The realization of informatization in the whole process of geological survey is the main direction of the develop-ment of geological survey.In the land quality geochemical survey,the arrangement of soil sampling points is much work,and how to efficiently and reasonably complete the arrangement of sampling points is the premise and key to the orderly develop-ment of field investigation.According to the relevant land quality geochemical survey specifications and based on the MapGIS platform,this paper realizes the automatic and intelligent arrangement of soil points under different work scales in the land quality geochemical survey,which mainly includes:①The preliminary layout and automatic numbering of soil double-layer sampling points in 1∶250 000 land quality geochemical survey;②The automatic layout of soil sampling points for 1∶50 000 land quality geochemical survey was realized under different average density requirements,and the layout results took into ac-count spatial uniformity and rationality;③Based on the K-means algorithm,the automatic point layout of differentiated sam-pling density of different land use types in the land parcel scale geochemical survey was realized,and the distribution of points within a single irregular block was uniform.Through comparison and verification,the automatic point layout method adopted in this paper can better meet the requirements of the relevant specifications and significantly reduce the work burden of technical personnel.
The ultra-deep marine carbonate formation of The Great Desert,Tarim Basin Area,NW China,hosting great potential reservoirs,is a prospective target for petroleum exploration.However,there are several challenges remain in ultra-deep desert seismic data processing:①Loose structures of near-surface in desert regions can bring severe seismic energy ab-sorption,showing distinct low-frequency characteristics,which will eventually affect the reconstruction of signals;②The differences between interlayer multiple wave and primary wave in travel time and velocity are relatively small in desert area.Therefore,it is much more challenging to identify and suppress interlayer multiple waves;③The relatively low-resolution seismic data in ultra-deep area(depth>7500 m)due to energy absorption and wavelet deformation cannot meet the require-ment of high-precision imaging;④The drastically varying velocity medium under the influence of lithology,primarily consis-ted of Permian igneous rocks and Calcareous limestone,causes excellent difficulties in velocity model building.We attempt to a-chieve high-precision exploration progress in Tarim basin:①We use microlog data to constrain the near-surface model build-ing;②The multiple suppression technology we are applying this paper can provide more accurate pre-stack data;③We adopt near-surface Q filtering and migration for high-frequency compensation to improve the seismic resolution;④We build the in-itial velocity model based on VSP data,update the initial velocity model with tomography,finally obtain high-precision ima-ging of ultra-deep carbonate.
Microtremor survey technology has the characteristics of high efficiency,non-destructive,environmental pro-tection,and good economic benefits.In order to overcome the shortcomings of traditional microtremor technology,a new engi-neering geological microtremor survey system has been developed by developing software,continuously optimizing iterative in-terpretation algorithm,field workflow,and other measures,so as to improve the application range and interpretation accuracy of microtremor technology.This technology is based on the extended spatial autocorrelation(ESPAC)theoretical algorithm and the H/V spectral ratio method.It uses a linear array to obtain core parameters such as phase velocity,H/V spectral ratio,peak frequency,etc.Through comprehensive analysis,it can quickly and intuitively obtain the geospatial distribution informa-tion of abnormal bodies,cooperate with geological mapping and drilling to find out the engineering geological conditions of sites along the tunnel project,and provide necessary engineering geological data for line design and construction.Taking a tunnel survey as an example,this paper interprets and infers the abnormal body of the tunnel by using the microtremor survey technol-ogy by linear array,high-density electrical method,and other comprehensive geophysical methods,combined with the geolog-ical conditions,and divides several abnormal zones and lithologic contact zones.The conclusion is consistent with the drilling and field geological mapping.Theory and practice show that the engineering geological microtremor survey technology has a-chieved good results in tunnel investigation and can be popularized and applied.
Channel sands are developed in the Jurassic in the Fudong slope area of Junggar Basin,characterized by faults and sand bodies jointly controlling reservoirs.However,sandstone and mudstone are affected by factors such as borehole col-lapse,and the logging curves are seriously distorted.So,the conventional curve correction methods are challenging to realize the accurate regression of sand and mudstone,which directly affect the accuracy of sand body and oil-gas detection.Through comprehensive comparative analysis in the work area,based on clarifying the characteristics of the low impedance of sandstone and high impedance of mudstone,two steps are adopted:Firstly,the effect of borehole expansion rate on density is used to cor-rect the overall background trend of sand and mudstone;secondly,the NMR porosity which corresponding to the sandstone is selected to constrain sandstone trend,in order to ensure the reasonable relative relationship between sand and mudstone.By su-perimposing the details of density amplitude change,the accurate correction of the logging curve is finally realized.An im-proved method of dichotomous logging environment correction is formed,effectively improving the quality of logging curves and provides reliable data for reservoir prediction and oil-gas detection in the study area.Compared with the conventional tech-nique,this method can precisely correct the area with poor data quality and significant area collapse without selecting marker layer and standard curve and realize accurate regression of sandstone and mudstone.The application of this method solves the geological problem of inaccurate prediction of channel sand body in the Fudong area for many years and guides the later well lo-cation deployment.
