The Bachu （巴楚） uplift is one of the most active tectonic regions nowadays in the Tarim basin, which is also a faulted block uplift that was intensively active during the Cenozoic. This study was based primarily on...The Bachu （巴楚） uplift is one of the most active tectonic regions nowadays in the Tarim basin, which is also a faulted block uplift that was intensively active during the Cenozoic. This study was based primarily on the geological structure interpretation of seismic profiles, applying the theories and methods of basin dynamics, structural analysis and tectono-stratigraphic analysis, the geometry and kinematics features of the fault systems in the Bachn uplift were analyzed in detail. Our study shows that each fault belt is mainly characterized by compression and overthrusting, most of the faults initiated and activated during the Mid-Late Himalayan period, and that the general structural styles of the Bachu uplift were basement-involved pop-up thrust faulted block uplift, of which the southern margin was covered by the large-scale decollement fault system. The basement-involved structures widely developed in the higher position of the basement uplift, while decollement fault system developed mainly at the position with gypsum mudstone. The evolution process of Bachu uplift included back-bulge slope of the peripheral foreland basin in Mid-Late Caledonian, forebulge in HercynianYanshanian and the latest compressional faulted block uplift in Mid-Late Himalayan. Meanwhile,the study also suggests that the formation, reconstruction and stabilization of the uplift were controlled by the development and evolution of fault systems clearly. In the early forebulge stage, it was mainly presented as flexural deformation without the developing of thrust faults in the Bachu area; to the late stage, under the influence of violent lateral compression deformation, the faulted block uplift formed finally.展开更多
Based on high-resolution 2D seismic profiles, the Paleozoic structural deformation char- acteristics of Bachu （巴楚） uplift of northwestern Tarim basin, NW China, are exhibited in this article. The deformation happe...Based on high-resolution 2D seismic profiles, the Paleozoic structural deformation char- acteristics of Bachu （巴楚） uplift of northwestern Tarim basin, NW China, are exhibited in this article. The deformation happened during three main geological periods： the end of Middle-Late Ordovician （O2-3）, the end of Early-Middle Devonian （D1-2）, and the end of Late Permian （P2）. In the Bachu uplift, there developed a series of NW-trending thrust faults and imbricate structures due to the effect of the NW-SE compression stress towards the end of Middle-Late Ordovician （O2-3） （middle Caledonian movement）, and there developed some NNE-trending thrust faults and fault blocks under the control of the NEE-SWW compression stress at the end of Early-Middle Devonian （D1-2） （early Hercynian movement）. However, at the end of Late Permian （P2） （late Hercynian movement）, some NE-trending thrust faults and associated folds developed as a result of the NE-SW compression stress. The first-stage （O2-3） deformation is obviously more violent than those of the latter two stages （D1-2 and P2）, which implies that the Tarim plate drifted quickly to the north at around the same time basin.展开更多
The thermal evolution of source rocks in the Paleozoic has long been a problem to petroleum exploration in the Bachu uplift, Tarim basin, since the thermal history in the Paleozoic could not be rebuilt objectively due...The thermal evolution of source rocks in the Paleozoic has long been a problem to petroleum exploration in the Bachu uplift, Tarim basin, since the thermal history in the Paleozoic could not be rebuilt objectively due to lack of effective thermal indicators in the Lower Paleozoic successions. The apatite and zircon （U-Th）/He thermochronometry can be used as a new kind of technique to study the thermal history and tectonic uplift of sedimentary basins. Based on the measured apatite and zircon （U-Th）/He ages, apatite fission track data and equivalence vitrinite reflectance （%EVRo）, the tectonothermal histories in 5 wells of the Bachu uplift were modeled. The modeling results show that there was relatively high gradient at the Early Paleozoic in the Bachu uplift and it decreased gradually during the entire Paleozoic： 33-35℃/km in the Cambrian- Ordovician, 32-33℃/km in the Silurian-Devonian, 30-32℃/km at the end of Carboniferous and 27.5- 31℃/km at the end of Permian. Therefore, the thermal history can be modeled by combining multiple thermal indicators of AFT, （U-Th）/He ages and EVRo data. Especially, this provides a new method to rebuild the thermal history for the Low Paleozoic carbonate successions in the Tarim Basin.展开更多
