This paper presents a regional 3D geological modeling method based on the stacking ensemble technique to overcome the challenges of sparse borehole data in large-scale linear underground projects.The proposed method t...This paper presents a regional 3D geological modeling method based on the stacking ensemble technique to overcome the challenges of sparse borehole data in large-scale linear underground projects.The proposed method transforms the 3D geological modeling problem into a stratigraphic property classification problem within a subsurface space grid cell framework.Borehole data is pre-processed and trained using stacking method with five different machine learning algorithms.The resulting modelled regional cells are then classified,forming a regional 3D grid geological model.A case study for an area of 324 km2 along Xuzhou metro lines is presented to demonstrate the effectiveness of the proposed model.The study shows an overall prediction accuracy of 85.4%.However,the accuracy for key stratigraphy layers influencing the construction risk,such as karst carve strata,is only 4.3%due to the limited borehole data.To address this issue,an oversampling technique based on the synthetic minority oversampling technique(SMOTE)algorithm is proposed.This technique effectively increases the number of sparse stratigraphic samples and significantly improves the prediction accuracy for karst caves to 65.4%.Additionally,this study analyzes the impact of sampling distance on model accuracy.It is found that a lower sampling interval results in higher prediction accuracy,but also increases computational resources and time costs.Therefore,in this study,an optimal sampling distance of 1 m is chosen to balance prediction accuracy and computation cost.Furthermore,the number of geological strata is found to have a negative effect on prediction accuracy.To mitigate this,it is recommended to merge less significant stratigraphy layers,reducing computation time.For key strata layers,such as karst caves,which have a significant impact on construction risk,further onsite sampling or oversampling using the SMOTE technique is recommended.展开更多
This study integrates seismic and petrophysical data to evaluate the subsurface geology of the Keva Field,located onshore in the Niger Delta,with the objective of constructing a 3D geological model and estimating the ...This study integrates seismic and petrophysical data to evaluate the subsurface geology of the Keva Field,located onshore in the Niger Delta,with the objective of constructing a 3D geological model and estimating the recoverable hydrocarbon volumes.Seismic lines and well log data from six wells—KV-2,KV-3,KV-4,KV-5,KV-6,and KV-7—were utilized for the interpretation.The seismic profiles revealed that the KV-4 well is the only well drilled on the up-thrown side of a significant horst fault block,bounded by four major normal faults,while all the other wells penetrated the downthrown side.Petrophysical analysis identified three key reservoirs,C500,D200,and E900,which exhibit excellent reservoir quality with high net-to-gross ratios,good porosity,and high hydrocarbon saturation.The identified depositional environments are tidal-and fluvial-dominated shoreface settings,with sheet sands deposited in distributary splay systems.The C500,D200,and E900 reservoirs have Gas Initially in Place(GIIP)values of 156.37,28.44,and 27.89 BSCF,respectively,with corresponding Estimated Ultimate Recovery(EUR)values of 104.77,19.06,and 18.69 BSCF,respectively.The Stock Tank Original Oil in Place(STOOIP)values are 24.43,91.29,and 86.41 MMSTB,with EURs of 7.32,27.4,and 25.92 MMSTB,respectively.The combined GIIP is 212.72 BSCF with EUR of 142.52 BSCF,while the total STOOIP is 202.13 MMSTB with a recoverable volume of 60.64 MMSTB.The reservoirs present an average porosity of 22.62%,with gas saturation of 84.66%and oil saturation of 73%.The evaluated reservoir qualities suggest high potential for optimized hydrocarbon production.展开更多
Qinshui Basin possesses enormous deep coalbed methane(CBM)resources.Fine and quantitative description of coal reservoirs is critical for achieving efficient exploration and development of deep CBM.This study proposes ...Qinshui Basin possesses enormous deep coalbed methane(CBM)resources.Fine and quantitative description of coal reservoirs is critical for achieving efficient exploration and development of deep CBM.This study proposes a 3D geological modeling workflow that integrates three parts:geological data analysis,3D geological modeling,and application of the model,which can accurately predict the favorable areas of CBM.Taking the Yushe-Wuxiang Block within the Qinshui Basin as a case study,lithology identification,sequence stratigraphy division,structural interpretation is conducted by integrating well logging,seismic,and drilling data.Six lithology types and regional structural characteristics of the Carboniferous-Permian coal-bearing strata are finely identified.Combining experimental testing on porosity and gas content and well testing on permeability,a 3D geological model that integrates the structural model,facies model,and property model was established.Utilizing this model,the total CBM resource volume in the study area was calculated to be 2481.3×108 m3.Furthermore,the model is applied to predict the distribution ranges of four types of CBM favorable areas.The workflow is helpful to optimize well deployment and improve CBM resource evaluation,ultimately provide theoretical guidance for subsequent efficient exploration and development.Our study constitutes a reference case for assessing potential of CBM in other blocks due to the successful integration of multiple available of data and its practical applications.展开更多
3D geological modeling, one of the most important applications in geosciences of 3D GIS, forms the basis and is a prerequisite for visualized representation and analysis of 3D geological data. Computer modeling of geo...3D geological modeling, one of the most important applications in geosciences of 3D GIS, forms the basis and is a prerequisite for visualized representation and analysis of 3D geological data. Computer modeling of geological faults in 3D is currently a topical research area. Structural modeling techniques of complex geological entities contain- ing reverse faults are discussed and a series of approaches are proposed. The geological concepts involved in computer modeling and visualization of geological fault in 3D are explained, the type of data of geological faults based on geo- logical exploration is analyzed, and a normative database format for geological faults is designed. Two kinds of model- ing approaches for faults are compared: a modeling technique of faults based on stratum recovery and a modeling tech- nique of faults based on interpolation in subareas. A novel approach, called the Unified Modeling Technique for stratum and fault, is presented to solve the puzzling problems of reverse faults, syn-sedimentary faults and faults terminated within geological models. A case study of a fault model of bed rock in the Beijing Olympic Green District is presented in order to show the practical result of this method. The principle and the process of computer modeling of geological faults in 3D are discussed and a series of applied technical proposals established. It strengthens our profound compre- hension of geological phenomena and the modeling approach, and establishes the basic techniques of 3D geological modeling for practical applications in the field of geosciences.展开更多
Taking hundreds of pieces of hazardous geological maps （1 ： 10 000） of Three Gorges res-ervoir area （3GR） as background, we establish regional three-dimensional （3D） geo-hazard modelusing DEM （digital elevatio...Taking hundreds of pieces of hazardous geological maps （1 ： 10 000） of Three Gorges res-ervoir area （3GR） as background, we establish regional three-dimensional （3D） geo-hazard modelusing DEM （digital elevation model） superposed surface images and geo-hazards elements. Based on landslides and other geo-hazard survey data,using improved B-REP（boundary representa-tion）entity data structure （two-body 3D data structure）, we set up 3D solid models for each hazardous bodies in each hazardous geological maps. Then we integrate the two types of 3D models with different scales from area to point, which are the regional geo-hazard 3D model and the solid models of each disaster body, in order to provide a visual processing and analysis plat-form for danger partition, stability evaluation, disaster prevention and control, early warning and command.展开更多
