- Home
- Conferences
- Conference Proceedings
- Conferences
74th EAGE Conference and Exhibition incorporating EUROPEC 2012
- Conference date: 04 Jun 2012 - 07 Jun 2012
- Location: Copenhagen, Denmark
- ISBN: 978-90-73834-27-9
- Published: 04 June 2012
901 - 948 of 948 results
-
-
Deconvolutive Time-frequency Distribution Based
Authors Y. M. A. Mahmoodi, H. R. Siahkoohi and M. Rezaee FarThe Wigner-Ville distribution is a time frequency tool widely used in seismic data analysis. Obtaining high time-frequency resolution is a fundamental significant in spectral decomposition. The Wigner-Ville distribution is a bilinear method for spectral decomposition that suffers from the cross terms problem. Various type of 2D band pass filters have been designed for reducing these cross terms. Although applying 2D band pass filters reduces the cross terms, however decreases time-frequency resolution distributions. In this paper we aim to improve time-frequency resolution of the Smoothed pseudo Wigner- Ville distribution via Deconvolutive Time-Frequency Distributions. The method attempts to compensate the damaging effects caused by applied 2D smoothing functions in order to eliminate the cross terms. Performance of the method was tested on both real and synthetic seismic data.
-
-
-
Microbial Gas System in the Polish Part of the Carpathian Foredeep between Pilzno and Przemyśl
Authors M. Kotulska and N. BroniakThe main purpose of study is to determine the molecular and isotopic composition and origin of gaseous hydrocarbons in the Miocene strata of the Polish part of the Carpathian Foredeep between Pilzno and Przemyśl. We carried out analyses of molecular composition and stable carbon isotope composition of methane, ethane, propane and carbon dioxide and stable carbon isotope composition of methane. In the autochthonous Miocene strata of the Carpathian Foredeep natural gas is accumulated in the Badenian and Lower Sarmatian reservoirs. It is dominated by methane from the microbial carbon dioxide reduction and occurrence in the marine environment. During the microbial and initial phase of low-temperature thermogenic and/or diagenetic processes the ethane and propane were produced. The molecular and isotopic compositions of accumulated gases are similar which indicates homogeneity of generation processes within the full Miocene succession. Gases was generated in claystone/mudstone horizon migrated to the overlying sandstone horizon which was covered by another claystone/mudstone bed.
-
-
-
New EPR (or ESR) Data on Urzhumian Stratotype Section Rocks - Enviroments and Geochemical Trends
Authors R. Gabdrakhmanov and N. Nurgalievalot of EPR parameters have been detected from rock powders: E’(g=2.0005 - quartz), Mn2+ (carbonates), (dolomite), Fe3+, SO2-, SO3-, Rorg. It was revealed remarkable variation of these parameters along the stratotypical Urzhumian section due to sedimentation and diagenesis of rocks. Seven typical mineralogical compositions have been determined by EPR signals composition: 1) calcite; 2) calcite and ferromagnetic minerals; 3) calcite and dolomite; 4) calcite, dolomite and ferromagnetic minerals; 5) calcite and ferromagnetic minerals; 5) dolomite and ankerite; 6) quartz and ferromagnetic minerals. It was demonstrated and estimated the distribution of these compositions within section in comparing with magnetic susceptibility change and variations of ratio Sr/Ba. It was selectively proved the palaeogeographic trend of sedimentary basin evolution from marine to continental environments and influence of late diagenetic processes on rocks formation.
-
-
-
Inversion Structures along Oblique Lineaments in the Apennine
Authors P. Pace, F. Calamita and V. SciscianiInversion tectonics of pre-existing extensional basins produces characteristic hydrocarbon traps. The positive reactivation along N-S oblique extensional paleo-lineaments in both the Central-Southern Apennines of Italy and in the Adriatic foreland occurs and shows different structural geometries with respect to NW-SE extensional paleo-lineaments, in which short-cut thrusts were developed.
-
-
-
Seismic Facies Analysis of Quaternary Deposits in German North Sea
More LessSeismic facies analysis was performed on approximately 1540 km of 2D high-resolution multi-channel seismic data from the German North Sea. Six seismic facies were defined in the study area. Facies 1 covers the Quaternary sand depositional system. Facies 2, 3, and 4 represent three types of tunnel-valley infill. These valleys were formed during different glacial periods in the study area. All of them are characterized by erosional incision into underlying deposits. Facies 5 probably represents the youngest post-glacial sediments after the retreat of last glacier. Facies 6 is a typical seismic reflector for peat.
-
-
-
Emplacement of Lavadores granite: AMS study
Authors P. Agarwal and H. Sant’OvaiaThe AMS studies were done on magnetite type granite, the Lavadores granite which is an example of late to post-orogenic Varsican granite in Northern Portugal (NW Iberian Peninsula). The post tectonic emplacement is supported by the magmatic nature of the microstructures. In the northern region Magnetic lineations are sub-vertical and sub-horizontal in the southern region. Magnetic foliations display a general WNW-ESE sub-vertical pattern consistent with a dextral kinematic. These AMS data suggest that the emplacement of the Lavadores granite was controlled by a major mechanical anisotropy formed by trans-tensional structures associated with the Porto-Tomar shear zone.