Based on new high-resolution seismic profiles and existing structural and sedimentary results, a superposition deformation model for Cenozoic Bachu Uplift of northwestern Tarim Basin, northwestern China is proposed. T...Based on new high-resolution seismic profiles and existing structural and sedimentary results, a superposition deformation model for Cenozoic Bachu Uplift of northwestern Tarim Basin, northwestern China is proposed. The model presents the idea that the Bachu Uplift suffered structure superposition deformation under the dual influences of the Cenozoic uplifting of Southern Tianshan and Western Kunlun orogen, northwestern China. In the end of the Eocene （early Himalayan movement）, Bachu Uplift started to be formed with the uplifting of Western Kunlun, and extended NNW into the interior of Kalpin Uplift. In the end of the Miocene （middle Himalayan movement）, Bachu Uplift suffered not only the NNW structure deformation caused by the Western Kunlun uplifting, but also the NE structure deformation caused by the Southern Tianshan uplifting, and the thrust front fault of Kalpin thrust system related to the Southern Tianshan orogen intrudes southeastward into the hinterland of Bachu Uplift and extends NNE from well Pil to Xiaohaizi reservoir and Gudongshan mountain, which resulted in the strata folded and denuded strongly. In the end of the Pliocene （late Himalayan movement）, the impact of Southern Yianshan orogen decreased because of the stress released with the breakthrough upward of Kalpin fault extending NE, and Bachu Uplift suffered mainly the structure deformation extending NW-NNW caused by the uplifting of Western Kunlun orogen.展开更多
Objective Oil and gas are abundant in the Ordovician Yingshan Formation carbonate karst reservoirs on the northern slope of Tazhong uplift in the Tarim Basin, and have extremely complicated oil-gas-water distribution...Objective Oil and gas are abundant in the Ordovician Yingshan Formation carbonate karst reservoirs on the northern slope of Tazhong uplift in the Tarim Basin, and have extremely complicated oil-gas-water distribution, however. The difference in burial depth of the reservoirs between east and west sides is up to 1000 m. Water-bearing formations exist between oil- and gas-bearing formations vertically and water-producing wells are drilled between oil- and gas-producing wells. Macroscopically, oil and gas occur at low positions, while water occurs at high positiona on the northern slope of Tazhong uplift. The mechanism of differential hydrocarbon enrichment in heterogeneous reservoirs is by far not clarified, which has affected the efficient exploration and development of oil and gas fields in this area.展开更多
Based on the outcrop survey,3D seismic data interpretation,drilling data analysis,the structural patterns and distribution of fault damage zones in carbonate strata of Tazhong Paleo-uplift were established to reveal t...Based on the outcrop survey,3D seismic data interpretation,drilling data analysis,the structural patterns and distribution of fault damage zones in carbonate strata of Tazhong Paleo-uplift were established to reveal the oil and gas enrichment law in the fault damage zones.The following findings were reached:(1)Through the filed survey,the fault damage zone system consists of fault core,damage zone with branch fault and fracture network.Affected by the active nature of the major faults,the fault damage zones differ in planar pattern and scale along the major faults.(2)3D seismic profiles reveal that there are three types of fault damage zones in carbonate strata in Tazhong paleo-uplift,strike-slip fault damage zones,thrust fault damage zones and superimposed fault damage zones.Featuring3 flowers and 3 root belts in vertical,the strike-slip fault damage zone can be subdivided into linear type,oblique type,feather type and horsetail type in plane.Thrust fault damage zones can be further divided into fault anticline type,anticline type and slope type.As the superimposition result of the above two kinds of fault damage zones,superimposed fault damage zones appear in three patterns,intersect type,encompassment type and penetrating type.(3)Cores from wells and geochemical data show oil and gas may migrate along the major fault and laterally.The feather type in strike-slip fault system,fault anticline type in thrust fault damage zone and intersect type in superimposed fault damage zone are possible sites for high production and efficiency wells.展开更多
he convergence between India and Eurasia is partly accommodated by motion of a few large blocks along strike\|slip faults. About 1800km long Altyn Tagh fault strikes in N60～80°E and allows the northeastward disp...he convergence between India and Eurasia is partly accommodated by motion of a few large blocks along strike\|slip faults. About 1800km long Altyn Tagh fault strikes in N60～80°E and allows the northeastward displacement of the Tibet plateau relative to the Tarim. The Altyn Tagh fault zone is a typical transpressional fault zone, characterized by blocks rotation and crustal shortening and vertical extrusion of blocks within the Altyn Tagh strike\|slip system. Differences of three\|dimensional deformation and configuration of the active structures are recognized at different segment of the Altyn Tagh fault zone.1\ Structural configuration of the Altyn Tagh fault zone\;In the Altyn Tagh strike\|slip fault zone, the assemblage pattern of the (active) faults is in the form of parallel plumes, especially in the eastern and the western segments of the Altyn Tagh fault zone. These plumes structures in the eastern segment are assembled by string\|like left lateral strike\|slip fault and broom\|like thrusting faults, and in the western segment by arc\|like left lateral strike\|slip faults along with thrusting faults and normal faults. In the middle segment of the Altyn Tagh fault zone, the structures are characterized by the string\|like left lateral strike\|slip faults in the center and reverse thrusting faults on the two sides.展开更多