Due to the complex nature of multi-source geological data, it is difficult to rebuild every geological structure through a single 3D modeling method. The multi-source data interpretation method put forward in this ana...Due to the complex nature of multi-source geological data, it is difficult to rebuild every geological structure through a single 3D modeling method. The multi-source data interpretation method put forward in this analysis is based on a database-driven pattern and focuses on the discrete and irregular features of geological data. The geological data from a variety of sources covering a range of accuracy, resolution, quantity and quality are classified and integrated according to their reliability and consistency for 3D modeling. The new interpolation-approximation fitting construction algorithm of geological surfaces with the non-uniform rational B-spline(NURBS) technique is then presented. The NURBS technique can retain the balance among the requirements for accuracy, surface continuity and data storage of geological structures. Finally, four alternative 3D modeling approaches are demonstrated with reference to some examples, which are selected according to the data quantity and accuracy specification. The proposed approaches offer flexible modeling patterns for different practical engineering demands.展开更多
In this research, a method called ANNMG is presented to integrate Artificial Neural Networks and Geostatistics for optimum mineral reserve evaluation. The word ANNMG simply means Artificial Neural Network Model integr...In this research, a method called ANNMG is presented to integrate Artificial Neural Networks and Geostatistics for optimum mineral reserve evaluation. The word ANNMG simply means Artificial Neural Network Model integrated with Geostatiscs, In this procedure, the Artificial Neural Network was trained, tested and validated using assay values obtained from exploratory drillholes. Next, the validated model was used to generalize mineral grades at known and unknown sampled locations inside the drilling region respectively. Finally, the reproduced and generalized assay values were combined and fed to geostatistics in order to develop a geological 3D block model. The regression analysis revealed that the predicted sample grades were in close proximity to the actual sample grades, The generalized grades from the ANNMG show that this process could be used to complement exploration activities thereby reducing drilling requirement. It could also be an effective mineral reserve evaluation method that could oroduce optimum block model for mine design.展开更多
Uncertainty in 3D geological structure models has become a bottleneck that restricts the development and application of 3D geological modeling.In order to solve this problem during periods of accuracy assessment,error...Uncertainty in 3D geological structure models has become a bottleneck that restricts the development and application of 3D geological modeling.In order to solve this problem during periods of accuracy assessment,error detection and dynamic correction in 3D geological structure models,we have reviewed the current situation and development trends in 3D geological modeling.The main context of uncertainty in 3D geological structure models is discussed.Major research issues and a general framework system of uncertainty in 3D geological structure models are proposed.We have described in detail the integration of development practices of 3D geological modeling systems,as well as the implementation process for uncertainty evaluation in 3D geological structure models.This study has laid the basis to build theoretical and methodological systems for accuracy assessment and error correction in 3D geological models and can assist in improving 3D modeling techniques under complex geological conditions.展开更多
3D geological modeling is an inevitable choice for coal exploration to adapt to the transformation of coal mining for green, fine, transparent and Intelligent mining. In the traditional Coalfield exploration geologica...3D geological modeling is an inevitable choice for coal exploration to adapt to the transformation of coal mining for green, fine, transparent and Intelligent mining. In the traditional Coalfield exploration geological reports, the spatial expression form for the coal seams and their surrounding rocks are 2D maps. These 2D maps are excellent data sources for constructing 3D geological models of coal field exploration areas. How to construct 3D models from these 2D maps has been studying in coal exploration industry for a long time, and still no breakthrough has been achieved so far. This paper discusses the principle, method and software design idea of constructing 3D geological model of an exploration area with 2D maps made by AutoCAD/MapGIS. At first, the paper analyzes 3D geological surface expression mode in 3D geological modeling software. It is pointed out that although contour method has unique advantages in coal field exploration, TIN (Triangular Irregular Network) is still the standard configuration of 3D modeling software for coal field. Then, the paper discusses the method of 2D line features obtaining elevation and upgrading 2D curve to 3D curve. Next, the method of semi-automatic partition is introduced to build the boundary ring of the surface patch, that is, the user clicks and selects the line feature to build the outer boundary ring of the surface patch. Then, Auto-process method for fault line inside of the outer boundary ring is discussed, it including construction of fault ring, determining fault ring being normal fault ring or reverse fault ring and an algorithm of dealing with normal fault ring. An algorithm of dealing with reverse fault ring is discussed detailly, the method of expanding reverse fault ring and dividing the duplicate area in reverse fault into two portions is introduced. The paper also discusses the method of extraction ridge line/valley line, the construction of fault plane, the construction of stratum and coal body. The above ideas and methods have been initially implemented in the “3D modeling platform for coal field exploration” software, and applied to the 3D modeling practice of data from several coal field exploration areas in Ningxia, Shanxi, Qinghai, etc.展开更多
The Zhuxi tungsten deposit in Jiangxi Province,South China,contains a total W reserve of about 2.86 Mt at an average grade of 0.54 wt%WO3,representing the largest W deposit in the world.Numerous studies on the metallo...The Zhuxi tungsten deposit in Jiangxi Province,South China,contains a total W reserve of about 2.86 Mt at an average grade of 0.54 wt%WO3,representing the largest W deposit in the world.Numerous studies on the metallogeny of the deposit have included its timing,the ore-controlling structures and sedimentary host rocks and their implications for mineral exploration.However,the deep nappe structural style of Taqian-Fuchun metallogenic belt that hosts the W deposit,and the spatial shape and scale of deeply concealed intrusions and their sedimentary host rocks are still poorly defined,which seriously restricts the discovery of new deposits at depth and in surrounding areas of the W deposit.Modern 3 D geological modeling is an important tool for the exploration of concealed orebodies,especially in brownfield environments.There are obvious density contrast and weak magnetic contrast in the ore-controlling strata and granite at the periphery of the deposit,which lays a physical foundation for solving the 3 D spatial problems of the ore-controlling geological body in the deep part of the study area through gravity and magnetic modeling.Gravity data(1:50000)and aeromagnetic data(1:50000)from the latest geophysical surveys of 2016-2018 have been used,firstly,to carry out a potential field separation to obtain residual anomalies for gravity and magnetic interactive inversion.Then,on the basis of the analysis of the relationship between physical properties and lithology,under the constraints of surface geology and borehole data,human-computer interactive gravity and magnetic inversion for 18 cross-sections were completed.Finally,the 3 D geological model of the Zhuxi tungsten deposit and its periphery have been established through these 18 sections,and the spatial shape of the intrusions and strata with a depth of 5 km underground were obtained,initially realizing―transparency‖for ore-controlling bodies.According the analysis of the geophysical,geochemical,and geological characteristics of the Zhuxi tungsten deposit,we discern three principles for prospecting and prediction in the research area,and propose five new exploration targets in its periphery.展开更多
