Architecture of fault zones determined from outcrop, cores, 3-D seismic tomography and geostatistical modeling: example from the Albalá Granitic Pluton, SW Iberian Variscan Massif

The 3-D seismic tomographic data are used together with field, core and well log structural information to determine the detailed 3-D architecture of fault zones in a granitic massif of volume 500×575×168 m at Mina Ratones area in the Albalá Granitic Pluton. To facilitate the integration of the different data, geostatistical simulation algorithms are applied to interpolate the relatively sparse structural (hard) control data conditioned to abundant but indirect 3-D (soft) seismic tomographic data. To effectively integrate geologic and tomographic data, 3-D migration of the velocity model from the time domain into the depth domain was essential. The resulting 3-D model constitutes an image of the fault zone architecture within the granitic massif that honours hard and soft data and provides an evaluation of the spatial variability of structural heterogeneities based on the computation of 3-D experimental variograms of Fracture Index (fault intensity) data. This probabilistic quantitative 3-D model of spatially heterogeneous fault zones is suitable for subsequent fluid flow simulations. The modeled image of the 3-D fault distribution is consistent with the fault architecture in the Mina Ratones area, which basically consists of two families of subvertical structures with NNE–SSW and ENE–WSW trends that displaces the surfaces of low-angle faults (North Fault) and follows their seismically detected staircase geometry. These brittle structures cut two subvertical dykes (27 and 27′ Dykes) with a NNE–SSW to N–S trend. The faults present high FI (FI>12) adjacent bands of irregular geometry in detail that intersect in space delimiting rhombohedral blocks of relatively less fractured granite (FI<6). Both structural domains likely correspond with the protolith and the damaged zone/fault core in the widely accepted model for fault zone architecture. Therefore, the construction of 3-D grids of the FI in granitic areas affected by brittle tectonics permits the quantitative structural characterization of the rock massif.     

Geological,geophysical and geochemical structure of a fault zone developed in granitic rocks: Implications for fault zone modeling in 3-D

The structure of a fault zone developed in granitic rocks can be established on the basis of the spatial variability of geological, geophysical and geochemical parameters. In the North Fault of the Mina Ratones area (SW Iberian Massif, Spain), fault rocks along two studied traverses (SR-2 and SR-3 boreholes) exhibit systematic changes in mineralogy, geochemistry, fabrics and microstructures that are related to brittle deformation and alteration of granite to form cataclasite and subsequent gouge. The spatial distribution and intensity of these changes suggest a North Fault morphology that is consistent with the fault-core/damage-zone model proposed by Chester et al. (1993) to describe a fault zone architecture. North Fault damage zone thickness can be defined by the development of mechanically related mesoscopic faults and joints, that produce a Fracture Index (FI)>10. High FI values are spatially correlated with relative low seismic velocity zones (V_P<5 km/s and V_S<2.5 km/s in the well-logs), more probably related to a high concentration of fractures and geochemical alteration produced by meteoric water-granite interaction along fault surfaces. This correlation is the base of a geostatistical model proposed in the final part of this study to image the fault zone architecture of a granitic massif.     

Simulation of three-dimensional tectonic stress fields and quantitative prediction of tectonic fracture within the Damintun Depression,Liaohe Basin,northeast China

Tectonic fractures are important factors that influence oil and natural gas migration and accumulation within “buried hill” reservoirs. To obtain a quantitative forecast of the development and distribution of reservoir fractures in the Damintun Depression, we analyzed the characteristics of regional structural evolution and paleotectonic stress field setting. A reasonable geological model of the research area was built based on an interpretation of the geological structure, a test for rock mechanics, and experiment on acoustic emission. Thereafter, a three-dimensional paleotectonic stress field during the Yanshan movement was simulated by the finite element method. Rock failure criterion and comprehensive evaluation coefficient of fractures were used to determine the quantitative development of fractures and predict zones that are prone to fracture development. Under an intense Yanshan movement, high stress strength is distributed in the south and northeast parts of the study area, where stress is extremely high. The fracture development zones are mainly controlled by the tectonic stress field and typically located in the same areas as those of high maximum principal and shear stresses. The predicted areas with developed fractures are consistent with the wells with high fracture linear density and in locations with high-producing oil and gas wells.     

