The isolated fracture-vug systems controlled by small-scale strike-slip faults within ultra-deep carbonate rocks of the Tarim Basin exhibit significant exploration potential.The study employs a novel training set inco...The isolated fracture-vug systems controlled by small-scale strike-slip faults within ultra-deep carbonate rocks of the Tarim Basin exhibit significant exploration potential.The study employs a novel training set incorporating innovative fault labels to train a U-Net-structured CNN model,enabling effective identification of small-scale strike-slip faults through seismic data interpretation.Based on the CNN faults,we analyze the distribution patterns of small-scale strike-slip faults.The small-scale strike-slip faults can be categorized into NNW-trending and NE-trending groups with strike lengths ranging 200–5000 m.The development intensity of small-scale strike-slip faults in the Lower Yingshan Member notably exceeds that in the Upper Member.The Lower and Upper Yingshan members are two distinct mechanical layers with contrasting brittleness characteristics,separated by a low-brittleness layer.The superior brittleness of the Lower Yingshan Member enhances the development intensity of small-scale strike-slip faults compared to the upper member,while the low-brittleness layer exerts restrictive effects on vertical fault propagation.Fracture-vug systems formed by interactions of two or more small-scale strike-slip faults demonstrate larger sizes than those controlled by individual faults.All fracture-vug system sizes show positive correlations with the vertical extents of associated small-scale strike-slip faults,particularly intersection and approaching fracture-vug systems exhibit accelerated size increases proportional to the vertical extents.展开更多
Natural fractures controlled by faults in ultradeep carbonate strata play substantial roles as both fluid migration channels and storage spaces.However,characterizing the heterogeneous distribution of underground frac...Natural fractures controlled by faults in ultradeep carbonate strata play substantial roles as both fluid migration channels and storage spaces.However,characterizing the heterogeneous distribution of underground fractures within the complex three-dimensional geometry of strike-slip fault zones remains challenging.This study investigates the characteristics of natural fractures controlled by strike-slip faults in the fractured Middle and Lower Ordovician reservoirs of the central and northern Tarim Basin,China.Seismics,cores,and image logs were integrated to quantitatively analyze the intensity and dip angle of natural fractures and findings were verified using published sandbox simulations.The carbonate reservoir contains three main types of natural fractures:tectonic fractures,abnormal high-pressure-related fractures,and stylolites.Strike-slip faults control the distribution and characteristics of tectonic fractures across various scales.Generally,both fracture intensity and porosity exhibit a decreasing trend as the distance from the main fault surface increases.Compared with those in non-stepover zones along a strike-slip fault,natural fractures and faults in stepover zones are more developed along the fault strike,with significantly greater development intensity in central stepover regions than that at its two ends.Furthermore,strike-slip faults influence the dip angles of both natural fractures and secondary faults.The proportion of medium-to-low-dip angle fractures and faults in the stepover zone is greater than that in the non-stepover zone.Additionally,the proportion of medium-to low-dip angle fractures and faults in the middle of the stepover is greater than that at both ends.Therefore,strike-slip fault structures control the dip angle of natural fracture and the heterogeneity of secondary fault and fracture intensity.The linking damage zone in the stepover contains a larger volume of fractured rocks,making it a promising petroleum exploration target.The development of stepovers and the orientation of present-day in-situ stress substantially influence the productivity of fractured reservoirs controlled by strike-slip faults.The analysis in this study reveals that reservoir productivity increases as the angle between the strike-slip fault segment and the maximum horizontal principal stress decreases.This study provides valuable insights for quantitatively evaluating fracture heterogeneity in fractured reservoirs and establishing optimized selection criteria for favorable targets in fault-related fractured reservoirs.展开更多
Recent exploration has highlighted the critical role of strike-slip faults in shaping ultra-deep carbonate reservoirs in the Tarim Basin.This study integrates satellite imagery,UAV photogrammetry,outcrop surveys and m...Recent exploration has highlighted the critical role of strike-slip faults in shaping ultra-deep carbonate reservoirs in the Tarim Basin.This study integrates satellite imagery,UAV photogrammetry,outcrop surveys and microscopic analysis to investigate the architecture of these faults and their impact on reservoir petrophysical properties.The strike-slip faults exhibit cores consisting of calcite bands,fault breccias and fractures,while the damage zones are predominantly fractured.Thicker fault cores and fault zones are associated with more extensive reservoir development.Individual strike-slip fault zones are primarily characterized by two sets of fractures intersecting the fault at small angles.When two fault systems interact,the dominant pattern is two sets of fractures intersecting the main fault at small angles and one set at larger angles,facilitating the formation of large-scale reservoirs.We propose a model for the fault core,which primarily consists of a calcite band and fault breccias.These breccias are composed of original host rock,calcite cement and quartz,which exhibit poor physical properties,while fractures and vugs show favorable reservoir characteristics.This model offers valuable insights into the development of fault-controlled reservoirs,particularly in the Tarim Basin.展开更多
Fault container and shaking table tests are crucial for studying co-seismic dislocation in cross-fault tunnels,with the design and functionality of the container significantly affecting the accuracy of dynamic respons...Fault container and shaking table tests are crucial for studying co-seismic dislocation in cross-fault tunnels,with the design and functionality of the container significantly affecting the accuracy of dynamic response analyses of tunnel linings.This research introduces a fault container developed as part of a significant active fault-crossing tunnel project in the high-intensity seismic zone of western China.The container is designed to simulate both strike-slip and dip-slip fault characteristics with adjustable fault angles.Extensive testing,including shaking table tests under strong seismic conditions,three-dimensional(3D)finite element numerical simulations,and hammer tests,were conducted to evaluate the modal characteristics of the container under various conditions.The study highlights the resonance characteristics of the soil-container system,the signal consistency across different dislocations,and the dynamic response patterns both with and without pulse-like seismic motions and varying intensities.The results indicate that the natural frequencies of the container and the model soil,determined through white noise scanning,are 23.74 Hz and 6.355 Hz,respectively,suggesting no resonance in the model soil-container structure.The dynamic response characteristics of the empty container show good integrity and versatility under various seismic excitations.The consistency of the free-field time history curve confirms that the newly developed fault container effectively simulates the continuity and boundary conditions of the free-field.Time domain analysis conducted before and after fault dislocation demonstrates the capability of the container to accurately replicate the coupling effects of fault and seismic motions.展开更多
