On the basis of 110 wells with 1 100 meters drilling cores and 500 wells with 107 000 meters long sections of igneous rocks in the Eastern sag of Liaohe depression,lithology and lithofacies of the Cenozoic intermediate and mafic igneous rocks and reservoir control factors were studied by means of description, core slice identification, and reservoir physical property data analysis. Based on these data, 16 types of volcanic, intrusive rocks and volcanic sedimentary rocks were recognized.Basaltic lava and basaltic volcanoclastic rocks are thick and widely distributed(91.0%). The volcanic rocks are mainly divided into 6 lithofacies and 16 sub-facies,of which the effusive lithofacies accounts for about 63.0%. The reservoir space can be grouped into 4 types and 9 sub-types, and the secondary porosity and fractures are widely developed in the study area. Trachytic lava and trachytic volcanoclastic rocks, basaltic volcanoclastic rocks, extrusive dome facies, volcanic conduit facies,and explosive facies are the most favorable reservoirs. Three factors including lithology, lithofacies and faults are considered to be related to the porosity and permeability of igneous rocks reservoirs. Lithology determines the type and microscopic characteristics of reservoirs; lithofacies controls the development of primary pores and distribution of reservoirs; faults control the range of igneous rocks, position of vent lithofacies and proximal lithofacies, and effectiveness of reservoirs. The favorable areas for petroleum accumulation are near oil sources, superior lithology and lithofacies belts with high structures adjacent to faults.

The research on diagenetic evolution and generation of high quality reservoir is of great significance to medium-deep oil & gas exploration. A comprehensive analysis on casting thin section, scanning electron microscope, mud X-ray diffraction (XRD) (clay and total rock), inclusion, conventional logging, nuclear magnetic resonance (NMR) logging and burial history was conducted to find out diagenetic evolution, fracture features and function, generation of high quality reservoir and controlling factors of glutenite in the study area. The results indicated that:1) The generation of high quality reservoir was mainly due to regional dissolution and non-structural fracture development with low compaction, weak cementation and enhanced porosity. 2) Protogenetic and diagenetic fractures are developed in glutenite reservoir. Protogenetic fractures are important storage space, and fractures can improve pore structure and properties of reservoir significantly. 3) The source-sink process controlled the formation of protogenetic fractures. The shrinkage fractures were generated during uplift, which was promoted by combination of mud without K⁺ and inner-gravel fracture. The rock components, which is lack of ion like Ca²⁺,Mg²⁺,Fe²⁺,Fe³⁺, reduced cement extent, retained porosity.As a result, it became a low-porosity reservoir earlier than accumulation.

This study is aim to clarify the complex dolomitization of dolostone in the Lower Qiulitage Group. Through analysis, the authors believe that the seepage reflux dolomitization was promoted by the migration of high concentration brine in marginal zone during the early shallow burial environment, which formed the residual particle dolomite with phantom structure with the characteristics of negative carbon and oxygen isotopic values, lower content of trace element iron, manganese, strontium and barium. The second stage fluid was mainly residual high salinity formation water in pore, which enhanced the dolomite recrystallization under the burial compaction, and caused the crystalline structure widely developed with the characteristics of positive oxygen isotopic and negative carbon isotopic values, high content of manganese and lower content of iron, lower content of strontium and higher content of barium. The inter-granular pores and dissolved pores were developed in this period. The third stage fluid was mainly hot magnesium-rich hydrothermal fluid along the basement faults, which formed a large number of saddle dolomite by tectonic and hydrothermal dolomitization with high content of manganese, lower content of iron, and negative oxygen isotopic values.