-
-
-
Distribution of Clay Mineral Assemblages in Lower Pliocene Sediments, Western Flank of the South Caspian Sea
Authors E. Abdullayev, W. Ehrmann, C. Khalifazade and E. HuseynovX-ray diffraction analysis (XRD) is used for identification of clay minerals in sediments of the Productive Series (Lower Pliocene) from the western flank of the South Caspian Sea. We investigate fine-grained sediments of the lower and upper divisions of the Productive Series cropping out in Kirmaky Valley, which is located onshore on the Apsheron Peninsula, Azerbaijan. The clay mineral assemblages of the investigated sediments consist of 44-64% illite, 5-33% smectite, 14-29% chlorite and 5-9% kaolinite. The dominance of illite and chlorite indicates physical weathering of the hinterland, possibly under arid conditions.
-
-
-
Examination of the Complex Transition Zone in the Southern Gulf of Paria, Trinidad-Venezuela
Authors B. Figueira and A. EscalonaThe Gulf of Paria straddles the border between Trinidad and Venezuela north of the Eastern and Columbus foreland basins. On both sides of the border hydrocarbons are produced from siliciclastic reservoirs of varying age, usually younger than Oligocene. The oils produced vary from light to heavy, and form a lineament following major thrusts in the region. It is a proven fact that the geological structures present in the Trinidad region are not only linked with structures present in Eastern Venezuela, but in most cases they share similar causal mechanisms. This paper presents an overview of the structural and stratigraphic evolution of the southern Gulf of Paria transition zone and applying the results to Hydrocarbon exploration. This work was based on analysis of a combined dataset of approximately 1425 km of 2D seismic lines and 10 wells.
-
-
-
Heavy Minerals Association from Gold Placers Found on Aries River, Romania
Authors G. Manuc, D. Popescu and D. JianuThe hydrographic basin of the Aries River covers almost an entire half of the Apuseni Mountains which contain some of the richest gold deposits in Europe that formed as a result of the Miocene volcanic activity in the Carpato-Pannonian area. The river and its tributaries carry gold and heavy minerals which the river will deposit in placers along its valley. The purpose of this study is the analysis of the high density minerals associated with the gold in order to understand the processes behind placer formation along the Aries river and see if the mineral associations could indicate the proximity of gold placers and the sources of the gold within the alluvial deposits.
-
-
-
Comparison and Validation of the Modified Kozeny-Carman correlation for the estimation of permeability
Authors D. M. Castellanos, I. Whyte and P. DiazPermeability of the rock can only be measure directly by performing RCAL/SCAL (Routine/Special Core Analysis) on core samples, which have to be captured and retrieved while drilling the well representing a variety of challenges. In this study the modified Kozeny-Carman correlation (Nooruddin and Hossain, 2011) has been studied in order to establish the accuracy of the permeability estimations. The variables involved within the correlation – shape factor (fg), specific surface area of the grain (SVgr), lithology factor (a) and cementation exponent (m) – are proved to represent the porous system. Two data sets were used to validate the accuracy of the correlation. Data set 1 has a very poor permeability-porosity relationship, with very low porosity values which inferred a lot of noise in the permeability results. Data set 2 has a good permeability-porosity relationship, and the grain size analysis report was useful to estimate pore throat radius (r) and consequently SVgr. a and m values were taken from the literature due to lack of SCAL data. Permeability data estimated by using the modified Kozeny-Carman correlation proved to be in agreement with RCAL permeability; however, it is very important to calibrate those measurements back to core analysis or reservoir rock measurements.
-
-
-
Multidisciplinary Data Integration for 3D Geological Outcrop Characterization - Jackfork Group, Hollywood Quarry Arkansas
Authors L. Castillo, A. Cadena, R. Brito, O. Davogustto and R. SlattThe Hollywood Quarry has been studied using many techniques in order to characterize its stratigraphy, structural deformation and general geological features. The quarry exposes deepwater sediments of the Jackfork Group (Pennsylvanian) often utilized by petroleum companies as a potential 3D deepwater outcrop analog. The main goal was to build a refined 3D geological model of the outcrop based on a previous model built from outcrop and subsurface gamma ray logs, facies descriptions, and porosity datasets (Goyeneche et al., 2005) and integrating new 2D near-surface seismic reflection sections and Ground Penetrating Radar (GPR) profiles, outcrop images (photomosaics), GPS data and stratigraphic columns acquired from newly exposed quarry walls. These exposures, never before seen, made it possible to compare our geological interpretation of the seismic and GPR data acquired prior to removal of the rock with the true outcrop geology revealed in the new exposures. These results allowed us to improve the characterization of the structural and stratigraphic geometries and, in particular, their response to the remote sensing methods. The correlations between the true outcrop geology and seismic/GPR data interpretation were good, thus demonstrating the value of using geophysical techniques for 3D outcrop characterization of reservoir analogs.
-
-
-
Oil Recovery Method
Authors S. A. Evdokimov, A. M. Evdokimov, N. G. Nourgalieva and E. A. EvdokimovaAt the late step of oil industry development special attention is paid to well exploitation, switching-off well or transfer to another category. It deals with the fact that a lot of big oilfields started to be at the latest step of development, which is characterized by high levels of water cuts with small oil output of producer wells, physical wear of production wells. The problem of energy conservation in oil industry becomes actual when water cuts of the produced fluid reaches a significant amount and continuous to grow when recoverable oil resources are exhausted. Increasing efficiency of oilfields development depends on creation of new technical and technological management facilities of oil production processes. Technological innovation of influence at reservoir depends on geological conditions of oilfield development and supply of fuel and energy resources of the process of oil production. It is not profitable to build oil and water treating equipment, pipeline for it’s transportation in small and remote oil deposits. It is proposed to use inactive well in order to separate oil and gas for these kinds of deposits. As a result there are consumption reducing for fluid transportation, oil and water treating.
