جستجوی مقالات مرتبط با کلیدواژه "شکستگی" در نشریات گروه "فنی و مهندسی"

Nowadays, numerous types of research have been conducted to identify automatically fault and fracture systems based on seismic data. Seismic coherence is one of the geometric indicators that is widely used in revealing seismic discontinuities such as faults, fractures, and river channels. One of the suitable tools for identifying faults and fractures is the use of seismic data, which is done using the ant-tracking algorithm. In this paper, by examining the ant tracking algorithm, faults and micro-faults in the Salman oilfield were identified. In the study area, five reservoir formations are present in the Salman field. In addition, five exploratory wells have been drilled in this area. An ant-tracking algorithm is an efficient tool for accurately identifying reservoir fractures. In this research, with the help of ant tracking algorithm, faults and deep fractures of the Salman oil field were investigated. According to the results, a salt anticline was observed in the Salman region and at the top of the anticline, there are significant normal faults that have caused the graben structure in the region. Also, normal faults are along the northwest-southeast. The sub-faults are also normal along the main faults. The ant conjugation algorithm of conjugate fractures in the area identified them.

Identifying faults and fractures in hydrocarbon reservoirs is of particular importance in the stages of enhanced recovering and development of oil fields. The correct description and drawing of faults and fractures can enable the implementation of development projects in the oil industry. One of the methods of describing the discontinuity in the layers is the use of seismic indicators. In this study, the algorithm developed by Hardap [1] was used along with the application of the latest methods of seismic markers in one of Iran's oil fields to evaluate its ability to identify faults and fractures. The results of this study for the reservoirs revealed that the thinned fault likelihood as well as fault likelihood show good consistency regarding to the quality and accuracy of discontinuities in the field. In this regard, the use of information on the slope and azimuth of layers plays an important role in increasing the accuracy of interpretation of discontinuities, especially fractures. Finally, the evaluation of these indicators shows that the main extension of the faults and fractures in the studied reservoir is in the north-south and northwest-southeast direction, which is consistent with the data of pictorial diagrams (Rose diagram) corresponds to the wells drilled in this field. Based on the distribution of the density of fractures at the location of the drilled wells, it can be concluded that in addition to the diagenesis phenomena, the fracture networks and their connection with each other can control the production of field wells.

Most hydrocarbon reserves are stored in natural fractured reservoirs and such systems can affect significantly on the reservoir performance. Therefore, geomechanical studies, understanding and investigating fracture patterns to optimize hydrocarbon production are of great importance for the geologists and oil engineers. Geomechanical studies generally include size and orientation of the three main axes of stress, including vertical stress (Sv), maximum horizontal stress (SHmax) and minimum horizontal stress (Shmin). Studies related to well logging and geomechanical issues are the main objectives of electrical imaging techniques of the well wall. Electrical, sonic or image log, which record high-quality images are pushed in to the well and provide important information regarding boundaries of bedding, structural elements such as faults, folds, discontinuities, fractures and even secondary porosities. Accordingly, in this study, in one of the west south oil fields of Iran using Fullbore Formation Micro Imager (FMI) regarding natural and induced fractures related to regional folding and faulting, some characteristics of the fracture patterns have been studied. These characteristics include the type of fracture, orientation, density, openness, amount of sleep and their relationship with regional construction of the ground. Despite the geological complexities of understudied field, orientations of sub surface fractures indicated clear relationship with the local folding axis and in some cases, it seems that it relates more the orientation of the maximum horizontal stress to the present location of the local strike slip fault too. Orientation of the maximum and minimum horizontal stress obtained N30E- N60W and N50E- N40W respectively based on two wells data analysis. According to the open fractures observed in the wells, three stages of fracture are proposed: pre-folding, early-folding and post-folding fractures.

