- Home
- Conferences
- Conference Proceedings
- Conferences
70th EAGE Conference and Exhibition incorporating SPE EUROPEC 2008
- Conference date: 09 Jun 2008 - 12 Jun 2008
- Location: Rome, Italy
- ISBN: 978-90-73781-53-5
- Published: 09 June 2008
501 - 556 of 556 results
-
-
Advantages and Disadvantages of Surface and Downhole Seismic Illustrated by Processing Results of 3D VSP and 3D+VSP
Authors A. A. Tabakov JSC and K. V. BaranovComparative analysis of Surface Seismic (SS) and VSP shows that each application has its own advantages and disadvantages. Surface Seismic never provides true velocity model and true signature. This is the reason for low resolution and inefficient processing of converted PS waves. In fact modern SS is on the limit of efficiency being still inadequate in many applications. VSP provide true velocities and true signature but quickly loses its efficiency in the vicinity of well. This is shown as comparison between Walkaway and CDP section. Example of 3D+VSP processing results shown that in this combined application signature and velocity model from VSP may be used to improve efficiency of Surface Seismic.
-
-
-
Moving Source VSP for the Exploration of a Geothermal Reservoir
More LessThe Upper Jurassic (Malm) which is present in most parts of the Southern German Molasse Basin is a highly-productive aquifer with increasing depths and temperatures from north (Danube river) to south (Alps). For a geothermal power plant projected in Unterhaching, south of Munich/Germany, two boreholes (doublet) have developed the Malm at a depth of approx. 3000 m. The reprocessing results of available seismic profiles imply important decision criterions for possible karstification zones. Supplementary vertical seismic profiling (VSP)- and moving source (MS-) VSP-measurements were carried out in the Unterhaching Gt 1 well for a more detailed investigation of the vicinity of the production borehole. VSP and MS-VSP data deliver a higher seismic resolution than the reflection seismic profiles. The energy of one heavy vibrator was sufficient to image the Malm down to its basis (about 3500 m). A fault system and different influx areas within the Malm, measured during a hydraulic test, could be identified in the MS-VSP data.
-
-
-
Imaging of Scattering Objects with VSP Data - Cross-correlation Stacking and NMO Enhancement
Authors A. Nikitchenko, D. Kiyashchenko, Y. Kiselev and B. KashtanThe diffractor imaging may be complimentory to conventional refrection imaging and useful for seismic interpretation. The faults, discontinuities and salt inclusions are scattering objects which are of interest for seismic exploration. In this paper the method of cross-correlation stacking is proposed for diffractor location near boreholes using VSP data. The method is well suited for imaging of scattering objects when the overburden is complex and even unknown. Also we present the technique of NMO enhancement of the diffracted waves which is found to be helpful in the case of weak scatterer in stratified medium.
-
-
-
Anisotropic Reflection and Transmission Joint Tomography - Method and Interests
Authors S. Le Begat, S. A. Petersen and L. JahrenIgnoring anisotropy in tomography leads to inaccurate distorted velocity fields and depth migrated images. However reflected data are known to not be able to constrain anisotropic parameters. Additional information is necessary. We do present an extension to anisotropy of a joint transmitted and reflected tomography based on locally coherent events. The application of the joint slope tomography to synthetic examples shows how borehole transmitted data significantly improve well-tie and refine velocity models coming from isotropic reflection tomography.
-
-
-
Multiple Migration for Velocity Model Building with VSP Data
Authors D. A. Nasyrov, D. A. Kiyashchenko, B. M. Kashtan, Y. V. Kiselev and V. N. TroyanThe quality of the subsurface images obtained using VSP data strongly depends on the velocity model used for migration. The velocity model derived from surface seismic is oftenly not accurate enough for VSP imaging and there is a need for it's improvement. We propose the method for updating of velocities using VSP data. The main idea is to use the images of the subsurface obtained using different types of waves: primary reflections and surface-related multiples. If the background velocity is correct, then these images will be similar, and they will not coincide, if the velocity model is erroneous. As a measure of similarity, we define the functional based on cross-correlation of these images. This velocity model is correct and it can be used in optimization procedure to uptade the model parameters. We studied the dependency of the functional from acquisition and frequency content of the signal. Also, we derived the gradient of the functional using adjoint-state method and demonstrated the possibility of velocity updating for simple synthetic model.