This study presents a comprehensive geological modeling approach to understanding the Hartha Formation in the Balad Oilfield.Utilizing Petrel software,a 3D geological model was developed,integrating well data,seismic ...This study presents a comprehensive geological modeling approach to understanding the Hartha Formation in the Balad Oilfield.Utilizing Petrel software,a 3D geological model was developed,integrating well data,seismic contour map,and log analyses to delineate the reservoir’s structural and petrophysical properties.Data preparation involved organizing well headers,tops,and logs from five key wells,followed by the creation of a structural contour map that identified major and minor faults influencing the reservoir.Structural modeling further enhanced the understanding of the Hartha Formation’s geometry,illustrating how tectonic influences and faulting impacted the spatial distribution of reservoir units.Facies modeling identified a predominance of mudstone and wackestone in the upper Hartha Formation,with improved reservoir qualities in the Har.UA and Har.UB units.Petrophysical modeling demonstrated variations in porosity and water saturation,highlighting the impact of structural features on fluid distribution.The findings underscore the complex geological interplay within the Hartha Formation,providing critical insights for future exploration and optimized hydrocarbon recovery strategies.展开更多
This paper reports an application of uncertainty visualisation of a regional scale(1:50000)3 D geological geometry model to be involved in GIS-based 3 D mineral potential assessment of the Xiangxibei lead-zinc mineral...This paper reports an application of uncertainty visualisation of a regional scale(1:50000)3 D geological geometry model to be involved in GIS-based 3 D mineral potential assessment of the Xiangxibei lead-zinc mineral concentration area in northwestern Hunan District,China.Three-dimensional(3 D)geological modelling is a process of interpretation that combines a set of input measurements in geometry.Today,technology has become a necessary part of GIS-based deep prospecting.However,issues of sparse data and imperfect understanding exist in the process so that there are several uncertainties in 3 D geological modelling.And these uncertainties are inevitably transmitted into the post-processing applications,such as model-based mineral resource assessment.Thus,in this paper,first,a big-data-based method was used to estimate the uncertainty of a 3 D geological model;second,a group of expectations of geological geometry uncertainty were calculated and integrated into ore-bearing stratoisohypse modelling,which is one of the major favourable parameters of assessment for Lead-Zinc(Pb-Zn)deep prospectivity mapping in northwestern Hunan;and finally,prospecting targets were improved.展开更多
An automatic generation method of geological cross-sections in dredging engineering based on 3D geological solid models is presented.The 3D geological models are built applying the non-uniform rational B-splines(NURBS...An automatic generation method of geological cross-sections in dredging engineering based on 3D geological solid models is presented.The 3D geological models are built applying the non-uniform rational B-splines(NURBS) technique,and a 2D profile can be calculated and generated automatically through Boolean operation to meet the demands of dredging projects.Moreover,an automatic marking method for geological attributes is put forward based on database technology,and the geological attributes include the profile name,scale,horizontal and vertical relative coordinates,geological lithology,and 2D standard lithology legend.At the same time,the automatic marking method can also provide an interactive mode for geological engineers to edit and modify the profile in the modeling system.Practical engineering applications show that the automatic generation method is a simple,flexible,fast and precise visual graphics rendering process that can create 2D standard profiles automatically and efficiently.This method also provides a convenient support tool for geological engineering digital analysis.展开更多
Three-dimensional geological modeling of reservoirs is an essential tool to predict reservoir performance and improve the understanding of reservoir uniqueness in Es1 formation. The paper focuses on the use of petrel ...Three-dimensional geological modeling of reservoirs is an essential tool to predict reservoir performance and improve the understanding of reservoir uniqueness in Es1 formation. The paper focuses on the use of petrel software to build three-dimensional reservoir geological model which characterizes and assesses block Nv32 that located in the west of the Shenvsi oilfield in the south of Cangzhou city, Hebei province of China, and has an oil-bearing area of 1.4 km<sup>2</sup>. This study is depending on integration data from well logs of 22 wells which provided from geology, geophysics, and petrophysics to identify and provide precise depict of the subsurface internal structure and the reservoir heterogeneity. Input data was used to build the structural model, sedimentary facies model, petrophysical properties (porosity, permeability, saturation, and N/G model, and finally to determine the reservoir volume. The lithological facies were simulated using the assigned value method. Moreover, Petrophysical properties (Porosity, permeability, oil saturation and net to gross) were constructed for each zone using the Sequential Gaussian Simulation method to guide the distribution of petrophysical properties of Es1 formation, block Nv32. Statistical analysis of the porosity, permeability, oil saturation and N/G model present that the porosity occurrence distribution is mainly concern between 0.2% - 36.39% of block Nv32 with an average porosity value of 17.5%, permeability between 0.017 mD to 974.8 mD, having an average permeability of 59.44 mD, oil saturation between 0.00 to 0.95 having an average value of 0.22, and N/G is mainly concentrated between 0.01 to 1.00 within an average value of 0.61. This research has indicated the reliability of the three-dimensional model technique as a suitable tool to provide a sufficient understanding of petrophysical distribution. The south-western and north-western indicate that oilfield is very promising an exploratory well should be drilled to find out the thickness and size of the reservoir.展开更多
Today’s era of big data is witnessing a gradual increase in the amount of data,more correlations between data,as well as growth in their spatial dimension.Conventional linear statistical models applied to mineral pro...Today’s era of big data is witnessing a gradual increase in the amount of data,more correlations between data,as well as growth in their spatial dimension.Conventional linear statistical models applied to mineral prospectivity mapping(MPM)perform poorly because of the random and nonlinear nature of metallogenic processes.To overcome this performance degradation,deep learning models have been introduced in 3 D MPM.In this study,taking the Huayuan sedimentary Mn deposit in Hunan Province as an example,we construct a 3 D digital model of this deposit based on the prospectivity model of the study area.In this approach,3 D predictor layers are converted from the conceptual model and employed in a 3 D convolutional neural network(3 D CNN).The characteristics of the spatial distribution are extracted by the 3 D CNN.Subsequently,we divide the 22 extracted ore-controlling variables into six groups for contrast experiments based on various combinations and further apply the 3 D CNN model and weight of evidence(WofE)method on each group.The predictive model is trained on the basis of the coupling correlation between the spatial distributions of the variables and the underground occurrence space of the Mn orebodies,and the correlation between different ore-controlling factors.The analysis of 12 factors indicates that the 3 D CNN model performs well in the 3 D MPM,achieving a promising accuracy of up to 100%and a loss value below 0.001.A comparison shows that the 3 D CNN model outperforms the WofE model in terms of predictive evaluation indexes,namely the success rate and ore-controlling rate.In particular,the 1–12 ore-controlling factors selected in experiment 5 provide a significantly better prediction effect than the other factors.Consequently,we conclude that the Mn deposit in the study area is not only related to the stratum and interlaminar anomalous bodies but also to the spatial distribution of the faults.The experimental results confirm that the proposed 3 D CNN is promising for 3 D MPM as it eliminates the interference factors.展开更多
