The authors focus on the ultra-low permeability reservoirs of Chang 4+5 reservoir period of Yanchang Group, Jing’an oil field, Ordos Basin. Cores, thin sections, wireline logs, and imaging logs were used to understand depositional systems, reservoirs and to furtherly characterize vertical and horizontal distribution patterns of sandstones. The results show that main reservoirs of Chang 4+5 of Yanchang Group are composed of medium-tofine grained arkose. Parallel beddings and cross beddings are common. Interpartical pores and a few fractures are main reservoir spaces and reservoir quality is poor. Sand bodies are uniformly distributed in the horizontal direction with brand shape and thickness between 2 to 5 meters. Front delta is the main sedimentary subfacies. Distributary main channel, distributary shallow channel, distributary shoal, and inner distributary bay are four main sedimentary microfacies. In the vertical direction, distributary main channels and distributary shallow channels are distributed reciprocally related to the variation of hydrodynamic power. The research result is a guidance on the hydrocarbon exploration in this region.

In the middle and late stage of oilfield exploitation of multi-period superimposed channel tight sandstone oil reservoir in Ansai oilfield, water content of the well is increasing and the effective production of the reservoir is uneven. The breakthrough and water-flooding occur easily during the integral fracturing, which can’t be adapted to the oilfield production situation today. In order to solve this problem, rock mechanics model and triaxial stress field distribution model are built by subdivision and correlation of single sand body between oil and water wells, full-length fracturing numerical simulation are carried out by combining with fracturing parameters design, stress intercalations were formed, which could constrain the distribution of fracturing fracture. Although fractures in the intercalations are formed during fracture operation, gaping fissures are closed with the decrease of pump pressure so that propping agents can’t enter into the intercalations to cause effective fractures, effective production of single sand body in the reservoirs is uneven, and effective producing degree of 60% of layers is relatively low. Thus for the 11 wells which have a low producing degree in the small layer, measures of additional perforation, multiple fracturing, shutting off water and exploitation when separated with other pay zone are proposed, which have an apparent stimulation effect after site implementation. Average daily increase of production is more than 1.2 t. In summary, the technique approach system of subdivision and fracturing treatment of multi-period superimposed channel tight single sand body is formed, which could guide the future development of the similar reservoirs.

For complex fault network, a new path cut algorithm was proposed, by which all types of complicated fault intersection can be dealt with, such as Y, λ, X, half-Y, half-λ contact relations. This fault modeling method not only avoids the limitation of the Pillar method and binary tree method, but also greatly improves the flexibility and accuracy of fault modeling. The method improves semi-automatic processing of the contact relationship between faults and quick updating of fault models. Through the validation of practical model, the modeling of complex fault network can be successfully and quickly solved, and the efficiency of modeling was also greatly improved.

In order to reveal hydrocarbon migration pathway and charging history of Yinan-2 gas reservoir in Kuqa Depression, 26 sand samples from well Yinan-2 were tested by using of Quantitative fluorescence techniques and fluid inclusions observation method based on well log curves and comprehensive geological data analysis. It is indicated that the Yinan-2 gas reservoir experienced oil charging of early stage, oil leakage and gas charging in late stage. Early oil accumulation of Yinan-2 gas reservoir may come from Jurassic coal bearing formation and Triassic lacustrine mudstone formation according to the quantitative grain fluorescence responds of sandstone samples. Current natural gas accumulation was migrated vertically from deep part, and the area below 4750 m might be an extensive and continuous gas-bearing area based on the analysis of quantitative grain fluorescence on extracts of sandstone samples. Besides, total scanning fluorescence fingerprint indicates that the current natural gas accumulation is derived from Jurassic coal seams and Triassic lacustrine mudstone formation.

To satisfy the functional requirements of huge geoscience model visualization, a triangle mesh simplification and restore algorithm is realized to support LOD (level of detail) scheme based on constrains of both topological rules and geoscience rules. A multi-resolution data structure required by the algorithm is introduced. The simplification and restore of triangle mesh are realized with the collapsible edges’ collapse and restore, in which the collapsibility is decided by the topological rules and geoscience rules in 3D geoscience models. Test results manifest that the algorithm can handle triangle meshes with good effect and high efficiency, and is able to support the LOD scheme.

