of study,the degree of study is relatively low, Geophysical exploration work before the deployment and implementation of Mesozoic group, mainly for the will as before upper palaeozoic Mesozoic basement treatment, didn’t do further research, the number of exploratory well drilling in palaeozoic era is few, rarely without drill upper palaeozoic well, the old seismic data do not reflect information of upper palaeozoic. Aim at the degree of study of tectonic framework and regional evolution of the upper Palaeozoic is much less.Therefore,the analysis of the important fault, the typical concave profile structure, will deepen the cognize of concave structure and the evolution characteristics of cognition,help reveal prototype basin characteristics and tectonic framework and regional evolution of carboniferous-Permian in yingen-ejinaqi basin and its adjacent area. It has great significance.of get breakthrough on oil and gas exploration and further analysis of oil and gas geological condition area.Based on the latest2D seismic profiles and drilling data, make the study on general characteristics of Tectonic framework, tectonic style, The features of basement structure, The main characteristics of fault development, the typical concave profile structure of Yingen-Ejinaqi basin.By using drilling, logging and seismic data in combination with main purpose layer of silver frontal basin were determined and the synthetic seismogram calibration. On the basis of the synthetic seismogram horizon calibration, combined with the feature of area geological structure, complete five seismic geological horizon tracking work, finding the main stratigraphic unit in the study area distribution with depth.Through the interpretation2D seismic profiles, studied on the carboniferous-Permian stratigraphic distribution and depth (time domain), found in the seismic profiles carboniferous-Permian stratum characterized by thick layers of middle-strong seismic amplitude reflection characteristics. Top and bottom are large surface of unconformity interface, below with volcanic rocks, has the characteristics of clutter reflection of basement. Roof strata. Above the interface for preferable continental clastic rock.Studies of depression structure-styles show there are variant typical sag in Yingen-ejinarift group basins, which are single-fault sag and double-fault sag. The single-fault sag may classify in detail as the following:single fault bench type; single fault trough type and singlefault overlap type etc. The double-fault sag mainly be double fault graben type.Carboniferous-Permian stratum is a large residual thickness stratum, with widely distribution scope,mostly distribut in the north of study region, such as lujing sag, sangendalai heave, tiancao sag, judong sag, jianguoyin sag, sag in the north of sedimentary thickness is thicker, The southern sag sedimentary thickness is thinner, wujiajin salient and baogeda salient can find carboniferous-Permian stratum information, speculates that due to basin in northern salient period is longer than the earlier, led to the north of carboniferous-Permian stratum denudation thickness is big. Wujiajing salient and baogeda salient burial depth is shallow, the carboniferous-Permian stratum is thickness,are the favourable area for Petroleum exploration of Carboniferous-Permianin study area.Bounded by Genlangwusu fault, in the north and west of study region, developed the Archeozoic,Paleoproterozoic and upper Paleozoic stratum.Upper palaeozoic development is complete, fold basement in the lower-Paleozoie.In the East and south region,developed Archeozoic,Paleoproterozoic and upper carboniferous stratum, missing the palaeozoic era> late Paleozoic Devonian and the lower Carboniferous stratum, with crystalline or sedimentary metamorphie basement in Preeambrian system.Faulted structure in the study area was divided into4levels, Level1fracture system, Level2fracture system, Level3fracture system,Level4fracture system. Level1fracture system control the original touch to the pattern of early and late Paleozoic. Level2fracture system control the Paleozoic basins of the meso-cenozoic basin or depression and uplift distribution pattern. Level3fracture system control the meso-cenozoic basin pattern and its depression and uplift distribution. Level4fracture system control sag and salient.In combination with predecessors’research and the comprehensive interpretation of seismic profiles, the end of the carboniferous in the study area and its tectonic evolution is divided into the following stages:①Carboniferous-Permian intracontinental rift valley and basin tectonic evolution stage②The tectonic movement of late Permian formation lung depression and white pattern③The Triassic mainly for extrusion uplift tectonic phase④The Jurassic-cretaceous intracontinental small fault basin tectonic evolution stage⑤At the end of late cretaceous tectonic movement, the formation of large thrust nappe⑥Eocene-Neogene basin and local segmentation fault depression phase... |
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