Hydrogeological modeling is an interesting and widely-used approach to improving our understanding of groundwater,both to test existing hypotheses on the behavior of hydrosystems and to predict their responses to vari...Hydrogeological modeling is an interesting and widely-used approach to improving our understanding of groundwater,both to test existing hypotheses on the behavior of hydrosystems and to predict their responses to various natural or man-made problems.Today,software such as Leapfrog Geo offers the possibility of building a 3D geological model with a more accurate representation of the subsurface.Statistical tools such as ordinary kriging can be used to simulate the spatial distribution of groundwater.These modeling approaches were combined to improve knowledge of the groundwater flow context within three massifs on the island of Grande Comore.The delineation of the 3D geometry of litho-stratigraphic units has enabled a more detailed conceptualization of groundwater flows in a complex volcanic environment.Piezometric interpolations were used to validate aquifer geometry.It has been demonstrated that an implicit geological model coupled with piezometry can provide very interesting information on the hydrogeological configuration of a volcanic massif.In the Karthala and Badjini massifs,the respective confined and semi-confined configurations of the aquifers are observed,with thicknesses that progressively decrease with distance from the coast.In the Grille massif,on the other hand,the aquifer configuration is unconfined,with thickness increasing with distance from the coast.In all three massifs,the flow of water in the underground hydrosystems is from the central part towards the coast,naturally following the geological configuration of the ground.It should be noted that the absence of data in the central parts of the massifs still leaves uncertainties about the geometry in these parts of the aquifers.However,the models that have been established provide valid hypotheses for characterizing the hydrogeological configuration at the scale of each massif.展开更多
Sequential indicator simulation is a commonly used method for discrete variable simulation in 3D geological modeling and a widely used stochastic simulation method, which can be used not only for continuous variable s...Sequential indicator simulation is a commonly used method for discrete variable simulation in 3D geological modeling and a widely used stochastic simulation method, which can be used not only for continuous variable simulation but also for discrete variable simulation. In this paper, the X Oilfield in the western South China Sea is taken as an example to compare the sequential indicator simulation method and the Indicator Kriging interpolation method. The results of the final comparison show that the results of the lithofacies model established by the Indicator Kriging deterministic interpolation method are overly smooth, and its coincidence rate with the geological statistical results is not high, thus cannot well reflect the heterogeneity of the underground reservoir, while the simulation results of the lithofacies model established by the sequential indicator stochastic simulation method can fit well with the statistical law of the well, which has eliminated the smoothing effect of Kriging interpolation, thus can better reflect the heterogeneity of the underground reservoir. Therefore, the sequential indicator simulation is more suitable for the characterization of sand bodies and the study of reservoir heterogeneity.展开更多
3D visualization is one of major problems in “Digital Mine” theory and its technological research field. Through the observation of 3D geological models, spatial structural information, connected with the informatio...3D visualization is one of major problems in “Digital Mine” theory and its technological research field. Through the observation of 3D geological models, spatial structural information, connected with the information of production management hidden in geological data, could be detected. In order to meet the requirement of more efficient coal exploration, a case study of geological characters of the Daliuta Coal Mine is presented in which 3D visual models of the ground surface and geologic bodies are established on the basis of data models and data structures of 3D geology modeling. The main conclusions of this study are as follows: (1) Through analysis and organization of spatial discrete data, the drillhole database is designed with the data of the Daliuta mine; the connections amomg drillhole data are real- ized and displayed in a 3D environment. (2) Combining real data of the Daliuta mine, drillhole visualization is realized in a 3D environment by using the CoalMiner system. (3) The ground surface modeling of the Daliuta coal mine adopted a surface-data model and a TIN data structure. (4) 3D models of coal seams and rock formations of the Daliuta mine are established, which provide a method for the simulation of complex surfaces of geologic bodies. In the end, the models are applied to the Daliuta coal mine and the result shows that better geological effects are obtained.展开更多
In most studies of tunnel boring machine(TBM)tunnelling, the groundwater pressure was not considered, or was simplified and exerted on the boundary of lining structure. Meanwhile, the leakage, which mainly occurs in t...In most studies of tunnel boring machine(TBM)tunnelling, the groundwater pressure was not considered, or was simplified and exerted on the boundary of lining structure. Meanwhile, the leakage, which mainly occurs in the segment joints, was often ignored in the relevant studies of TBM tunnelling. Additionally, the geological models in these studies were simplified to different extents, and mostly were simplified as homogenous bodies. Considering the deficiencies above, a 3D refined model of the surrounding rock of a tunnel is firstly established using NURBS-TIN-BRe P hybrid data structure in this paper. Then the seepage field of the surrounding rock considering the leakage in the segment joints is simulated. Finally, the stability of TBM water diversion tunnel is studied coupled with the seepage simulation, to analyze the stress-strain conditions, the axial force and the bending moment of tunnel segment considering the leakage in the segment joints. The results illustrate that the maximum radial displacement, the minimum principal stress, the maximum principal stress and the axial force of segment lining considering the seepage effect are all larger than those disregarding the seepage effect.展开更多
Reliable 3D modelling of underground hydrocarbon reservoirs is a challenging task due to the complexity of the underground geological formations and to the availability of different types of data that are typically af...Reliable 3D modelling of underground hydrocarbon reservoirs is a challenging task due to the complexity of the underground geological formations and to the availability of different types of data that are typically affected by uncertainties. In the case of geologically complex depositional environments, such as fractured hydrocarbon reservoirs, the uncertainties involved in the modelling process demand accurate analysis and quantification in order to provide a reliable confidence range of volumetric estimations. In the present work, we used a 3D model of a fractured carbonate reservoir and populated it with different lithological and petrophysical properties. The available dataset also included a discrete fracture network(DFN) property that was used to model the fracture distribution. Uncertainties affecting lithological facies, their geometry and absolute positions(related to the fault system), fracture distribution and petrophysical properties were accounted for. We included all different types of uncertainties in an automated approach using tools available in today’s modelling software packages and combining all the uncertain input parameters in a series of statistically representative geological realizations. In particular, we defined a specific workflow for the definition of the absolute permeability according to an equivalent, single porosity approach, taking into account the contribution of both the matrix and the fracture system. The results of the analyses were transferred into a 3D numerical fluid-dynamic simulator to evaluate the propagation of the uncertainties associated to the input data down to the final results, and to assess the dynamic response of the reservoir following a selected development plan. The "integrated approach" presented in this paper can be useful for all technicians involved in the construction and validation of 3D numerical models of hydrocarbon-bearing reservoirs and can potentially become part of the educational training for young geoscientists and engineers, since an integrated and well-constructed workflow is the backbone of any reservoir study.展开更多
基金supported by Yunlong Lake Laboratory of Deep Underground Science and Engineering Project(Grant No.104023004)the National Natural Science Foundation of China(Grant Nos.52178328,and 42377190).