High-resolution reflection seismic imaging of the upper crust at Laxemar, southeastern Sweden

A major cost in exploring the upper 1–2 km of crystalline crust with reflection seismics is the drilling required for explosive sources. By reducing the charge size to a minimum, shallow inexpensive shotholes can be drilled with handheld equipment. Here, we present results from a full-scale test using small charges for high-resolution seismic surveying over a nuclear waste disposal study site (not an actual site). Two 2–2.5-km-long crossing profiles were acquired in December 1999 with 10-m shot and geophone spacing in the Laxemar area, near Oskarshamn in southeastern Sweden. After standard processing, including dip moveout (DMO), several subhorizontal to moderately dipping reflections are imaged. Many of the dipping ones can be correlated to fracture zones observed in a ca. 1700-m-deep borehole where the profiles cross and/or to fracture zones mapped on the surface. The imaged fracture zones form a complex 3D pattern illustrating the necessity of having 3D control before interpreting seismic reflection data. Analyses of sonic and density logs from the borehole show that greenstones have significantly higher impedances than the more dominant granite found in the borehole (granite/greenstone reflection coefficient is +0.065). These greenstones may contribute to the reflectivity when associated with fracture zones. In some cases, where they are present as larger subhorizontal lenses, they may be the dominant source of reflectivity. A set of north-dipping (10°) reflectors at 3–3.5-km depth can be correlated to a similar set observed below the island of Ävrö about 3 km to the east.     

Characterization of the Cretaceous aquifer structure of the Meskala region of the Essaouira Basin,Morocco

The aquifer of early Cretaceous age in the Meskala region of the Essaouira Basin is defined by interpretation of geological drilling data of oil and hydrogeological wells, field measurement and analysis of in situ fracture orientations, and the application of a morphostructural method to identify lineaments. These analyzes are used to develop a stratigraphic–structural model of the aquifer delimited by fault zones of two principal orientations: NNE and WNW. These fault zones define fault blocks that range in area from 4 to 150 km². These blocks correspond either to elevated zones (horsts) or depressed zones (grabens). This structural setting with faults blocks of Meskala region is in accordance with the structure of the whole Essaouira Basin. Fault zones disrupt the continuity of the aquifer throughout the study area, create recharge and discharge zones, and create dip to the units from approximately 10° to near vertical in various orientations. Fracture measurements and morphometric-lineament analyzes help to identify unmapped faults, and represent features important to groundwater hydraulics and water quality within fault blocks. The above geologic features will enable a better understanding of the behaviour and hydro-geo-chemical and hydrodynamics of groundwater in the Meskala aquifer.     

基于GIS的岩石裂隙空间分布模式研究

文中以甘肃北山花岗岩中发育的构造裂隙(主要指节理尺度)为研究对象,应用地质统计分析理论,以裂隙面密度P21 作为地质统计分析的区域性变量,探索花岗岩岩体裂隙空间分布模式。结果表明:甘肃北山芨芨槽候选场址区域内花岗岩岩体裂隙空间分布具有明显的各向异性特征,变异主轴方向明显; 变异主轴区域内的裂隙分组地质统计特征显示,区域内第1分组裂隙并非是传统意义上的均匀随机分布,而是具有明显的空穴效应特征,应该在三维裂隙网络建模工作中予以考虑。本文在考虑本组裂隙空穴效应特征基础上,针对三维裂隙网络建模方法提出了新的建议。     

Estimation of water flow from upper reservoir of Azad pumped storage power plant,using geostatistical methods

The objective of this paper is to estimate water seepage from the upper reservoir of Azad pumped storage power plant (PSPP), based on combined geotechnical investigations and geostatistical methods. Azad PSPP has been located in Sanandaj Province in Iran. In order to select the optimum water tightening alternative, such as clay blanket, concrete cover (or concrete lining), geomembrane, asphalt cover etc, estimation of water seepage from the reservoir is essential. Six exploratory boreholes were drilled at the pumped storage reservoir area and permeability tests (Lugeon tests) were conducted in all of them. Records at the boreholes have been considered as the main source for seepage calculations. Due to expansion of upper reservoir and a few boreholes, distribution of permeability and permeability changes in the reservoir area is not indicator of reservoir. In this research using geostatistical method (Kriging), lugeon values have been estimated for walls of reservoir. According to correspondence between estimated permeability distribution and geological conditions, the estimated values are acceptable. In addition results show that in about 60% of tests, permeability is very high and potential of water seepage is very high. Seepage was estimated for reservoir by using both analytical (vedernikov method) and numerical method. Results from both methods are very close and the average of seepage is around 280000 m³/day. From the results and general geological considerations, seepage is concentrated at fault zones. Results show that by using appropriate permeability distribution, the estimated values of water seepage are reliable. Due to the high amount of water seepage and economic importance of water in this region, water tightening is necessary.     

