Four periods of structural stress fields can be recognized during Early Creraceous in Lingshan Island and adjacent areas based on field geological investigation and summary of the previous data, which is derived from the occurrence data of the stress response structures, i.e., X-type shear jointing, dykes and folds. They are the tectonic stress period of extension in the direction of NW formed the offshore basins during the Laiyang stage, followed extrusion in the direction of NW in the late Laiyang stage, during the Qingshan stage further extension in the direction of NW turned the offshore basins into rift basins, and followed basin inversion in the direction of NW in the late Early Cretaceous. It is concluded that the two extensional phases in Early Cretaceous were dynamically associated with either gravity collapse or lithospheric delamination of the thicked crust or lithosphere in North China and the NW-SE extrusion records the effect by the transmission of the NW-directed subduction of Izanaqi plate to the NW-directed subduction of paleo Pacific plate towards the bottom of the Asian continent.

In order to study the distribution of fractures controlled by layer curvature, fold and fault-related folds in East Kuqa, including one anticline (Biyoulebaoguzi Anticline profile), one fault-bent fold (Kezilenuergou Faultbent Fold profile) and one drag fold (Yangxia Coal-mine Drag-fold profile), are selected as investigating profile, and density of their structural factures and the layer curvature of middle-lower Jurassic and Triassic are measured. The result shows that the layer curvature has an effect on the fracture density; structural fractures are easier to be developed in the layers with larger curvature compared with those with smaller one within the same stratum. Besides, there is a positive linear relationship between fracture density and layer curvature. The mechanics of layer curvature’s effect on structural fracture from angle of solid mechanics is discussed: fracture density is tightly related to stress distribution, and stress is proportional to curvature in bent beam model; hence, a positive linear relationship exists between the fracture density and layer curvature, which is applied to both elastic and plastic folds.

In order to study the distribution of fracture controlled by layer thickness and lithology, clastic rock of 6-7th Member, Yanchang Formation in Longdong area is selected as investigated subject, and the areal density of their structural fractures is meassured. Measured fracture densities show that the layer thickness of clastic sequence has an effect on fracture density. Compared with thicker layer, it is easier for thinner layer to develop structural fracture, which is related to the different stress concentration near fracture tip in different layer thickness. Within a certain thickness range, fracture density has an exponential relationship with layer thickness, while the fracture density remains mostly unchanged when thickness exceeds 250 cm. Under the condition of same layer thickness and different lithology, the value of fracture densities from small to large follow the order of medium sandstone, fine sandstone, siltstone and mudstone, which means that in the same tectonic setting and layer thickness, the smaller the size range is, the larger the fracture density will be. Besides, there is an exponential relationship
between fracture density and grain size, which may be caused by the different stress between grains of different size. By multivariate statistics and mechanism analysis, layer thickness is the key factor in controlling fractures’ development compared with lithology.

By the use of well logging data, the tectonic fracture porosity was calculated, the influence of tectonic fractures to Young’s modulus was quantitatively described with the theory that the development of tectonic fractures would decrease the value of Young’s modulus, and the “Fracture Evaluation Indicator ( f )” was first proposed to evaluate the levels of tectonic fracture development. The development evaluation of Ahe low porosity and low permeability sandstone fractures was carried out with the fracture evaluation indicator, and the evaluating results showed that the Well Yinan-2 areas and the glutenite with mudstone segment of Ahe formation are the most tectonic fracture developed places in the horizontal and vertical plane of Yinan-Tuzi areas respectively.

Combining the core observation and related logging data of the drillings in Sinian-Cambrain stratum, the dolomite reservoir section fractures were studied. It shows that fractures have a connected effect on native holes and some secondary holes, and plays a certain role in the transformation of the dolomite reservoir. After studying the relation between the fracture efficiency and fracture opening degree or fracture dip angle in four blocks of the Tarim Basin, Tazhong Area,Yaha Area, Yingmaili Area, and Bachu area, it is concluded that dolomite fractures which have narrower opening degree and higher angle have a higher effectiveness, and such kind of fractures play an important role in the transformation of dolomite reservoir.

Based on the geological setting of Muglad Basin during the Early Cretaceous, using linear elastic theory with two dimensional finite element modeling, through the analysis of the stress field, the result of stress field modeling offered a reliable evidence to the mechanics of Muglad Basin. The modeling results suggest that Muglad Basin is a passive rift basin that developed under the joint influence of strike slipping and tension force. This viewpoint reveals that strike-slipping and extensional process coexisted in African Continent during the Early Ceta- ceous. Muglad Basin is formed and developed under the joint influence rather than simply of the strike slipping.