文摘This paper presents a regional 3D geological modeling method based on the stacking ensemble technique to overcome the challenges of sparse borehole data in large-scale linear underground projects.The proposed method transforms the 3D geological modeling problem into a stratigraphic property classification problem within a subsurface space grid cell framework.Borehole data is pre-processed and trained using stacking method with five different machine learning algorithms.The resulting modelled regional cells are then classified,forming a regional 3D grid geological model.A case study for an area of 324 km2 along Xuzhou metro lines is presented to demonstrate the effectiveness of the proposed model.The study shows an overall prediction accuracy of 85.4%.However,the accuracy for key stratigraphy layers influencing the construction risk,such as karst carve strata,is only 4.3%due to the limited borehole data.To address this issue,an oversampling technique based on the synthetic minority oversampling technique(SMOTE)algorithm is proposed.This technique effectively increases the number of sparse stratigraphic samples and significantly improves the prediction accuracy for karst caves to 65.4%.Additionally,this study analyzes the impact of sampling distance on model accuracy.It is found that a lower sampling interval results in higher prediction accuracy,but also increases computational resources and time costs.Therefore,in this study,an optimal sampling distance of 1 m is chosen to balance prediction accuracy and computation cost.Furthermore,the number of geological strata is found to have a negative effect on prediction accuracy.To mitigate this,it is recommended to merge less significant stratigraphy layers,reducing computation time.For key strata layers,such as karst caves,which have a significant impact on construction risk,further onsite sampling or oversampling using the SMOTE technique is recommended.
基金the support of African Union Commission through the Pan African University Life and Earth Sciences Institute(including Health and Agriculture),Ibadan,Nigeria,for funding this study。
文摘This study integrates seismic and petrophysical data to evaluate the subsurface geology of the Keva Field,located onshore in the Niger Delta,with the objective of constructing a 3D geological model and estimating the recoverable hydrocarbon volumes.Seismic lines and well log data from six wells—KV-2,KV-3,KV-4,KV-5,KV-6,and KV-7—were utilized for the interpretation.The seismic profiles revealed that the KV-4 well is the only well drilled on the up-thrown side of a significant horst fault block,bounded by four major normal faults,while all the other wells penetrated the downthrown side.Petrophysical analysis identified three key reservoirs,C500,D200,and E900,which exhibit excellent reservoir quality with high net-to-gross ratios,good porosity,and high hydrocarbon saturation.The identified depositional environments are tidal-and fluvial-dominated shoreface settings,with sheet sands deposited in distributary splay systems.The C500,D200,and E900 reservoirs have Gas Initially in Place(GIIP)values of 156.37,28.44,and 27.89 BSCF,respectively,with corresponding Estimated Ultimate Recovery(EUR)values of 104.77,19.06,and 18.69 BSCF,respectively.The Stock Tank Original Oil in Place(STOOIP)values are 24.43,91.29,and 86.41 MMSTB,with EURs of 7.32,27.4,and 25.92 MMSTB,respectively.The combined GIIP is 212.72 BSCF with EUR of 142.52 BSCF,while the total STOOIP is 202.13 MMSTB with a recoverable volume of 60.64 MMSTB.The reservoirs present an average porosity of 22.62%,with gas saturation of 84.66%and oil saturation of 73%.The evaluated reservoir qualities suggest high potential for optimized hydrocarbon production.
基金funded by the NSFC-Shanxi Coal-based Low Carbon Joint Fund of China(No.U1910205)the National Natural Science Foundation of China(Grant No.42272197).
文摘Qinshui Basin possesses enormous deep coalbed methane(CBM)resources.Fine and quantitative description of coal reservoirs is critical for achieving efficient exploration and development of deep CBM.This study proposes a 3D geological modeling workflow that integrates three parts:geological data analysis,3D geological modeling,and application of the model,which can accurately predict the favorable areas of CBM.Taking the Yushe-Wuxiang Block within the Qinshui Basin as a case study,lithology identification,sequence stratigraphy division,structural interpretation is conducted by integrating well logging,seismic,and drilling data.Six lithology types and regional structural characteristics of the Carboniferous-Permian coal-bearing strata are finely identified.Combining experimental testing on porosity and gas content and well testing on permeability,a 3D geological model that integrates the structural model,facies model,and property model was established.Utilizing this model,the total CBM resource volume in the study area was calculated to be 2481.3×108 m3.Furthermore,the model is applied to predict the distribution ranges of four types of CBM favorable areas.The workflow is helpful to optimize well deployment and improve CBM resource evaluation,ultimately provide theoretical guidance for subsequent efficient exploration and development.Our study constitutes a reference case for assessing potential of CBM in other blocks due to the successful integration of multiple available of data and its practical applications.
基金Project 2001AA135170 supported by the National High-Tech Research and Development (863) Program of China and 06ZR14031 by the Natural ScienceFoundation of Shanghai Municipality
文摘3D geological modeling, one of the most important applications in geosciences of 3D GIS, forms the basis and is a prerequisite for visualized representation and analysis of 3D geological data. Computer modeling of geological faults in 3D is currently a topical research area. Structural modeling techniques of complex geological entities contain- ing reverse faults are discussed and a series of approaches are proposed. The geological concepts involved in computer modeling and visualization of geological fault in 3D are explained, the type of data of geological faults based on geo- logical exploration is analyzed, and a normative database format for geological faults is designed. Two kinds of model- ing approaches for faults are compared: a modeling technique of faults based on stratum recovery and a modeling tech- nique of faults based on interpolation in subareas. A novel approach, called the Unified Modeling Technique for stratum and fault, is presented to solve the puzzling problems of reverse faults, syn-sedimentary faults and faults terminated within geological models. A case study of a fault model of bed rock in the Beijing Olympic Green District is presented in order to show the practical result of this method. The principle and the process of computer modeling of geological faults in 3D are discussed and a series of applied technical proposals established. It strengthens our profound compre- hension of geological phenomena and the modeling approach, and establishes the basic techniques of 3D geological modeling for practical applications in the field of geosciences.