Fushan sag is a Cenozoic faulted lake basin on the slope of Hainan uplift in the southern margin of Beibuwan basin. This paper makes full use of the high-resolution three-dimensional seismic data covering the whole study area. Guided by various theories such as sequence stratigraphy and sedimentology, combined with relevant technologies such as sedimentary petrology and seismic sedimentology,a comprehensive study of the whole study area is carried out. In the period of SQEls₂EST+LST of Liushagang Formation in Paleogene, four types of deep-lacustrine gravity flow sedimentary lithofacies were identified in Fushan sag. Through lithofacies assemblage and its transformation characteristics, sand dispersion system and seismic facies analysis, the distribution characteristics of sedimentary system were carefully analyzed, and then the sedimentary model of deep-lacustrine gravity flow in Fushan sag was established. The lake floor fan deposits with typical turbidite channel developed mainly in the western eastern regions. In this area, the distal solitary bodies formed by sandy clastic deposits are dominant. This study not only has direct significance for the study of sedimentary system in Fushan sag, but also provides theoretical support for many continental fault basins with the same background in Southern China.

Half graben is a common sag pattern in the continental margin basins in East China, and its steep slope zone is one of the favorable oil and gas accumulating areas. Boundary faults play an important role in controlling the accumulation of oil and gas in steep slope zones. The internal structure of fault zone leads to different oil and gas accumulation models in footwall from those of hanging wall. Taking the X sag boundary fault in Huizhou depression of PRMB as an example, which is a long-term active fault developed with complete binary structure of fracture zone and fault core, we analyzed the control difference of the fault on oil and gas accumulation in the footwall and hanging wall. By means of qualitative and quantitative methods, we considered that the X fault developed continuous compact fault rocks with good lateral sealing in the main target layers; the vertical sealing of faults resulted in the difference of reservoir formation between the two pans; the migration of oil and gas into the reservoir of X fault footwall was also different from that of the hanging wall; because of the shielding of fault core, oil and gas were not directly charge in traps, but migrated to the footwall through connected sand bodies at the end of the fault or the transition zone in a manner similar to spiral staircase. In a word, the fault controlled structure in the X fault footwall has exploration potential, and which has been proved by drilling.

Evaporates are widely developed in Lanping basin and closely related to base metal. In this study, the rare earth elements and trace elements of 49 gypsum, limestone and paste mud samples from Triassic Sanhedong Formation and Paleogene Yunlong Formation in Lanping basin were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The results show that the geochemical characteristics of gypsum and limestone are similar but different from those of plaster. The characteristics of rare earth partitioning mode of gypsum and limestone are relatively flat and chaotic. The difference is that both positive and negative Eu anomalies of gypsum occur, while only negative Eu anomalies are found in limestone.The characteristic ratios of Sr/Ba, Sr/Cu, V/Cr, V/(V+Cr), Ni/Co, U/Th and δU of gypsum and limestone are similar,but they are significantly different from paste. The rare earth elements of paste show an obvious "V" shape of negative Eu anomaly,more steep than those of gypsum and limestone. It indicates that gypsum and limestone were formed in a salt-water-anoxic reductive environment of dry climate, with different material sources:The salt source of gypsum was participated by deep brine, while the limestone was not involve in deep brine.Plaster was formed in warm and humid oxidation environment of brackish water, fresh water and oxygen-rich water, and its material source is similar to that of limestone, which may be caused by cyclical changes in climate.

In this paper, the authors review the history of grain size analysis, summarize the commonly used grain size types, introduce the grain size standards and the five grain size analysis methods usually used in sedimentology at present, and give a detailed classification of sedimentation method, field interference analysis method and image method. In addition, the scope of application, the principle of measurement, the advantages and disadvantages of each grain size analysis method are also introduced in detail. Of them,direct measurement method is simple, but poor in accuracy; Sieving analysis is common, but can only precede loose or weakly cemented sediments and cannot reflect grain shape; Sedimentation method is suitable for the analysis of loose samples, weak cemented samples and liquid samples, and can measure fine grained sediments such as fine sand, silt and mud; Field interference method is mainly based on the diffraction, scattering and voltage impulse response of detritus grains, both solid and liquid samples, with high accuracy, and wide applicability; Image method is diverse, simple and intuitive, and strongly operable. In general, in the next few decades, these grain size analysis methods will still co-exist with old and new technologies.