The strike-slip fault system in the central Tarim Craton controls a complex petroleum system with estimated reserves exceeding 1×10^(9)t,the fault-related fractures are important for hydrocarbon accumulation.In t...The strike-slip fault system in the central Tarim Craton controls a complex petroleum system with estimated reserves exceeding 1×10^(9)t,the fault-related fractures are important for hydrocarbon accumulation.In this paper,the basic parameters such as density and width of fractures are counted and classified,and the effects of fractures on reservoirs are analyzed.The results show that:(1)Structural fractures and stylolite were widely developed in Halahatang area and experienced at least three stages of activity based on the infilling materials and crosscutting relationship.(2)Fracture density,width,aperture,and dip angle vary in different wells,but the relationship between the above parameters and the distance to the fault core indicates the fracture differences in the fault damage zone and further provides a method to divide the inner units in the fault damage zone.In addition,oil and gas wells with high production mainly concentrate in the inner unit.(3)The infilling materials and degree of fractures vary.Fractures formed in the early stage are more filled and less open,while the fractures formed in the late stage are relatively less filled and more open.(4)Fractures improve porosity to a certain extent but greatly increase permeability,especially in the inner zone of fault damage zone with large quantity,multiple inclinations,less filling and large width.These features contribute to the formation of a higher-quality reservoir,further improving oil and gas production.This paper provides a quantitative characterization method for the study of strike-slip fault-related fracture-caved reservoirs,and points out that fault damage zone,especially the inner zone of the fault damage zone,is the potential goal for oil and gas exploration.展开更多
In the ultra-deep strata of the Tarim Basin,the vertical growth process of strike-slip faults remains unclear,and the vertical distribution of fractured-cavity carbonate reservoirs is complex.This paper investigates t...In the ultra-deep strata of the Tarim Basin,the vertical growth process of strike-slip faults remains unclear,and the vertical distribution of fractured-cavity carbonate reservoirs is complex.This paper investigates the vertical growth process of strike-slip faults through field outcrop observations in the Keping area,interpretation of seismic data from the Fuman Oilfield,Tarim Basim,NW China,and structural physical simulation experiments.The results are obtained mainly in four aspects.First,field outcrops and ultra-deep seismic profiles indicate a three-layer structure within the strike-slip fault,consisting of fault core,fracture zone and primary rock.The fault core can be classified into three parts vertically:fracture-cavity unit,fault clay and breccia zone.The distribution of fracture-cavity units demonstrates a distinct pattern of vertical stratification,owing to the structural characteristics and growth process of the slip-strike fault.Second,the ultra-deep seismic profiles show multiple fracture-cavity units in the strike-slip fault zone.These units can be classified into four types:top fractured,middle connected,deep terminated,and intra-layer fractured.Third,structural physical simulation experiments and ultra-deep seismic data interpretation reveal that the strike-slip faults have evolved vertically in three stages:segmental rupture,vertical growth,and connection and extension.The particle image velocimetry detection demonstrates that the initial fracture of the fault zone occurred at the top or bottom and then evolved into cavities gradually along with the fault growth,accompanied by the emergence of new fractures in the middle part of the strata,which subsequently connected with the deep and shallow cavities to form a complete fault zone.Fourth,the ultra-deep carbonate strata primarily develop three types of fractured-cavity reservoirs:flower-shaped fracture,large and deep fault and staggered overlap.The first two types are larger in size with better reservoir conditions,suggesting a significant exploration potential.展开更多
During strike-slip fault dislocation,multiple fault planes are commonly observed.The resulting permanent ground deformation can lead to profound structural damage to tunnels.However,existing analytical models do not c...During strike-slip fault dislocation,multiple fault planes are commonly observed.The resulting permanent ground deformation can lead to profound structural damage to tunnels.However,existing analytical models do not consider multiple fault planes.Instead,they concentrate the entire fault displacement onto a single fault plane for analysis,thereby giving rise to notable errors in the calculated results.To address this issue,a refined nonlinear theoretical model was established to analyze the mechanical responses of the tunnels subjected to multiple strike-slip fault dislocations.The analytical model considers the number of fault planes,nonlinear soil‒tunnel interactions,geometric nonlinearity,and fault zone width,leading to a significant improvement in its range of applicability and calculation accuracy.The results of the analytical model are in agreement,both qualitatively and quantitatively,with the model test and numerical results.Then,based on the proposed theoretical model,a sensitivity analysis of parameters was conducted,focusing on the variables such as the number of fault planes,fault plane distance(d),fault displacement ratio(η),burial depth(C),crossing angle(β),tunnel diameter(D),fault zone width(Wf),and strike-slip fault displacement(Δfs).The results show that the peak shear force(Vmax),bending moment(Mmax),and axial force(Nmax)decrease with increasing d.The Vmax of the tunnel is found at the fault plane with the largest fault displacement.C,D,andΔfs contribute to the increases in Vmax,Mmax,and Nmax.Additionally,increasing the number of fault planes reduces Vmax and Mmax,whereas the variation in Nmax remains minimal.展开更多
Abstract The nearly E-W-trending Aqqikkudug-Weiya zone, more than 1000 km long and about 30 km wide, is an important segment in the Central Asian tectonic framework. It is distributed along the northern margin of the ...Abstract The nearly E-W-trending Aqqikkudug-Weiya zone, more than 1000 km long and about 30 km wide, is an important segment in the Central Asian tectonic framework. It is distributed along the northern margin of the Central Tianshan belt in Xinjiang, NW China and is composed of mylonitized Early Palaeozoic greywacke, volcanic rocks, ophiolitic blocks as a mélange complex, HP/LT-type bleuschist blocks and mylonitized Neoproterozoic schist, gneiss and orthogneiss. Nearly vertical mylonitic foliation and sub-horizontal stretching lineation define its strike-slip feature; various kinematic indicators, such as asymmetric folds, non-coaxial asymmetric macro- to micro-structures and C-axis fabrics of quartz grains of mylonites, suggest that it is a dextral strike-slip ductile shear zone oriented in a nearly E-W direction characterized by “flower” strusture with thrusting or extruding across the zone toward the two sides and upright folds with gently plunging hinges. The Aqqikkudug-Weiya zone experienced at least two stages of ductile shear tectonic evolution: Early Palaeozoic north vergent thrusting ductile shear and Late Carboniferous-Early Permian strike-slip deformation. The strike-slip ductile shear likely took place during Late Palaeozoic time, dated at 269±5 Ma by the40Ar/39Ar analysis on neo-muscovites. The strike-slip deformation was followed by the Hercynian violent S-type granitic magmatism. Geodynamical analysis suggests that the large-scale dextral strike-slip ductile shearing is likely the result of intracontinental adjustment deformation after the collision of the Siberian continental plate towards the northern margin of the Tarim continental plate during the Late Carboniferous. The Himalayan tectonism locally deformed the zone, marked by final uplift, brittle layer-slip and step-type thrust faults, transcurrent faults and E-W-elongated Mesozoic-Cenozoic basins.展开更多
Recent studies, focused on dihedral angles and intersection processes, have increased understandings of conjugate fault mechanisms. We present new 3-D seismic data and microstructural core analysis in a case study of ...Recent studies, focused on dihedral angles and intersection processes, have increased understandings of conjugate fault mechanisms. We present new 3-D seismic data and microstructural core analysis in a case study of a large conjugate strike-slip fault system from the intracratonic Tarim Basin, NW China. Within our study area, ＂X＂ type NE and NW trending faults occur within Cambrian- Ordovician carbonates. The dihedral angles of these conjugate faults have narrow ranges, 19~ to 62~ in the Cambrian and 26~ to 51~ in the Ordovician, and their modes are 42~ and 44~ respectively. These data are significantly different from the ~60~ predicted by the Coulomb fracture criterion. It is concluded that： （1） The dihedral angles of the conjugate faults were not controlled by confining pressure, which was low and associated with shallow burial; （2） As dihedral angles were not controlled by pressure they can be used to determine the shortening direction during faulting; （3） Sequential slip may have played an important role in forming conjugate fault intersections; （4） The conjugate fault system of the Tarim basin initiated as rhombic joints; these subsequently developed into sequentially active ＂X＂ type conjugate faults; followed by preferential development of the NW-trending faults; then reactivation of the NE trending faults. This intact rhombic conjugate fault system presents new insights into mechanisms of dihedral angle development, with particular relevance to intracratonic basins.展开更多