基金supported by the 3D Model Library of Geo-hazards in the 3GR (No. SXJC-3ZH1A7)the software development of 3D area disaster geology map in the 3GR (No. SXJC-3ZH1A6)+1 种基金survey data acquisition and geologic map CAD system in the 3GR (No. SXKY4-02)985 Platform Projects,3D modeling and space analysis system of geo-hazards and the National Natural Science Foundation of China (No. 41172300)
文摘Taking hundreds of pieces of hazardous geological maps （1 ： 10 000） of Three Gorges res-ervoir area （3GR） as background, we establish regional three-dimensional （3D） geo-hazard modelusing DEM （digital elevation model） superposed surface images and geo-hazards elements. Based on landslides and other geo-hazard survey data,using improved B-REP（boundary representa-tion）entity data structure （two-body 3D data structure）, we set up 3D solid models for each hazardous bodies in each hazardous geological maps. Then we integrate the two types of 3D models with different scales from area to point, which are the regional geo-hazard 3D model and the solid models of each disaster body, in order to provide a visual processing and analysis plat-form for danger partition, stability evaluation, disaster prevention and control, early warning and command.
基金Supported by the National Natural Science Foundation of China(No.51379006 and No.51009106)the Program for New Century Excellent Talents in University of Ministry of Education of China(No.NCET-12-0404)the National Basic Research Program of China("973"Program,No.2013CB035903)
文摘Due to the complex nature of multi-source geological data, it is difficult to rebuild every geological structure through a single 3D modeling method. The multi-source data interpretation method put forward in this analysis is based on a database-driven pattern and focuses on the discrete and irregular features of geological data. The geological data from a variety of sources covering a range of accuracy, resolution, quantity and quality are classified and integrated according to their reliability and consistency for 3D modeling. The new interpolation-approximation fitting construction algorithm of geological surfaces with the non-uniform rational B-spline(NURBS) technique is then presented. The NURBS technique can retain the balance among the requirements for accuracy, surface continuity and data storage of geological structures. Finally, four alternative 3D modeling approaches are demonstrated with reference to some examples, which are selected according to the data quantity and accuracy specification. The proposed approaches offer flexible modeling patterns for different practical engineering demands.
基金the management of Sierra Rutile Company for providing the drillhole dataset used in this studythe Japanese Ministry of Education Science and Technology (MEXT) Scholarship for academic funding
文摘In this research, a method called ANNMG is presented to integrate Artificial Neural Networks and Geostatistics for optimum mineral reserve evaluation. The word ANNMG simply means Artificial Neural Network Model integrated with Geostatiscs, In this procedure, the Artificial Neural Network was trained, tested and validated using assay values obtained from exploratory drillholes. Next, the validated model was used to generalize mineral grades at known and unknown sampled locations inside the drilling region respectively. Finally, the reproduced and generalized assay values were combined and fed to geostatistics in order to develop a geological 3D block model. The regression analysis revealed that the predicted sample grades were in close proximity to the actual sample grades, The generalized grades from the ANNMG show that this process could be used to complement exploration activities thereby reducing drilling requirement. It could also be an effective mineral reserve evaluation method that could oroduce optimum block model for mine design.
基金provided by the Talent Training Project of the National Natural Science Foundation of China (No.J0730534)the National Natural Science Foundation of China (No.40902093)+1 种基金the Morning Light Plan of the Shanghai Educational Development Foundation (No.2007CG34)the Open Foundation of the Shanghai Key Laboratory of Urbanization and Ecological Restoration (No.200803)
文摘Uncertainty in 3D geological structure models has become a bottleneck that restricts the development and application of 3D geological modeling.In order to solve this problem during periods of accuracy assessment,error detection and dynamic correction in 3D geological structure models,we have reviewed the current situation and development trends in 3D geological modeling.The main context of uncertainty in 3D geological structure models is discussed.Major research issues and a general framework system of uncertainty in 3D geological structure models are proposed.We have described in detail the integration of development practices of 3D geological modeling systems,as well as the implementation process for uncertainty evaluation in 3D geological structure models.This study has laid the basis to build theoretical and methodological systems for accuracy assessment and error correction in 3D geological models and can assist in improving 3D modeling techniques under complex geological conditions.
文摘3D geological modeling is an inevitable choice for coal exploration to adapt to the transformation of coal mining for green, fine, transparent and Intelligent mining. In the traditional Coalfield exploration geological reports, the spatial expression form for the coal seams and their surrounding rocks are 2D maps. These 2D maps are excellent data sources for constructing 3D geological models of coal field exploration areas. How to construct 3D models from these 2D maps has been studying in coal exploration industry for a long time, and still no breakthrough has been achieved so far. This paper discusses the principle, method and software design idea of constructing 3D geological model of an exploration area with 2D maps made by AutoCAD/MapGIS. At first, the paper analyzes 3D geological surface expression mode in 3D geological modeling software. It is pointed out that although contour method has unique advantages in coal field exploration, TIN (Triangular Irregular Network) is still the standard configuration of 3D modeling software for coal field. Then, the paper discusses the method of 2D line features obtaining elevation and upgrading 2D curve to 3D curve. Next, the method of semi-automatic partition is introduced to build the boundary ring of the surface patch, that is, the user clicks and selects the line feature to build the outer boundary ring of the surface patch. Then, Auto-process method for fault line inside of the outer boundary ring is discussed, it including construction of fault ring, determining fault ring being normal fault ring or reverse fault ring and an algorithm of dealing with normal fault ring. An algorithm of dealing with reverse fault ring is discussed detailly, the method of expanding reverse fault ring and dividing the duplicate area in reverse fault into two portions is introduced. The paper also discusses the method of extraction ridge line/valley line, the construction of fault plane, the construction of stratum and coal body. The above ideas and methods have been initially implemented in the “3D modeling platform for coal field exploration” software, and applied to the 3D modeling practice of data from several coal field exploration areas in Ningxia, Shanxi, Qinghai, etc.
基金jointly supported by the National Key R&D Program of China(Grant No.2016YFC0600201)China Geological Survey project(Grant Nos.DD20190012,DD20160082)the National Natural Science Foundation of China(Grant Nos.92062108,41630320,41574133)。
文摘The Zhuxi tungsten deposit in Jiangxi Province,South China,contains a total W reserve of about 2.86 Mt at an average grade of 0.54 wt%WO3,representing the largest W deposit in the world.Numerous studies on the metallogeny of the deposit have included its timing,the ore-controlling structures and sedimentary host rocks and their implications for mineral exploration.However,the deep nappe structural style of Taqian-Fuchun metallogenic belt that hosts the W deposit,and the spatial shape and scale of deeply concealed intrusions and their sedimentary host rocks are still poorly defined,which seriously restricts the discovery of new deposits at depth and in surrounding areas of the W deposit.Modern 3 D geological modeling is an important tool for the exploration of concealed orebodies,especially in brownfield environments.There are obvious density contrast and weak magnetic contrast in the ore-controlling strata and granite at the periphery of the deposit,which lays a physical foundation for solving the 3 D spatial problems of the ore-controlling geological body in the deep part of the study area through gravity and magnetic modeling.Gravity data(1:50000)and aeromagnetic data(1:50000)from the latest geophysical surveys of 2016-2018 have been used,firstly,to carry out a potential field separation to obtain residual anomalies for gravity and magnetic interactive inversion.Then,on the basis of the analysis of the relationship between physical properties and lithology,under the constraints of surface geology and borehole data,human-computer interactive gravity and magnetic inversion for 18 cross-sections were completed.Finally,the 3 D geological model of the Zhuxi tungsten deposit and its periphery have been established through these 18 sections,and the spatial shape of the intrusions and strata with a depth of 5 km underground were obtained,initially realizing―transparency‖for ore-controlling bodies.According the analysis of the geophysical,geochemical,and geological characteristics of the Zhuxi tungsten deposit,we discern three principles for prospecting and prediction in the research area,and propose five new exploration targets in its periphery.