-
-
-
Experimental Investigation of Near Miscibility Effect on Relative Permeability Curves
Authors M. Parvazdavani, M. Masihi and M. H. GhazanfariThe requirement of reliable relative permeability data is more intensified when the miscibility condition approaches. In this work the relative permeability of CO2 and oil has been measured at different miscibility conditions using conventional methods. Fractured dolomite and sandstone core plugs samples were used in the experiments. Due to some errorful assumptions of conventional methods such as immiscible, incompressible displacement, inverse modeling was used for predicting the reliable relative permeability of oil and gas phases at near miscible condition from measured oil production and pressure drop data. The initial guesses of relative permeabilities were provided from conventional semi analytical method. The results showed that by approaching the miscible conditions, the conventional methods underestimate the values of oil-phase relative permeability, while the values of gas phase do not change considerably. Moreover, the effects of near miscibility on the gas phase relative permeability curve were stronger. By having a fair relation between the criteria of approaching to near miscible and the errorness of conventional methods, we modified the conventional method. The results of this work can be helpful in understanding of the near miscible relative permeability behavior at low IFT conditions.
-
-
-
Reservoir Evaluation and Saturation Monitoring Using RST Fluid Analysis for Improve Oil Recovery
Authors I. A. Jimoh, S. N. Rudyk and E. G. SogaardTo manage existing fields as effectively and efficiently as possible, there is a need to monitor movement of formation fluids within the reservoir as well as production from individual wells. Result from the case study of an unnamed well in Nigeria using the data acquired with reservoir saturation tool (RST) and interpreted with GeoFrame petrophysical software was able to identified formation fluid contacts, define saturation of those fluids, and locate potential cased-off, bypassed oil. From the sigma mode interpretation there is no gas within the zone of interest. The cross plot of the near and far carbon oxygen ratio statistically plot in the lower left corner of the quadrilateral indicated the annulus hold up value of zero. The final C/O interpretation shows that the original oil water contact in the zone of interest has risen to 2302m and the flushed zone is between 2302-2308m. The section above this depth (2294-2298 m) is possibly at initial water saturation and offers a choice for future re-drill.
-
-
-
Using Geochemical Techniques to Study Surface/Groundwater Interaction
Authors S. Munir, A. Mashiatullah and S. MehmoodQuality of groundwater samples in vicinity of Lei Nala in Islamabad was assessed using physio chemical and geochemical parameters. Lei Nala was sampled at four (4) different locations, ten (10) shallow groundwater samples (up to 200 feet) and twelve (12) deep groundwater (>200 feet) were collected for analysis. Absence of carbonate ions (CO3-2) in all groundwater samples indicates presence of limestone dissolution giving rise to bicarbonate and ultimately Ca-Mg type waters. Piper diagram reveals dominance of Ca-Mg-type of water in the studied area. The percentage of samples falling under Ca-Mg-type was 53.86 %. For anion concentration, HCO3-type of water predominated with 96.15 % samples. The results of physiochemical parameters of water quality are well with in the guidelines/recommended limits as stated by the WHO (World Health Organization), European Union (EU) and Pakistan Environmental Protection Agency (Pak-EPA).
-
-
-
Carbon Dioxide Storage in Reservoir Structures on Example of Jastrzabka Stara Oil Deposit
By J. NosalCarbon dioxide is one of the greenhouse gases, which occur in the atmosphere as a result of Earths processes and human activity. In case of the descending concentration of CO2 in the atmosphere, global society decided to invite and implement new technologies, which allow to combust fossil fuels with any carbon dioxide emission. One of these technology is carbon dioxide capture and injection to geological structures (Carbon Capture and Storage - CSS). CO2 is supposed to be storaged in sedimentary basins and possibility of long - term storage is related to their stable structure. Depleted oil and gas fields tend to be a perfect structures to carbon dioxide injection. They are natural traps holding reservoir liquids and in case of hydrocarbon exploration and production are well recognized. In addition, enhanced oil recovery associated with CO2 injection increase the reservoir production. Advantages and disadvantages of CO2 storage and parameters of geological structures capable for sequestration are discussed. Possibility of use the enhanced oil recovery methods are presented in relation to Jastrzabka Stara oil deposit (SE Poland, Carpathian Fordeep).
-
-
-
A Successful ASP Flooding with Organic Alkaline
Authors A. Naghizadeh Dilmaghani and S. TeimoorzadiThis paper describes the use of a new type of Organic Alkaline that replaces and improves upon traditional Inorganic Alkalines such as Sodium Hydroxide and Sodium Carbonate.The new Organic Alkaline was evaluated in ASP formulations containing commonly used Surfactants and Polymers. Organic Alkaline(s) uses can have very benefit.One of the most importanant benefit of Organic alkaline(s) is that it is non-toxic , so it can consider HSE (Health and Safety Environment) conception.Other advantage of OrganicAlkalines are that they are easily absorbed in environment.Their non-toxic, biodegradable properties make them particularly suitable for environmentally sensitive applications such as offshore and inland lakes.