Recent studies on the Xianshuihe-Xiaojiang fault system suggest that the Late Quaternary strike-slip rate is approximately uniform along the entire length of the fault zone, about 15±2 mm/a. This approximately un...Recent studies on the Xianshuihe-Xiaojiang fault system suggest that the Late Quaternary strike-slip rate is approximately uniform along the entire length of the fault zone, about 15±2 mm/a. This approximately uniform strike slip rate strongly supports the clockwise rotation model of the southeastern Tibetan crust. By approximating the geometry of the arc-shaped Xianshuihe-Xiaojiang fault system as a portion of a small circle on a spherical Earth, the 15±2 mm/a strike slip rate corresponds to clockwise rotation of the Southeastern Tibetan Block at the （5.2±0.7）×10^-7 deg/a angular velocity around the pole （21°N, 88°E） relative to the Northeast Tibetan Block. The approximately uniform strike slip rate along the Xianshuihe-Xiaojiang fault system also implies that the Longmeushan thrust zone is not active, or at least its activity has been very weak since the Late Quaternary. Moreover, the total offset along the Xiaushuihe-Xiaojiang fault system suggests that the lateral extrusion of the Southeastern Tibetan Block relative to Northeastern Tibetan Block is about 160 km and 200-240 km relative to the Tarim-North China block. This amount of lateral extrusion of the Tibetan crust should have accommodated about 13-24% convergence between India and Eurasia based on mass balance calculations. Assuming that the slip rate of 15±2 mm/a is constant throughout the entire history of the Xianshuihe-Xiaojiang fault system, 11±1.5 Ma is needed for the Xianshuihe-Xiaojiang fault system to attain the 160 km of total offset. This implies that left-slip faulting on the Xianshuihe-Xiaojiang fault system might start at 11±1.5 Ma.展开更多
The Karatau fault is one of the important strike-slip faults in central Asia,and the South Turgay Basin is located towards its northern end.Detailed seismic interpretation indicated that the strikeslip tectonism of th...The Karatau fault is one of the important strike-slip faults in central Asia,and the South Turgay Basin is located towards its northern end.Detailed seismic interpretation indicated that the strikeslip tectonism of the Karatau fault weakened gradually from west to east in the South Turgay Basin.Typical flower structures developed on the section,and strike-slip faults showed an echelon pattern on planar view.The Karatau strike-slip fault affected the South Turgay Basin in two periods：（1） The South Turgay strike-slip pull-apart rift basin formed as a result of regional extensive stress in the Early-Middle Jurassic,characterized by the juxtaposition of horsts and grabens.The formation of horsts provided favorable reservoir spaces for later hydrocarbon accumulation,and different filling stages of grabens controlled different reservoir-forming factors in grabens.（2） Two stages of tectonic inversion occurred in the Late Jurassic and Late Cretaceous and played a crucial role in the final shape of the structure in the South Turgay Basin.The oil and gas migrated to form reservoirs and mainly concentrated in the horsts,graben slopes and in both sides of the strike-slip fault zone.In the case of the degree of accumulation of petroleum,the factor explaining why horsts are better than grabens is the strike-slip pull-apart of the South Turgay Basin,and the structure inversion of the South Turgay Basin explains why the west graben is better than the east one.Overall,the Karatau strike-slip fault played a very important role in the formation of the South Turgay Basin and its hydrocarbon accumulations.展开更多
Because of its rich oil and gas resources and the special tectonic location of the Liaohe Western Sag （the Tanlu Fault traverses the sag）, Bohai Bay Basin, a detailed study of its strike-slip tectonics is significan...Because of its rich oil and gas resources and the special tectonic location of the Liaohe Western Sag （the Tanlu Fault traverses the sag）, Bohai Bay Basin, a detailed study of its strike-slip tectonics is significant in revealing the sag＇s tectonic evolution, its control on hydrocarbon accumulation, and the activity history of the northern section of the Tanlu Fault in the Cenozoic. Through systematic structure analysis of 3D seismic data of the Liaohe Western Sag, combined with balanced section analysis, a variety of structural features in relation to right-lateral strike-slip faults, such as echelon normal faults, ＂comb＂ structure, ＂flower＂ structure,＂interpretable＂ and ＂buried＂ strike-slip faults have been revealed exist in the Liaohe Western Sag. According to the research in this paper, the complex structural phenomena in the Liaohe Western Sag could be reasonably interpreted as right-lateral strike-slip activity and the strike-slip activities of the Liaohe Western Sag began in the early Oligocene. The activity was weak at the beginning （E3s1-2）, then strengthened gradually and reached its strongest level in the late Oligocene （E3d1）. In the Miocene, the strike-slip activity was low and then strengthened significantly once again from the Pliocene to the present. It is speculated that the entire northern section of the Tanlu Fault has had a similar evolution history since the Oligocene.展开更多
We present in this paper some new evidence for the change during the Quaternary in kinematics of faults cutting the eastern margin of the Tibetan Plateau. It shows that significant shortening deformation occurred duri...We present in this paper some new evidence for the change during the Quaternary in kinematics of faults cutting the eastern margin of the Tibetan Plateau. It shows that significant shortening deformation occurred during the Early Pleistocene, evidenced by eastward thrusting of Mesozoic carbonates on the Pliocene lacustrine deposits along the Minjiang upstream fault zone and by development of the transpressional ridges of basement rocks along the Anninghe river valley. The Middle Pleistocene seems to be a relaxant stage with local development of the intra-mountain basins particularly prominent along the Minjiang Upstream and along the southern segment of the Anninghe River Valley. This relaxation may have been duo to a local collapse of the thickened crust attained during the late Neogene to early Pleistocene across this marginal zone. Fault kinematics has been changed since the late Pleistocene, and was predominated by reverse sinistral strike-slip along the Minshan Uplift, reverse dextral strike-slip on the Longmenshan fault zone and pure sinistral strike-slip on the Anninghe fault. This change in fault kinematics during the Quaternary allows a better understanding of the mechanism by which the marginal ranges of the plateau has been built through episodic activities.展开更多
Through fault structure analysis and chronology study, we discuss the origin and growth mechanisms of strike-slip faults in the Tarim Basin.(1) Multiple stages strike-slip faults with inherited growth were developed i...Through fault structure analysis and chronology study, we discuss the origin and growth mechanisms of strike-slip faults in the Tarim Basin.(1) Multiple stages strike-slip faults with inherited growth were developed in the central Tarim cratonic basin. The faults initiation time is constrained at the end of Middle Ordovician of about 460 Ma according to U-Pb dating of the fault cements and seismic interpretation.(2) The formation of the strike-slip faults was controlled by the near N-S direction stress field caused by far-field compression of the closing of the Proto-Tethys Ocean.(3) The faults localization and characteristics were influenced by the pre-existing structures of the NE trending weakening zones in the basement and lithofacies change from south to north.(4) Following the fault initiation under the Andersonian mechanism, the strike-slip fault growth was dominantly fault linkage, associated with fault tip propagation and interaction of non-Andersonian mechanisms.(5) Sequential slip accommodated deformation in the conjugate strike-slip fault interaction zones, strong localization of the main displacement and deformation occurred in the overlap zones in the northern Tarim, while the fault tips, particularly of narrow-deep grabens, and strike-slip segments in thrust zones accumulated more deformation and strain in the Central uplift. In conclusion, non-Andersonian mechanisms, dominantly fault linkage and interaction, resulted in the small displacement but long intraplate strike-slip fault development in the central Tarim Basin. The regional and localized field stress, and pre-existing structures and lithofacies difference had strong impacts on the diversity of the strike-slip faults in the Tarim cratonic basin.展开更多