In hydrocarbon reservoirs of hard formations, hydrocarbon extraction and field development are strongly dependent on the geomechanical conditions of the reservoir, such as fractures and faults status and in-situ stress conditions. Image logs are powerful tools used to evaluate geomechanical conditions of hydrocarbon reservoirs in recent decades. In this study, using the FMI image log, which has a high resolution, coverage percentage and accuracy, the status of fractures, faults, and in-situ stress conditions of the upper Arab Formation in one of the Persian Gulf oil fields were investigated. Accordingly, 206 open fractures in 10 crashed zone with N60E-S60W domain trend and 96 closed fractures with two N45W-S45E and N50E-S50W trends in the Upper Arab Formation of well A were detected and based on the orientation, they mainly were categorized in longitudinal tensile fracture. Also, based on the observed induced fractures and breakouts, maximum and minimum horizontal stresses are oriented in N50E-S50W and N40W-S40E directions, respectively

Cracking is the breaking of bonds in a part of the propellant polymer due to the existing stresses that change the structure of the propellant polymer and they are classified into two general categories: macrocrack and microcrack. The service life of rocket engines is largely a function of the mechanical properties of the solid rocket propellant, the aging characteristics of the rocket propulsion, the grain design, and the environmental conditions that it undergoes during operation. The mechanical properties of solid rocket propellants are critical to the good performance of rocket engines. Increased combustion of propellant grains due to the presence of undesirable cracks and cavities can cause improper performance. This article reviews the causes of cracks due to heat stress, mechanical fatigue, humidity, temperature, corrosion, light, as well as crack detection methods such as radiography, mechanical waves, microscopy and infrared waves

Geometric analysis of fractures in calcareous reservoirs containing hydrocarbon resources is of particular importance. Knowing the location and distribution of fractures in such reservoirs can play an effective role in providing field development plans, determining suitable sites for new drilling and reducing exploration costs. This study was carried out to evaluate the relative frequency of fractures method to identify regional fractures in the Bibihakimeh oilfield. The required data have been extracted by analyzing the underground countor maps in the Bibihakimeh oilfield. Then, the accuracy of the fracture map prepared based on this method was evaluated with the relevant data of reservoir parameters in the studied oilfields. Data on mud loss, thermal gradient, overburden thickness, total organic carbon and production index confirm results obtained from the relative frequency of fractures in the center of the oilfield. Comparison of the results with the map of basement faults in the study area shows that the performance of these regional fractures has caused curvature development and fractures concentration in some parts of the Bibihakimeh oilfield. These regional fractures act as a conduit for heat transfer from the depth to the surface, which in turn has led to a sharp increase in thermal gradient and production in wells in the central parts of the studied oilfield.

Water supply networks are directly related to the economic and social development of urban communities. Due to the rapid increase in population and urbanization, these networks should be properly maintained and rehabilitated. In this paper, an unsupervised learning method with OPTICS density-based clustering algorithm is used to determine the priority areas for rehabilitation. 361 burst event data in one of the Mashhad water network zones were analyzed. The algorithm identified a total number of 16 clusters at 5 different levels of importance. These 16 clusters, which are considered sub-clusters for higher levels, were compared in terms of burst rate. Three clusters with failure rates of 79.1, 62.2, and 50.1 (failures/100 km/year) were introduced as the main priorities for rehabilitation and renovation, respectively. The average burst rate in the whole network was 14.8. The identified clusters were examined in terms of pipe material and diameter and their most affecting factors on the burst rate. The obtained results showed that the OPTICS clustering algorithm has a significant ability to determine priority zones for the rehabilitation plan, by identifying multiple clusters and their according levels. Therefore, the proposed method can be used as a practical and flexible tool to prioritize the rehabilitation process of water networks and identify the main causes of failure events, avoiding complex computational methods or the personal judgment of experts.

Bearings are one of the main components used in the drive-train of electrical machines. Early fault diagnosis and classification of bearing fault for maintenance of electromechanical system are very important. With progresses in measurement and digital systems, extensive range of real-time data can be available in electrical machines. Since fault diagnosis based on signal processing methods from extracted signals may not be possible due to different reasons such as noise level, natural frequencies of system, saturation of core,, severity of fault and load torque, deep learning methods have been considered in recent years. In this paper, time series deep learning method for condition monitoring of bearing in electrical machine for the purpose of detection and classification of fault is considered. Obtained results by means of proposed method have been compared with pervious techniques. Experimental results show that proposed deep learning method can detect and classify bearing fault with accuracy above 90%.

Geometry of fractures including orientation, spacing, aperture and etc. are the influential parameters on permeability in rocks. In order to investigate the effect of spacing and orientation of fractures on permeability in laboratory scale, selecting proper sample is essential in terms of physical and mechanical properties. Therefore, in this study, two types of samples (concrete and fibrous fiber) were selected. Then, physical and mechanical parameters, which consist of density, water absorption, porosity, wave velocity, uniaxial compressive strength and permeability, were measured. The test results showed that the concrete sample is not appropriate sample for studying effect of fracture parameters on permeability due to high porosity, water absorption, permeability and brittle behavior of sample. However, the sample of fibrous fiber not only possesses the favorable physical and mechanical properties but also is suitable to create the fractures with different spacing and orientations as well as the same aperture owing to flexibility and ductile behavior.