-
-
-
Improved Oil Recovery by the Efficiency of Nano-particle in Imbibition Mechanism
Authors G. Cheraghian and S. TardastiPrevious studies have indicated that the oil recovery from porous media may be substantially increased by the injection of miscible fluids.This all sounds great and water flooding has been used successfully for decades, however, it is important to take care to design and operate the flood appropriately. In this experiment, two nano-particles dissolved in water are used to inject into simulated environment and here they are Titanium dioxide and Fumed silica. Using nano-particles in all samples has resulted in recovery increase. Among the applications of the study is improvement in oil recovery (IOR) which can be applied in many water wet reservoirs dominated by inhibition mechanism to extract more flow through really small caliber pores . Using nano-particles in all samples has resulted in recovery increase. Finally,Considering the experiments, it is demonstrated that flows with nano and in particular Titanium dioxide nano have highest amount of recovery. So, using nano-particles in water flooding projects and even some of the polymer flooding ones (for IOR process).
-
-
-
Optimal Well Location in Surfactant Flooding by Genetic Algorithm
Authors R. Ravandoust and M. ChahardahcherikAs many fields around the world are reaching maturity, the need to develop new tools that allows reservoir engineering to optimize reservoir performance is becoming more demanding. One of the more challenging and influential problems along these lines is the well placement optimization problem. Determining of the location of new wells is a complex problem that depends on reservoir and fluid properties, well and surface equipment specifications, and economic criteria. Various approaches have been proposed for this problem. Among those, direct optimization using the simulator as the evaluation function, although accurate, is in most cases infeasible due to the number of simulations required. The optimization algorithm used in this work is the genetic algorithm which is a method based on natural evolution process. Optimal placement of up to three surfactant injection wells was studied at two fields. One of the Iranian conventional field and a hypothetic fractured field. The net present value of the surfactant and water flooding projects was used as the objective function. Profits and costs during the time period of the project were taken into consideration.
-
-
-
Uncertainty Analysis of Selected Geological Properties of the Radecin CO2 Potential Storage Site - NW Poland
By M. A. MichnaThe study presents the risks associated with the precision of structural mapping and uncertainty analysis of basic property parameters of the Radecin anticline. Investigated area is located in the SW Poland on the Gorzw Block. Lower Jurassic aquifer was selected as a potential site for CO2 storage. The author defined to what extent the amount and distribution of input data analysed within the structure affects the credibility of the sealing horizon and how the variable property parameters influence on volumetric calculations of GIIP in the reservoir. Structural uncertainty was performed by comparing deterministic versions of horizons with stochastic realizations. Using the Uncertainty and optimization module in Petrel, author created the workflow to investigate four property parameters in the model. The results shows that poor data control determine the significant range of structural uncertainty. Currently used input data do not allow to control enough well the SE part of the anticline. In Volume Calculation the most sensitive parameter is gas saturation. Investigated Net-To-Gross cutoff has very small impact on the changing proportion of reservoir/non reservoir cells. That's why this parameter may be omitted.
-
-
-
CBM Production Estimation with Varying Reservoir Properties
By A. GhosalCoalbed Methane (CBM) is an unconventional energy resource that has become an important source of energy in many countries. Highly varying porosity and permeability affect the production of gas from these reservoirs and a detailed study of the change in production rate and capacity is required for identifying and predicting the expected production of these reservoirs in the future. In this paper, the effect of various petro-physical parameters like porosity and permeability on CBM production has been estimated by considering a real world dataset. The changes in the gas production rate with time have been illustrated considering a range of reservoir parameters. It has been found that the change in permeability with constant porosity greatly affects the production rates with permeability being directly proportional to the rate of gas production. The change in porosity with constant permeability also affects the production of the gas by reducing the production rate with increased porosity since the higher amount of water in the pores now hinders the flow rate of the adsorbed gas. The increasing porosity also delays the production rate to achieve its maximum value as the water in the pores must be released before the gas can be produced.
-
-
-
Parameters Analysis of Natural Gas Flows in Supersonic Separators
More LessThe supersonic separation is a new technology which can be used to condensate and separate water and heavy hydrocarbons from natural gas. In a supersonic separator, natural gas has an extremely short residence time to prevent hydrate problems and eliminates the need for chemicals and associated regeneration systems, providing an environmentally friendly facility for sustainable development. The dynamics parameters of natural gas in a supersonic separator and the effects of back pressure on the gas flows were numerically calculated using the standard k- model with real gas model. The results show that natural gas expands in the supersonic separator to supersonic velocities with resulting in low pressure (25 bar, from about 101 bar) and temperatures (-75 ˚C, from 30 ˚C), which causes the condensation and nucleation of some components. The higher back pressure induces the shock position shift forward from diffuser to nozzle. The shock goes into the diffuser when the pressure recovery efficiency is less than 0.7. If the pressure recovery efficiency is more than 0.8, the shock moves into the nozzle, resulting in the re-evaporation of the condensed components, which leads to the failure of the gas and liquid separation of this device.
-
-
-
Landslide Susceptibility Assessment Using Quantitative Methods - Case Study in Satu Mare County, Romania
By A. A. HulpoiFollowing abundant rainfall of autumn 2008 and the snow melting in the spring of 2009, land instability increased, leading to reactivation of landslides and the activation of new ones, some of them large and with significant damage. Besides the high intensity of the rainfall, geological structure, hidro-geological conditions and anthropogenic factor are the main causes for the occurrence of landslides. Mapping these phenomena became an important task for the future development of the studying area, because the industrial development of this area depends on the infrastructure. Using different types of maps, for different causative factors, quantitative methods of landslide susceptibility assessment and GIS software, we can create different maps for two different methods of evaluation (logistic regression and a bivariate approach using Weight of Evidence and compare them. Based on the observations from both approaches to evaluation, logistic regression was considered the better model, and was thus presented as the final landslide susceptibility map for the study area.