The final temperature, heating time and the final oil and gas conversion rate of in-situ transformation of oil shale are closely related to the economic cost of in-situ mining. The relationship between hydrocarbon yield-conversion rate and hydrocarbon yield-activation energy of oil shale under different heating rates was obtained by using Rock-Eval 6 rock pyrolysis analyzer. The relationship between activation energy and conversion rate was established based on hydrocarbon yield. Further, based on the principle of chemical kinetics, the process of oil shale organic matter (kerogen) evolution was approximated to the thermal cracking reaction with the first-order reaction characteristics, and the relationship between reciprocal of temperature (1/T) and logarithm of heating time (ln t) under different conversion rates was obtained, and the temperature-time-conversion diagram of in-situ conversion of oil shale was established. Taking the oil shale of E_2-3 y Formation in Maoming Basin of Guangdong Province as an example, the temperature-time-conversion diagram of oil shale was drawn by the above method. It is shown that it would take 98 years to extract oil shale in this area by heating to 350℃ with 90% conversion rate, and 147 years to heat to 200℃ with 10% conversion rate without other measures. In fact, the in-situ heating of underground oil shale is heterogeneous,and the energy consumption of heating is large. It is possible to reduce the temperature and improve the quality of oil shale by adding catalyst to oil shale in-situ production.

The Maozu Pb-Zn deposit is a large deposit located in the northeastern Yunnan metallogenic province at the southwestern margin of the Yangtze plate. The ore-bodies are stratified and hosted in dolostone of Sinian Dengying Formation. The ore minerals are primarily sphalerite and galena,and the gangue minerals are mainly dolomite,calcite and fluorite. The C, O, Sr isotopes and REE geochemistry of the massive hydrothermal dolomite, calcite, fluorite and surrounding rocks were analyzed. The results show that the chondrite-normalized curves, δ¹³C and ⁸⁷Sr/⁸⁶Sr values of the massive hydrothermal dolomite and calcite are similar to those of the Sinian dolostone, indicating that C, O and Sr were mainly derived from the dissolution of the host rock. The massive hydrothermal dolomite and calcite have higher ∑REE than those of the surrounding rocks, implying that some other fluid with much higher ∑REE joined the ore-forming fluid. Fluorite is characterized by LREE depletion, and the chondrite-normalized curve is quite consistent, indicating that fluorite was formed at a later stage with more other fluid joined. The massive hydrothermal dolomite, calcite and fluorite show that positive Eu anomalies, and the δ¹⁸O values of the massive hydrothermal dolomite and calcite are lower than those of the host rock of the Sinian dolostone, indicating that these three gangue minerals might have been formed by high temperature fluid. The Sinian dolostone and the three kinds of gangue minerals show obvious negative Ce anomalies, implying that the ore-forming fluid might mainly come from Sinian Dengying Formation,which inherited the characteristics of the surrounding Sinian rocks. The ⁸⁷Sr/⁸⁶Sr ratios of calcite and fluorite are higher than those of the Permian Emeishan basalt and surrounding rocks of Sinian dolostone, but lower than those of the Proterozoic basement rocks (Kunyang and Huili Group). So, it is likely that the ore-forming fluid might mainly come from the surrounding rocks of Sinian Dengying Formation and other strata, and then mixed with the fluid that derived from or flowed through the Proterozoic basement rocks.