The formation of strath and strath terrace is closely related to tectonic uplift in the drainage basin. Based on the investigation of straths at Yandantu and Changcaogou on the eastern segment of the northern margin f...The formation of strath and strath terrace is closely related to tectonic uplift in the drainage basin. Based on the investigation of straths at Yandantu and Changcaogou on the eastern segment of the northern margin fault of Altun, and in combination with the paleoclimatic data, the tectonic uplift since late Epipleistocene as revealed by stream terraces at the two places is discussed. At Yandantu, three levels of stream terraces(T 1, T 2 and T 3)have developed since 16ka BP, where T 1, T 3 and T 2 are fill terraces and the buried major straths are exposed. The ages of three treads are dated to be about 16.1ka BP, 12.8ka BP and 6.2ka BP, respectively. The three terraces reflect three tectonic uplift events, while the ages of the treads represent the occurrence time of these events. The stream is still beveling the bedrock and widening the channel at present, and the modern strath is being generated. The uplift rate is 4.8～4.5mm/a since 16.1 ka BP in this area. From 12.8ka B.P to 6.2ka BP, The uplift rate was 6.4mm/a. The uplift rate is 3.1mm/a since 6.2ka BP. At Changcaogou, four levels of stream terraces(T 1, T 2, T 3 and T 1′)have developed since 7ka BP. All of them are fill terraces. There are buried straths under the deposits. The buried major strath is exposed on T 3 and T 2 and the minor strath on T 1′and T 1. The ages of treads of the three terraces (T 3, T 2 and T 1′) are 7 ka BP, 3 ka BP and 2.5 ka BP, respectively. The four terraces reflect two uplift events induced by tectonic activities. One occurred in about 7 ka BP, and the other in 3ka BP. The uplift rate is 5.9mm/a since 7.0 ka BP at Changcaogou. From 7ka BP to 3ka BP, the uplift rate was 7.0mm/a, and since 3ka BP till now, the uplift rate is 4.7 mm/a.展开更多
Lying on the west edge of Dongting Lake,the Taiyangshan area in Hunan Province is part of a hilly region which has uplifted since the Late Cenozoic.According to field investigation of the six existing faults in the Ta...Lying on the west edge of Dongting Lake,the Taiyangshan area in Hunan Province is part of a hilly region which has uplifted since the Late Cenozoic.According to field investigation of the six existing faults in the Taiyangshan area,we found that four of them are not active in the Quaternary,and that the Gangshi-Hefu fault is likely to have been active in the early Mid-Pleistocene.The geological evidence derived suggests that the Xiaowupu fault was active from the late Mid-Pleistocene to the early late-Pleistocene.It cut the stratum with a TL age of 123±10ka BP and has the property of thrusting.The research results are of great significance for understanding the seismogenic structure of the Changde earthquake with M6 3/4 in 1631.展开更多
The Altyn Tagh fault zone(ATFZ),which defines the northern boundary of the Tibetan Plateau,is one of the most striking features related to the India/Eurasia collision.Concurrent with the strike-slip movement,vertical ...The Altyn Tagh fault zone(ATFZ),which defines the northern boundary of the Tibetan Plateau,is one of the most striking features related to the India/Eurasia collision.Concurrent with the strike-slip movement,vertical uplift,and topographic building have formed a~3000-4000 m height difference between the Tarim Basin(TB)in the north and the Tibetan Plateau in the south.However,the spatial uplift characteristics and mechanism have not been well understood,particularly in the Late Quaternary.This research presents a comprehensive geomorphic analysis to establish the Late Quaternary tectonic uplift pattern for the entire ATFZ.We statistically excluded climatic and lithological factors that provided prominence for tectonism;combined with leveling data,river incision rate,and seismicity data,we reveal the along-strike and across-fault vertical deformation variations.The spatial distribution of the integrated geomorphic index(IGI)suggests significant differences between the two sides of the ATFZ.The IGI values decrease with slip rates in the northwestern side of the ATF,whereas wave-like in the southeastern side.The significant along-strike deformation difference between the two sides of the ATFZ may cause by differential rheology.These findings are crucial for assessing regional seismic hazards and providing new independent data to understand the Late Quaternary deformation style of the northern boundary of the Tibetan Plateau.展开更多
The paper focuses on the characteristics of faulting and magmatism of the Okinawa Trough and the relation between them. En-echelon grabens are ranked oblique to the continental shelf edge uplift, and the Longwang upli...The paper focuses on the characteristics of faulting and magmatism of the Okinawa Trough and the relation between them. En-echelon grabens are ranked oblique to the continental shelf edge uplift, and the Longwang uplift, the rifting block ridge in the northern segment and the ＂Mianhua uplift＂ in the southern segment have possibly preserved characteristics of volcanism and magmatism occurring with those rifting phases. The clockwise rotation of the southern Ryukyu Islands, driven by collision between Luzon and Taiwan, has played a key role in the crustal oceanization, enhancing the crustal extension of the southern segment and inducing volcanic magmatism in those grabens, among which the Yaeyama graben is a typical example of the presence of oceanic crust. Faulting and magmatism were mainly migrating towards the island arc asymmetrically. The crustal oceanization of the Okinawa Trough is difficultly interpreted by the linear magnetic anomaly model, which is fit for the symmetric spreading of the mid-oceanic ridges.展开更多