Basing on the “3D Engineering Investigation Information System”, a “3D Underground Construction Deformation Display System” is developed. Empirical methods were used to predict the deformation of strata and buildings in the system. 3D regular grid model and triangulated irregular network (TIN) model were used for the 3D deformation field visualization. For the TIN model, the adaptive TIN keep-geometry refinement algorithm were developed. This algorithm can depict the deformation field in higher resolution without remarkable data size increase. Therefore the modeling and analysis of very large areas become possible.

The authors introduce the basic principles of Kriging and the simulation of variogram and elaborate the method in details, including several aspects: formation of the block model, collection and exploration of experimental data, semivariogram analysis, interpolation etc. The authors present a method which integrates 3D solid modeling with Kriging. The method can provide important decision support aid for urban development planning and construction by 3D visualization. Finally, the practical effect of the method is shown in a case study, and the sampling area locates in Beijing and 887 samples are adopted. The anthors present the analysis results of the model, verify the accuracy of the result, and carry on comparative analysis with 2D model. The results demonstrate the validity of method presented base on 3D GIS and Kriging, and 3D visualization makes it convenient to make decision for professionals.

Seismological interpretation revealed that basalts are overlain by rhyolite in the Halahatang area, Northern Tarim, Northwest China. The overlying rhyolite is dated by SIMS zircon U-Pb method, yielding a precise concordia age of 287.3 ±2.0 Ma, which limits the latest eruption age of the underlying basalt and reveals that the eruption age of the main pulse of the Tarim flood basalt is before 287 Ma, not ~275 Ma.

Based on the previous research in the realization and application of Kriging method on the computer, the authors introduce the theory, procedure and key technologies of the application of 3D geosciences modeling technology in creating orebody grade model. The basic procedure is as follows: construct 3D surface model of orebody with actual geological data; generate 3D block model of orebody from tin model; generate 3D grade model of orebody with Kriging method; estimate mine reserves using the grade model. Besides, this paper applies the above method to estimate the reserves of a copper mine in Tibet to provide empirical evidence. Analysis and comparison of the estimation results illustrate the advantages of application of 3D geosciences modeling technology on Kriging method for solid mine reserves estimation.

A practical 3D spatial analysis for 3D-urban-GIS named Volume Intersection Analysis is presented. With the Volume Intersection Analysis, two volume datasets are put sequentially in, then a result which describes the intersection information between the two datasets is put out. The result is a collection of relations, and each relation describes that a volume object in the first dataset intersects with one or more volume objects in the second dataset. A robust and fast algorithm for the Volume Intersection Analysis is implemented based on the OO3D data model, and its practicality is verified based on a 3D-urban-GISproject (TG-U-3D). The Volume Intersection Analysis is applied to aid detecting land-use conflicts in urban underground space planning process, and finding out the stratums that city facilities lie in or pass through.

The authors take a research on hazard zonation of debris flows based on GIS in Xiuyan County of Anshan City, Liaoning Province. Due to the uncertainty of the research on debris flows, the authors adopt the approach of certainty factors to research hazard zonation for debris flows. The graphs of hazard distribution and correlative affecting factors are obtained by digitizing and spatial analyzing the investigation data of geologic hazard of Xiuyan County. Then the unique-condition units are derived through overlying the graphs. CF values from each group of data are calculated and then they are used in logistic regression to set up the hazard evaluation model of debris flows in Xiuyan County. The graph of the hazard zonation of debris flows is obtained by using this model. This method proves to show the characters of the hazard of debris flows well by testing the hazard point data.

Weights of evidence (wofe) modeling and its application based on GIS are introduced. Wofe is applied to the zonation of karst collapse. Sensitivity of karst collapse around West Lake of Hangzhou is analysed. The cell size used in the analysis is 10 m×10 m. Spatial data of strata, structure and overburden is extracted from the study area. Spatial association between evidences and karst collapse is analysed, and contrasts are calculated. The studentized contrasts, which serve as a guide to statistical significance of spatial association, give cut off values to convert multiclass evidential data into binary pattern. Five evidences appropriate to the model are finally selected and converted into binary patterns, such as the strata unit, strata boundary of Gufeng formation - Qixia formation and of Huanglong formation - Laohudong formation, proximity to EW-NW trending structure features, proximity to NE trending structure features. Posterior probability of each cell which reflects degrees of karst potential collapse is calculated. The ratio of numbers of known collapses to the numbers of predicted collapses is 0.864, which indicates conditional independence among evidences with respect to karst collapse. The special application of wofe shows that the model is adapted to zonation of karst collapse.