The characteristics of the Bolokenu-Aqikekuduk（Bo-A） fault,a right-lateral strike-slip fault that runs for more than 700 km long and obliquely cuts North Tianshan Mountains,are evaluated here based on remote sensing...The characteristics of the Bolokenu-Aqikekuduk（Bo-A） fault,a right-lateral strike-slip fault that runs for more than 700 km long and obliquely cuts North Tianshan Mountains,are evaluated here based on remote sensing data,and through an analysis of the results from field investigations as well as climate-geomorphic events. The fault is composed of a western segment with a NW strike and an eastern segment with a NWW strike.The western segment is nearly 250 km long,extending northwestward into Kazakhstan with a right-lateral strike-slip rate of 5 mm/a.This domain consists of 4-5 rupture sections,with 3-4 deformation belts,caused by ancient or historical earthquakes,and suggesting the potential for the occurrence of further strong earthquakes（with M≈7.5） in future. The eastern segment of the fault shows a right-lateral strike-slip rate of 1-1.4 mm/a,with the development of 3-4 deformation belts caused by ancient or historical earthquakes,and with a potential for future strong earthquake with M≈7.0. A typical strain partitioning style in the compression area has developed between the intermontane BoA fault and the piedmont thrust structures of Northern Tianshan Mountains,under the effect of oblique compression,as indicated by the piedmont thrust structure and the strike-slip fault in the mountains.展开更多
Vertical differential structural deformation(VDSD),one of the most significant structural characteristics of strike-slip fault zones(SSFZs)in the Shunbei area,is crucial for understanding deformation in the SSFZ and i...Vertical differential structural deformation(VDSD),one of the most significant structural characteristics of strike-slip fault zones(SSFZs)in the Shunbei area,is crucial for understanding deformation in the SSFZ and its hydrocarbon accumulation significance.Based on drilling data and high-precision 3-D seismic data,we analyzed the geometric and kinematic characteristics of the SSFZs in the Shunbei area.Coupled with the stratification of the rock mechanism,the structural deformations of these SSFZs in different formations were differentiated and divided into four deformation layers.According to comprehensive structural interpretations and comparisons,three integrated 3-D structural models could describe the VDSD of these SSFZs.The time-space coupling of the material basis(rock mechanism stratification),changing dynamic conditions(e.g.,changing stress-strain states),and special deformation mechanism of the en echelon normal fault array uniformly controlled the formation of the VDSD in the SSFZs of the Shunbei area.The VDSD of the SSFZs in this area controlled the entire hydrocarbon accumulation process.Multi-stage structural superimposing deformation influenced the hydrocarbon migration,accumulation,distribution,preservation,and secondary adjustments.展开更多
Fault attributes generally display a consistent power–law-scaling relationship.Based on new 3 D seismic data,however,we found some exceptional fault attribute relationships of lengths(L)–throw(T)(vertical component ...Fault attributes generally display a consistent power–law-scaling relationship.Based on new 3 D seismic data,however,we found some exceptional fault attribute relationships of lengths(L)–throw(T)(vertical component of displacement),overlap zone length(Lo)–width(Wo)from a strike-slip fault system of the Ordovician carbonates in the Tarim Basin.The L–T relationship shows two linear segments with breakup at^40 km in fault length.This presents an exceptional throw increase in the second stage,which is attributed to a localization of vertical displacement and deformation in overlapping zones other than the different fault scales in a mature fault zone.The Lo–Wo relationship in the overlapping zones shows multiply stepped-shape patterns,suggesting multiple fault differential growth and periodic increase in fault size.Therefore,we propose a new alternative growth model of fault attributes in strike-slip fault zones,in which the overlapping zones accumulated localized displacement and deformation in the intracratonic strike-slip fault zone.展开更多
Based on 3D seismic and drilling data, the timing, evolution and genetic mechanism of deep strike-slip faults in the central Sichuan Basin are thoroughly examined by using the U-Pb dating of fault-filled carbonate cem...Based on 3D seismic and drilling data, the timing, evolution and genetic mechanism of deep strike-slip faults in the central Sichuan Basin are thoroughly examined by using the U-Pb dating of fault-filled carbonate cement and seismic-geological analysis. The strike-slip fault system was initially formed in the Late Sinian, basically finalized in the Early Cambrian with dextral transtensional structure, was overlaid with at least one stage of transpressional deformation before the Permian, then was reversed into a sinistral weak transtensional structure in the Late Permian. Only a few of these faults were selectively activated in the Indosinian and later periods. The strike-slip fault system was affected by the preexisting structures such as Nanhuanian rifting normal faults and NW-striking deep basement faults. It is an oblique accommodated intracratonic transfer fault system developed from the Late Sinian to Early Cambrian to adjust the uneven extension of the Anyue trough from north to south and matches the Anyue trough in evolution time and intensity. In the later stage, multiple inversion tectonics and selective activation occurred under different tectonic backgrounds.展开更多
Existing analytical methods of buried steel pipelines subjected to active strike-slip faults depended on a number of simplifications.To study the failure mechanism more accurately,a refined strain analytical methodolo...Existing analytical methods of buried steel pipelines subjected to active strike-slip faults depended on a number of simplifications.To study the failure mechanism more accurately,a refined strain analytical methodology was proposed,taking the nonlinear characteristics of soil-pipeline interaction and pipe steel into account.Based on the elastic-beam and beam-on-elastic-foundation theories,the position of pipe potential destruction and the strain and deformation distributions along the pipeline were derived.Compared with existing analytical methods and three-dimensional nonlinear finite element analysis,the maximum axial total strains of pipe from the analytical methodology presented are in good agreement with the finite element results at small and intermediate fault movements and become gradually more conservative at large fault displacements.The position of pipe potential failure and the deformation distribution along the pipeline are fairly consistent with the finite element results.展开更多
Based on the 3 D seismic structure interpretation of Bohai Sea, combined with physical modeling of structure, structural style analysis and apatite fission track simulation, the structural characteristics and genetic ...Based on the 3 D seismic structure interpretation of Bohai Sea, combined with physical modeling of structure, structural style analysis and apatite fission track simulation, the structural characteristics and genetic mechanism of the Cenozoic strike-slip faults in Bohai Sea were investigated. The results show that Tanlu strike-slip fault experienced three stages of strike-slip activities in the Cenozoic,and the transition from left-lateral strike to right-lateral strike-slip was completed at the end of the fourth member of the Shahejie Formation. The strike-slip faults in the Bohai Sea have the characteristics of multi-stage and multi-strength stress superposition. According to the superimposed forms of different strengths, different properties and different ratios, they can be divided into three major genetic types,extension and strike-slip superimposition, extension and extrusion superimposition, extrusion and strike-slip superimposition, and fifteen typical structure patterns. Affected by multiple changes in the direction and rate of subduction of the Cenozoic Pacific plate, the difference between the Cenozoic extension and the strike-slip in the Bohai Sea area leads to the diversity of the fault system and the zoning of the depression structure. According to superimposition features of faults, the Bohai Sea area can be divided into the Liaoxi S-type weak strike-slip zone, Liaodong braided strong strike-slip zone, Boxi conjugated medium strike-slip zone, Bodong brush structure medium strike-slip zone and Bonan parallel strong strike-slip zone. These zones differ in oil and gas accumulation features.展开更多
基金supported by the National Natural Science Foundation of China(No.U21B2062).