Boli basin, between Yishu fracture belt and Dunmi fracture belt, is the biggest Mesozoic coal basin in the east of Heilongjiang Province. Now it is a fault-fold remnant basin. The basin’s shape is generally consisten...Boli basin, between Yishu fracture belt and Dunmi fracture belt, is the biggest Mesozoic coal basin in the east of Heilongjiang Province. Now it is a fault-fold remnant basin. The basin’s shape is generally consistent with the whole distribution of the cover folds, an arc protruding southwards. The basement of the basin can be divided into three fault blocks or structural units. The formation and evoluation of the basin in Mesozoic was determined by the basement fault blocks’ dis- placement features rusulted from by the movement of the edge faults and the main basement faults.展开更多
The development, evolution and formation mechanism of faults and their control on the migration and accumulation of Mesozoic oil and gas in the middle-shallow layers of the slope zone of Mahu sag were studied by the i...The development, evolution and formation mechanism of faults and their control on the migration and accumulation of Mesozoic oil and gas in the middle-shallow layers of the slope zone of Mahu sag were studied by the interpretation of seismic and drilling data. Two types of faults, normal and strike-slip, are developed in the middle-shallow layers of the slope zone of the Mahu sag and they are mostly active in the Yanshanian period. They are divided into four grade faults: The grade I strike-slip faults with NWW to near EW direction are related to the left-lateral transpressive fault zones in the northwest of Junggar Basin since the end of the Triassic. The grade II faults with NE to NNE direction are the normal faults located at the junction of the fault zone and the slope zone, and their formation is related to the extension at the top of the nose-like structures in the fault zone. The grade III faults, which are also the normal faults, are the result of the extension at the top of the lower uplifts in the slope zone and differential compaction. The grade IV faults with NE direction are normal faults, which may be related to the extension environment at the tip of the lower uplifts. Faults not only are the channel for the vertical migration of oil and gas, but also control the oil-gas accumulation. There are two types of oil-gas reservoirs in the middle-shallow layers of slope zone of Mahu sag: fault block reservoirs and fault-lithologic reservoirs. They have large traps and promising exploration potential.展开更多
Based on three-dimensional seismic interpretation, structural and sedimentary feature analysis, and examination of fluid properties and production dynamics, the regularity and main controlling factors of hydrocarbon a...Based on three-dimensional seismic interpretation, structural and sedimentary feature analysis, and examination of fluid properties and production dynamics, the regularity and main controlling factors of hydrocarbon accumulation in the Tazhong uplift, Tarim Basin are investigated. The results show that the oil and gas in the Tazhong uplift has the characteristics of complex accumulation mainly controlled by faults, and more than 80% of the oil and gas reserves are enriched along fault zones. There are large thrust and strike-slip faults in the Tazhong uplift, and the coupling relationship between the formation and evolution of the faults and accumulation determine the difference in complex oil and gas accumulations. The active scale and stage of faults determine the fullness of the traps and the balance of the phase, that is, the blocking of the transport system, the insufficient filling of oil and gas, and the unsteady state of fluid accumulation are dependent on the faults. The multi-period tectonic sedimentary evolution controls the differences of trap conditions in the fault zones, and the multi-phase hydrocarbon migration and accumulation causes the differences of fluid distribution in the fault zones. The theory of differential oil and gas accumulation controlled by fault is the key to the overall evaluation, three-dimensional development and discovery of new reserves in the Tazhong uplift.展开更多
Under strong seismic excitation, a rigid block will uplift from its support and undergo rocking oscillations which may lead to （complete） overturning. Numerical and analytical solutions to this highly nonlinear vibr...Under strong seismic excitation, a rigid block will uplift from its support and undergo rocking oscillations which may lead to （complete） overturning. Numerical and analytical solutions to this highly nonlinear vibration problem are first highlighted in the paper and then utilized to demonstrate how sensitive the overturning behavior is not only to the intensity and frequency content of the base motion, but also to thc presence of strong pulses, to their detailed sequence, and even to their asymnletry. Five idealised pulses capable of representing ＂rupture-directivity＂ and ＂fling＂ affected ground motions near the fault, are utilized to this end ： the one-cycle sinus, the one-cycle cosinus, the Ricker wavelet, the truncated （T）-Ricker wavelet, and the rectangular pulse ＂Overturning-Acceleration Amplification＂ and ＂Rotation＂ spectra are introduced and presented. Artificial neural network modeling is then developed as an alternative numerical solution. The neural network analysis leads to closed-form expressions for predicting the overturning failure or survival of a rigid block, as a function of its geometric properties and the characteristics of the excitation time history. The capability of the developed neural network modeling is validated through comparisons with the numerical solution. The derived analytical expressions could also serve as a tool for assessing the destructiveness of near-fault ground motions, for structures sensitive to rocking with foundation uplift.展开更多