-
-
-
Seismic Evidence for Gas Hydrate in Dongsha Area, Northern South China Sea
Authors L. Li, X. H. Lei, G. X. Zhang and X. ZhangA large cold vent, named Jiulong Methane Seepage, was discovered in the Dongsha Area of northern South China Sea (SCS) in 2004. We present seismic evidence of the existence of gas hydrates and free gas beneath Jiulong Methane Seepage. Bottom Simulating Reflectors (BSRs) are identified in the seismic profiles, inferring the presence of gas hydrate. Seismic attributes, interval velocity model, relative acoustic P-impedance inversion were conducted to better image the distribution of gas hydrate. Hydrate-bearing sediments are characterized by weak reflection (blanking zone) above BSRs, high velocities and relatively small impedance differences, while the enhanced reflection, low frequency, and low velocities suggest the presence of associated free gas below solid hydrate. The formation of gas hydrate is related to widespread faults and mud diapirs (gas chimneys) in Dongsha Area. The presence of faults and mud diapirs provide useful conduits to gas migration upward, linking the free gas zone below BSRs and hydrate zone and seafloor, and hence causing methane leakage on the seafloor.
-
-
-
Building of Log-based 3-D Geological Models of Fields with High Lithological Variability
More LessThe Leno-Tungusky petroleum province (Eastern Siberia) has one of the most complex geological structures. An important factor is the process of secondary alteration of reservoir rocks in this area. Re-crystallization, claying, carbonatization, sulphatization, and salinization of pore space greatly reduce the quality of reservoir properties, often turning the rock into a non-reservoir category. In such geological conditions, the accuracy of three-dimensional model is of paramount importance. The methodology for three-dimensional geological modeling based on well log data was developed. It is shown that this approach improves the accuracy of the forecast distribution reservoirs compared to the standard method.
-
-
-
Mineralogy and Geochemistry of Mississippian and Devonian Black Shales at the Northern Margin of the Rhenohercynian Zone
Authors D. Rippen, A. K. Uffmann and R. LittkeDifferent black shale sequences occurring in the Devonian and Mississippian at the northern margin of the Rhenish Massif and the Ardennes have not been considered economically interesting targets so far. Due to their high thermal maturity, all oil potential has been exhausted. Nevertheless, some of these shales are still within the gas window. Therefore, these sequences may well act as economically feasible gas shales in the future. To evaluate the shale gas potential, extensive measurements on these black shales have been performed, including mineralogical investigations, analysis of organic and inorganic geochemical composition, as well as vitrinite reflectance measurements. Next to gathering information on Devonian and early Mississippian black shale sequences, this study mainly focused on the marine, organic-rich “Hangende Alaunschiefer” (Upper Alum Shale) in Germany and the Belgian “Chokier Formation” of late Mississippian age. Results of these extensive measurements revealed that especially the properties of the Upper Alum Shale and the Chokier Formation are similar to producing gas shale formations in the USA. Therefore, these sequences may become an important target for future shale gas exploration in Europe.
-
-
-
Unique Yaregskoe Oilfield - Geological Aspects and Features of Petromine Development System
More LessThis work generalizes the research of the unique Yaregskoye oilfield using electron spin resonance, optical and electronic microscopy and chromatography-mass spectrometry which were made by us in laboratories of KFU geological faculty. We have particularly studied the material constitution and structural-textural features of sandstones of the III oil-containing bed, it’s genesis and we also have interpret the processes of Yaregskoye oilfield oil enrichment with vanadium on the basis of the hydrogeological (infiltration) mechanism. There are probably both mechanisms of oil enrichment with vanadium on Yaregskoye oil field, but according to the data we got the dominant role in generation of Yaregskoye vanadium-containing field of oil and gas obviously belongs to the processes related to underground waters infiltration and their contact to an oil body eventually. The results we got during this research work are of great practical and scientific importance, because they help us understand the nature of oil fields connected with vanadium-containing doleritic dykes and approximate to the generation nature of vanadium-containing fields of oil and gas.
-
-
-
GPR Investigations as a Tool for Revealing Ancient Structures in the Archaeological Site Orgame/Argamum, Romania
Authors A. Mărășescu, A. Mârza and R. OrzaOrgame/Argamum is one of the most important archaeological site located on the Black Sea coast of Romania, proving more than two millennia of inhabited area. The 3D GPR survey was carried out in order to obtain more detailed information about the uppermost structure of Orgame/Argamum archaeological site, using a GSSI SIR 3000 System. For this preliminary investigation, two sites were chosen, both being recommended by the archaeological working team, which, at the moment of the data acquisition have already excavated a part of the ancient necropolis. The geophysical investigations performed on the archaeological site offered a 3D image about its subsurface structure, being in a good correlation with the direct information available in the field. Also, we were able to accurately pinpoint the future digging sites.
-
-
-
Rational Complex Processing Graph of and Interpretation of Geophysical Information of Pirkivska Field
Authors V. D. Petruniak, I. Ustenko and S. VyzhvaTo create a processing graph were performed studies of the frequency spectrum of input seismographic records, determining the frequency range of useful components of the wave field, assessing the level and impact of ; noise events, and a test of sequence and parameters of defined procedures.