文摘The isolated fracture-vug systems controlled by small-scale strike-slip faults within ultra-deep carbonate rocks of the Tarim Basin exhibit significant exploration potential.The study employs a novel training set incorporating innovative fault labels to train a U-Net-structured CNN model,enabling effective identification of small-scale strike-slip faults through seismic data interpretation.Based on the CNN faults,we analyze the distribution patterns of small-scale strike-slip faults.The small-scale strike-slip faults can be categorized into NNW-trending and NE-trending groups with strike lengths ranging 200–5000 m.The development intensity of small-scale strike-slip faults in the Lower Yingshan Member notably exceeds that in the Upper Member.The Lower and Upper Yingshan members are two distinct mechanical layers with contrasting brittleness characteristics,separated by a low-brittleness layer.The superior brittleness of the Lower Yingshan Member enhances the development intensity of small-scale strike-slip faults compared to the upper member,while the low-brittleness layer exerts restrictive effects on vertical fault propagation.Fracture-vug systems formed by interactions of two or more small-scale strike-slip faults demonstrate larger sizes than those controlled by individual faults.All fracture-vug system sizes show positive correlations with the vertical extents of associated small-scale strike-slip faults,particularly intersection and approaching fracture-vug systems exhibit accelerated size increases proportional to the vertical extents.
基金supported by the National Natural Science Foundation of China(No.U21B2062)funding from the Chinese Scholarship Council(CSC)and the American Association of Petroleum Geologists Foundation Grantsin-Aid Program.
文摘Natural fractures controlled by faults in ultradeep carbonate strata play substantial roles as both fluid migration channels and storage spaces.However,characterizing the heterogeneous distribution of underground fractures within the complex three-dimensional geometry of strike-slip fault zones remains challenging.This study investigates the characteristics of natural fractures controlled by strike-slip faults in the fractured Middle and Lower Ordovician reservoirs of the central and northern Tarim Basin,China.Seismics,cores,and image logs were integrated to quantitatively analyze the intensity and dip angle of natural fractures and findings were verified using published sandbox simulations.The carbonate reservoir contains three main types of natural fractures:tectonic fractures,abnormal high-pressure-related fractures,and stylolites.Strike-slip faults control the distribution and characteristics of tectonic fractures across various scales.Generally,both fracture intensity and porosity exhibit a decreasing trend as the distance from the main fault surface increases.Compared with those in non-stepover zones along a strike-slip fault,natural fractures and faults in stepover zones are more developed along the fault strike,with significantly greater development intensity in central stepover regions than that at its two ends.Furthermore,strike-slip faults influence the dip angles of both natural fractures and secondary faults.The proportion of medium-to-low-dip angle fractures and faults in the stepover zone is greater than that in the non-stepover zone.Additionally,the proportion of medium-to low-dip angle fractures and faults in the middle of the stepover is greater than that at both ends.Therefore,strike-slip fault structures control the dip angle of natural fracture and the heterogeneity of secondary fault and fracture intensity.The linking damage zone in the stepover contains a larger volume of fractured rocks,making it a promising petroleum exploration target.The development of stepovers and the orientation of present-day in-situ stress substantially influence the productivity of fractured reservoirs controlled by strike-slip faults.The analysis in this study reveals that reservoir productivity increases as the angle between the strike-slip fault segment and the maximum horizontal principal stress decreases.This study provides valuable insights for quantitatively evaluating fracture heterogeneity in fractured reservoirs and establishing optimized selection criteria for favorable targets in fault-related fractured reservoirs.
基金supported by the National Natural Science Foundation of China(Grant No.U21B2062).
文摘Recent exploration has highlighted the critical role of strike-slip faults in shaping ultra-deep carbonate reservoirs in the Tarim Basin.This study integrates satellite imagery,UAV photogrammetry,outcrop surveys and microscopic analysis to investigate the architecture of these faults and their impact on reservoir petrophysical properties.The strike-slip faults exhibit cores consisting of calcite bands,fault breccias and fractures,while the damage zones are predominantly fractured.Thicker fault cores and fault zones are associated with more extensive reservoir development.Individual strike-slip fault zones are primarily characterized by two sets of fractures intersecting the fault at small angles.When two fault systems interact,the dominant pattern is two sets of fractures intersecting the main fault at small angles and one set at larger angles,facilitating the formation of large-scale reservoirs.We propose a model for the fault core,which primarily consists of a calcite band and fault breccias.These breccias are composed of original host rock,calcite cement and quartz,which exhibit poor physical properties,while fractures and vugs show favorable reservoir characteristics.This model offers valuable insights into the development of fault-controlled reservoirs,particularly in the Tarim Basin.
基金supported by the National Natural Science Foundation of China(Grant Nos.52108361 and 41977252)the Sichuan Science and Technology Program of China(Grant Nos.2024ZYD0154 and 2024NSFSC0159)the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Independent Research Project(Grant Nos.SKLGP2022Z015 and SKLGP2020Z001).
文摘Fault container and shaking table tests are crucial for studying co-seismic dislocation in cross-fault tunnels,with the design and functionality of the container significantly affecting the accuracy of dynamic response analyses of tunnel linings.This research introduces a fault container developed as part of a significant active fault-crossing tunnel project in the high-intensity seismic zone of western China.The container is designed to simulate both strike-slip and dip-slip fault characteristics with adjustable fault angles.Extensive testing,including shaking table tests under strong seismic conditions,three-dimensional(3D)finite element numerical simulations,and hammer tests,were conducted to evaluate the modal characteristics of the container under various conditions.The study highlights the resonance characteristics of the soil-container system,the signal consistency across different dislocations,and the dynamic response patterns both with and without pulse-like seismic motions and varying intensities.The results indicate that the natural frequencies of the container and the model soil,determined through white noise scanning,are 23.74 Hz and 6.355 Hz,respectively,suggesting no resonance in the model soil-container structure.The dynamic response characteristics of the empty container show good integrity and versatility under various seismic excitations.The consistency of the free-field time history curve confirms that the newly developed fault container effectively simulates the continuity and boundary conditions of the free-field.Time domain analysis conducted before and after fault dislocation demonstrates the capability of the container to accurately replicate the coupling effects of fault and seismic motions.
基金supported by the Natural Science Foundation of China-Youth Foundation(42402163)Natural Science Foundation of Sichuan Province of China(2024NSFSC0814)Science and Technology Cooperation Project of the CNPC-SWPU Innovation Alliance(2020CX010101).