基金supported by the National Science and Technology Major Project (No. 2011ZX05009-001)the National Natural Science Foundation of China (No. 41102071)
文摘The Bachu （巴楚） uplift is one of the most active tectonic regions nowadays in the Tarim basin, which is also a faulted block uplift that was intensively active during the Cenozoic. This study was based primarily on the geological structure interpretation of seismic profiles, applying the theories and methods of basin dynamics, structural analysis and tectono-stratigraphic analysis, the geometry and kinematics features of the fault systems in the Bachn uplift were analyzed in detail. Our study shows that each fault belt is mainly characterized by compression and overthrusting, most of the faults initiated and activated during the Mid-Late Himalayan period, and that the general structural styles of the Bachu uplift were basement-involved pop-up thrust faulted block uplift, of which the southern margin was covered by the large-scale decollement fault system. The basement-involved structures widely developed in the higher position of the basement uplift, while decollement fault system developed mainly at the position with gypsum mudstone. The evolution process of Bachu uplift included back-bulge slope of the peripheral foreland basin in Mid-Late Caledonian, forebulge in HercynianYanshanian and the latest compressional faulted block uplift in Mid-Late Himalayan. Meanwhile,the study also suggests that the formation, reconstruction and stabilization of the uplift were controlled by the development and evolution of fault systems clearly. In the early forebulge stage, it was mainly presented as flexural deformation without the developing of thrust faults in the Bachu area; to the late stage, under the influence of violent lateral compression deformation, the faulted block uplift formed finally.
基金supported by the National Science and Technology Project of Tenth Five Years (No. 2001BA605A06A)Science and the Technology Cooperation Programs of SINOPEC, China (Nos. FYWX04-06, XBKT2007KY10-021)
文摘Based on high-resolution 2D seismic profiles, the Paleozoic structural deformation char- acteristics of Bachu （巴楚） uplift of northwestern Tarim basin, NW China, are exhibited in this article. The deformation happened during three main geological periods： the end of Middle-Late Ordovician （O2-3）, the end of Early-Middle Devonian （D1-2）, and the end of Late Permian （P2）. In the Bachu uplift, there developed a series of NW-trending thrust faults and imbricate structures due to the effect of the NW-SE compression stress towards the end of Middle-Late Ordovician （O2-3） （middle Caledonian movement）, and there developed some NNE-trending thrust faults and fault blocks under the control of the NEE-SWW compression stress at the end of Early-Middle Devonian （D1-2） （early Hercynian movement）. However, at the end of Late Permian （P2） （late Hercynian movement）, some NE-trending thrust faults and associated folds developed as a result of the NE-SW compression stress. The first-stage （O2-3） deformation is obviously more violent than those of the latter two stages （D1-2 and P2）, which implies that the Tarim plate drifted quickly to the north at around the same time basin.
基金The National Major Fundamental Research and Development Project(2005CB422102)Notional Key Project for Oil and Gas(2008ZX05007-03)Key Project of SINOPEC provided financial support for this work
文摘The thermal evolution of source rocks in the Paleozoic has long been a problem to petroleum exploration in the Bachu uplift, Tarim basin, since the thermal history in the Paleozoic could not be rebuilt objectively due to lack of effective thermal indicators in the Lower Paleozoic successions. The apatite and zircon （U-Th）/He thermochronometry can be used as a new kind of technique to study the thermal history and tectonic uplift of sedimentary basins. Based on the measured apatite and zircon （U-Th）/He ages, apatite fission track data and equivalence vitrinite reflectance （%EVRo）, the tectonothermal histories in 5 wells of the Bachu uplift were modeled. The modeling results show that there was relatively high gradient at the Early Paleozoic in the Bachu uplift and it decreased gradually during the entire Paleozoic： 33-35℃/km in the Cambrian- Ordovician, 32-33℃/km in the Silurian-Devonian, 30-32℃/km at the end of Carboniferous and 27.5- 31℃/km at the end of Permian. Therefore, the thermal history can be modeled by combining multiple thermal indicators of AFT, （U-Th）/He ages and EVRo data. Especially, this provides a new method to rebuild the thermal history for the Low Paleozoic carbonate successions in the Tarim Basin.