-
-
-
Channel Detection Using LTFT and Q Factor Estimation
Authors S. K. Cherati and H. R. SiahkoohiElastic energy of a seismic wave is attenuated while propagation through the earth. Generally, attenuation is determined by quality factor (Q) which is a dimensionless parameter. Due to the frequency dependency of attenuation, it is usually studied in frequency domain based on power spectrum and statistical methods. We used the local time-frequency transform (Fomel et al., 2010) as a time-frequency representation tool and the spectral ratio method to estimate Q for a given seismic data set using. Performance of the method was tested on both real and synthetic seismic data. A channel within a stacked volume was detected by estimating Q cube using the method.
-
-
-
Inverse scattering internal multiple prediction on data from a physical modeling experiment
Authors M. Hernandez, K. Innanen and J. WongThe internal multiple attenuation algorithm derived from the inverse scattering series is a powerful means to predict and suppress interbed multiples. Examples of significant multiple suppression in marine field data cases have been well-documented, and more recently land application has also had positive outcomes. Especially as applicability moves onto land, questions of (1) optimal choice of integration limits, (2) minimum allowable proximity of sub-events, etc., grow in importance. One possible way of systematically studying these issues is via physical modeling. Using the CREWES physical modeling facility, a large contrast layered target was designed to generate size able interbed multiples in near offset reflection data. A 1D version of the prediction component of the algorithm was applied to data with some minimal preprocessing. In this paper we present our initial results and preliminary conclusions.
-
-
-
The Analysis of the Body and Surface Waves Retrieved from Ambient-noise Recordings
More LessWe applied seismic interferometry by cross-correlation on two passive seismic dataset recorded in the Mizil area, Romania, to retrieve the body and surface waves. The Mizil area is located next to the seismically active Vrancea zone. The passive measurements were performed in 2009 and 2011 using vertical component geophones planted along two orthogonal directions; geophone spacing was 2.5 m. A number of 1183 noise panels of 16s length were recorded in 2009 and 600 noise panels of 10 s length were recorded in 2011. The spectral analysis of the passive data showed that the noise recorded in 2009 is richer in high frequencies compared to the one recorded in 2011. The body waves were retrieved using ambient-noise recordings without surface waves. By comparing the retrieved waves with those we have seen on active seismic data recorded on a seismic profile in the vicinity of the passive survey, we notice that some of the retrieved waves correspond with geological markers identified on the active seismic data. The surface waves were retrieved using the whole passive data; those reflected waves, at the same time with the surface waves, are not visible, being covered by the surface waves because of their high amplitude.
-
-
-
Application of Full-waveform Inversion to Characterize Quick-clay Landslide Site in Southwest Sweden
Authors A. Adamczyk, M. Malinowski and A. MalehmirLandslides are one of the most commonly occurring natural disasters. Recognition of the geometry of clay layers and the behaviour of their physical properties during and after a disturbance (e.g., excess rainfall) is crucial to understanding the mechanism of a landslide. A multidisciplinary geophysical survey led by Uppsala University was conducted over a landslide scar near the Gta river in southwest Sweden. Here, we present the application of full-waveform inversion/tomography (FWT) to two perpendicular seismic profiles that cross the landslide scar. Obtained high-resolution P-wave velocity models portrait geometry of the low-velocity zones attributed to the quick-clay layer.
-
-
-
Heavy Metal Pollution Mapping Using Magnetic Susceptibility in Copsa Mica, Romania
Authors A. M. Sirbu and C. IacobCopsa Mica, Romania, is best known for its status (in the 1990s) as one of the most polluted cities in Europe. Studies show that magnetic susceptibility can successfully describe the pollution distribution in industrial areas. This paper approaches the applicability of field magnetic susceptibility investigations in realizing a fast screening of heavy-metal distribution, in order to optimize the quality and to reduce at a minimum the costs of geochemical investigations. The obtained results revealed a high applicability of this method for environmental problems, being an effective way of reducing the costs for geochemical studies.
-
-
-
4D ERT for a Continuous CO2 Leakage Monitoring
Authors B. Blanco, F. Chasserot, S. Elfilali, E. Stozicky, R. Trocque and F. Vidry4D seismic and 4D micro-gravimetry are ideal geophysical techniques to monitor the volume and density of a CO2 plume respectively. However, as acquisitions are only done once a year, they cannot prevent leakages. Thus, the continuous monitoring of carbon sequestration sites would be required for wider social acceptance. Electrical Resistivity Tomography (ERT) is a non-destructive technique, which may provide information about contrasts in resistivity. During December 2011, we simulated two CO2 leakages of 1kg and 5kg at 5.3 m depth and we made several ERT acquisitions. This experiment proves that time-lapse ERT and 4D ERT are able to detect any CO2 leakage before it reaches the surface.