The effects of subducted sediments and altered oceanic crust (AOC) on back-arc magmatism were studied using independent component analysis on multi-isotope dataset. Sr-Nd-Pb isotope data of magmatic rocks from Lau and Manus basins, as well as the Pacific and Indian oceanic ridges, were analyzed, and five independent components (ICs) were identified. The negative correlation between IC1 and ⁸⁷Sr/⁸⁶Sr and Th/Nb suggests that the IC1 represents the influence of hydrous melt derived from subducted sediments on the sub-arc mantle, and can be used to distinguish back-arc basin from mid-ocean ridge settings. The negative correlation between IC5 and Ba/Th suggests that IC5 may reflect the influence of aqueous fluid derived from the AOC on the sub-arc mantle. Furthermore, the correlation between IC5 and Th/U indicates that the IC5 values may be related to the age of recycled oceanic crust in the mantle. A comparison between the IC1 and IC5 values of Lau and Manus basins shows that the eastern rift (ER) of Manus basin exhibits similar IC5 but lower IC1 relative to that of Lau basin, whereas the manus spreading center (MSC) and extensional transform zone (ETZ) of Manus basin show similar IC1 but higher IC5 compared with that of Lau basin. These differences suggest that the influences of sediment melts are the strongest in the ER, while AOC fluid exerts similar influence on ER and Lau basin, but much less on MSC and ETZ. We believe that the difference in the degree of sediment melt influence may be associated with variable sediment thickness being subducted into the New Britain and Tonga trenches, while the extent of AOC fluid influence is controlled by the distance of back-arc ridges away from the trench.

The main rock types of igneous rocks in Fozichong ore field are granite,granite porphyry,granodiorite(quartz diorite),granodiorite porphyry,dacite porphyry and tuff. We measured the ages of 14 igneous rock samples in this area by LA-ICP-MS zircon U-Pb dating. The Dachong quartz diorite was formed in Permian ((256.8±2.0) Ma);Nuodong Pluton((152.6±1.2) Ma) and Guangping Pluton((152.9±2.9) Ma) were formed in the Late Jurassic of Yanshanian;granite porphyry,granite diorite porphyry,less spot granite porphyry,granite diorite porphyry,dacite porphyry and tuff were formed in the Early Cretaceous of Yanshanian (100 Ma±). The ages of the igneous rocks in Fozichong ore field are mainly concentrated in Silurian (440 Ma±),Late Permian(256 Ma±),Late Jurassic(152 Ma±), and late Early Cretaceous(100 Ma±).According to the spatial distribution,ore body characteristics and the relationship with igneous rocks,the granite porphyry is considered to be the metallogenic geological body,and the metallogenic age is defined as the late Early Cretaceous (about 100 Ma).

Erlangping rock mass is in the east of Northern Qinling Mountains, and composed of porphyritic biotite monzonitic granite. The zircon U-Pb dating and geochemical features of Erlangping rock mass are significant to recognize the deep tectonic evolution of the northern Qinling Mountains in Late Mesozoic. The LA-ICP-MS zircon U-Pb dating results show that the formation age of Erlangping rock body is (114.0±0.5) Ma (MSWD=1.5). Erlangping rock mass is characterized by higher SiO₂ and alkali, and lower MgO and CaO, and compositional spots fall into the high-K calc-alkaline series in the SiO₂-K₂O diagram. Erlangping rock mass are enriched in large ion lithophile elements and depleted of high field-strength elements, which formed peaks of Rb and Th, and troughs of Nb,Sr, P and Ti in spider diagram. In the chondrite-normalized REE patterns, Erlangping rock mass shows the characteristics of LREE-enrichment and HREE depletion with Eu negative anomaly, and the (La/Yb)_N ratios are from 8.39 to 13.73. It suggests that the compositional change of Erlangping rock mass is controlled mainly by source composition and degree of partial melting. The partial melting source of Erlangping rock mass falls in amphibolite-facies with a crust thickness of about 40 km. The residual phases of partial melting source include mainly hornblende and plagioclase. Yanzhen regional lithosphere delamination took place in about 130 Ma, which triggered the deep magma intrusion in Erlangping area, and the later source rock partial melting and mixing with deep magma. They ascended and solidified in about 114 Ma. Erlangping rock mass is the product of delayed magmatism in about 15 Ma in response to the Yanzhen regional lithosphere delamination.