The traditional Hilbert-Huang transform(HHT)is a time-frequency analysis method with poor recognition accuracy and suffers from endpoint effects and modal aliasing.The improved Complete Empirical Mode Decomposition(ICEEMD)can decompose complex seismic signals into a series of single-component signals,which can better solve the prob-lem of modal aliasing.However,the instantaneous amplitude and instantaneous frequency extracted by the combined Hilbert transform still have serious endpoint effects on the processing of real seismic data.FWEO(Frequency-weighted Energy Oper-ator)is a non-negative frequency-weighted operator that combines TK energy difference algorithm and the Hilbert transform complex analysis idea,and has higher time resolution than the Hilbert transform.However,due to the algorithm itself,the FWEO energy can only be applied to single-component signals and not directly to complex seismic data.Therefore,this paper combines the advantages of the improved complete empirical mode decomposition method and FWEO energy separation algo-rithm to extract the instantaneous amplitude and frequency information of the actual seismic records in a work zone in the South China Sea and compares the prediction results with the logging data with good prediction agreement and high recognition accu-racy,which proves that the method can accurately reflect the reservoir characteristics.
Weiyuan shale gas has complex geological conditions,strong heterogeneity,thin reservoirs,and unstable lateral distribution.The results obtained by conventional seismic processing methods have low resolution and cannot identify thin lay-ers,formation pinch-out points,and micro-fractures.In order to solve these problems,this paper uses high-fidelity,high-resolution seismic processing technology to process the seismic data of Weiyuan shale gas.The orderly combination of meth-ods such as correction,pre-stack residual multiple suppression,and high-precision well seismic calibration quantitative qual-ity control can effectively improve the resolution,signal-to-noise ratio,and fidelity of complex seismic data.The processing results prove that this method can improve seismic data's resolution and well-seismic correlation coefficient in this area.At the same time,the interpretability of thin layers,the continuity of events,the accuracy of pinch-out points,and the reliability of fault detection are enhanced.
Given the increasing number of geological disasters in Guangdong Province in recent years,in order to improve the application efficiency of geophysical exploration in geological disaster exploration,this paper takes the geological disaster exploration results in Guangdong Province during the"13th five-year plan"as the primary material,analyzes and studies the electrical structure of several typical slope bodies in Guangdong Province in the form of geological physical model,and summa-rizes its key points.On this basis,Combined with the author's own work experience for many years,a set of geophysical explo-ration interpretation methods are formulated through targeted research.The results show that the electrical structure of the weathered layer of granite type slope can be divided into 2～3 physical interface layers,there is generally no apparent physical interface between the medium and slightly weathered layers,and there is generally a gradient physical interface between the bed-rock and the overlying weathered layer;There is a physical interface between the weathered layer of sedimentary rock and meta-morphic rock slope and the underlying bedrock,where the high and low resistances change sharply;The weak structural plane in the tectonic unstable slope generally appears in the form of low resistivity zone,gradient zone,high and low resistivity transi-tion zone on the electrical structural plane;The physical interface(high and low resistivity sharp transition zone,gradient zone,etc.)in the slope structure in Guangdong Province is often consistent with the geological interface(weathering zone,sliding surface,fault surface,lithologic interface,bedding surface,etc.);Establish physics-Geological model→anomaly determination→anomaly classification and class by class/interpretation→qualitative interpretation→quantitative interpretation→geological in-terpretation→put forward the location and technical requirements of the verification project→physical property measurement,supplement and collect data,and do further interpretation of the geophysical exploration interpretation method process,which can achieve good results in many practical work applications,and the results are convenient for Party A's personnel to use di-rectly.The research results of this paper can provide a reference for the following research work,such as the failure mecha-nism,evolution process,disaster monitoring and early warning,post-disaster management,geophysical exploration method selection,and results interpretation of slope disasters.
The induced polarization method has many characteristics,such as observation parameters,flexible observation device,and sensitive response to mineral resources,and is particularly advantageous in the exploration of mineral resources in the middle and deep areas.This paper conducts a systematic and in-depth study on the observation method,forward and in-version theory and method of the IP in the well.Firstly,two kinds of observation arrays of IP methods in the well are de-signed.Then,the theoretical formula of 2.5-d finite element forward modeling for the induced polarization method based on a continuous medium model is derived,and the linear equation of joint constraint inversion of resistivity and induced polarization data acquired in the well is given.Finally,through the inversion calculation of the complex geoelectric model and the experi-mental data of the flume,the feasibility of the well-inducing method in the middle and deep mineral resources is verified.