-
-
-
Flood Front Tracking and Pulse Test Time Lags (SPE-114233)
By I. ErshaghiAn important issue in the management of oil and gas reservoirs is ways to maximize the areal sweep efficiency during injection processes. As such any imaging mechanism to map the interface movement is a great help. To obtain this information, limited number of tools exist and it is our expectation that the extended application of interwell pulse tests can provide better insight into the flow boundaries. The improvement of sensor technology and data mining opens up new opportunities to obtain very useful information from continuous recording of data at the producing wells. In reality, each injection well can be subjected to pre-scheduled or unsupervised rate changes. These rate changes create pulsation in the reservoir. On the receiving end the producing wells, according to distance and formation and fluid properties between wells, detect the pulse but with a delay called the time lag. Our hypothesis is that the tracking of the time lags could be indicative of the injection fluid front plus indigenous reservoir properties. To separate the two effects, we postulate that a comparison of time lags with the first available time lag could primarily relate to front location. The difference between displacing and displaced fluid properties, cause different time lags. Our approach to this problem is combination of analytical and numerical solutions. The analytical experimentations can calibrate the numerical solution. Linear and radial flow geometries both for homogenous and composite reservoir have thus far been studied. The result of these systems demonstrate the potential of the proposed approach.
-
-
-
Hydrocarbon Potential Monitoring of By-passed Pay Zones Using TDT and CHFR Logs
By G. HamadaDetection of pay zones and monitoring the rate of advance of water zones represent main task of the petroleum engineer, this is improve the efficiency of producing wells. The ability to detect pay zones and definition of new water levels are necessary to propose remedial actions to reduce water cut values. Good cased hole well logging program is required to answer this question. The main technique, which has been used for monitoring reservoir saturations, is TDT tool. But, it was hard to interpret the TDT data in the low formation water salinity reservoirs. This problem can not be solved because it is related to the theory itself of TDT measurement, which depends on salt content in formation brine. Cased Hole Formation Resistivity tool (CHFR technique was proposed to overcome many of the pulsed neutrons tool limitations. A comparison study was done between the two available techniques, TDT and CHFR as methods for reservoir saturation monitoring, in addition to the results of open-hole resistivity logs as reference runs. It was found that water saturations calculated from CHFR logs were more accurate than TDT log in most of the cases.
-
-
-
Quantitative Estimation of Pressure and Saturation Changes Using 4D Seismic - A Case Study in the Marlim Field, Brazil
Authors R. C. Sansonowski and C. MacBethThe technique of Floricich (2006) is used to estimate pressure and saturation changes from 4D seismic data without the need for rock or fluid physics. The methodology is applied to an Oligocene field, offshore Brazil, with encouraging results. Estimates of the amount of injected water in the system between the two vintages are obtained using the saturation maps and the simulation model, and the comparison is used to assess the material balance in the area.
-
-
-
Prestack Time Lapse Inversion of Seismic Data from Heidrun Field, Norway
Authors P. S. Routh, M. L. Gurch, P. D. Anno, N. J. Ventzel and T. RøsteWe present prestack inversion of time lapse data acquired over the Heidrun Field in Norway between 1986 and 2006. Common image point gathers after migration are inverted simultaneously to estimate the elastic parameters and the source wavelet. The inversion methodology directly estimates the perturbation in the elastic parameters due to 4D effects. In this paper we focus our attention on prestack analysis, particularly the gather conditioning prior to 4D prestack inversion. Examining the residual gathers and data misfit maps from the prestack inversion provides a diagnostic check on the quality of the prestack processing. In many instances the prestack inversion reinforces 4D interpretation of the previous post-stack inversion. In some instances the 4D prestack inversion resolves ambiguity in the interpretation.
-
-
-
Quantitative Evaluation of Reservoir Fault Communication Using 4D Seismic - An Application to the Heidrun Field
Authors A. Benguigui and C. MacBethIn compartmentalized reservoir settings, it is known that fault seal properties control the fluid flow and pressure development, and strongly affect reservoir management decisions in terms of the chosen drainage strategy for field production. Fault transmissibilities inserted into the simulation model to represent the behaviour of faults are based on geological understanding and are uncertain because of the sparse nature of well data used in their estimation. Here, 4D seismic data is used to supplement and more fully resolve the spatial distribution of the fault properties. To achieve this task, inter-compartment amplitude contrast and statistics of spatial variability for the 4D signatures are considered. These 4D measures are then calibrated at the wells to the geology based estimates of fault permeability. Application of this technique to the Heidrun field provides an adjustment of the inter-compartment transmissibility factors in the simulation model. Predictions using this updated flow simulator model appear encouraging.
-
-
-
Seismic Facies Characterization and Distribution in Reservoir Grid - Experience Feedback
Authors E. Brechet, W. Pillet and M. FerociWith the improvement of the seismic characterization chain (processing, inversion, lithoseismic classifications), even more detailed facies cubes are obtained and used for mapping precisely still a wide range of heterogeneities inside reservoirs models. This paper describes how the evolution of techniques and methods since 2000, on a deep offshore turbidites field of Angola, improved year after year the description of reservoir properties in the field reservoir model. It represents a quick experience feedback comparing methods and evaluating pros and cons.