Longjiang basin is one of the important volcanic fault basins in the western periphery of Songliao basin. It is comprised of three volcanic units, Longjiang, Guanghua and Ganhe Formations, in ascending order. A detailed zircon U-Pb chronology was studied on the igneous rock from Longjiang basin. The zircon U-Pb ages are (129.7±2.4) Ma,(129.0±2.3) Ma and (125.6±1.3) Ma in Longjiang Formation, (122.5±1.4) Ma,(119.9±1.1) Ma and (116.7±1.5) Ma in Guanghua Formation. The zircon U-Pb age of basaltic trachy-andesite of Ganhe Formation is (114.3±2.9) Ma, showing that the ages of volcanic rocks in Longjiang basin range from 129.7 to 114.3 Ma, corresponding to the Early Cretaceous. Many captured zircons in the basaltic trachy-andesite of Ganhe Formation reflect the record of magmatic events of Late Permian(254 Ma), Late Carboniferous(302 Ma),Late Devonian(367 Ma),Early Silurian(433 Ma),Paleoproterozoic(2 395 Ma),and Neoarchean(2 523 Ma), implying the existence of ancient crystallization basement under Longjiang basin.

Different landslide prediction models have the problem of predicting the same landslide in advance or delay, and the prediction accuracy is quite different. At present, the fusion multi-model early-warning method fails to fully reflect the characteristics of individual model prediction, and the fusion early-warning accuracy is not high. On the basis of analyzing the reliability of these models, two landslide occurrence membership functions of delay and advance were designed respectively. According to the principle of minimum risk, the membership function of landslide warning was determined, and multi-model fusion of landslide early warning was realized by fuzzy integral. Sixteen known landslides were used to evaluate the reliability of the prediction models, and the other four known landslides were used to carry out the fusion early warning experiment of the landslide three days before and one day before the landslide occurrence, and the false alarm rate of multi-model fusion early warning was reduced by 16.6% and 25% respectively, compared with the average false alarm rate of multiple single models. The experiment shows that using early warning membership function for multi-model landslide early warning can improve the early warning accuracy for about 20%.

In order to explore the law of change between seepage and deformation of soil mass while inflating air into a slope, a two-dimensional finite element model of a 12 m-thick and 100 m-long slope was established to perform a non-complete coupled simulation of seepage and deformation. The formation process of unsaturated zone in slope and the change of the vertical displacement of slope surface soil was obtained by using the intercepting water with compressed air method to reduce the underground water level of slope. The result shows that the formation process of a complete and stable unsaturated zone can be divided into initial inflating stage, unsaturated zone expanding and water level rising stage, unstable two-phase flow stage, and stable unsaturated zone stage. If the aerated pressure is too large or too small, a stable and complete unsaturated zone cannot be formed. When the aerated pressure is 100 kPa, the vertical displacement of surface soil increases at first and then reduces. There is a certain synergy with the development of soil unsaturated zone. Under different aerated pressures, the vertical displacement of surface soil upstream to the aerated point increases with the increase of the aerated pressure, and the vertical displacement of surface soil downstream to the aerated point is uncertain.

Loess samples were prepared using pore-filling method to observe and analyze their microstructures. The pore structures and the change with depth increase were analyzed by scanning electron microscope and digital image analysis system. The five samples belong to porous soil according to the void ratio or pore area ratio. The results indicate that the connectivity of loess pore decreased with depth increase gradually, the pore structure changed from unstable overhead macro pores or mesopores into stable small or micro mosaic pores,and quantitatively, the area of macro pores and mesopores decreased by 63.04%, while the area of small pores and micro pores increased by 40.57% and 22.47% respectively. By analyzing pore shapes, the area change of micro pores, small pores, mesopores and macro pores mentioned above was resulted from the area change of elongated or irregular pores. From the area point of view, in the micro pores, small pores, mesopores and macro pores, the elongated pores were dominant, and the number of all these four kinds of pores decreased in turn significantly. This is mainly determined by the number of round pores, indicating that the round pores are small.