文摘The strike-slip fault system in the central Tarim Craton controls a complex petroleum system with estimated reserves exceeding 1×10^(9)t,the fault-related fractures are important for hydrocarbon accumulation.In this paper,the basic parameters such as density and width of fractures are counted and classified,and the effects of fractures on reservoirs are analyzed.The results show that:(1)Structural fractures and stylolite were widely developed in Halahatang area and experienced at least three stages of activity based on the infilling materials and crosscutting relationship.(2)Fracture density,width,aperture,and dip angle vary in different wells,but the relationship between the above parameters and the distance to the fault core indicates the fracture differences in the fault damage zone and further provides a method to divide the inner units in the fault damage zone.In addition,oil and gas wells with high production mainly concentrate in the inner unit.(3)The infilling materials and degree of fractures vary.Fractures formed in the early stage are more filled and less open,while the fractures formed in the late stage are relatively less filled and more open.(4)Fractures improve porosity to a certain extent but greatly increase permeability,especially in the inner zone of fault damage zone with large quantity,multiple inclinations,less filling and large width.These features contribute to the formation of a higher-quality reservoir,further improving oil and gas production.This paper provides a quantitative characterization method for the study of strike-slip fault-related fracture-caved reservoirs,and points out that fault damage zone,especially the inner zone of the fault damage zone,is the potential goal for oil and gas exploration.
基金Supported by the National Natural Science Foundation of China(42362026)Key R&D Project of Xinjiang Uygur Autonomous Region(2024B01015).
文摘In the ultra-deep strata of the Tarim Basin,the vertical growth process of strike-slip faults remains unclear,and the vertical distribution of fractured-cavity carbonate reservoirs is complex.This paper investigates the vertical growth process of strike-slip faults through field outcrop observations in the Keping area,interpretation of seismic data from the Fuman Oilfield,Tarim Basim,NW China,and structural physical simulation experiments.The results are obtained mainly in four aspects.First,field outcrops and ultra-deep seismic profiles indicate a three-layer structure within the strike-slip fault,consisting of fault core,fracture zone and primary rock.The fault core can be classified into three parts vertically:fracture-cavity unit,fault clay and breccia zone.The distribution of fracture-cavity units demonstrates a distinct pattern of vertical stratification,owing to the structural characteristics and growth process of the slip-strike fault.Second,the ultra-deep seismic profiles show multiple fracture-cavity units in the strike-slip fault zone.These units can be classified into four types:top fractured,middle connected,deep terminated,and intra-layer fractured.Third,structural physical simulation experiments and ultra-deep seismic data interpretation reveal that the strike-slip faults have evolved vertically in three stages:segmental rupture,vertical growth,and connection and extension.The particle image velocimetry detection demonstrates that the initial fracture of the fault zone occurred at the top or bottom and then evolved into cavities gradually along with the fault growth,accompanied by the emergence of new fractures in the middle part of the strata,which subsequently connected with the deep and shallow cavities to form a complete fault zone.Fourth,the ultra-deep carbonate strata primarily develop three types of fractured-cavity reservoirs:flower-shaped fracture,large and deep fault and staggered overlap.The first two types are larger in size with better reservoir conditions,suggesting a significant exploration potential.
基金support from the National Natural Science Foundation of China(Grant Nos.52378411,52208404)China National Railway Group Limited Science and Technology Research and Development Program(Grant No.K2023G041).
文摘During strike-slip fault dislocation,multiple fault planes are commonly observed.The resulting permanent ground deformation can lead to profound structural damage to tunnels.However,existing analytical models do not consider multiple fault planes.Instead,they concentrate the entire fault displacement onto a single fault plane for analysis,thereby giving rise to notable errors in the calculated results.To address this issue,a refined nonlinear theoretical model was established to analyze the mechanical responses of the tunnels subjected to multiple strike-slip fault dislocations.The analytical model considers the number of fault planes,nonlinear soil‒tunnel interactions,geometric nonlinearity,and fault zone width,leading to a significant improvement in its range of applicability and calculation accuracy.The results of the analytical model are in agreement,both qualitatively and quantitatively,with the model test and numerical results.Then,based on the proposed theoretical model,a sensitivity analysis of parameters was conducted,focusing on the variables such as the number of fault planes,fault plane distance(d),fault displacement ratio(η),burial depth(C),crossing angle(β),tunnel diameter(D),fault zone width(Wf),and strike-slip fault displacement(Δfs).The results show that the peak shear force(Vmax),bending moment(Mmax),and axial force(Nmax)decrease with increasing d.The Vmax of the tunnel is found at the fault plane with the largest fault displacement.C,D,andΔfs contribute to the increases in Vmax,Mmax,and Nmax.Additionally,increasing the number of fault planes reduces Vmax and Mmax,whereas the variation in Nmax remains minimal.
文摘Abstract The nearly E-W-trending Aqqikkudug-Weiya zone, more than 1000 km long and about 30 km wide, is an important segment in the Central Asian tectonic framework. It is distributed along the northern margin of the Central Tianshan belt in Xinjiang, NW China and is composed of mylonitized Early Palaeozoic greywacke, volcanic rocks, ophiolitic blocks as a mélange complex, HP/LT-type bleuschist blocks and mylonitized Neoproterozoic schist, gneiss and orthogneiss. Nearly vertical mylonitic foliation and sub-horizontal stretching lineation define its strike-slip feature; various kinematic indicators, such as asymmetric folds, non-coaxial asymmetric macro- to micro-structures and C-axis fabrics of quartz grains of mylonites, suggest that it is a dextral strike-slip ductile shear zone oriented in a nearly E-W direction characterized by “flower” strusture with thrusting or extruding across the zone toward the two sides and upright folds with gently plunging hinges. The Aqqikkudug-Weiya zone experienced at least two stages of ductile shear tectonic evolution: Early Palaeozoic north vergent thrusting ductile shear and Late Carboniferous-Early Permian strike-slip deformation. The strike-slip ductile shear likely took place during Late Palaeozoic time, dated at 269±5 Ma by the40Ar/39Ar analysis on neo-muscovites. The strike-slip deformation was followed by the Hercynian violent S-type granitic magmatism. Geodynamical analysis suggests that the large-scale dextral strike-slip ductile shearing is likely the result of intracontinental adjustment deformation after the collision of the Siberian continental plate towards the northern margin of the Tarim continental plate during the Late Carboniferous. The Himalayan tectonism locally deformed the zone, marked by final uplift, brittle layer-slip and step-type thrust faults, transcurrent faults and E-W-elongated Mesozoic-Cenozoic basins.
基金partly supportedby National Natural Science Foundation of China(Grant No.41472103)
文摘Recent studies, focused on dihedral angles and intersection processes, have increased understandings of conjugate fault mechanisms. We present new 3-D seismic data and microstructural core analysis in a case study of a large conjugate strike-slip fault system from the intracratonic Tarim Basin, NW China. Within our study area, ＂X＂ type NE and NW trending faults occur within Cambrian- Ordovician carbonates. The dihedral angles of these conjugate faults have narrow ranges, 19~ to 62~ in the Cambrian and 26~ to 51~ in the Ordovician, and their modes are 42~ and 44~ respectively. These data are significantly different from the ~60~ predicted by the Coulomb fracture criterion. It is concluded that： （1） The dihedral angles of the conjugate faults were not controlled by confining pressure, which was low and associated with shallow burial; （2） As dihedral angles were not controlled by pressure they can be used to determine the shortening direction during faulting; （3） Sequential slip may have played an important role in forming conjugate fault intersections; （4） The conjugate fault system of the Tarim basin initiated as rhombic joints; these subsequently developed into sequentially active ＂X＂ type conjugate faults; followed by preferential development of the NW-trending faults; then reactivation of the NE trending faults. This intact rhombic conjugate fault system presents new insights into mechanisms of dihedral angle development, with particular relevance to intracratonic basins.