-
-
-
Seismic Attributes Used for Reservoir Simulation – Application to a Heavy Oil Reservoir in Canada
Authors C. C. Dumitrescu and L. LinesCold heavy oil production with sand has become one of the main non-thermal schemes for developing heavy oil reservoirs in Canada. One challenge in modeling the fluid flow in the reservoir simulation studies is reservoir heterogeneity. Several seismic attributes were used to estimate the porosity (ranging from 19% to 35%) at the Plover Lake oil sands reservoir in Canada. First, the top and the base of the reservoir were mapped based on several seismic attribute volumes that include the density. From petrophysical analysis we learned that density is a key physical property in differentiating between sand and shale within the oil sands. Probabilistic neural network (PNN) analysis was used to derive the relationship between density log data and external attributes (PP and PS migrated stacks, AVO attributes and inversion results). Secondly, we used geostatistics to estimate a porosity map within the reservoir. The study is based on a set of porosity logs at well locations and several seismic attribute maps. Kriging, cokriging, kriging with external drift (KED) and multiattribute analysis for maps plus KED, were tested in order to improve the results. The KED with porosity from multiattribute analysis is the most realistic, honoring the wells and the seismic.
-
-
-
Prediction of Properties of Gas Hydrate Bearing Sediments from the Dynamic of Reflected Waves without Borehole Data
Authors R. L. Pevzner, A. L. Volkonskaya, S. V. Bouriak, A. A. Bocharova and N. V. BlinovaThis paper proposes an approach to predict the properties of the gas hydrate bearing sediment using the seismic reflectivity variation with the angle of incidence, without borehole data. The approach demonstrated high accuracy and robustness of the result when tested on the synthetic models. The technique was also tested on the real data from the Tuapse Trough of the Black Sea and the obtianed values of gas hydrate and free gas saturations fit well to the previously published results from the neighbouring areas.
-
-
-
Quantitative Structural Effects in Layered Media, an Application of Anisotropic Dynamic Ray Tracing to AVAZ Studies
Authors L. Cherel, K. Dehghan, A. Jardin and P. FroidevauxAdvances in 3D seismic acquisition and processing are providing new tools for the analysis of fractured zones. Studying the amplitude variation as a function of azimuth is one of the current methods to determine the anisotropic parameters. Based on recent studies conducted with field data, several questions remain, notably the validity of the Amplitude versus Azimuth (AVAZ) analysis of the datasets when the seismic processing is based on some large simplifications of the real situation. In this paper, we apply an anisotropic dynamic ray tracing to 3D isotropic and Horizontal Transversely Isotropic (HTI) models to perform a feasibility study and to analyze the uncertainties related to geometrical spreading compensation. We compare the error introduced by a standard geometrical compensation with the anisotropic variation due to HTI reservoir. This study demonstrates, even in case of moderate structured subsurface, the full true amplitude PSTM or PSDM workflow providing the exact geometrical spreading compensation should be performed to study the anisotropic amplitude.
-
-
-
Methods for Blocky Seismic AVA Inversion
Authors I. Jensås, J. Eidsvik and U. TheuneThis paper presents a statistical inversion scheme that aims at the enhancement of layer boundaries in seismic AVA inversion. By employing a Cauchy norm to the gradients of the model parameters we are inverting for, we are able to enforce a sparse distribution of these gradients and thereby achieving sharper boundaries in the inverted data. We include tests of this approach on synthetic data. In addition, we present work carried to also determine facies from the described blocky inversion method.
-
-
-
Effective Reflection Coefficients for Curved Interfaces in TI Media
Authors M. Ayzenberg, I. Tsvankin, A. Aizenberg and B. UrsinWe introduce so-called “effective” reflection coefficients (ERC) for curved interfaces in transversely isotropic media. If the reflector is plane, ERC describe the exact reflected wavefield for the full range of incidence angles, while plane-wave reflection coefficients become inadequate at near-critical and post-critical angles. For curved reflectors, ERC provide a practical way of computing the wavefield without using such time-consuming methods as finite differences. We analyze parameter dependence of ERC and evaluate the potential of using them in amplitude-versus-offset inversion and Kirchhoff-type modeling.