-
-
-
Advance in Carbonate Rock Physics - Mineralogy Analysis and Acoustic Velocity Mapping on Thin Slice Image Using ANN
Authors P. D. Wardaya and B. E. B. NurhandokoBackpropagation neural network is trained to recognize and classify constituents of carbonate rock and give appropriate acoustic velocity value to each constituents from their color difference. Carbonate minerals;Calcite and Dolomite are known can be distinguished visually using acid solution alizarin red s where calcite turns red while dolomite remain colorless. pore space which is impregnated using blue dyed epoxy will seen blue. Lavenberg marquadt training method is used to train the network. it reaches convergence after 25 iterations and yields nearly perfect classification. The result is 2D matrix (classified image) where the pixel value represents each constituents. The network is then trained to give the acoustic velocity value to each constituents derived from table of minerals constants. We assume that pore spaces is fully filled by brine water so their acoustic value is brine's. This results a acoustic velocity map or velocity model which is the used in virtual experiment of wave propagation simulation. Acoustic wave is propagated through the velocity model at various frequency from 10-35 KHz. The travel time and velocity are measured at each frequency of wave. we find the positive dispersion where velocity of wave increases as frequency increases.
-
-
-
Single Station Ambient Noise Observations in Tehran
Authors M. Fotouhimehr, E. Shabani, N. Mirzaei and E. HaghshenasIn this study first, we checked particle motion behavior of ambient noise recordings in Tehran. The results show the predominance of Rayleigh waves in ambient noise wave field. Then, we investigated H/V curves of ambient noise recordings. After modeling ellipticity curves of Rayleigh waves, we investigate coincidence of H/V ratio peak with the peak related to fundamental mode of Rayleigh waves. To sum up, in the desired area fundamental mode of Rayleigh wave accounts for the peak observed on the H/V curves, related to site resonance frequency.
-
-
-
Defining Optimized Parameters of Seiscomp3 for Real-time Seismic Data Processing in Central Alborz Region, Iran
Authors A. A. Amjadi, Z. Shomali and M. HatamiSeiscomp3 is one of the few software programs used nowadays for real-time data processing including earthquake location. It uses continuous waveforms as an input, automatically computes Short Term Average to Long Term Average ratio (STA/LTA), picks phases, and then locates events by pre-defined travel-time tables in a grid formatted file. In this study, continuous waveforms recorded by Iranian Seismological Center affiliated to University of Tehran (IRSC), Central Alborz region of 2010 were used. The region includes 3 seismic sub networks including Tehran, Sari and Semnan with 19 short period stations. Using sesicomp3 in offline mode is important for calibration and optimization of parameters such as defining optimized filter, suitable STA/LTA ratio, and proper velocity model and so on. Obtaining optimized parameters for seiscomp3 in Central Alborz region is the essence of this study as micro seismic events that were not detected in the IGUT routine bulletin for the year 2010 were found using seiscomp3. Now there is an opportunity to locate events automatically in real-time mode and more accurate results can be obtained compared to routine manual phase picking done by IGUT.
-
-
-
Empirical Spectral Ground Motion Prediction Equations for Iran
Authors F. Mehrabi, N. Mirzaei, H. Hamzehloo and A. MoradiUsing qualified accelerograms of the Iranian Strong Motion Network (ISMN), ground motion prediction equations for 5%-damped elastic response spectral acceleration in the period range of 0 to 3 seconds are developed for the purpose of seismic hazard analysis. The coefficients are included to model the effects of magnitude, source-to-site distance, local site effects and faulting mechanisms on the observed ground motions. Along with comparison to other ground motion models, the validity of the proposed equations is assessed by testing their applicability and investigating the distribution of residuals against the explanatory variables.
-
-
-
Local Earthquake Tomography in the Central Alboz-Iran to Determining Upper Crust Velocity Anomaly
Authors T. Akbari, H. Shomali and A. TryggvasonSeismic inversion for three-dimensional variations of velocity is often used to delineate velocity anomalies including magma bodies in the crust and upper mantle. A 3-D Vp and Vs model is obtained for the upper crust in the Central Alborz Mountains using the local travel-time earthquake tomography method. About 350 seismic events distributed around Alborz Mountain Ranges from surface down to a depth of about 30 km have been used to elucidate the P and S wave velocity structure. The seismic arrival times are directly inverted using a 1D velocity model as the starting model in the inversion. The simultaneous inversion of hypocentral and velocity model parameters had a remarkable impact on improving the location of the earthquakes. The optimal gridding and regularization parameters are estimated via synthetic modeling. Tomography results show considerable velocity anomaly in Damavand cone nearby the region. Both the P- and S-wave velocities are reduced compared to the surrounding below 10 km depth.
-
-
-
Variations of Moho Depth in Zagros, Central Iran and Alborz Zones Using P and S Receiver Functions
Authors N. Mohammadi, F. Sodoudi and A. Gholamir methods to detect the Moho depth variations within Iranian plateau. Due to the different deformation zones existed in the study region, our results show significant variations of the Moho beneath the Iranian plateau. Moho depth beneath Central Alborz is observed around 55±2 km, which is interpreted related to the shortening of the collision of Arabian–Eurasian plate. Moho depth decreases to 37±2 km beneath Central Iranian Plateau indicating less affected by the lithospheric thickening resulted from the collision. Our observations depict the increasing of the crustal thickness beneath the UDAM and SSZ zones along the lower latitudes, which implies that the convergent rate increases from NW to SE across the Zagros collision zone.