Wellbore stability modeling for drilling operations is primarily to create a safe mud weight (mud pressure) window. The designed mud density will be high enough to ensure borehole stability and low enough to not fracture the formation (i.e., mud losses do not occur) Therefore, the safe mud weight should be greater than the pore pressure gradient and shear failure gradient and less than the fracture gradient. In this article in order to investigate the effect of fracture in wellbore failure mechanism and determination of safe mud window, analytical and numerical approach was conducted. In order to shear failure analysis in wellbore in fractured formation, Mohr–Coulomb, Jaeger failure criterion was used. For numerical simulation the distinct element method was used. The simulation of a wellbore in Persian Gulf for fracture formation was implemented in order to understanding the effect of discontinuity in wellbore failure mechanism. The results showed, in a specific angle (β), that represents the direction of fracture orientation relative to the horizontal stress, the fractures do not have any effect on strength of the rock mass. Furthermore, in fractured formation, shear failure do not occur in the direction of minimum horizontal stress, but the orientation of discontinuity specifies the failure and slips direction in wellbore. In this article the maximum mud pressure to prevent failure in wellbore occurs in (β=45+ϕ_w/2=52.25). Also in the range of (17.5≤θ≤46.5) the fractures do not have any effect on strength of the rock mass. The practical mud pressure which was used in drilling operation in real condition in Siri oil field was (40.55 Mpa) and the mud pressure determine in analytical solution is (36.92 Mpa). The numerical result (distinct element method) shows, the overall condition of normalized yield zone, shear failure slips along the fractures and tensile failure in two different pressure (36.92 - 40.55 Mpa) are almost similar. Parametric study results showed that in higher horizontal stress ratio (σ_H/σ_h ), wellbore is more instable and in an isotopic stress regimes the shear and slips along the discontinuity was eliminated.

To study of relationship between mineralization and brittle structures in Torud area field studies and analysis of more than 170 planar structures (fracture, fault and dyke) were carried out. These studies show relationship between mineralising fluid flow and fractures with special orientation, as well as densely fractured zones (fault damage zones) is clearly visible in form of the precipitation of Cu–bearing minerals in the fractures. Results show preferred orientation of the NE–SW trending fractures, which are mineralized, is related to strike–slip stress field with NE–SW trending shortening axis. Also, these results show the mineralization is controlled not only by fractures as a function of local stress field but also is controlled by fault damage zones.

The Sefid-Zakhur Anticline is Located in the Fars Region, 160 Km South-East of Shiraz and South of the Aghar Gas Field, in the West of the Dalan and the Gas Field of Day. In General, Fractures of Hydrocarbon Reservoirs Have a Many Complexions which can Play an Important Role in all Stages of the Reservoir such as Exploration, Development and Expansion, So the First Step is to Study Fractures Especially Reservoirs Failure Identification of Fractures, their Estimation and Analysis. Exploring, Evaluating and Researching Hydrocarbon Fields Requires a Large Amount of Information from Wells, Which Is Usually Not Due to Cost and Problems. In this Research, Firstly, according to Raw Data Obtained from Drilling and with the Help of Commercial Software, Petrophysical Parameters of Sefid-Zakhur Formation as Type of Lithology, Porosity, Shale Volume and Water Saturation, using Evaluate a Probabilistic Method. Based on the Results of Cross-Plot Neutron-Density and M-N Plot, Lithology is Dominated by Carbonate Formation and a Small Percentage of Sandstone and Shale. The Average Water Saturation in the Studied well is 36%. Also, due to the Low volume of Shale 15%, the Average and Total Porosity is Equal in Most of the Wells. To Determine Electro-Facies in the Studied Field of the Method Multi-Resolution Graph-Based Clustering (MRGC) use and Determine 6 Electro-Facies of that Number Facies 2 Due to the Low Volume of Shale, It Has the Best Reservoir Quality and Facies Number 4 Have a Poor Reservoir Quality Due the High Volume of Shale. Method used in this Research a Convenient Method to Analyze the Reservoir Zones and Especially it can be used in Wells Lacking Cores. In the Next Step, The Method is Referred to for Fracture Zones was Determined using the Petrophysical Logs.