-
-
-
AVO Inversion of Long-offset Synthetic PP Data Based on Effective Reflection Coefficients
Authors L. V. Skopintseva, M. A. Ayzenberg, M. Landrø, T. V. Nefedkina and A. M. AizenbergConventional AVO inversion is based on the application of plane-wave reflection coefficients or their linearizations for pre-critical incidence angles in media with almost flat, weak-contrast reflecting interfaces. Since AVO inversion should account for the real curvature and contrast at the interfaces, the search of a more adequate mathematical apparatus for the correct description of wave reflection in real media remains an open seismic problem. We propose an improved AVO inversion based on replacement of the plane-wave reflection coefficients with the effective reflection coefficients. The improved inversion is free of the drawbacks discussed above and can be applied in pre-, near- and post-critical domains. We present the results of the improved AVO inversion of long-offset PP data for a test model. To estimate the validity of the improved AVO inversion, its results are compared with the results of the AVO inversion based on the plane-wave reflection coefficients
-
-
-
PZPS Event Matching and Simultaneous Inversion - A Critical Input to 3D Mechanical Earth Modeling
Authors A. Murineddu, A. Rasmussen, F. R. Mohamed, A. S. Wendt and M. NickelA 3D Mechanical Earth Model (3D MEM) of a field was built integrating geophysical, geological, and petrophysical data. The 3D MEM represented the close-to-initial field property conditions, and is an ideal basis for analyzing wellbore and formation stability, subsidence and compaction, and cap-rock and fault sealing during initial and depleted field conditions. The lateral resolution of the elastic rock properties input for the 3D MEM was obtained using a PZPS simultaneous inversion of OBC data. Simultaneous inversion of PZ and PS data required adequate alignment of the two datasets. PZ and PS data were aligned by an automated event registration where major events were aligned in an iterative process refining the matching result with each iteration step. The use of PZ and PS data in the simultaneous inversion showed superior density results compared to inversion with PZ-data only. In addition, the acoustic impedance and Vp/Vs ratio inversion results were improved showing a high degree of lateral continuity, and a better match with the wellbore log data. The final high resolution inversion results provided a well-constrained data basis for the subsequent distribution of geomechanical properties throughout the 3D Mechanical Earth Model.
-
-
-
Case Study - Arbroath - an Integrated Petrophysical and Seismic Elastic Inversion Process for De-risking Infill Drilling
Authors S. Helmore, A. P. Merry, F. Conti, S. Cuddy, T. Kayes and J. CassThe Arbroath field is located in UKCS block 22/17 and produces 38o API oil from the Forties Sandstone turbidite reservoir at approximately 2500m TVDSS. Production began in 1990 and the field still produces significant oil volumes today. In 2006, a re-appraisal of 1993 and 2000 vintage 4D seismic data over the field was initiated to de-risk infill drilling targets. This included a petrophysical and petroacoustic review, 4D seismic re-processing, relative elastic impedance inversion, and a related sand failure study. During the petrophysics and sand failure analysis, a multi-dimensional clustering technique was employed and compared with other statistical log prediction techniques. As a pre-conditioning for elastic inversion, frequency split structurally oriented filtering was used to de-noise critical low frequency components of the elastic stacks in order to expand the low frequency bandwidth. This paper presents the integrated progression from seismic data review with petrophysical and petroacoustic analysis leading to prediction of un-swept oil, and assisting infill well placement and design. We highlight the innovative technology used during each of the stages.
-
-
-
Application of Extended Elastic Impedance Attributes to the Hassi Messaoud Field, Algeria
Authors G. C. Robinson, A. Ouenes, M. Touami, M. A. Messaoud, A. Fekhar and L. OkbiThe Hassi Messaoud field is a giant oilfield in Algeria, producing since 1957. It is a complex field whose Cambro-Ordovician clastic reservoir exhibits significant lateral heterogeneities, thickness variations caused by Hercynian erosion, and igneous rocks intruded into and extruded above the reservoir. 3D seismic data, in addition to providing structural information, is being used to help delineate development well locations. This study describes the contribution of extended elastic impedance attributes to field development in the Hassi Messaoud field.
-
-
-
Unbiased Deterministic Seismic Inversion
By H. ÖzdemirLow frequencies outside the seismic bandwidth must be modeled from log data during deterministic seismic inversion to absolute rock properties. Consequently inversion results away from existing wells can be biased, leading to wrong drilling and development decisions. The risk of bias increases as more bandwidth is added from the logs (model) and less from the seismic (measurement). By optimizing the source and the cable depths, two-source and two-streamer over/under acquisition and processing technology can achieve effective source and receiver ghost suppression providing seismic data rich in low frequencies extending down to about 3 Hz. This is about a one-octave gain over conventional single-streamer technology and, as a result, deep targets below screening layers, such as basalt, can be imaged. It also helps to minimize any possible model bias during seismic inversion. Porosity modeling and fluid substitution modeling using extracted wavelets show that unbiased inversion results can be achieved with the over/under data using only about 0- to 3 Hz background models. Therefore, the reservoir properties away from the wells can be reliable mapped because the model data contribution is limited to a very low-frequency regional trend.