Four sections of dolomite, grainstone, micritic limestone and granulir micritic limestone in Dawangou of Keping area are selected, and their structural fractures are statistically analyzed. The results of fracture density measurements show that the value of the fracture density from big to small is dolomite, grainstone, micritic limestone and granulir micritic limestone, which means in the same tectonic setting dolomite is easier to produce structural fracture. Also, the purer and the bigger granules the carbonate have, for example limestone, the more difficulty to produce structural fracture. The relationship between the structural fracture and the rock mechanics parameters is discussed.

Three periods of structural stress fields can be recognized since Permian in Junggar Basin and adjacent areas based on structural evolution analysis, that is the end of Permian, the end of Jurassic (or lasting to the end of K1) and Neogene. Their maximum principal stress orientation are respectively NWW-NW, near SN, and NNE, which are derived from the occurrence data of the stress-response structures, i. e. , dykes, joints, slickensides, folds and faults. Furthermore, the authors simulated the stress field since Neogene based on 2D finite-element method, to deeply analyze the following questions: distribution and direction of stresses in the whole basin; influence of the geometry model for the stress field; as well as the dynamics of structures related to stress field.

Hohhot region is the high intensity earthquake zone due to the growth of a number of active faults. The ultra-low frequency electromagnetic detection method is used to study active faults in the region, through high-precision processing of detecting data and precise image interpretation. By usingthe above technology, the location, the displacement, the nature and the activity of the main three faults are clarified to serve for the urban planning, earthquake disaster prevention and mitigation in Hohhot. The difference between the maximum and minimum displacement of Dahei River fault is 110m, which are 60 mof Xiaohei River fault and 64 mof Xinhua Square fault. These data show that the Dahei River fault is the most active fault at the end of Neogene period.

Mesoproterozoic mafic dyke swarms are extensively developed in the Western Shandong, the east of the North China Craton, which intruded the Early Precambrian crystal basement. The dorminant orientation of these mafic dykes is nearly N-S trending. The mafic dyke swarms in the Western Shandong belong to LREE enrichment magmatic rocks, and are formed in a continental rift environment according to petrology and geochemistry of these mafic dykes. The flow structures and geometry evidences of the dykes indicatethat the magma source of these dykes intruded the pre-existingtensional rupture . The dyke swarms in the Western Shandong intruded from North to South. Angles between the long axis orientations of magnetic fabric textures and the middle line of dykes suggest that the flow direction of these dykes is from North to South. Further it indicate that the dykes intruded fromNorth to South. These flow structures, geochemistry and magnetic fabric textures suggest that magma come from enriched mantle magma source beneath the Yanliao-Zhongtiao aulacogens based on space-time relationship between the mafic dyke swarms and Yanliao-Zhongtiao aulacogens.

The source of passive ultra-lowfrequency(ULF), the elimination of noise, and the interaction of ULF with underground substances are discused andtested. The zero magnetic field experiment shows that the ULFreceived by instrument comes from the emission of underground object. Because of the complexity of the source and exploration situation, it’s necessary for the received original ULF data to be filtered in order to get the clearer exploration curves which are less jammed. The exploration result of Tacan No.1 Well in Tarim Basin shows that the passive ULF technique can gain the deep geological information rapidly and accurately.

To predict the distribution of the favorable volcanic facies belts of Yingcheng Group in Xujiaweizi Depression, it's necessary to analyze the factors to control the reservoir capabilities of the volcanic rocks. Observation of cores and thin sections indicates that primary pores are the basic reservoir space of the volcanic rocks, while secondary pores have important influence. Through statistics of the pore types and comparison of the physical properties of the volcanic rocks, the authors find that the control factors of the volcanic reservoir capabilities are lithofacies, fractures, and dissolution by the acidic fluid. The formations that have been dissoluted under the unconformities on top of the volcanic edifices near the main faults will be the most important exploration targets.