In order to study microstructure and mechanical properties of broken phyllite, the typical broken phyllite along the Wenchuan-Maerkang expressway was taken as the research object. X-ray powder diffraction, thin slice identification, uniaxial and triaxial compression tests were carried out. The results show that:1) The microstructure and mineral components are very complex. Most of the rocks have obvious brittle, plastic deformations and fractures with poor structural stability. 2) Significant anisotropy of broken phyllite was observed. Some mechanical parameters increased after the first decrease, such as the elastic modulus, compressive strength, cohesion and friction angle. These mechanical parameters showed a V-shape when the angle varied from 0° to 90°. 3) The failure modes of broken phyllite are closely related to angles and the confining pressure, which can be summed up in five types:tensile splitting along structural plane, shearing slip failure structural plane, Y type tensile-shear compound failure, compound shear failure across and along structural plane, and shear failure cross structural plane. 4) With the increasing of confining pressure, the strength, deformation parameters and failure modes of rock samples gradually weakened. 5) The combination of the maximum principal stress and the structural plane controls the failure mode and mechanism of rock, and it is the fundamental reason for the anisotropy of broken phyllite.

In order to provide decision-making basis for prevention and control of land subsidence in Shengze of Wujiang, the authors analyzed the influence of building load and groundwater exploitation on land subsidence. Based on the Biot's consolidation theory and ground water seepage theory, a three-dimensional fully coupled mathematical model of building load, groundwater exploitation on land subsidence was established. By using this model, the trend of land subsidence was simulated from 2015-09-01 to 2030-08-31 under the conditions of only building load, only groundwater exploitation, and the superposition of building load and groundwater exploitation. According to the prediction results, the effect of building load on land subsidence in Shengze is greater than that of groundwater exploitation. With the first weak clayed soil aquifer and the first confined aquifer as the main compressible layers, under the individual action, the single-layer compression accounted for 43.04% and 54.06% respectively; while with the first confined aquifer and its overlying weak clay soil aquifer as the main compression layer of the superposition of the building load and the groundwater exploitation, the total compression amount accounted for 71.30% of the total compression. The sum of the linear superposition of ground subsidence caused by the building load and groundwater exploitation alone is larger than the ground subsidence caused by the superposition of the two.The land subsidence caused by the superposition of the building load and the groundwater exploitation has a coupling effect.

The quality and evolution of oil and gas reservoirs are often controlled by sedimentation and diagenesis. Diagenesis is the most direct factor affecting porosity and permeability of reservoirs. The evolution of porosity and permeability is determined by water-rock reaction throughout the whole process of diagenesis.The clastic rock reservoir of Lower Shihezi-Shanxi Group in the northeast Ordos basin was taken as the study object. Reactive transport modeling was used to carry out the quantitative research on the effects of water-rock interaction on the permeable properties of the reservoir in oil, gas bearing basin and on the changes of reservoir permeability and reservoir mineral dissolution, precipitation. The results show that in the early stage of diagenesis, mineral dissolution was dominant, which increased porosity of reservoir from 0.30 to 0.36 and permeability of reservoir from 5.00×10^-15 m² to 8.70×10^-15 m² respectively. During the oil and gas filling stage (mainly CO₂), the precipitation of mineral was dominant in the whole geochemical reaction, resulting in the decrement of porosity (from 0.20 to 0.15) and permeability (from 5.00×10^-13 m² to 2.00×10^-13 m²).