新疆柯坪-巴楚地区碳酸盐岩构造裂缝发育的控制因素及油气勘探意义

构造裂缝发育程度是碳酸盐岩地区构造裂缝定量研究的重要方面,对碳酸盐岩裂缝油气藏的储层预测具有重要意义。论文基于野外地质实际考察,研究岩性、地层厚度、构造性质等因素对构造裂缝的影响,建立比较系统的构造裂缝发育分布规律,建立构造裂缝发育的地质模型。白云岩的裂缝密度明显大于灰岩类的裂缝密度。地层越厚裂缝密度越小,但裂缝规模较大。走滑断裂控制的构造裂缝的裂缝密度与距断裂的距离呈指数关系且存在"断裂控制的裂缝带","断裂控制裂缝带"与断裂的性质、规模和断距等因素密切相关。提出不同性质断裂"断裂控制裂缝带"宽度与断层破碎带宽度的比值K,这个比值的发现对断裂控制的裂缝油气勘探开发具有重要的应用价值。     

Localization of water bearing fractured zones in a hard rock area using integrated geophysical techniques in Andhra Pradesh,India

Knowledge of the existence of fracture zones, their extent, intensity and direction is very useful for assessing groundwater in hardrock regions and in this context geophysical methods are widely accepted as a powerful means of study. In the modern era of exploration, application of the Resistivity Imaging technique gives a new opportunity for groundwater study in hardrock regions. Exploration surveys were conducted at one of the important sites in Maheshwaram watershed, Andhra Pradesh, India with a multielectrode resistivity imaging system. To reduce the ambiguity of geophysical interpretation some complementary geophysical studies like ground Magnetic and VLF were also carried out.A number of 2D resistivity images were prepared in a grid pattern, which clearly show the weathered and fractured zones in different parts of the study area. With the help of all 2D profiles a quasi-3D image has been created, which indicates the orientation and extension of the fracture zone in a horizontal as well as vertical direction in the study area. Strong agreement exists among the anomalies identified using the ground magnetic, VLF and resistivity imaging methods. The litholog data available in the study area also helps to interpret geophysical results to find a potential groundwater bearing zone in that area.     

Fracture corridors as seal-bypass systems in siliciclastic reservoir-cap rock successions: Field-based insights from the Jurassic Entrada Formation (SE Utah,USA)

Closely spaced, sub-parallel fracture networks contained within localized tabular zones that are fracture corridors may compromise top seal integrity and form pathways for vertical fluid flow between reservoirs at different stratigraphic levels. This geometry is exemplified by fracture corridors found in outcrops of the Jurassic Entrada Formation in Utah (USA). These fracture corridors exhibit discolored (bleached) zones, interpreted as evidence of ancient fracture-enhanced circulation of reducing fluids within an exhumed siliciclastic reservoir-cap rock succession. Extensive structural and stratigraphic mapping and logging provided fracture data for analysis with respect to their occurrence and relationships to larger faults and folds. Three types of fracture corridors, representing end-members of a continuum of possibly interrelated structures were identified: 1) fault damage zone including segment relays; 2) fault-tip process zone; and 3) fold-related crestal-zone fracture corridors. The three types exhibit intrinsic orientations and patterns, which in sum define a local- to regional network of inferred vertical and lateral, high-permeability conduits. The results from our analysis may provide improved basis for the evaluation of trap integrity and flow paths across the reservoir-cap rock interface, applicable to both CO₂ storage operations and the hydrocarbon industry.     

Long-term stability of flow-path structure in crystalline rocks distributed in an orogenic belt, Japan

Most evaluations of the contaminant retardation processes likely to be important in geological disposal (e.g. for high level radioactive waste (HLW)) consider only the present characteristics of fractures and associated mineral infills. Relatively little attention has been given to possible long-term changes in these features, and their influence on groundwater flow. The work reported here seeks to provide analogous evidence that such changes are not likely to be important and hence to improve confidence in the presently adopted evaluation methodology and its long-term applicability.