Robust variogramis the basic guarantee of the effective spatial prediction using kriging methods. The existing variogram estimators behave poorly in practice. Some are not robust against the outliers in data; others are complex in algorithmin order to achieve robustness or hard to be used widely. The authors propose a simple variogramesti mator based on medianfiltering method, by taking into account correlation of neighbor hoodlags to improve its robustness against outliers. The robustness properties between the existing estimators and the proposed one are compared and analyzed. Experiments are carried out with data existing different types of outliers. The results show that the proposed variogram estimator is not only highly robust against outliers, but also easy to be used generally.

The overall structure and principal functions of three-dimension geological modeling and visualization system were discussed. It was used in Anqing copper mineral exploration. The system is mainly composed of three-dimension structure modeling , three-dimensional attribute modeling and three-dimensional geological visualization. Based on the modeling functions and the actual data of Anqing copper mineral exploration, three-dimensional geological models were built. Through the visual analysis, good prospects for exploration were revealed by the extension trend to east southerly direction of copper iron ore. It shows that the three-dimensional geological modeling and visualization system will be very helpful for enhancing the efficiency and accuracy of mineral prospecting to build.

A set of three-dimensional engineering investigation information system was built based on the practical engineering investigation application need and preliminary work. The system was composed by two major parts, two-dimensional subsystem and three-dimensional modeling subsystem.Many functions were achieved such as the fast flexible 3D construction of geological interfaces, internal attributes of geological bodies and engineering structures. And the data conversion interfaces to other calculation and simulation analysis software were also provided. Through practical test the system proved efficient during the engineering investigation.

To solve the increasingly outstanding urban geological problems and help researchers with visual analysis to urban geological survey data, three-dimensional geological structure model of Cenozoic erathem in Beijing was constructed for the first time. Due to the difference of precision in source data, the Cenozoic model was divided into two parts to be constructed respectively. Quaternary, the first part, was constructed via a former algorithm, the three-dimensional geological multi-body modeling algorithm from netlike cross-sections with topology. The stretching strategy was utilized to improve the solution of the algorithm to multivalue problem. Paleogene and Neogene, the second part, were modeled by using vertical addition of DEM. The constructed model deepened the cognition of geological researchers to the Cenozoic geological setting in Beijing. It also provided data support to the increase of exploiting efficiency of underground water and the rationalization of engineering planning.

A new method is proposed for 3D computerized modeling of geological objects from sets of intersected folded cross-sections, and two key problems of “high-precision modeling” and “rapid modeling” are solved. This method expands source data and improves automatization degree for 3D geological modeling. Besides, reconstructed geological objects are more real and smoother, and model quality is improved. Finally, a 3D prototype system is developed based on this method. A case study at the Olympic site in Beijing shows that the method can be applied to practical geological areas.

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

A memory prototype of variation function based on COMPOSITE design pattern is proposed, through which a uniform visiting interface is implemented and greatly improves the maintainability and expansibility of indispensable code in whole project Furthermore serialization of variation function and dynamically loading from storage is implemented with XML Serialization of variation function with XML not only can store away model's information, but can reveal the inner structure of model, and provide basis of evaluation, analysis, contrast and selection of models, as well as repetition use of model under analogical geological environment

The history and current status of urban informationization are firstly analyzed The design for 3DUGS (3D geological data management and service system), including system target, architecture and main functions, data analysis and processing procedure, key tecknologies, is introduced Finally, the application of this design in the development of Beijing 3DUGS is presented

Dynamic predictive model based on unsaturated flow theory was built through combination of infinite slope stability analysis model and Iverson transient rainfall infiltration model. The model was test on typical region of Southern China. The results show that this method can predict the occurrence and development process of regional rainfall-triggered geological hazards dynamically. So a more precise quantitative analysis method was raised for the prediction of regional rainfall-triggered geologic hazard.