The plane and profile geological models at the end of Neocene in the midwest of Tabei uplift are established on the basis of seismic data of oil field and tectonic analysis, and the numerical simulation results of tectonic stress field in the area are obtained using linear elastic finite element method. Modeling results indicate that N-S regional compressive stress dominates the stress field of the whole area at that time, as well as that all faults of Yaha, Luntai, Hongqi, Yingmai 7 are compresso-shear structures with sinistral strike slip, while Kalayuergun fault is right lateral, and Yangtake fault is pure compressive thrust. In the condition of regional compressive stress, local stress field is formed, and affected by the main faults, which controlles the generation of secondary structures. In the modeling results of profile stress field, the orientation of the major principal stress change from horizon to incline in the middle of the uplifting area and the vertical stress component becomes bigger, which is the main factor to control the development of the compressional and subtuberant structures.

Through the analysis of subsidence history in the north of western Ordos basin, as a result of the terranes northward accretion and the successive collision of the Baykala block in the Middle Triassic, the Qiangtang block in the Late Triassic, the Lhasa block in the Middle Jurassic, the Gangdese block in the Cretaceous and the subduction of Izanagi plate in Yanshanian period, the studied region became a intracontinental foreland basin from Late Triassic to Cretaceous. Because of the collision of the terranes, the episodic tectonic activity occurred in the orogenic belt, resulting in the episodic subsidence of the basin. Each compression and thrusting of orogenic belt led to the subsidence of the foreland basin and the sediment filling, directly controlling the filling sequences and sedimentary characteristics of the foreland basin.

Liaohe basin is a Cenozoic rift valley with numerous volcanic activities developed in East Depression. Based on the large amount of K-Ar geochronology, petrology and geochemistry data, the Cenozoic volcanic activities in this depression are divided into 4 periods, which are Fangshenpao, Shasan, Shayi and Dongying periods. The Shasan and Dongying periods are two summits of volcanic activities, with accurate isotopic age of 43~38Ma and 32~25Ma respectively. This paper provides an accurate isotopic chronology constraints for the study of Cenozoic tectonic evolution of Bohai basin and Eastern China.

Several analysis methods such as casting slice, scanning electron microscope, porosity and permeability data, mercury injection data and density of fissures are used to study the reservoir properties of volcanic rocks in Huang-Yu-Re area, the east sag of Liaohe basin. Volcanic rocks in this area are mainly composed of basalt, diabase, tuff and trachyte. The dominating type of volcanic reservoir space includes secondary solution pores and structural fissures. It is proved by the result of oil test that the combination of such three parameters as the density of fissures, porosity data and permeability data can be used to evaluate the quality of reservoirs in Huang-Yu-Re area more exactly, among which the density of fissures is the leading reference for the evaluation. The capability of the reservoir in Huang-Yu-Re area is highly improved by fissures which are mainly caused by the action of the fault. The definition of special type of reservoir, whose general property is not very good but the density of fissures is very high, is significant to the evaluation of reservoir of the whole area.

By the use of the previous information of M_L 6.5 earthquake in the west of Beijing in 1730 together with the data of drills, electromagnetism and gravity, the Qinglongqiao-Qiliqu and Shahe active faults are identified for the first time. Although at present all aspects of the earthquake are not fully known, the authors consider that the two active faults are responsible for the earthquake and the first one plays the leading role. The establishment of seismogenic faults and epicenter of the earthquake will benefit for the disaster mitigation and city construction of Beijing.

A rare kind of primary round columnar joints is developed in the basic dyke swarms in the western Shandong，which is made of the radial joints and the round columnar joints with same axis vertical to the strike of the dyke, arranged one by one along the strike of the dyke. The round columnar joints are one of the flow structures showing the horozontal emplacement of basic dyke swarms. The round columnar joints show that the basic dyke has rheological behaviour of the viscous shearing in magma emplacement. Usually the dip of the axis of round columnar joints vertical to the dyke boundary shows the dip of the dyke and the tilting of the block with the dyke. The round columnar joints show that the dyke swarms are in upper crust brittle tectonic setting, and the western Shandong block is brittle extensional in the Mesoproterozoic time.

Fractal theory and fractal geostatistics are introduced, and the fractal distribution of sand body in Yushulin oil field, Daqing, is simulated by the fractal interpolation program, based on the fractal geostatistics. The practical and feasible method modeling the nonlinear distribution of reservoir heterogeneity is proposed for the oil field development.

The central Bohai Sea is one of the thinest lithosphere in eastern China where strike-slip and extension faults are very intensive with intensive magmatic activity, including the volcanic rocks and intrusion, which show the conspicious high positive magnetic anomalies. The spatial distribution, shape and property of high magnetic anomalies in the central Bohai Sea are inversed by the magnetic tomography, based on the analysis of regional geology and seismic sections in the Bohai basin.