-
-
-
Modelling of Fracture Strength Distribution in Elastically Heterogeneous Rocks
Authors C. Langenbruch and S. A. ShapiroModelling the stress conditions inside hydrocarbon and geothermal reservoirs is important to predict fracture behaviour during the injection of fluids. We analyse the influence of elastic heterogeneity on stress and fracture strength distribution in rocks. Therefore, we simulate the distribution of elastic modules inside a reservoir rock as a 3D fractal random medium according to parameters obtained from sonic well logging data. Using an ABAQUS finite element stress analysis model we determine the stress field inside the rock volume. By applying geo-mechanical considerations we then compute the fracture strength distribution and analyse relations between elastic modules stress state and fracture strength. The stress modelling analysis performed in this paper suggests that the stress state in elastically heterogeneous rocks can be highly heterogeneous. Our modelling study according to elastic heterogeneity derived from sonic well log data along the KTB main hole results in a broadly distributed fracture strength between -10 to 20 MPa. We find strong relations between elastic modules, stress state and fracture strength, which can be applied to predict the stress distribution in hydrocarbon and geothermal reservoirs and the occurrence probability of fluid injection induced seismicity.
-
-
-
Random Sampling Data Interpolation with Weighted Matching Pursuit (WMP)
Authors X. Wang and H. Z. WangSeismic data interpolation can be done by an inverse Fourier transform if the Fourier spectrum of regular and un-aliasing seismic data is well estimated. The pseudo random sampling of the seismic data in time-space, which is based on a regular pattern, yields a F-K spectrum in which the aliasing looks like white noises. Therefore, restoring the F-K spectrum of the regular and non-aliasing data is similar a process of de-noising in F-K domain. A new method which is called WMP is introduced. This method is based on fast MP algorithm with a weighted operator formed with the Radon spectrum of seismic data by assuming that the events are linear. The noise can be removed clearly with the help of the weighted operator, which is proven by numerical examples. The method can be easily extended to high-dimensions.
-
-
-
Spatial Distribution of Trap Types Relative to the Regional Structural Framework, Baffin Bay, Offshore Greenland
Authors P. W. Bradbury and K. FrontThe Baffin Bay area offshore northwest Greenland represents a vast frontier exploration province. The aim of this work has been to create a new structural elements map for the region and assess the spatial distribution of trapping styles within a more detailed framework. The assessment was carried out using a large TGS 2D seismic database (>200,000 km2) acquired between 2007 and 2010 and associated gravity and magnetic data. The main basins in the area are the Melville Bay Basin and Kivioq Basin. In these basins and surrounding areas five distinct trap styles comprise the majority of closures. The trap styles include 1) Tilted fault blocks associated with Cretaceous to Palaeocene rifting. 2) Anticlines formed through differential compaction situated over basement highs. 3) Anticlinal closures formed through regional compression during Palaeogene uplift and localized compression in hangingwall fault blocks. 4) Hangingwall anticlines formed during Palaeogene inversion of normal fault blocks. 5) Stratigraphic traps comprising fans and pinchouts. More than 80 closures have been identified from a high level screening within Cretaceous to Palaeogene levels. The structural style, interpreted age of formation and areal extent of the mapped closures is reviewed.
-
-
-
Facies Characterization by Seismic Texture Analysis Using Grey Level Co-occurrence Matrix Based Attributes
Authors C. G. Eichkitz, J. Amtmann and M. G. SchreilechnerThe grey level co-occurrence matrix is a measure of the texture of an image. It describes how often different combinations of pixel brigthness values occur in an image. Based on this, several textural attributes can be calculated. In this work we developed a principal workflow for the calculation of these attributes. To decrease computational times we adapted calculation methods previously used for image classification of sea ice images. This workflow – including the enhanced calculation methods – is applied on two 3D seismic data sets from sedimentary basins. Different attributes and calculation parameters are tested to define channel systems and faults. The first tests show good results for the identification of both. Especially channel systems can clearly be identified. Additionaly, it is possible to directly extract channel-geobodies from the grey level co-occurrence matrix-based attributes.
-
-
-
Regularized Full Waveform Inversion Including Prior Model Information
Authors A. Asnaashari, R. Brossier, S. Garambois, F. Audebert, P. Thore and J. VirieuxIn this study, we propose a regularized time-domain Full Waveform Inversion (FWI) scheme based on a two-term model penalty in the misfit definition: the Tikhonov term to ensure smoothness and a prior model term to attract the inversion toward a given direction. We illustrate that the prior model could reduce the sensitivity of inversion with respect to a non-accurate initial model. This procedure delivers a robust model as compared to ''classical'' FWI and can help inversion to solve the cycle-skipping problem. In the Marmousi dataset application, an investigation was done to identify the respective influences of initial model and prior model in complex media. Finally, we propose a simple dynamic approach based on a first derivative of the objective function curve to take out gradually the effect of the prior model in the inversion scheme, once the cycle-skipping problem has been solved.
-
-
-
A New Technology to Meet Tight Gas Formation
More LessWe develop a new method to accurately determine gas saturation in tight gas reservoir using a three detector neutron logging tool with pulsed neutron source. This tool obtains the thermal neutron counting ratio R13 between near and far detectors and the ratio R23 between the middle and far detectors. With this method, the difference D between R13 and R23 is related to gas saturation and porosity. Monte Carlo simulation is used to evaluate the performance of the tool. The simulation results are analyzed with the new method to estimate gas saturation. The result shows that D can be used to determine gas saturation and using D to determine gas saturation has higher sensitivity than other ratio of thermal neutron counts or other difference of ratios. Another finding is that D logging response is affected by factors such as lithology, shale content, formation water salinity, borehole fluid, borehole size which should be corrected in the log data interpretation. We have applied the new method to process log data from two wells, yielding reliable interpretation result. The field data application result validates our new method and demonstrates its potential value and prospect in the gas saturation evaluation for tight gas reservoirs.
-