基金supported mainly by the National Key Basic Research Program(No.2004CB418401)the National Natural Science Foundation of China(grant No.40472109)+1 种基金partly from the Joint Earthquake Science Foundation of China(grant No.105066)the SASAKAWA Scientific Grant from the Japan Science Society.
文摘Recent studies on the Xianshuihe-Xiaojiang fault system suggest that the Late Quaternary strike-slip rate is approximately uniform along the entire length of the fault zone, about 15±2 mm/a. This approximately uniform strike slip rate strongly supports the clockwise rotation model of the southeastern Tibetan crust. By approximating the geometry of the arc-shaped Xianshuihe-Xiaojiang fault system as a portion of a small circle on a spherical Earth, the 15±2 mm/a strike slip rate corresponds to clockwise rotation of the Southeastern Tibetan Block at the （5.2±0.7）×10^-7 deg/a angular velocity around the pole （21°N, 88°E） relative to the Northeast Tibetan Block. The approximately uniform strike slip rate along the Xianshuihe-Xiaojiang fault system also implies that the Longmeushan thrust zone is not active, or at least its activity has been very weak since the Late Quaternary. Moreover, the total offset along the Xiaushuihe-Xiaojiang fault system suggests that the lateral extrusion of the Southeastern Tibetan Block relative to Northeastern Tibetan Block is about 160 km and 200-240 km relative to the Tarim-North China block. This amount of lateral extrusion of the Tibetan crust should have accommodated about 13-24% convergence between India and Eurasia based on mass balance calculations. Assuming that the slip rate of 15±2 mm/a is constant throughout the entire history of the Xianshuihe-Xiaojiang fault system, 11±1.5 Ma is needed for the Xianshuihe-Xiaojiang fault system to attain the 160 km of total offset. This implies that left-slip faulting on the Xianshuihe-Xiaojiang fault system might start at 11±1.5 Ma.
基金supported by the Major National Science and Technology Projects of China (No. 2008ZX05029-002)CNPC Research Topics of China (No.07B60101)
文摘The Karatau fault is one of the important strike-slip faults in central Asia,and the South Turgay Basin is located towards its northern end.Detailed seismic interpretation indicated that the strikeslip tectonism of the Karatau fault weakened gradually from west to east in the South Turgay Basin.Typical flower structures developed on the section,and strike-slip faults showed an echelon pattern on planar view.The Karatau strike-slip fault affected the South Turgay Basin in two periods：（1） The South Turgay strike-slip pull-apart rift basin formed as a result of regional extensive stress in the Early-Middle Jurassic,characterized by the juxtaposition of horsts and grabens.The formation of horsts provided favorable reservoir spaces for later hydrocarbon accumulation,and different filling stages of grabens controlled different reservoir-forming factors in grabens.（2） Two stages of tectonic inversion occurred in the Late Jurassic and Late Cretaceous and played a crucial role in the final shape of the structure in the South Turgay Basin.The oil and gas migrated to form reservoirs and mainly concentrated in the horsts,graben slopes and in both sides of the strike-slip fault zone.In the case of the degree of accumulation of petroleum,the factor explaining why horsts are better than grabens is the strike-slip pull-apart of the South Turgay Basin,and the structure inversion of the South Turgay Basin explains why the west graben is better than the east one.Overall,the Karatau strike-slip fault played a very important role in the formation of the South Turgay Basin and its hydrocarbon accumulations.
基金National Natural Science Foundation (40772086)Common advanced projects of CNPC oil and gas exploration (07-01C-01-04)
文摘Because of its rich oil and gas resources and the special tectonic location of the Liaohe Western Sag （the Tanlu Fault traverses the sag）, Bohai Bay Basin, a detailed study of its strike-slip tectonics is significant in revealing the sag＇s tectonic evolution, its control on hydrocarbon accumulation, and the activity history of the northern section of the Tanlu Fault in the Cenozoic. Through systematic structure analysis of 3D seismic data of the Liaohe Western Sag, combined with balanced section analysis, a variety of structural features in relation to right-lateral strike-slip faults, such as echelon normal faults, ＂comb＂ structure, ＂flower＂ structure,＂interpretable＂ and ＂buried＂ strike-slip faults have been revealed exist in the Liaohe Western Sag. According to the research in this paper, the complex structural phenomena in the Liaohe Western Sag could be reasonably interpreted as right-lateral strike-slip activity and the strike-slip activities of the Liaohe Western Sag began in the early Oligocene. The activity was weak at the beginning （E3s1-2）, then strengthened gradually and reached its strongest level in the late Oligocene （E3d1）. In the Miocene, the strike-slip activity was low and then strengthened significantly once again from the Pliocene to the present. It is speculated that the entire northern section of the Tanlu Fault has had a similar evolution history since the Oligocene.
基金supported jointly by the China Geological Survey project(grant number:1212011120167,12120114002201)China National Natural Science Foundation(grant number 41472178)
文摘We present in this paper some new evidence for the change during the Quaternary in kinematics of faults cutting the eastern margin of the Tibetan Plateau. It shows that significant shortening deformation occurred during the Early Pleistocene, evidenced by eastward thrusting of Mesozoic carbonates on the Pliocene lacustrine deposits along the Minjiang upstream fault zone and by development of the transpressional ridges of basement rocks along the Anninghe river valley. The Middle Pleistocene seems to be a relaxant stage with local development of the intra-mountain basins particularly prominent along the Minjiang Upstream and along the southern segment of the Anninghe River Valley. This relaxation may have been duo to a local collapse of the thickened crust attained during the late Neogene to early Pleistocene across this marginal zone. Fault kinematics has been changed since the late Pleistocene, and was predominated by reverse sinistral strike-slip along the Minshan Uplift, reverse dextral strike-slip on the Longmenshan fault zone and pure sinistral strike-slip on the Anninghe fault. This change in fault kinematics during the Quaternary allows a better understanding of the mechanism by which the marginal ranges of the plateau has been built through episodic activities.
基金Supported by the National Natural Science Foundation of China(91955204)PetroChina-Southwest Petroleum University Innovation Consortium Science and Technology Cooperation Project(2020CX010101)。
文摘Through fault structure analysis and chronology study, we discuss the origin and growth mechanisms of strike-slip faults in the Tarim Basin.(1) Multiple stages strike-slip faults with inherited growth were developed in the central Tarim cratonic basin. The faults initiation time is constrained at the end of Middle Ordovician of about 460 Ma according to U-Pb dating of the fault cements and seismic interpretation.(2) The formation of the strike-slip faults was controlled by the near N-S direction stress field caused by far-field compression of the closing of the Proto-Tethys Ocean.(3) The faults localization and characteristics were influenced by the pre-existing structures of the NE trending weakening zones in the basement and lithofacies change from south to north.(4) Following the fault initiation under the Andersonian mechanism, the strike-slip fault growth was dominantly fault linkage, associated with fault tip propagation and interaction of non-Andersonian mechanisms.(5) Sequential slip accommodated deformation in the conjugate strike-slip fault interaction zones, strong localization of the main displacement and deformation occurred in the overlap zones in the northern Tarim, while the fault tips, particularly of narrow-deep grabens, and strike-slip segments in thrust zones accumulated more deformation and strain in the Central uplift. In conclusion, non-Andersonian mechanisms, dominantly fault linkage and interaction, resulted in the small displacement but long intraplate strike-slip fault development in the central Tarim Basin. The regional and localized field stress, and pre-existing structures and lithofacies difference had strong impacts on the diversity of the strike-slip faults in the Tarim cratonic basin.