Jiyang depression is a field where nonhydrocarbon is rich.These resources have close relation with the activities of the volcanos. At the same time,the activities of volcanos have deep contact with the activities of the faults. The growth of the faults in Jiyang depression is great. By the research of the index number of the faults growth and the other researches, NW direction faults are the most ones in Mesozoic, NW and NE and approximately EW directions all exist in Cenozoic. The above reflects the whole geotectonic background that sinistral shearing stress field exists in Mesozoic, but dextral shearing stress field exists in Cenozoic.

The Mesoproterozoic mafic dyke swarms are extensively distributed in the central North China Craton(NCC), which are not deformed and metamorphic, emplacing the pre-existed fractures, so the dyke swarms become the conspicuous marks to reconstruct the Mesoproterozoic tectonic stress field of the central NCC. The mafic dykes in the northern block are transtensional while the dykes in the central and southern blocks are extensional. The Mesoproterozoic tectonic stress field could be simulated on the analysis of the distribution and mechanical origin of the Mesoproterozoic mafic dyke swarms in the central NCC. The simulation result shows that the mafic dyke swarms were formed in the extensional tectonic setting in the NCC in the Mesoproterozoic time, which are related to the extension of the Mesoproterozoic Yanliao-Zhongtiao aulacogens cross the central NCC.

Based on the analysis of distribution of upper Jurassic and lower Cretaceous strata and basin-controlled faults, Tanlu fault zone strike slip to develop the three NW-trending grabens from north to south western to Tanlu fault zone in late Jurassic and early Cretaceous, which are Bohai graben, Jiyang graben and Luxinan graben. Based on the analysis of regional geology, the basic tectonic pattern of Bohai basin is the Cenozoic basin pattern since early Paleogene. The outline, structure, deposit characteristics and heat flow distributions show that the basin is pull-apart basin in Cenozoic time. The tectonic evolution pattern can be reconstructed based on the analysis of Cenozoic strata, deposit thickness, location and activity of basin-controlled faults in the different depresses in Bohai basin. The characteristics of structure and depositment in this Mesozoic and Cenozoic time show that Bohai basin is a Mesozoic and Cenozoic composite basin.

On the basis of analysis and comparison between two drills, one in the center of Bohai Sea, another near the west shore of Bohai Sea, ultra-long electromagnetic wave remote sensing can be applied to forecast the interfaces between the different rocks, and help to choose the location of drill and drilling plan. The ultra-long electromagnetic remote sensing also can be applied to general investigation in the prospecting area and organizing the structural map on the basis of the profiles and plane. Based on the analysis of the ultra-long electromagnetic wave curves from Tanggu to Dalian, the geological body to effect the high gravity and magnetic anomalies could be a mafic intrusion. The magma activity provided the heat source to organic maturation in the center of Bohai Sea, so the center of Bohai Sea could be the prospection of deep gas in Bohai Sea.

The origin model of Bohai Bay basin is proposed on the basis of analyzing the boundary pattern, strike-slip and extensional structures, deposit and deep geology characteristic on the boundary and in the basin. Bohai Bay basin can be classified into three tectonic belts(or areas): two strike-slip tectonic belts on eastern boundary and western boundary and a central pull-apart extensional area. According to the analysis of Mesozoic and Cenozoic tectonic evolution, Bohai Bay basin is a strike-slip pull-apart basin formed in the Cenozoic Eocene epoch. The extensional structures developed in the central Bohai Bay basin are induced by strike slip. The eastern and western strike-slip tectonic belts are basic geological conditions to form the Cenozoic Bohai Bay strike-slip pull-apart basin.

The carbondioxide gas fields are a kind of high economic nonhydrocarbon ones. It is very important to research origin of carbondioxide gas fields in theory and practice on exploration and development and utilization. The carbondioxide gas fields in Jiyang basin are researched in detail on the analysis of origin, geological conditions and tectonic background in this paper. On the basis of gas ingredients and carbon isotopes, the carbondioxide gas in Jiyang basin is from mantlevolcanic magma. According to the locations of carbondioxide gas fields, volcanics and faults, the carbondioxide gas fields are closely relative to the Middle and Late Neozoic volcanoes. The NW Shicun fault is the regional transporting path of carbondioxide gas. NE and nearly EW faults control the local reservoir structures. The Tanlu fault zone to the east of Jiyang basin may be the source of mantle magma with carbondioxide gas on the basis of tectonic background.