In the orogenic belt that is formed by the Japanese islands, there are wide areas of crystalline rock. The rocks in each area have a distinctive age sequence which is partly reflected in the characteristics of the fracture systems and associated mineral fillings that occur. These characteristics generally imply that groundwater and solutes can be conducted through fracture networks, except in the cases of fault zones or crushed zones. The structural and mineralogical features of these networks readily illustrate how certain contaminants might react and be retarded by the fracture fillings and open pore geometry, due to chemical sorption and/or physical retardation.

Here, we describe the fracture systems developed in crystalline rocks with different ages that are intruded into the Japanese orogenic belt. The aim is to build a model for the long-term fracturing process and hence to evaluate fracture ‘stability’. In particular, the comparisons are made between the fracture geometries and the frequencies observed in the 1.9–0.8 Ma Takidani Granodiorite (the youngest exposed pluton in the world), the ca. 67 Ma Toki Granite and the ca. 117 Ma Kurihashi Granodiorite located in central to northwest Japan. The observations show that all these crystalline rocks have similar fracture frequencies, with 1 to 2 fractures per meter in the massive part of rock bodies. Mineralogical studies and dating analyses of fracture fillings also suggest that fractures are relatively physically stable. Major new fractures tend not to be created in the massive part of rock bodies even when a pluton has been subjected to the regional stresses of plate movements with a duration of about 100 Ma. The results show the unique characteristics of the fracture forming process and the relatively stable geometries of fracture network systems in crystalline rocks distributed within the orogenic belt. This analogue also enables us to provide a model to build confidence in a technical approach applicable for modeling of hydrogeology and geology over long time scales under the orogenic stress field present in Japan. The model may also be useful for other stable tectonic settings as well as for a characterizing sites in crystalline rocks for the possible geological disposal of HLW and other toxic wastes.     

Structural geochemistry of gold mineralization in the Linglong-Jiaojia district, Shandong Province, China

The Linglong-Jiaojia district is one of the most important regions containing gold deposits in China. These gold deposits can be divided into: a) the pyrite-gold-quartz vein type (Linglong type), which is controlled by brittle-ductile to ductile deformation structures, and b) the alteration-zone type (Jiaojia type), characterized by small veinlets, or the disseminated type recognized in brittle shear zones. Lode gold deposits in the Jiaojia area occur in NE brittle fracture zones, formed in a dominantly simple shear deformation regime, mainly in thrust attitude with a minor sinistral strike slip component. In the Linglong area, the lode gold deposits are located at the intersection of three types of structures: NNE and NE brittle-ductile fault zones and the ENE ductile reverse shear zone in the south of the area. The structural characteristics of these brittle shear zones are consistent with a tectonic NNW-SSE principal stress field orientation. Similar stresses explain the ENE Qixia fold axes, the Potouqing and several other ENE reverse ductile shear zones elsewhere in the region, the Tancheng-Lujiang fault zone and its subsidiaries in the vicinity of the Linglong-Jiaojia district, as well as the southern ENE suture zone north of Qingdao. Therefore these structural systems occurred as part of different major tectonic events under NNW-SSE compression principal stress fields in the area. Gold deposits are hosted in smaller-scale structures within the brittle fault zones and brittle-ductile shear zones. Although ore bodies and, on a smaller scale, quartz ore veins often seem to be randomly oriented, it is possible to explain their distribution and orientation in terms of the simple shear deformation process under which they were developed. The progressive simple shear failure is characterized by various fracture modes (tension and shear) that intervene in sequence. The tension and shear fractures are influenced by the stress level (depth of burial beneath the paleosurface) in their structural behavior, show variable dilatancy (void openings) and extend on all scales. By making use of these characteristics, a progressive failure analysis can be applied to predicting the shape and extent of ore bodies as well as the styles of mineralization at any given location.     

基于构造应变分析的裂缝预测方法及其应用

地层应变是构造裂缝产生的直接因素,根据构造应变大小可以预测构造裂缝发育的位置和强度,对研究区的主要裂缝发育区进行划分。文章以松辽盆地徐家围子断陷徐中地区营城组四段（简称营四段）为研究对象,在建立研究区精细的三维构造模型基础上,利用“构造恢复”方法实现研究区古构造恢复,通过开展有限应变值计算来预测构造裂缝的平面分布。研究表明:研究区营四段主要包括3个造缝期,即营城组末期、泉头组—青山口组时期、嫩江组时期,其中,营城组末期与泉头组—青山口组时期的构造变形较为强烈,是裂缝的主要形成时期。根据应变大小与试气产量的关系,将研究区划分为3类裂缝发育区,Ⅰ类裂缝发育区已钻井验证,表明利用构造应变对裂缝的预测结果可靠,Ⅱ类裂缝发育区可作为深层天然气的下一步挖潜的重要方向,Ⅲ类裂缝发育区产能较低,裂缝对储层的改造作用有限。      