文摘This study presents a comprehensive geological modeling approach to understanding the Hartha Formation in the Balad Oilfield.Utilizing Petrel software,a 3D geological model was developed,integrating well data,seismic contour map,and log analyses to delineate the reservoir’s structural and petrophysical properties.Data preparation involved organizing well headers,tops,and logs from five key wells,followed by the creation of a structural contour map that identified major and minor faults influencing the reservoir.Structural modeling further enhanced the understanding of the Hartha Formation’s geometry,illustrating how tectonic influences and faulting impacted the spatial distribution of reservoir units.Facies modeling identified a predominance of mudstone and wackestone in the upper Hartha Formation,with improved reservoir qualities in the Har.UA and Har.UB units.Petrophysical modeling demonstrated variations in porosity and water saturation,highlighting the impact of structural features on fluid distribution.The findings underscore the complex geological interplay within the Hartha Formation,providing critical insights for future exploration and optimized hydrocarbon recovery strategies.
基金financially supported by the National Natural Science Foundation of China(Nos.41972311,41672330)the National Key Research and Development Program of China(No.2017YFC0601501)the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(No.2006BAB01A01)。
文摘This paper reports an application of uncertainty visualisation of a regional scale(1:50000)3 D geological geometry model to be involved in GIS-based 3 D mineral potential assessment of the Xiangxibei lead-zinc mineral concentration area in northwestern Hunan District,China.Three-dimensional(3 D)geological modelling is a process of interpretation that combines a set of input measurements in geometry.Today,technology has become a necessary part of GIS-based deep prospecting.However,issues of sparse data and imperfect understanding exist in the process so that there are several uncertainties in 3 D geological modelling.And these uncertainties are inevitably transmitted into the post-processing applications,such as model-based mineral resource assessment.Thus,in this paper,first,a big-data-based method was used to estimate the uncertainty of a 3 D geological model;second,a group of expectations of geological geometry uncertainty were calculated and integrated into ore-bearing stratoisohypse modelling,which is one of the major favourable parameters of assessment for Lead-Zinc(Pb-Zn)deep prospectivity mapping in northwestern Hunan;and finally,prospecting targets were improved.
基金Supported by the Science Fund for Creative Research Groups of National Natural Science Foundation of China(No.51021004)Tianjin Research Program of Application Foundation and Advanced Technology(No.12JCZDJC29200)National Key Technology R and D Program in the 12th Five-Year Plan of China(No.2011BAB10B06)
文摘An automatic generation method of geological cross-sections in dredging engineering based on 3D geological solid models is presented.The 3D geological models are built applying the non-uniform rational B-splines(NURBS) technique,and a 2D profile can be calculated and generated automatically through Boolean operation to meet the demands of dredging projects.Moreover,an automatic marking method for geological attributes is put forward based on database technology,and the geological attributes include the profile name,scale,horizontal and vertical relative coordinates,geological lithology,and 2D standard lithology legend.At the same time,the automatic marking method can also provide an interactive mode for geological engineers to edit and modify the profile in the modeling system.Practical engineering applications show that the automatic generation method is a simple,flexible,fast and precise visual graphics rendering process that can create 2D standard profiles automatically and efficiently.This method also provides a convenient support tool for geological engineering digital analysis.
文摘Three-dimensional geological modeling of reservoirs is an essential tool to predict reservoir performance and improve the understanding of reservoir uniqueness in Es1 formation. The paper focuses on the use of petrel software to build three-dimensional reservoir geological model which characterizes and assesses block Nv32 that located in the west of the Shenvsi oilfield in the south of Cangzhou city, Hebei province of China, and has an oil-bearing area of 1.4 km<sup>2</sup>. This study is depending on integration data from well logs of 22 wells which provided from geology, geophysics, and petrophysics to identify and provide precise depict of the subsurface internal structure and the reservoir heterogeneity. Input data was used to build the structural model, sedimentary facies model, petrophysical properties (porosity, permeability, saturation, and N/G model, and finally to determine the reservoir volume. The lithological facies were simulated using the assigned value method. Moreover, Petrophysical properties (Porosity, permeability, oil saturation and net to gross) were constructed for each zone using the Sequential Gaussian Simulation method to guide the distribution of petrophysical properties of Es1 formation, block Nv32. Statistical analysis of the porosity, permeability, oil saturation and N/G model present that the porosity occurrence distribution is mainly concern between 0.2% - 36.39% of block Nv32 with an average porosity value of 17.5%, permeability between 0.017 mD to 974.8 mD, having an average permeability of 59.44 mD, oil saturation between 0.00 to 0.95 having an average value of 0.22, and N/G is mainly concentrated between 0.01 to 1.00 within an average value of 0.61. This research has indicated the reliability of the three-dimensional model technique as a suitable tool to provide a sufficient understanding of petrophysical distribution. The south-western and north-western indicate that oilfield is very promising an exploratory well should be drilled to find out the thickness and size of the reservoir.
基金financially supported by the Chinese MOST project“Methods and Models for Quantitative Prediction of Deep Metallogenic Geological Anomalies”(No.2017YFC0601502)and“Research on key technology of mineral prediction based on geological big data analysis”(No.6142A01190104)。
文摘Today’s era of big data is witnessing a gradual increase in the amount of data,more correlations between data,as well as growth in their spatial dimension.Conventional linear statistical models applied to mineral prospectivity mapping(MPM)perform poorly because of the random and nonlinear nature of metallogenic processes.To overcome this performance degradation,deep learning models have been introduced in 3 D MPM.In this study,taking the Huayuan sedimentary Mn deposit in Hunan Province as an example,we construct a 3 D digital model of this deposit based on the prospectivity model of the study area.In this approach,3 D predictor layers are converted from the conceptual model and employed in a 3 D convolutional neural network(3 D CNN).The characteristics of the spatial distribution are extracted by the 3 D CNN.Subsequently,we divide the 22 extracted ore-controlling variables into six groups for contrast experiments based on various combinations and further apply the 3 D CNN model and weight of evidence(WofE)method on each group.The predictive model is trained on the basis of the coupling correlation between the spatial distributions of the variables and the underground occurrence space of the Mn orebodies,and the correlation between different ore-controlling factors.The analysis of 12 factors indicates that the 3 D CNN model performs well in the 3 D MPM,achieving a promising accuracy of up to 100%and a loss value below 0.001.A comparison shows that the 3 D CNN model outperforms the WofE model in terms of predictive evaluation indexes,namely the success rate and ore-controlling rate.In particular,the 1–12 ore-controlling factors selected in experiment 5 provide a significantly better prediction effect than the other factors.Consequently,we conclude that the Mn deposit in the study area is not only related to the stratum and interlaminar anomalous bodies but also to the spatial distribution of the faults.The experimental results confirm that the proposed 3 D CNN is promising for 3 D MPM as it eliminates the interference factors.