基金Project supported by the National Science and Technology Project of Tenth Five Years (No.2001BA605A06A)Science and Tech-nology Cooperation Program of SINOPEC (No.FYWX04-06),China
文摘Based on new high-resolution seismic profiles and existing structural and sedimentary results, a superposition deformation model for Cenozoic Bachu Uplift of northwestern Tarim Basin, northwestern China is proposed. The model presents the idea that the Bachu Uplift suffered structure superposition deformation under the dual influences of the Cenozoic uplifting of Southern Tianshan and Western Kunlun orogen, northwestern China. In the end of the Eocene （early Himalayan movement）, Bachu Uplift started to be formed with the uplifting of Western Kunlun, and extended NNW into the interior of Kalpin Uplift. In the end of the Miocene （middle Himalayan movement）, Bachu Uplift suffered not only the NNW structure deformation caused by the Western Kunlun uplifting, but also the NE structure deformation caused by the Southern Tianshan uplifting, and the thrust front fault of Kalpin thrust system related to the Southern Tianshan orogen intrudes southeastward into the hinterland of Bachu Uplift and extends NNE from well Pil to Xiaohaizi reservoir and Gudongshan mountain, which resulted in the strata folded and denuded strongly. In the end of the Pliocene （late Himalayan movement）, the impact of Southern Yianshan orogen decreased because of the stress released with the breakthrough upward of Kalpin fault extending NE, and Bachu Uplift suffered mainly the structure deformation extending NW-NNW caused by the uplifting of Western Kunlun orogen.
基金financially supported by the National Science Foundation of China(grant No.41372146)
文摘Objective Oil and gas are abundant in the Ordovician Yingshan Formation carbonate karst reservoirs on the northern slope of Tazhong uplift in the Tarim Basin, and have extremely complicated oil-gas-water distribution, however. The difference in burial depth of the reservoirs between east and west sides is up to 1000 m. Water-bearing formations exist between oil- and gas-bearing formations vertically and water-producing wells are drilled between oil- and gas-producing wells. Macroscopically, oil and gas occur at low positions, while water occurs at high positiona on the northern slope of Tazhong uplift. The mechanism of differential hydrocarbon enrichment in heterogeneous reservoirs is by far not clarified, which has affected the efficient exploration and development of oil and gas fields in this area.
基金Supported by the China National Science and Technology Major Project(2016ZX05004-004)
文摘Based on the outcrop survey,3D seismic data interpretation,drilling data analysis,the structural patterns and distribution of fault damage zones in carbonate strata of Tazhong Paleo-uplift were established to reveal the oil and gas enrichment law in the fault damage zones.The following findings were reached:(1)Through the filed survey,the fault damage zone system consists of fault core,damage zone with branch fault and fracture network.Affected by the active nature of the major faults,the fault damage zones differ in planar pattern and scale along the major faults.(2)3D seismic profiles reveal that there are three types of fault damage zones in carbonate strata in Tazhong paleo-uplift,strike-slip fault damage zones,thrust fault damage zones and superimposed fault damage zones.Featuring3 flowers and 3 root belts in vertical,the strike-slip fault damage zone can be subdivided into linear type,oblique type,feather type and horsetail type in plane.Thrust fault damage zones can be further divided into fault anticline type,anticline type and slope type.As the superimposition result of the above two kinds of fault damage zones,superimposed fault damage zones appear in three patterns,intersect type,encompassment type and penetrating type.(3)Cores from wells and geochemical data show oil and gas may migrate along the major fault and laterally.The feather type in strike-slip fault system,fault anticline type in thrust fault damage zone and intersect type in superimposed fault damage zone are possible sites for high production and efficiency wells.
文摘he convergence between India and Eurasia is partly accommodated by motion of a few large blocks along strike\|slip faults. About 1800km long Altyn Tagh fault strikes in N60～80°E and allows the northeastward displacement of the Tibet plateau relative to the Tarim. The Altyn Tagh fault zone is a typical transpressional fault zone, characterized by blocks rotation and crustal shortening and vertical extrusion of blocks within the Altyn Tagh strike\|slip system. Differences of three\|dimensional deformation and configuration of the active structures are recognized at different segment of the Altyn Tagh fault zone.1\ Structural configuration of the Altyn Tagh fault zone\;In the Altyn Tagh strike\|slip fault zone, the assemblage pattern of the (active) faults is in the form of parallel plumes, especially in the eastern and the western segments of the Altyn Tagh fault zone. These plumes structures in the eastern segment are assembled by string\|like left lateral strike\|slip fault and broom\|like thrusting faults, and in the western segment by arc\|like left lateral strike\|slip faults along with thrusting faults and normal faults. In the middle segment of the Altyn Tagh fault zone, the structures are characterized by the string\|like left lateral strike\|slip faults in the center and reverse thrusting faults on the two sides.