Tectonics of the Siberian Craton: Interpretation of geological, geophysical, geochronological, and isotopic geochemical data

The tectonic scheme of the Siberian Craton proposed in this paper is compiled on the basis of a geological map of the craton prepared from numerous magnetometric maps and gravity measurements on various scales, the scheme of axes of magnetic anomalies, and the synthesis of geological information on the exposed territories. The shields and platform territories of the ancient Siberian Craton comprises Archean blocks and Paleoproterozoic foldbelts. The granite-greenstone terranes and granulite-gneiss domains were formed in the Meso- and Neoarchean. The granite-greenstone terranes exposed and overlapped by sedimentary cover are identical, although they generally differ in internal structure and rock compositions both at the infra- and supracrustal levels. The Archean granulite-gneiss domains are recognized either as special tectonic units or as deep sections of granite-greenstone terranes. Two groups of the Paleoproterozoic collisional belts that amalgamated separate Archean blocks of the Siberian Craton into a common stable structural unit evolved 2.1–1.9 and 1.9–1.8 Ga ago. Three types of deep faults arose in the Paleoproterozoic: (1) translithospheric fault zones as boundaries of tectonic blocks and collisional belts, (2) intracrustal fault zones that originated as a result of nonuniform uplift of particular segments of the common plate, and (3) transcrustal zones formed in a plate that overrode another, plunging plate.     

Statistical approach for the geochemical signature of two active normal faults in the western Corinth Gulf Rift (Greece)

Soil–gas measurements of different gas species were performed in two distinct areas of the Corinth Gulf Rift (Greece): the Aigion-Neos Erineos-Lambiri (ANEL) fault zone and the Rion-Patras fault zone. Both zones lie in one of the most seismically active areas of the Euro-Mediterranean region, where a fast-opening continental rift is located. In particular, the geochemical investigations were focused on fault segments and fracture systems previously inferred by geomorphological, lithological and structural studies.In this work the applicability of soil–gas geochemistry surveys for the exploration of buried/hidden faults was tested by using various statistical methods. Moreover, a comprehensive geostatistical treatment of the collected data provided new insights into the control exerted by active structures on deep-seated gas migration towards the surface. In both investigated areas, the highest ²²²Rn and CO₂ concentration peaks correspond with zones where the interaction among fracture and fault segments was inferred by structural and morphological methods. This indicates a clear correlation between the shape and orientation of the anomalies and the different attitude and kinematic behavior of the faults recognized in the two areas. Furthermore, obtained results show that gases migrate preferentially through zones of brittle deformation by advective processes, as suggested by the relatively high rate of migration needed to obtain anomalies of short-lived ²²²Rn in the soil pores.     

Prediction of the collapsing risk of mining slopes based on geostatistical interpretation of geotechnical parameters

Almost all collapses of rock slopes especially in open pit mines are related to discontinuities such as bedding planes, faults and major joints.Geostatistical assessments can be used for understanding the distribution of regionalized variables in any spatial study. In this paper3D spatial dispersion of the fault planes in the Gole Gohar open pit iron mine, located in Kerman province, south east of Iran, is modeled. Then, regionalized variable theory is used to analyze and interpret spatial distribution of the following geotechnical parameters: Geological strength index (GSI), Rock quality designation (RQD), Cohesion (C) and angle of internal friction (f). In order to define regionalized variable distribution, variogram functions were determined for identifying the regional behavior. Structural analysis of variograms showed that the mentioned parameters have spatial structures that make it possible to set up a geostatistical model to predict their values for each non-sampled block on the pit wall. Results showed that there is a relation between the low values of geotechnical parameters and the existence of discontinuities around the pit area. The role of discontinuities in the occurrence of collapses in the area was clearly demonstrated by comparing the estimated parameters models and the model of discontinuities dispersion.     