文摘Hydrogeological modeling is an interesting and widely-used approach to improving our understanding of groundwater,both to test existing hypotheses on the behavior of hydrosystems and to predict their responses to various natural or man-made problems.Today,software such as Leapfrog Geo offers the possibility of building a 3D geological model with a more accurate representation of the subsurface.Statistical tools such as ordinary kriging can be used to simulate the spatial distribution of groundwater.These modeling approaches were combined to improve knowledge of the groundwater flow context within three massifs on the island of Grande Comore.The delineation of the 3D geometry of litho-stratigraphic units has enabled a more detailed conceptualization of groundwater flows in a complex volcanic environment.Piezometric interpolations were used to validate aquifer geometry.It has been demonstrated that an implicit geological model coupled with piezometry can provide very interesting information on the hydrogeological configuration of a volcanic massif.In the Karthala and Badjini massifs,the respective confined and semi-confined configurations of the aquifers are observed,with thicknesses that progressively decrease with distance from the coast.In the Grille massif,on the other hand,the aquifer configuration is unconfined,with thickness increasing with distance from the coast.In all three massifs,the flow of water in the underground hydrosystems is from the central part towards the coast,naturally following the geological configuration of the ground.It should be noted that the absence of data in the central parts of the massifs still leaves uncertainties about the geometry in these parts of the aquifers.However,the models that have been established provide valid hypotheses for characterizing the hydrogeological configuration at the scale of each massif.
文摘Sequential indicator simulation is a commonly used method for discrete variable simulation in 3D geological modeling and a widely used stochastic simulation method, which can be used not only for continuous variable simulation but also for discrete variable simulation. In this paper, the X Oilfield in the western South China Sea is taken as an example to compare the sequential indicator simulation method and the Indicator Kriging interpolation method. The results of the final comparison show that the results of the lithofacies model established by the Indicator Kriging deterministic interpolation method are overly smooth, and its coincidence rate with the geological statistical results is not high, thus cannot well reflect the heterogeneity of the underground reservoir, while the simulation results of the lithofacies model established by the sequential indicator stochastic simulation method can fit well with the statistical law of the well, which has eliminated the smoothing effect of Kriging interpolation, thus can better reflect the heterogeneity of the underground reservoir. Therefore, the sequential indicator simulation is more suitable for the characterization of sand bodies and the study of reservoir heterogeneity.
基金Project 2002CB412601 supported by Chinese Ministry of Science and Technology
文摘3D visualization is one of major problems in “Digital Mine” theory and its technological research field. Through the observation of 3D geological models, spatial structural information, connected with the information of production management hidden in geological data, could be detected. In order to meet the requirement of more efficient coal exploration, a case study of geological characters of the Daliuta Coal Mine is presented in which 3D visual models of the ground surface and geologic bodies are established on the basis of data models and data structures of 3D geology modeling. The main conclusions of this study are as follows: (1) Through analysis and organization of spatial discrete data, the drillhole database is designed with the data of the Daliuta mine; the connections amomg drillhole data are real- ized and displayed in a 3D environment. (2) Combining real data of the Daliuta mine, drillhole visualization is realized in a 3D environment by using the CoalMiner system. (3) The ground surface modeling of the Daliuta coal mine adopted a surface-data model and a TIN data structure. (4) 3D models of coal seams and rock formations of the Daliuta mine are established, which provide a method for the simulation of complex surfaces of geologic bodies. In the end, the models are applied to the Daliuta coal mine and the result shows that better geological effects are obtained.
基金Supported by the Foundation for Innovation Research Groups of the National Natural Science Foundation of China(No.51321065)Tianjin Research Program of Application Foundation and Advanced Technology(No.12JCZDJC29200)Tianjin Natural Science Foundation(No.13JCYBJC19500)
文摘In most studies of tunnel boring machine(TBM)tunnelling, the groundwater pressure was not considered, or was simplified and exerted on the boundary of lining structure. Meanwhile, the leakage, which mainly occurs in the segment joints, was often ignored in the relevant studies of TBM tunnelling. Additionally, the geological models in these studies were simplified to different extents, and mostly were simplified as homogenous bodies. Considering the deficiencies above, a 3D refined model of the surrounding rock of a tunnel is firstly established using NURBS-TIN-BRe P hybrid data structure in this paper. Then the seepage field of the surrounding rock considering the leakage in the segment joints is simulated. Finally, the stability of TBM water diversion tunnel is studied coupled with the seepage simulation, to analyze the stress-strain conditions, the axial force and the bending moment of tunnel segment considering the leakage in the segment joints. The results illustrate that the maximum radial displacement, the minimum principal stress, the maximum principal stress and the axial force of segment lining considering the seepage effect are all larger than those disregarding the seepage effect.
文摘Reliable 3D modelling of underground hydrocarbon reservoirs is a challenging task due to the complexity of the underground geological formations and to the availability of different types of data that are typically affected by uncertainties. In the case of geologically complex depositional environments, such as fractured hydrocarbon reservoirs, the uncertainties involved in the modelling process demand accurate analysis and quantification in order to provide a reliable confidence range of volumetric estimations. In the present work, we used a 3D model of a fractured carbonate reservoir and populated it with different lithological and petrophysical properties. The available dataset also included a discrete fracture network(DFN) property that was used to model the fracture distribution. Uncertainties affecting lithological facies, their geometry and absolute positions(related to the fault system), fracture distribution and petrophysical properties were accounted for. We included all different types of uncertainties in an automated approach using tools available in today’s modelling software packages and combining all the uncertain input parameters in a series of statistically representative geological realizations. In particular, we defined a specific workflow for the definition of the absolute permeability according to an equivalent, single porosity approach, taking into account the contribution of both the matrix and the fracture system. The results of the analyses were transferred into a 3D numerical fluid-dynamic simulator to evaluate the propagation of the uncertainties associated to the input data down to the final results, and to assess the dynamic response of the reservoir following a selected development plan. The "integrated approach" presented in this paper can be useful for all technicians involved in the construction and validation of 3D numerical models of hydrocarbon-bearing reservoirs and can potentially become part of the educational training for young geoscientists and engineers, since an integrated and well-constructed workflow is the backbone of any reservoir study.