In view of the deficiency of matter-element extension evaluation model in calculating correlation function, the authors built a groundwater quality evaluation model to improve the matter-element extension evaluation model, through using analytic hierarchy process and entropy method to work out comprehensive weight of every evaluating index,so as to avoid the absolute subjectivity and absolute objectivity of the index weight, and built a comprehensive evaluation index system of groundwater quality based on sensory, general chemistry and toxicology. This model was used to evaluate the groundwater quality of Guxian Town in Pingdu, and the application results of this model were compared with those obtained from integrated evaluating method and attribute recognition method. The result of this evaluation model is 70% the same as the result of the other two assessment methods; and the difference between them is basically within the same level; while between the other two methods, the result of one is only 50% the same as that of the another one, and the difference between these two assessment results can reach up to three levels.

Daggyai geothermal system in Tibet includes the biggest geyser in mainland China. Arsenic, as one of the most harmful substances, commonly exists in geothermal water, and the highest arsenic concentration detected in Daggyai geothermal springs reaches 9.75 mg/L, unneglectable potential arsenic pollution in shallow groundwater and rivers should be noticed. Thioarsenic usually exists as the dominant species of arsenic in sulfide-rich thermal springs;however there are few related studies in China. We focused on Daggyai geothermal system, and analyzed the chemical components of the geothermal spring samples. Thioarsenic species in each sample were calculated by using the hydro-geothermal simulation software PHREEQC. The results are as follows:Arsenic in Daggyai geothermal water consists of arsenate, arsenite, and thioarsenic, among which the arsenate and arsenite are the main species. There are interchanges between arsenate and arsenite when pH changes. The descending order of thioarsenic species in terms of their average ratio is monothioarsenate, trithioarsenate, ditthioarsenate, monothioarsenite and tetrathioarsenate. The proportion of thioarsenic to total arsenic concentration is mainly controlled by sulfide concentration, pH and Eh in geothermal water. High concentration of sulfide can promote the process of arsenic changing into thioarsenic, and strong reducing environment is required for the existence of thioarsenic. Moreover, the percentage of thioarsenic seems to have a positive correlation with pH value.

Derivative conversion, as a commonly used data processing method of potential field, has important physical significance. Due to the measurement error and noise, the derivative conversion in wavenumber domain is unstable,and the accuracy of derivative results is poor. In order to reduce noise interference and to improve the accuracy of derivative calculation, an arbitrary-order derivative conversion combining Chebyshev low-pass filter with routine derivative operator in wavenumber domain is proposed. Through analyzing the filtering properties of the filter and the characteristics of the radially averaged power spectrum of potential field anomalies, the parameters of the Chebyshev low-pass filter method are determined, which can reduce the interference of human choice. The 2D and 3D model tests show that compared with the other three methods,routine FFT (fast Fourier transformation), upward continuation and ISVD (integrated second vertical derivative), the root mean square error (RMSE) of the derivative calculated by this method and the theoretical value is the smallest, and the accuracy of its derivation result is higher. In the data processing of Bouguer gravity anomaly in Hulin basin, the second vertical derivative calculated by the proposed method is less affected by noise, and has higher reliability. Eight large faults and eleven small faults recognized based on this result are confirmed by previous studies.

To solve the singularity of design matrix using the discretized data during the process in regional gravity modeling, the Tikhonov regularization method is introduced to transform the traditional point-mass kernel radial basis function model, and a corresponding regularization model is established. Experiments are conducted using some simulation data sets which are for model setting and model testing, besides a comparative experiment is designed based on traditional way in which the discretized data is gridded. Meanwhile the optimal structure of the two models are determined by ranging the parameters of them, such as the depth and the resolution. The results show that the regularized point mass kernel radial basis function can directly use the discretized data to model the local gravitational field. And the accuracy of the two models is equal when they are in their separate optimal structures with no error in the modeling data; while with 3 mGal-error White Gaussian Noise input, the regularization method put forward in this paper has improved by 27.9%, which means it can effectively restrain the error amplification caused by ill-conditioned design matrix, and the accuracy and stability are improved.