-
-
-
Fracture Characterization with Azimuthal Attribute Analysis of PS-wave Data - Modelling and Application
Authors Z. Qian, X. Li and M. ChapmanWe carry out azimuthal seismic anisotropy analysis of P- and PS-wave for fracture characterization with numerical modelling and a 3D3C dataset. Numerical results reveal that both the amplitudes and interval travel-time of the R-component of PS-wave can be used to infer fracture properties through ellipse fitting as that in azimuthal P-wave attribute analysis. In the real 3D3C data analysis, the fracture properties obtained from the azimuthal R-component analysis of the PS-wave data agrees with that inferred from the geological and logging information.
-
-
-
Integrating Seismic Attributes for Estimation of Transport Properties of Dual Porosity Rock
Authors E. A. Kozlov, V. S. Vinnikovsky, O. Y. Kirseleva and A. A. BovykinAt an oil field in the North-Eastern Europe, the rates of oil production from a dual porosity carbonate reservoir are known to be strongly dependent on fracture permeability, so we use a set of permeability-sensitive seismic attributes for the reservoir characterization. The set, chosen with account for the results of "fracture permeability substitution" modeling, includes coherence, azimuthal anisotropy, spectral decomposition, and scattering attributes. As is not uncommon for dual porosity rocks, available core/well log data on permeability relate more to matrix permeability than to fracture permeability. Indeed, cross-correlation "core/log permeability ↔ well productivity" here is less tight than the resulting cross-correlations "attribute ↔ core/log permeability" and “attribute ↔ well productivity". Hence, in the case of dual porosity rocks, the modelling-supported integrated analysis of permeability-sensitive seismic attributes can add essential independent information on (mainly fracture) permeability to the estimates of (mainly matrix) permeability derived routinely from cores and/or well logs.
-
-
-
New Petrophysical Workflow Helps Improving Fluid Forecasts and Production Rates in the Estancia Cholita Field, Argentina
Authors F. J. Vittore, O. R. Ortiz and A. PolThe project focuses on the optimization of the completion stage of wells of the Estancia Cholita Field, San Jorge Basin, Argentina. Its principal objective was to develop a workflow to improve identification of oil reservoirs and increase the current primary recovery factor of the field. During the study, a reservoir characterization methodology was developed to select the intervals of major potential of the well and to identify the water zones. The methodology leads to a calculation of a variable RW profile for every well. The petrophysical model was designed to use the RW profiles to guide the evaluation. Preliminary results of this work show an increase in oil production and of the primary recovery factor of the field; this was achieved by increasing the number of intervals that tested oil, decreasing the number of water, gas and dry tests, hydraulic fracturing of damaged intervals, detection of bypassed oil zones, and by an indirect identification of formation damage. Likewise, as a result of a better understanding of the reservoir behavior, the methodology has allowed optimizing completion costs and equipment time thanks to the reduction of perforating water and gas intervals and the decrease in the number of remedial cementing operations.
-
-
-
Complex Evaluation of the Mezösas-W Fractured Metamorphic HC-reservoir Pannonian Basin, Hungary
Authors T. M. Tóth, T. Földes, B. Kiss, B. Vásárhelyi and J. ViszkokA fractured metamorphic HC reservoir is studied in the basement of the Pannonian Basin. In the complex evaluation petrology, structural geology, rock mechanics, Computer Tomography, fracture network modelling and seismic attribute modelling are compiled. Our result suggest that the most intensely fractured, most porous zones belong to the amphibolite bodies and to shear zones between neighbouring metamorhic units. Large gneiss blocks are essentially impermeable.
-
-
-
Fractured Reservoir Modeling - Jihar Field Case
Authors T. B. P. Babic-Puntarec, M. T. Tuschl and A. K. KolakC2 and D1 reservoirs of Jihar field in Syria are formed in highly fractured limestone/dolomite of Triassic age and contain condensate-rich gas cap and volatile oil leg. There has been two years of production from two wells so far. Dual porosity model is being created to predict reservoir behavior. Matrix model framework is built based on seismic interpretation together with well data. Reservoirs are divided into zones according to reservoir quality. Fractional layering is used to keep porosity variations from log analysis and facies modeling is performed using Sequential Indicator method. Petrophysical parameters of matrix are based on log analyses but core data is also considered. The ultimate goal is to find 3D grid properties which describe fracture properties. Two different Discrete Fracture Network (DFN) models are developed based on intensity to incorporate actual fracture statistics in the determination of fracture permeability, porosity, and shape factor. One single-set model is created and three-set model is established. History matching started on a global level, by matching overall energy (pressure) and total production rate. Interactive updating of geological model with knowledge from simulation realizations resulted in better understanding of reservoir properties, recovery mechanisms and enabled definition of possible production prediction cases.