Nezamabad fault zone with sinistral strike-slip (Dominant Mechanism) and NE-NW striking has located in the southwest of Iran, it is considered as one of the most important structures in the Zagros fold-thrust belt. This fault has caused complex structural deformations in the region. Also, there is an evidence for fault movement in the Khaftar anticline. This study aimed to fractal analysis, the impact of the Nezamabad fault on the lineaments extracted from the satellite image of Khaftar anticline. The box-counting method is an appropriate method for analyzing the fracture pattern for this study. Using this method, fractal dimensions were calculated for different parts of the Khaftar anticline. The difference between the fractal dimensions obtained from the lineaments associated with the Nezamabad fault well identifies how this fault is affected and the areas with different structural maturity in different parts of the Khaftar anticline. So that part A and C and their southern limbs, which include the SLA and SLC parts, have more fractal dimensions than other parts of the anticline, and these areas, especially the southern limbs of parts A and C are more active than other parts. Also, the difference in fractal dimensions of the Khaftar anticline as a result of differences in density, severity, and direction of stress due to Nezamabad fault performance in the area was evaluated.

The study of the fracture systems and their spatial extensions can help in developing oilfields, reducting the costs of exploration and improving overall understanding of the hydrocarbon reservoir systems. In this study, using different tools such as Landsat OLI-8 satellite imagery, remote sensing techniques, by Geomatica and Rockwork softwares, the structural lineaments map of the Bibi Hakimeh oil field (Surface fractures of the field in Aghajari Formation), is prepare and compared by the data obtained from FMI logs (In Asmari Formation). According to the circular diagram, in Bibi Hakimeh oil field the shear fractures (SO1) and surface axial parallel fractures (SX) have the highest percentages. According to the density map, the highest lineation densities have been seen in the middle belt of the fold from the east to the west, adjacent to the axis of the fold, that are related to the tensile joints in the axis. According to studies on the density map, extraction oil wells in the Bibi Hakimeh oilfield, mainly found in the areas with the highest fracture density. Comparison between the results of the fracture process of FMI 4 logs related to Bibi Hakimeh oilfield with the results of structural studies in this study shows that the trend of fractures in FMI data in the East part are completely compatible with the results of remote sensing studies,Therefore, studies are proposed to develop extraction wells and location for the exploration of new exploratory wells in the east and in sections with high fracture density obtained in this study.

Summary Simulating a rock fracture distribution is an important issue, which is common in various fields of geosciences. This issue is of particular importance in determination of hydraulic conductivity of rock mass and forecasting the amount of water entering the underground spaces. Theoretical studies has been demonstrated that the result of three-dimensional (3D) modeling discrete fracture network is closer to reality than other models. One of the limitations of the statistical methods for modeling fracture network is the lack of spatial behavior considerations of modeling fracture network parameters. In other words, based on Monte Carlo algorithm in statistical methods, generation of fracture network parameters are based on probability distribution functions, and are carried out randomly. In this study, a computational GFracIUT code is developed. In order to generate the 3D discrete fracture network and considering geometrical parameters of the fractures surveyed from the outcrops and boreholes, probability density functions are developed using geostatistical methods. In the mentioned code, initially the density of micro-fractures are conjectured using sequential Gaussian simulation. Then, the locations of the centres of the micro-fractures are determined by Poisson’s process. When the center locations of the micro-fractures are determined orientation components estimated using geostatistical approaches. The developed program is capable of modeling fractures with various geometrical shapes according to operator’s desired specifications. As examples in this regard, disc and quadrilateral shapes have been considered in this paper. In order to practically apply the program, an area in Gachsaran oil field has been considered as a case study.   Introduction Fracture is one of the main characteristics of the rock mass. Fracture network modeling by statistical method has some limitations. One of the limitations of the statistical methods for modeling fracture network is the lack of spatial behavior considerations of modeling fracture network parameters. Geostatistical methods can be employed to spatially characterize fracture network.   Methodology and Approaches First, using the GFracIUT code, we obtain the fracture density map by employing sequential Gaussian simulation method. Then, the location of the centre of each micro-fracture by Poisson’s process is determined using the software. Finally, the micro-fractures orientation component is estimated by geostatistical methods.   Results and Conclusions In this study, a computational GFracIUT code is developed. The GFracIUT code is composed of two steps: positioning the centers of fractures using the fractures density data by sequential Gaussian simulation, and assigning the directions (strikes and dips) of the fractures. In order to practically apply the software, an area in Gachsaran oil field has been considered as a case study.