基金the National 973 Plan"The mechanism of Wenchuan earthquake and regional geodynamics of large area"(Project No.2008CB425703)
文摘The characteristics of the Bolokenu-Aqikekuduk（Bo-A） fault,a right-lateral strike-slip fault that runs for more than 700 km long and obliquely cuts North Tianshan Mountains,are evaluated here based on remote sensing data,and through an analysis of the results from field investigations as well as climate-geomorphic events. The fault is composed of a western segment with a NW strike and an eastern segment with a NWW strike.The western segment is nearly 250 km long,extending northwestward into Kazakhstan with a right-lateral strike-slip rate of 5 mm/a.This domain consists of 4-5 rupture sections,with 3-4 deformation belts,caused by ancient or historical earthquakes,and suggesting the potential for the occurrence of further strong earthquakes（with M≈7.5） in future. The eastern segment of the fault shows a right-lateral strike-slip rate of 1-1.4 mm/a,with the development of 3-4 deformation belts caused by ancient or historical earthquakes,and with a potential for future strong earthquake with M≈7.0. A typical strain partitioning style in the compression area has developed between the intermontane BoA fault and the piedmont thrust structures of Northern Tianshan Mountains,under the effect of oblique compression,as indicated by the piedmont thrust structure and the strike-slip fault in the mountains.
基金financially supported by the China Petroleum&Chemical Corporation(SINOPEC)(Grant No.P18047-2)the National Natural Science Foundation of China(Grant No.U19B6003-01)the National Key Research and Development Program of China(Grant No.2017YFC0601405)。
文摘Vertical differential structural deformation(VDSD),one of the most significant structural characteristics of strike-slip fault zones(SSFZs)in the Shunbei area,is crucial for understanding deformation in the SSFZ and its hydrocarbon accumulation significance.Based on drilling data and high-precision 3-D seismic data,we analyzed the geometric and kinematic characteristics of the SSFZs in the Shunbei area.Coupled with the stratification of the rock mechanism,the structural deformations of these SSFZs in different formations were differentiated and divided into four deformation layers.According to comprehensive structural interpretations and comparisons,three integrated 3-D structural models could describe the VDSD of these SSFZs.The time-space coupling of the material basis(rock mechanism stratification),changing dynamic conditions(e.g.,changing stress-strain states),and special deformation mechanism of the en echelon normal fault array uniformly controlled the formation of the VDSD in the SSFZs of the Shunbei area.The VDSD of the SSFZs in this area controlled the entire hydrocarbon accumulation process.Multi-stage structural superimposing deformation influenced the hydrocarbon migration,accumulation,distribution,preservation,and secondary adjustments.
基金partly supported by the National Natural Science Foundation of China(Grant No.91955204)Science and Technology Cooperation Project of the CNPC-SWPU Innovation Alliance(Grant No.2020CX010300)。
文摘Fault attributes generally display a consistent power–law-scaling relationship.Based on new 3 D seismic data,however,we found some exceptional fault attribute relationships of lengths(L)–throw(T)(vertical component of displacement),overlap zone length(Lo)–width(Wo)from a strike-slip fault system of the Ordovician carbonates in the Tarim Basin.The L–T relationship shows two linear segments with breakup at^40 km in fault length.This presents an exceptional throw increase in the second stage,which is attributed to a localization of vertical displacement and deformation in overlapping zones other than the different fault scales in a mature fault zone.The Lo–Wo relationship in the overlapping zones shows multiply stepped-shape patterns,suggesting multiple fault differential growth and periodic increase in fault size.Therefore,we propose a new alternative growth model of fault attributes in strike-slip fault zones,in which the overlapping zones accumulated localized displacement and deformation in the intracratonic strike-slip fault zone.
基金Supported by the Science and Technology Cooperation Project of CNPC-SWPU Innovation Alliance (2020CX010101)National Natural Science Foundation of China (91955204)。
文摘Based on 3D seismic and drilling data, the timing, evolution and genetic mechanism of deep strike-slip faults in the central Sichuan Basin are thoroughly examined by using the U-Pb dating of fault-filled carbonate cement and seismic-geological analysis. The strike-slip fault system was initially formed in the Late Sinian, basically finalized in the Early Cambrian with dextral transtensional structure, was overlaid with at least one stage of transpressional deformation before the Permian, then was reversed into a sinistral weak transtensional structure in the Late Permian. Only a few of these faults were selectively activated in the Indosinian and later periods. The strike-slip fault system was affected by the preexisting structures such as Nanhuanian rifting normal faults and NW-striking deep basement faults. It is an oblique accommodated intracratonic transfer fault system developed from the Late Sinian to Early Cambrian to adjust the uneven extension of the Anyue trough from north to south and matches the Anyue trough in evolution time and intensity. In the later stage, multiple inversion tectonics and selective activation occurred under different tectonic backgrounds.
基金Project(50439010) supported by the National Natural Science Foundation of ChinaProject(DUT10ZD201) supported by the Fundamental Research Funds for the Central Universities in China
文摘Existing analytical methods of buried steel pipelines subjected to active strike-slip faults depended on a number of simplifications.To study the failure mechanism more accurately,a refined strain analytical methodology was proposed,taking the nonlinear characteristics of soil-pipeline interaction and pipe steel into account.Based on the elastic-beam and beam-on-elastic-foundation theories,the position of pipe potential destruction and the strain and deformation distributions along the pipeline were derived.Compared with existing analytical methods and three-dimensional nonlinear finite element analysis,the maximum axial total strains of pipe from the analytical methodology presented are in good agreement with the finite element results at small and intermediate fault movements and become gradually more conservative at large fault displacements.The position of pipe potential failure and the deformation distribution along the pipeline are fairly consistent with the finite element results.
基金Supported by the China National Science and Technology Major Project(2016ZX05024-002,2016ZX05024-003)
文摘Based on the 3 D seismic structure interpretation of Bohai Sea, combined with physical modeling of structure, structural style analysis and apatite fission track simulation, the structural characteristics and genetic mechanism of the Cenozoic strike-slip faults in Bohai Sea were investigated. The results show that Tanlu strike-slip fault experienced three stages of strike-slip activities in the Cenozoic,and the transition from left-lateral strike to right-lateral strike-slip was completed at the end of the fourth member of the Shahejie Formation. The strike-slip faults in the Bohai Sea have the characteristics of multi-stage and multi-strength stress superposition. According to the superimposed forms of different strengths, different properties and different ratios, they can be divided into three major genetic types,extension and strike-slip superimposition, extension and extrusion superimposition, extrusion and strike-slip superimposition, and fifteen typical structure patterns. Affected by multiple changes in the direction and rate of subduction of the Cenozoic Pacific plate, the difference between the Cenozoic extension and the strike-slip in the Bohai Sea area leads to the diversity of the fault system and the zoning of the depression structure. According to superimposition features of faults, the Bohai Sea area can be divided into the Liaoxi S-type weak strike-slip zone, Liaodong braided strong strike-slip zone, Boxi conjugated medium strike-slip zone, Bodong brush structure medium strike-slip zone and Bonan parallel strong strike-slip zone. These zones differ in oil and gas accumulation features.