-
-
-
Isotopic Signature of Nitrogen - An Indicator for Timing N2 Generation and N2 Charging of Dutch Natural Gas Accumulations
More LessThis paper provides data on the isotopic composition of nitrogen in natural gases of offshore and onshore Netherlands and proposes a process-based interpretation of the observed regional variation in isotopic characteristics. The nitrogen isotopic data clearly reveal a distinct regional distribution which - in combination with the regional differences in geological history - strongly suggests that differences in isotopic signature are related to regional differences in: 1. timing of nitrogen generation and accumulation: - Early generation and accumulation of hydrocarbon and nitrogen gas in northern offshore area 1 (before Late Cretaceous inversion); - Late generation and accumulation of hydrocarbon and nitrogen gas in southern area 2 comprising inverted basins (principally during Tertiary and Quaternary); 2. origin and liberation process of the nitrogen: - In area 1: main origin of nitrogen is the inorganic fixed nitrogen in clay minerals in Carboniferous shales; liberation of nitrogen during rifting period (probably Late Jurassic-Early Cretaceous rifting) is triggered by devolatization reactions during very deep burial, by short-term thermal processes (magmatic activity/igneous intrusions), and/or fluid-rock interaction; - In area 2: main origin of nitrogen are organic sources; liberation of nitrogen during maturation of the Westphalian coals and carbonaceous shales.
-
-
-
High-grading the Prospect Portfolio with Latest Technology - Impact on Southern Permian Basin
Authors M. Bruehl, B. Spaargaren, R. van Spaendonck and W. van LingenIn 2004/5 NAM acquired a proprietary long-cable survey with 6 km streamers in the Dutch offshore, the first 3D survey to be shot in the Southern Permian Basin with these streamer lengths. The long-cable acquisition geometry was deemed necessary because step change improvements in imaging was required to support additional exploration drilling. The quality of the seismic image is crucial to optimally leverage Shell’s DHI enhancement technique called CTD stacking. This technique was specifically designed for the Rotliegend stratigraphy. For the discovered fields, CTD stacks of the vintage data delivered a high success rate (70%) in estimating the encountered gas water contact (GWC). For the remaining prospect portfolio, however, the approach provided less conclusive results. Improved data quality was considered essential to achieve a similar success rate. The combination of long-cable 3D data and CTD stacking technology had significant impact on our business: • We were better able to image deep Rotliegend fault blocks • We obtained better structural definition underneath salt ridges • We achieved more consistency in the DHIs and were therefore better able to rank the portfolio
-
-
-
Experimental Investigation of Clay Smear During Fault Formation
Authors F. D. E. Cuisiat and E. SkurtveitFaults that affect fluid flow in hydrocarbon reservoirs are produced by the deformation of a large variety of sediment types under different stress conditions. Deformation processes comprise grain reorientation, clay smear and cataclasis. A new ring shear device was constructed in order to investigate experimentally deformation processes in sediments during faulting and consequent effect on fluid flow. Three main types of shear bands are observed from the experiments: 1. Sand shear in areas with sand-sand juxtaposition. Grain size reduction is strongly dependent on the burial depth during shearing. 2. Clay smear mixed with sand grains, typically for shallow burial depth. 3. Complex shear zones made of clay and sand shear with massive grain crushing on both sides of the clay smear, typically for greater burial depths. At shallow burial depth, clay smear is the main mechanism responsible for permeability reduction as sand-sand juxtaposition shear is dominated by grain rolling causing only minor permeability reduction. At greater burial depths, permeability reduction is dominated by grain crushing.
-
-
-
An Integrated 3D Seismic Analysis and Potential Fields Inversion Reveal a TBR Analog for the Dnieper-Donets Basin
Searching for oil and gas in the Lower Carboniferous Carbonate Platform of the Dnieper-Donets basin (DDB) is facing with particular problems caused by lack of specific knowledge about the morphology and origin of carbonate reservoir. An integrated 3D seismic analysis and potential fields inversion coupled with examination of outcropped analogs in the Southern Donbass for these carbonates have revealed that Bogatoyka gas condensate field reservoir is of hydrothermal origin, similar to the Trenton-Black River one in North America.