Due to the significant impact of fractures on the better and more effective production and harvesting, the identification of this phenomenon is a very important. Imaging logs are very powerful tools to study the fractures in the boreholes. In an imaging log, a fracture is seen in the form of a sine curve. In this paper, first, the useful features are extracted by using feature extraction methods such as the Gabor filter bank, Zernike moments, Hu's seven invariant moments and directional Walsh-Hadamard transform, and then, a SOM neural network is used to classify the imaging log. The experimental results showed that the proposed algorithm is able to detect the existing fractures successfully with high accuracy in the imaging logs. In the proposed algorithm, the feature extraction methods are used, which are suitable for extracting the feature of texture objects. The results show that the accuracy of the proposed method is very high to extract fracture pixels, and it has also low sensitivity to noise in the imaging logs. The proposed algorithm in this paper was applied to two types of FMI and RMI image datasets, and the result of the classification has better accuracy in comparison with other algorithms.

Analysis of seismic sections perpendicular to the fold axis and draw the circles surrounding on this profiles indicate the more bending in forelimb due to the more uplift in sedimentary units in effect the compression performance and thrust faults that caused fractures development and density in the southwest limb. Increasing loss of drilling mud in the forelimb anticline wells is associated with development of tensile and longitudinal fracturs related to increase in shortening and anticline uplift, thrust faults propagation and create the duplex structures in near there wells. The maximum and minimum in-situ stresses directions in well No. 2 located in the medial part of anticline are respectively N50 and N140 which are dependent on the Zagros neogene folding. Tensile-indused fractures or maximum in-situ stress direction was inclined in the eastern part of anticline and showing N30E direction. Borehole Breakout or minimum in-situ stress direction is perpendicular to tensile frauture and has N120 orientation. In the southwest part of this anticline, UGC Map is showing that contours of similar thicknesses are inclined and respect to the adjacent anticline was sinistrally displaced. Very high drilling mud losses in well NO.4 located in fold southeast plange is due to the location of this well in minimum distance to strike slip fault trace between two anticlines and due to concentrated stresses resulting from dual intraction the northeast fault lineament releated from folding and operation the sinstral fault after the zagros neogene folding.

To study of petroleum reservoirs which their productions are function of their fractured system, fractures assessment is necessary and important in oil production optimization and field development. The purpose of this research is recognition of a quick method for identification of fractured zones using petrophysical logs which are handy in all wells, and their effects on porosity and permeability of Asmari reservoir of Balarood oil field. The result shows that although some factors such as lithology and reservoir fluids effects on petrophysical logs, requiring minor corrections to logs by means of mathematical methods such as derivation can be used to determine fractured zones on logs, which show great consistency with image logs and velocity deviation log. Results show that zones of abundant bearing fractures can be easily recognized on first stage of derivation on petrophysical logs. Derivation process of any log is defined as a function for that log. Tectonic information and geological prospective of oil field will have an apparent contribution in identification of fractured zones. In addition, fractures and porous zones have had effective impact on the reservoir rock properties. The results indicated that the production in the Asmari reservoir of this field is a combination of fractures and rock matrix and fracture analysis can be done by using petrophysical logs in old drilled wells without image logs as well. As six logs RHOB, NPHI, GR, DT, PEF, CAL have vital role in petrophysical studies, these six tools are the best logs to diagnosis of fractured zones due to their responses against the fracture along with doing some corrections in these logs.

Shale volume is one of the main parameters in petrophysical and reservoir studies. Using core to petrophysical parameter determination has some problems and limitations such as coring costs too much and normally it cannot be completely recovered (especially in fractured reservoirs). Image logs dominantly have been used for fracture analysis in Iran, while they have been used to a lesser extent in other fields such as shale volume calculation, porosity, sedimentary environment recognition, etc. In this study, the shale volume of Dalan formation was estimated by applying Binarization method to the FMI image log in one of carbonate reservoirs of the SouthWestern oil fields of Iran. For the validation of suggesting approach, shale volume has also been estimated from GR log Index (CGR) and was compared with FMI shale volume. Shale volume resulted from FMI and CGR logs are compatible and shale volume determination using FMI has some errors caused by locating open fractures next to the shale interlayers.