Marine controlled-source electromagnetic (MCSEM) has been widely used in offshore hydrocarbon exploration in recent years. Huge drilling cost has been saved because of its high sensitivity to resistive oil reservoirs. The ocean sedimentary environment creates strong stratification and anisotropy in submarine media. Thus, the modeling for MCSEM needs to be made for anisotropic media. In this study, we solved the problem of electromagnetic (EM) field in wavenumber domain by introducing two scalar potentials that are continued upwards and downwards based on the continuation conditions of EM field and coupled to transmitting source at the location of transmitting dipole. The EM field in the space domain was calculated by using Hankel Transform. Through the analysis of anisotropic characteristics, we found that the anisotropy has a great influence on the responses of MCSEM, and only the vertical resistivity and the thickness have an influence on the responses of MCSEM for the resistive reservoir. We set up a procedure to distinguish the earth's anisotropy from the polar plots of marine apparent resistivity. This study lays a foundation for the inversion and interpretation of marine EM data.

In this paper, a three-dimensional limited memory quasi-Newton algorithm inversion for controlled source electromagnetic method based on impedance information is discussed. Firstly, the synthetic data from theoretical model is used to verify the accuracy and feasibility of the limited memory quasi-Newton inversion method. The observed data type is Z_xy, using staggered grid finite difference method to calculate the forward responses, and the limited memory quasi-Newton algorithm to perform the inversion. The numerical simulations show that the limited memory quasi-Newton inversion method has fast iteration speed, 4 minutes in one iteration, and the fitting error decreases from 146.00 to 1.78 with stable convergence; the location of the anomalous body agrees well with the theoretical model, which validates the limited memory quasi-Newton method for three-dimensional inversion of controllable sources electromagnetic method. To further verify the practicability of this method, it is applied to the exploration of concealed molybdenum deposits. The inversion results show that there are high resistivity anomalies in the deep part of the northwest and low resistivity anomalies in the upper part of the survey area. The profile of line 3 through the borehole shows a high conductivity region at the depth of -500 m——100 m, and a high resistant anomaly in its east. It is speculated that the low resistivity zone is a mineralized alteration zone with deep extension. The anomaly is consistent with the molybdenum vein revealed by drilling data, which proves the accuracy of the inversion. Therefore, the reliable three-dimensional resistivity distribution can be obtained by inverting the impedance information with limited memory quasi-Newton three-dimensional inversion method.

Oil sands, as an important part of the world's energy of 21st century, have been studied by a lot of geological workers on their geological characteristics of formation and distribution of metallogenic belt and so on, rather than remote sensing exploration. The basis of identification of different features by remote sensing technology is the reflectivity difference at the same wavelength position and the variation of reflectivity with wavelength.In this study, the authors got the spectral reflectance characteristics through analyzing the spectral data of oil sands. In order to recognize oil sands on remote sensing satellite image of Landsat 8 OLI, based on the oil spectrum characteristics and the correspondingcorrelation analysis, two recognition models were proposed and applied to the two research areas of Lenghu and Mahai in Qaidam basin. The results show that it is feasible to use remote sensing image to detect oil sands prospecting target area; the oil sands extraction model based on correlation analysis is better than the spectral feature analysis model; the ratio method is better in improving the oil sands remote sensing information in Lenghu area, while the difference method is better in Mahai area.

Support vector machine is a kind of black box model,and its feature cannot be selected directly when learning model;while decision tree model has the ability of feature selection during the process of recursive creation.For lithology classification,we combined decision tree with support vector machine.In consideration with the importance of the features,we used the tree height to extract the features after the decision tree establishment,and furthermore,we used the features with higher classification ability to fed into the support vector machine.The results show that the feature extraction of decision tree can reduce the input characteristics,so this,in turn,makes the SVM model more stable and accurate through controlling the complexity of the model effectively.The accuracy of test set of the model can be increased by more than 10%.