Pointer octree, linear octree and other octree models have low efficiency either on storage or processing of massive dataset, which is a key problem in true three dimensional geo science modeling. The authors present a large virtual octree model which is based on multi linear structure and has no pointer or location code in its octants. The new model is both efficient on storage by a multilevel compression method which is based on regularly partitioned blocks, and is efficient on octant accessing by a multilevel index method which is based on fast morton segmentation and array operation. The new model is consistent both in core and out of core, and implementation details about block swap is presented finally. The large virtual octree model is effective to process high resolution and massive property dataset, and will promote the true three dimensional geoscience modeling.

Contour lines are lines connecting points of equal elevation. In maps of smaller scale derived from original map, they should be simplified so as to have acceptable visual effect for the target scale representation and hence simplification of contour lines is known as an important issue in cartographic generalization. There are many researches on line simplification. Among all the algorithms, Douglas-Peucker algorithm is recognized as the most visually effective way, which delivers the best perceptual representations of the original lines. On the other hand, classical D-P algorithm also has some drawbacks especially potential topological error. It is difficult to preserve topological consistency between simplified lines and original lines. Self-intersection or intersection of generalized lines may be yielded after D-P algorithm. In this paper, a pre-processing algorithm is proposed to divide contour lines safely based on constrained Delaunay triangulation and self-adaptive monotone chain, which is theoretically proved to preserve topological coherence after sequent D-P algorithm. Testing results show that original data can be compressed down to 10% through simplification, while no intersection or self-intersection occurs.

Debris flow is the special disaster occurred in the catchments, which is controlled by the geomorphic system. The theory of geomorphic information entropy which can be used to indict the characteristics of evolution of landforms is the combination of information and Strahler's area-altitude analysis. So, it is possible to use geomorphic information entropy to study debris flow catchments and make hazard assessment of debris flow catchments. This paper carries the geomorphic information entropy analysis on the geomorphologic evaluation stage of 21 debris flow catchments in Hadabei, which is located in the southwest part of Xiuyan County with damaged debris flows in 1982. According to the result, the geomorphic information entropy analysis on debris flow catchments is objective, credible, easy to carry out and helpful for evaluation, warning and reduction of debris flow.

During time from June 17-23 in 2005, an extraordinary storm event happened in Jian'ou city, Fujian province; it induced lots of small and medium scale shallow landslides. This paper describes the treating process to get fusion SPOT-5 images using geometric correction, spatial calibration, image enhancement, data fusion and other processing methods based on panchromatic and multi-spectral SPOT-5 images before and after the event, taking the method of comparative analysis using the fusion images and field survey to gain the key interpretation to getting the total information of 2186 landslides. The paper also gets the 92 percent of field affirming exactness using field validation method by choosing 300 interpreted landslides randomly from all of 2186 ones at last. According to the research, using fusion SPOT-5 images in the application of abstraction of small and medium scale landslide information is available.

The uncertainty reasoning especially the probability reasoning was imported into the slope geological hazard zonation. Based on the analysis on the uncertain factor method, subjective bayes method, bayes network method and influence diagram method, the methods of their usage in the slope geological hazard zonation were pointed. A new way of the hazard zonation based on the uncertainty reasoning which is a development of the traditional methods was promoted and tested in Xiuyan County of Anshan city in Liaoning Province.

The authors present a new method for three-dimensional (3D) geological modeling from a set of topological and polygonal cross-sections, and introduce topological relationships (connectivity, adjacency and inclusion) of "polygons -arcs- nodes" in cross-sections to generate Triangulated Irregular Network (TIN) by connecting adjacent open arcs instead of close contours. This method is especially suitable for cases where there are several connected polygons in a cross-section, which are general in geological applications. Besides, cross-sections are not required to be planar or parallel in this method, and topological relationships are embedded in the generalized 3D geological models. Some special ideals are also proposed for some complex geological phenomena, such as stratum dying out, faults terminated within strata, etc. Finally, a 3D geological modeling and visualization software platform was developed based on this method. A case study was conducted by using the real data at the Olympic site in Beijing, China.