文摘The formation of strath and strath terrace is closely related to tectonic uplift in the drainage basin. Based on the investigation of straths at Yandantu and Changcaogou on the eastern segment of the northern margin fault of Altun, and in combination with the paleoclimatic data, the tectonic uplift since late Epipleistocene as revealed by stream terraces at the two places is discussed. At Yandantu, three levels of stream terraces(T 1, T 2 and T 3)have developed since 16ka BP, where T 1, T 3 and T 2 are fill terraces and the buried major straths are exposed. The ages of three treads are dated to be about 16.1ka BP, 12.8ka BP and 6.2ka BP, respectively. The three terraces reflect three tectonic uplift events, while the ages of the treads represent the occurrence time of these events. The stream is still beveling the bedrock and widening the channel at present, and the modern strath is being generated. The uplift rate is 4.8～4.5mm/a since 16.1 ka BP in this area. From 12.8ka B.P to 6.2ka BP, The uplift rate was 6.4mm/a. The uplift rate is 3.1mm/a since 6.2ka BP. At Changcaogou, four levels of stream terraces(T 1, T 2, T 3 and T 1′)have developed since 7ka BP. All of them are fill terraces. There are buried straths under the deposits. The buried major strath is exposed on T 3 and T 2 and the minor strath on T 1′and T 1. The ages of treads of the three terraces (T 3, T 2 and T 1′) are 7 ka BP, 3 ka BP and 2.5 ka BP, respectively. The four terraces reflect two uplift events induced by tectonic activities. One occurred in about 7 ka BP, and the other in 3ka BP. The uplift rate is 5.9mm/a since 7.0 ka BP at Changcaogou. From 7ka BP to 3ka BP, the uplift rate was 7.0mm/a, and since 3ka BP till now, the uplift rate is 4.7 mm/a.
基金funded by the National Science and Technology Support Project entitled "Study on Key Technologies for Strong Earthquake Zoning (2006BAC13B01)"
文摘Lying on the west edge of Dongting Lake,the Taiyangshan area in Hunan Province is part of a hilly region which has uplifted since the Late Cenozoic.According to field investigation of the six existing faults in the Taiyangshan area,we found that four of them are not active in the Quaternary,and that the Gangshi-Hefu fault is likely to have been active in the early Mid-Pleistocene.The geological evidence derived suggests that the Xiaowupu fault was active from the late Mid-Pleistocene to the early late-Pleistocene.It cut the stratum with a TL age of 123±10ka BP and has the property of thrusting.The research results are of great significance for understanding the seismogenic structure of the Changde earthquake with M6 3/4 in 1631.
基金supported by the Natural Science Foundation of Xinjiang(No.2022D01C361)the National Natural Science Foundation of China(Nos.42462023,41888101)+1 种基金the Tianchi Talents Program fund(No.TCBR202105)the Startup Research Fund of Xinjiang University(No.620320044)。
文摘The Altyn Tagh fault zone(ATFZ),which defines the northern boundary of the Tibetan Plateau,is one of the most striking features related to the India/Eurasia collision.Concurrent with the strike-slip movement,vertical uplift,and topographic building have formed a~3000-4000 m height difference between the Tarim Basin(TB)in the north and the Tibetan Plateau in the south.However,the spatial uplift characteristics and mechanism have not been well understood,particularly in the Late Quaternary.This research presents a comprehensive geomorphic analysis to establish the Late Quaternary tectonic uplift pattern for the entire ATFZ.We statistically excluded climatic and lithological factors that provided prominence for tectonism;combined with leveling data,river incision rate,and seismicity data,we reveal the along-strike and across-fault vertical deformation variations.The spatial distribution of the integrated geomorphic index(IGI)suggests significant differences between the two sides of the ATFZ.The IGI values decrease with slip rates in the northwestern side of the ATF,whereas wave-like in the southeastern side.The significant along-strike deformation difference between the two sides of the ATFZ may cause by differential rheology.These findings are crucial for assessing regional seismic hazards and providing new independent data to understand the Late Quaternary deformation style of the northern boundary of the Tibetan Plateau.
基金The National Major Fundamental Research and Development Project of China under contract Nos G2000046703 and 2007CB411702the Scientific Research Fund of the Second Institute of Oceanography, State Oceanic Administration under contract No.JT0705
文摘The paper focuses on the characteristics of faulting and magmatism of the Okinawa Trough and the relation between them. En-echelon grabens are ranked oblique to the continental shelf edge uplift, and the Longwang uplift, the rifting block ridge in the northern segment and the ＂Mianhua uplift＂ in the southern segment have possibly preserved characteristics of volcanism and magmatism occurring with those rifting phases. The clockwise rotation of the southern Ryukyu Islands, driven by collision between Luzon and Taiwan, has played a key role in the crustal oceanization, enhancing the crustal extension of the southern segment and inducing volcanic magmatism in those grabens, among which the Yaeyama graben is a typical example of the presence of oceanic crust. Faulting and magmatism were mainly migrating towards the island arc asymmetrically. The crustal oceanization of the Okinawa Trough is difficultly interpreted by the linear magnetic anomaly model, which is fit for the symmetric spreading of the mid-oceanic ridges.