-
-
-
Barque Pre-SDM - Shallow Initial Geological Model Building, and Impact on Deep Reservoir Imaging
Authors R. Wervelman, A. Fongers, H. Poelen, W. Sikkema, P. Milcik and T. BrothersTo de-risk the development of the Barue PH01 extension, there was a need to further improve the quality of the existing (2000) Pre-SDM imaging. Especially the shallow strata, i.e. the Liassic and the Upper Triassic, demonstrate a strong deformation. During the inversion of the Solepit basin they formed Riedel shears with strongly tilted fault blocks. The impact these dipping strata might have on the Pre-SDM velocities has been recognised as one of the main causes of the pre-existing imaging uncertainties. Hence, in the new velocity-depth model-building exercise, most attention has been given to the construction of a ‘geologically plausible’ velocity field for the shallow strata. As tomographic updating based upon RMO only will most probably not give a satisfactory result due to lack of (shallow) offsets, an initial geological model has been built using sonic data, seismic dip, faults and paleo-surfaces. This initial model has subsequently been updated using standard tomographic updating techniques. The final Pre-SDM image, resulting from this procedure, shows a marked improved over earlier depth imaging results; similarly, the existing TZ-conversion uncertainties have been significantly reduced.
-
-
-
Complex Imaging Challenges - Offshore South East India
Authors I. F. Jones, P. Sangvai, A. Biswal, M. Mathur, J. F. Fruehn, P. Smith, D. G. King, M. C. Goodwin and V. VallerImaging in deep water environments poses a specific set of challenges, both in the data pre-conditioning and the imaging. These challenges include scattered complex 3D multiples, aliased noise; and low velocity shallow anomalies associated with channel fills and gas hydrates. In this paper, we describe our approach to tackling these problems, concentrating our attention on multiple suppression, scattered noise attenuation, iterative velocity model building and depth imaging.
-
-
-
Quantitative Integration of Seismic and CPT for Soil Property Estimation - Sensitivity Analyses on Field and Lab Data
By R. GhoseWe have shown that if seismic Vs and CPT qc in sand are estimated sufficiently accurately at a given location, then different depth zones within the sand body representing different porosity and effective horizontal stress manifest correlating patterns between Vs and qc. If the depth-specific correlation in sand can be well captured between the two independent measurements, then this correlation can be used, together with their underlying physics and a knowledge of the intrinsic parameters, to estimate in-situ porosity, horizontal stress and their lateral variations. In-situ estimation of these two properties is quite difficult, although these are crucial parameters to the engineers. The proposed approach offers a solution to this problem.
-
-
-
Bayesian Inversion Whispers
Authors J. Gunning, M. E. Glinsky, M. C. Haase, V. Charoing, G. Duncan, R. Hill, G. O‘Halloran and L. DangMany times we are faced with the business decision of whether or not to develop a sand which is at the limit of seismic resolution and near the noise level of the data. The critical issue is developing a reasonable certainty that there is enough volume of hydrocarbons to develop. A popular approach is to use Bayesian methods to determine the probability of an economic volume of hydrocarbons being present. A problem with this approach when it is applied for the marginal cases that we have described is a bias to the answer. Often, this comes from a relatively strong prior constraint on the gross thickness and net-to-gross of the sands, imposed to keep the inversion focused on the correct seismic reflector. The data is whispering what the answer should be through the Bayesian apparatus, but this whisper is overwhelmed by the prior constraints. We found a simple solution to this problem – run the seismic inversion several times using the output mean of the previous inversion as the input mean of the next inversion. This methodology made the difference, in conjunction with a bandwidth improvement in the seismic data, in proving that a well should be drilled.
-
-
-
GeoMind, a Geophysical Multilingual Internet-driven Information Service
Authors J. Sedlák, T. Mardal, G. Detzky, L. Sörés, L. Vértesy, V. Hladík, R. Tomas and V. SzalaiováVarious dispersed geophysical databases exist in European countries, both in public and private organisations. They have different standards and languages applied. Thus the usefulness and availability are limited. The existence of data is often unknown even for geo-experts. The GeoMind project aims to enhance the public utilisation activity of geophysical information by integration of national databases and making those available via Internet on a certain level, offering cross-border, European-wide, unified electronic service. The project was launched in September 2006 and is planned for 24 months.
-
-
-
Finite Element-finite Difference Method in 2-D Seismic Modeling
Authors T. Liu, T. Y. HU and J. H. YangSeismic modeling can be used to study the propagation of seismic wave and it is also a useful tool of seismic data processing and interpretation, as the geological model become more complex, especially in northwestern China. In this paper, Finite element-Finite Difference Method(FE-FDM) has been developed, as a new technique of jointed with FEM and FDM; FE-FDM employs semi-discretization of FEM in spatial domain, and FD method to solve wave equations with significant advantages and accuracy. After introducing the principle and the analysis of stability condition, two case studies are given to show that (1) FE-FDM has high accuracy, (2) it shows good image ability when simulating the geological model for some complex interface area, (3) good seismic modeling can be used to guide seismic interpretation.