塔木察格盆地南贝尔凹陷东次凹构造转换带与油气成藏关系

塔木察格盆地位于蒙古国东部,与中国的海拉尔盆地同属一个盆地,为叠置于兴蒙造山带之上的拉张一挤压型中新生代陆相断陷盆地.南贝尔凹陷位于海拉尔一塔木察格盆地中部断陷带的中部,面积为3 200 km2.南贝尔凹陷东次凹南一北洼槽构造转换带位于南贝尔凹陷东次凹中部,为反向聚敛叠覆型构造转换带,是重要的含油气构造带.转换带对油气...     

高放废物处置北山预选区地表岩体结构与岩体质量相关性及其应用研究

岩体工程质量是影响高放废物地质处置（HLW）工程长期稳定性和安全性的关键因素,也是处置库场址比选的重要依据。在地表岩体节理调查统计的基础上,采用RMR(relative metabolic rate)分级方案,探讨北山高放废物处置预选区内以花岗岩为主体围岩的岩体质量与岩体结构的对应特征,建立结构面间距D与RMR岩体质量总评分值之间的定量关系,对北山预选区芨芨槽地表岩体质量分布进行研究。研究结果表明,RMR与D值的点群分布具有扇形发散的正相关特征,随D值的增大,RMR亦呈增长趋势,但低级序岩体结构与岩体质量比高级序岩体表现出更好的对应关系。研究认为,选用RMR与D的点群中心线对应的线性方程评价花岗岩候选区的岩体质量可达到快速评价岩体质量、查明各级岩体空间分布特征的目的,同时也便于对不同候选场区进行大范围岩体质量对比。分析结果显示,北山芨芨槽预选地段BS16钻孔周边3 km2范围内主要以Ⅰ、Ⅱ级岩体为主,岩体质量总体较好且分布相对较为均匀。     

Occurrence of springs in massifs of crystalline rocks,northern Portugal

An inventory of artesian springs emerging from fractures (fracture springs) was conducted in the Pinh?o River Basin and Morais Massif, northern Portugal, comprising an area of approximately 650 km². Over 1,500 springs were identified and associated with geological domains and fracture sets. Using cross-tabulation analysis, spring distributions by fracture sets were compared among geological environments, and the deviations related to differences in rock structure and, presumably, to differences in deformational histories. The relation between spring frequencies and rock structures was further investigated by spectral determination, the model introduced in this study. Input data are the spring frequencies and fracture lengths in each geological domain, in addition to the angles between fracture strikes and present-day stress-field orientation (θ). The model's output includes the so-called intrinsic densities, a parameter indexing spring occurrence to factors such as fracture type and associated deformational regime and age. The highest densities (12.2 springs/km of lineament) were associated with young shear fractures produced by brittle deformation, and the lowest (0.1) with old tensional and ductile fractures. Spectral determination also relates each orientation class to a dominant structural parameter: where spring occurrence is controlled by θ, the class is parallel to the present-day stress-field orientation; where the control is attributed to the length of fractures, the spring occurrence follows the strike of large-scale normal faults crossing the region. Electronic Publication     

The application of remote sensing and structural analysis in groundwater exploration in basement terrains, Darfur region, Western Sudan

Darfur region is one of the most vulnerable areas in Sudan that suffer from shortage in water supply. The objective of the current study is to utilize remote sensing techniques combined with the structural analysis to recognize the most potential fracture zones for groundwater occurrences in the hard rock terrains of Darfur region. The old ductile deformation features in Darfur region delineated from Landsat imageries are used for the structural analysis to determine and classify the fractures in the hard rock terrains of the region. Based on the structural analysis conducted in this study, Darfur region was divided into two domains—the western domain of the pre-Pan-African age that is affected by the two deformational phases (D1 and D2), and the eastern domain represented by the basement related to the Pan-African orogeny. The most potential fractures in the western domain are in the NW–SE and NE–SW trends that classified as extensional and release open fractures for the deformations D1 and D2. In the eastern domain, the main potential fractures for groundwater occurrence are in E–W and N–S directions that are classified as extensional and release open fractures of the deformation D3. From the results of the structural analysis, the main potential fracture systems in Darfur region trend are NW–SE, NE–SW, and E–W directions. The intersections of these fracture systems are the most promising targets for drilling, with consideration of the topography, the rates of recharge, and the underlying geology. The geophysical data and boreholes information in Zalingei and north of El Geneina areas in West Darfur confirm the results obtained from remote sensing data and structural analysis, in which the NW–SE, NE–SW, and E–W fractures trends are the most potential fractures in Darfur region.