文摘Boli basin, between Yishu fracture belt and Dunmi fracture belt, is the biggest Mesozoic coal basin in the east of Heilongjiang Province. Now it is a fault-fold remnant basin. The basin’s shape is generally consistent with the whole distribution of the cover folds, an arc protruding southwards. The basement of the basin can be divided into three fault blocks or structural units. The formation and evoluation of the basin in Mesozoic was determined by the basement fault blocks’ dis- placement features rusulted from by the movement of the edge faults and the main basement faults.
基金Supported by the China National Science and Technology Major Project(2017ZX05008-001,2011ZX05003-003)
文摘The development, evolution and formation mechanism of faults and their control on the migration and accumulation of Mesozoic oil and gas in the middle-shallow layers of the slope zone of Mahu sag were studied by the interpretation of seismic and drilling data. Two types of faults, normal and strike-slip, are developed in the middle-shallow layers of the slope zone of the Mahu sag and they are mostly active in the Yanshanian period. They are divided into four grade faults: The grade I strike-slip faults with NWW to near EW direction are related to the left-lateral transpressive fault zones in the northwest of Junggar Basin since the end of the Triassic. The grade II faults with NE to NNE direction are the normal faults located at the junction of the fault zone and the slope zone, and their formation is related to the extension at the top of the nose-like structures in the fault zone. The grade III faults, which are also the normal faults, are the result of the extension at the top of the lower uplifts in the slope zone and differential compaction. The grade IV faults with NE direction are normal faults, which may be related to the extension environment at the tip of the lower uplifts. Faults not only are the channel for the vertical migration of oil and gas, but also control the oil-gas accumulation. There are two types of oil-gas reservoirs in the middle-shallow layers of slope zone of Mahu sag: fault block reservoirs and fault-lithologic reservoirs. They have large traps and promising exploration potential.
基金Supported by the China Science and Technology Major Project(2017ZX05008-004-001,2017ZX05001-001)Chinese Academy of Sciences Strategic Pilot Project(XDA14010302)
文摘Based on three-dimensional seismic interpretation, structural and sedimentary feature analysis, and examination of fluid properties and production dynamics, the regularity and main controlling factors of hydrocarbon accumulation in the Tazhong uplift, Tarim Basin are investigated. The results show that the oil and gas in the Tazhong uplift has the characteristics of complex accumulation mainly controlled by faults, and more than 80% of the oil and gas reserves are enriched along fault zones. There are large thrust and strike-slip faults in the Tazhong uplift, and the coupling relationship between the formation and evolution of the faults and accumulation determine the difference in complex oil and gas accumulations. The active scale and stage of faults determine the fullness of the traps and the balance of the phase, that is, the blocking of the transport system, the insufficient filling of oil and gas, and the unsteady state of fluid accumulation are dependent on the faults. The multi-period tectonic sedimentary evolution controls the differences of trap conditions in the fault zones, and the multi-phase hydrocarbon migration and accumulation causes the differences of fluid distribution in the fault zones. The theory of differential oil and gas accumulation controlled by fault is the key to the overall evaluation, three-dimensional development and discovery of new reserves in the Tazhong uplift.
文摘Under strong seismic excitation, a rigid block will uplift from its support and undergo rocking oscillations which may lead to （complete） overturning. Numerical and analytical solutions to this highly nonlinear vibration problem are first highlighted in the paper and then utilized to demonstrate how sensitive the overturning behavior is not only to the intensity and frequency content of the base motion, but also to thc presence of strong pulses, to their detailed sequence, and even to their asymnletry. Five idealised pulses capable of representing ＂rupture-directivity＂ and ＂fling＂ affected ground motions near the fault, are utilized to this end ： the one-cycle sinus, the one-cycle cosinus, the Ricker wavelet, the truncated （T）-Ricker wavelet, and the rectangular pulse ＂Overturning-Acceleration Amplification＂ and ＂Rotation＂ spectra are introduced and presented. Artificial neural network modeling is then developed as an alternative numerical solution. The neural network analysis leads to closed-form expressions for predicting the overturning failure or survival of a rigid block, as a function of its geometric properties and the characteristics of the excitation time history. The capability of the developed neural network modeling is validated through comparisons with the numerical solution. The derived analytical expressions could also serve as a tool for assessing the destructiveness of near-fault ground motions, for structures sensitive to rocking with foundation uplift.