Based on the application results of microtremor technology in recent years,this paper proposes two indicators that can be used to evaluate the detection ability of microtremor observation:detection depth and longitudinal resolution.A-mong them,the main factors affecting the detection depth of the observation are the side length of the observation and the dom-inant frequency of the geophone;The main factors affecting the longitudinal resolution of the observation observation are obser-vation form and sampling interval.Based on comparative tests,the technical route of microtremor technology to achieve large detection depth in a thick coverage area is established,and it is verified in the west section of the petrochemical fault of Urumqi Bagang-Shihua.The detection results are consistent with the known data,which proves that the test conclusion is effective and reliable.
In order to improve the efficiency and accuracy of ground-penetrating radar for non-metallic pipeline detection,this paper uses the electromagnetic wave simulation software GPRMax3.0 to design the orthorectified model based on the em-pirical diameter-to-depth ratio of 1∶10 and applies different frequency antennas to carry out orthorectified detection simula-tion of non-metallic pipelines under different conditions.The effective bathymetric range of 100 M,270 M,and 400 M anten-nas for non-metallic pipelines is summarized through the mutual simulation verification and actual detection results.This pa-per's experimental results can play aspecific reference significance for ground-penetrating radar in urban underground non-metallic pipeline detection.
The shale is an unconventional reservoir with porosity generally less than 10%and permeability generally less than 1mD.This feature of low porosity and low permeability makes it difficult to accurately obtain the porosity value by con-ventional experimental methods and logging interpretation methods.In this paper,the shale samples of the Ek2 in Cangdong sag are selected to test their porosity values separately by mercury intrusion,gas,liquid,and nuclear magnetic resonance(NMR)methods.The porosity values of the NMR experiment and NMR logging are compared.The experimental results show that NMR technology is a relatively suitable method for obtaining shale porosity,and the high-precision NMR instruments can measure more comprehensive shale porosity values under the condition of selecting a smaller echo interval(TE=0.1 ms).However,in the shale section with high organic matter content(TOC≥9%),the signal-to-noise ratio of NMR logging shows a certain correlation.Low signal-to-noise ratio(SNR)may cause the high porosity value obtained by NMR logging.Therefore,in the actual logging evaluation process,the influence of SNR should be considered.
With the acceleration of social development and urbanization,seismic data acquisition is facing increasingly severe envi-ronmental noise impacts.The effective control of environmental noise is the most effective measure to improve the signal-to-noise ra-tio of seismic data.However,with the introduction of high-density seismic exploration technology and the integration of technology and economy,the contradiction between efficient seismic acquisition and strict control of complex noise is becoming increasingly severe.Therefore,it is particularly important to find the balance point between the quality of seismic data and the efficiency of seismic acquisi-tion.This article first analyzes the characteristics of environmental noise in the Sichuan basin and its control measures;Secondly,the impact of environmental noise of different intensities on seismic data was analyzed,and the attenuation effect of environmental noise of different intensities was analyzed;Finally,the threshold value of environmental noise that needs to be controlled is found through the attenuation effect of different intensities of environmental noise.Research has shown that environmental noise with an intensity below 20μV has a relatively small impact on seismic data evaluation,while environmental noise with an intensity below 40μV can be effectively attenuated through seismic processing technology.
The current well control amplitude processing technology uses single well data to control the amplitude recovery effect of sidetrack,but it can't deal with the parameter difference between multiple wells and control the data recovery effect far away from sound points.This paper uses the correlation coefficient as the standard to optimize the quality control wells.The amplitude energy trend of well synthetic seismic records is used as the scale to control the compensation effect of n parameter in the exponential function compensation method to ensure the correctness of the vertical energy trend of seismic data.The S-shape well model is constructed based on the logging data of two quality control wells and interpretation horizon.Based on the S-shape well model profile as the standard,the compensation effect of n parameter and regional amplitude compensation factor are controlled to ensure the correctness of the amplitude trend of seismic data far away from well points.The results show that the quality control method proposed in this paper for amplitude preserving processing of seismic data is effective and provides a basis for judging the correctness of the relative relationship between vertical and horizontal amplitude of seismic data.
The working area of A hollow in Lufeng Sag is small,and the oil-gas reserves are rich.The resolution of the o-riginal seismic data is low,and after multiple reprocessing,the contact relationship of the target layer is difficult to determine.The imaging of complex fault zones and the high-dip-angle basement is fuzzy,which is challenging to meet the exploration needs.Therefore,the second three-dimensional seismic data acquisition is carried out in this area,and the acquisition azimuth is orthogonal.Given the three-dimensional seismic data collected in different directions in the same block,the difference of seismic data in different directions is analyzed,and the combined tomography inversion technology with fault constraint is pro-posed to obtain the velocity field with higher accuracy.Through the dip angle and azimuth attribute of TTI anisotropy,the co-axial dislocation of steep dip strata in different azimuth data is solved,the migration and positioning accuracy is improved,and the fusion imaging of two-dimensional data is better realized.The imaging quality of Paleogene steep dip strata is improved,stratigraphic continui-ties、the signal to-noise ratio is higher,which provides reliable basic data for subsequent geological e-valuation.
Landslides occur frequently in the Loess Plateau of China,seriously threatening the development of the economy and the safety of life and property.Using time-series InSAR to identify potential active landslides and monitor their deforma-tion can help prevent and reduce the hazards caused by disasters.InSAR can observe surface deformation on a large scale.In this paper,we focus on Xining City as the research area.We adopted Sentinel-1 A radar images with 83 view ascending orbit and 87 view descending orbit.We used the small baseline set(SBAS)time-series InSAR technique to obtain the surface de-formation rate and temporal shape variables from January 2019 to November 2021 in the study area,and we detected 74 signifi-cant deformation areas.Based on geomorphology features and optical images,we identified 35 as active loess landslides.Ac-cording to the time-series deformation analysis of active landslides,the interaction of internal conditions(engineering rock group,fault)and external conditions(rainfall)is the main factor that activates the unstable slope or accelerates the slope move-ment.
陕西省潼关地区北部属于深部地热资源勘查开发的空白区,区域内无深部地球物理和钻孔资料,地下地质情况和构造情况不明.为了查明潼关县北部古城景区地热资源分布情况,使用二维地震反射波法进行勘查,查明了各个时代地层的埋深及厚度、热储层位特征和断裂构造空间分布情况.在物探勘查工作基础上,于圈定的地热有利地段布设一眼地热孔,最终成孔深度为2300 m,出水量为63.2 m3/h,温度为74℃.勘探成果表明,地震反射波法在潼关地区地热资源勘查中具有较好的应用效果.
密度界面反演方法可推断构造界面起伏形态,对于分析区域地质构造、地球深部构造和划分构造单元具有重要意义.当涉及到区域性乃至全球尺度问题时,通常采用球坐标系的密度界面反演方法.传统球坐标系密度界面反演方法在地表观测面的计算精度较低,且未能考虑地下密度的纵横向变化.这里针对上述问题,开展球坐标系变密度界面正演及反演方法研究,通过理论推导和高斯-勒让德积分算法改进,给出球坐标系变密度界面高精度正演方法,运用迭代优化算法而给出球坐标系变密度界面反演方法.最后利用球壳模型和起伏界面数据试验验证该方法的有效性,适用于大区域、地表观测面的变密度界面反演.
受地表沙漠覆盖和复杂山前构造等影响,塔里木盆地西南部的油气地质勘探难度大,基础地质调查薄弱,油气勘探历经数十年至今尚未获得实质性重大突破.通过开展高精度无人机航空磁测,采用全夜航模式,获取到蕴含丰富地质构造信息的航空磁测数据.利用非线性滤波、低通滤波、小波变换等方法,剔除干扰异常,实现了局部异常和背景场的分离,揭示了与油气成藏相关的局部圈闭构造及其展布规律;运用三维欧拉反褶积计算区域磁性基底深度,清晰地展示了盆地基底的隆坳格局及主要生油凹陷特征,为进一步开展油气勘探战略选区及深部资源评价提供了重要成果.
突水灾害在隧(巷)道等隐蔽工程中是重大安全隐患,查明隐伏的强富水区域是亟需研究和解决的重要工程需求,其中水量的预测是重难点.针对此问题,这里开展激电法半衰时探水技术的研究,基于岩石电化学测试分析不同孔隙度含水量条件下相关参数的规律,采用物理模拟实验研究二次时差与含水量之间关系.研究表明:①电阻率与孔隙度含水量之间为正线性相关,极化率和半衰时与孔隙度含水量之间近似"正态"相关;②二次时差法探水机理中二次时差与含水量关系较为复杂,并非简单的线性相关,二次时差法需基于较多已知条件方可粗略估算含水量,目前该方法实际应用仅可作为探水的辅助手段.
在地质灾害监测过程中,地下岩体破裂事件的定位是实时监测的一项关键技术.针对传统的定位方法均存在着不同程度的误差,为了减小事件定位的误差,提高定位精度,提出了一种改进鼠群优化算法用于地下岩体破裂事件的定位,以提高岩体的定位精度.首先,将Levy飞行策略引入鼠群优化算法中,以增强算法的局部搜索能力和全局寻优能力;其次,采用时差定位(Time difference of arrival,TDOA)方法建立目标函数,将目标函数作为算法的适应度函数进行岩体破裂事件定位;最后,验证了该算法的有效性和可行性,与其他定位算法比较,本算法定位精度较高,并且具有较好的鲁棒性和收敛性.