-
-
-
From Reservoir Studies Best Practices to an Advanced Web Based System to Set Up and Monitor Project Activities
Authors B. Volpi, E. Aliverti, G. Astorino, M. Botta, M. Calzari, F. M. Contento, M. Piantanida and C. TarchianiDuring the last 10-15 years many oil companies have adopted general best practices in order to assure high quality field studies. Though best practices represent a significant guideline for each task of the process, actually, it is often difficult to keep the reservoir study fully consistent with them. For this reason, an advanced web based system has been developed in order to transform best practices into an interactive tool to be used to set-up, support and monitor field studies. This system can be a very useful tool for senior professionals, project leaders and reservoir managers; it can be used to identify the best methodology, workflow and applications for the study to be carried out, as well as the best way to improve the collaboration within the project team and to ensure the interoperability of tools that will be used. Once the workflow has been set up, the process can be monitored step by step, the involvement of the different specialists activated when needed and the production of the deliverables assured at the right time. Eventually, the system allows each member of the team to interactively access the best practices and any available lesson learnt from previous studies.
-
-
-
Structural and Thermal Constraints to the Tectonic Evolution of Foredeep Successions in the Northern Apennines, Italy
Authors F. Botti, L. Aldega, M. Barsella, S. Corrado, M. Marroni, F. Meneghini, S. Palandri and L. PandolfiA multi-method investigation (structural analysis, organic matter thermal maturity and clay mineralogy) was carried out on highly deformed foredeep successions in the Northern Apennine with special regard to shear zones in the Lago Trasimeno area (Rentella Unit) to unravel the main structural mechanisms and the thermal condition of the Miocene accretionary processes of the Northern Apennines belt. The Rentella Unit consists of a foredeep succession deposited in a paleogeographic domain between the Tuscan and the Umbria-Marche Domains. Meso- and microstructural data indicate shear planes compatible with C-planes (N160°, 45°SW). C-planes veins show dilational jogs and a staircase shape coherent to a top-to-the-NE sense of shear. Type II calcite twins in the shear zone associated veins suggest temperatures of 150-200°C. Temperature-dependent clay minerals and vitrinite reflectance indicate lower maximum paleo-temperatures (<100-110°C) in the early diagenesis and in the immature to early-mature stages of hydrocarbon generation. Thermal parameters suggest the development of the shear zone in the foredeep deposits at shallow depths (<3 km). Hot fluids coming from deeper structural levels within the collisional prism caused higher temperatures recorded in calcite twins of the shear zone veins.
-
-
-
Survey of Heterogeneity of Oil-gas Saturation of Reservoir Using Seismic Emission Waves SLEC Technology
Considered is application of passive seismic monitoring technology SLEC (Seismic Location of Emission Centers) to survey the heterogeneity of oil saturation of reservoir in one of the fields of Orenburg region (Volga-Ural area, Russia). Presented is a brief description of SLEC technology designed for surface-based passive monitoring of seismic emission of geological formations and estimation of characteristics of reservoirs, particularly, reservoir fluid saturation type. Among benefits of SLEC technology are its surface based observation system and the use of Slionkin Focusing Transformation algorithms allowing to focus SLEC locator to any points of a geological formation (within the range of a few kilometers), thus allowing distinguish between useful and interference sources of emission signals. Presented are results of long-term SLEC monitoring. A comparison of SLEC processing results – map of oil saturation index versus production data acquired in operating wells and well test data supports the reliability of SLEC-based maps of reservoir oil saturation heterogeneity. These heterogeneity maps can be used to improve the efficiency of oil production and for post-exploration of the field.
-
-
-
Finite-difference Simulation of Acoustic Log in 3D Heterogeneous VTI with Attenuation
Authors E. V. Lys, V. Lisitsa, G. Reshetova and V. TcheverdaOn the base of the application of a finite-difference approximation of an initial boundary value problem for elastic wave equations (velocity/stress formulation), numerical method and its algorithmic implementation have been developed in order to perform a computer simulation of sonic logging. The very general statement is dealt with – surrounding medium allowed to be 3D vertical transversely isotropic heterogeneous with attenuation and source can be located at any point inside or (VTI) outside the well. To provide the most precise description of the sharpest interface of the problem – the interface of the well, we formulate the problem in cylindrical coordinates with axis directed along the well. In order to truncate area of computations two approaches are used: classical version of Perfectly Matched Layer (PML) and extension on the base of optimal grid. Implementation of parallel computations is done via Domain Decomposition Data exchange between Processor Units is performed with the help of Message Passing Interface library. Results of numerical experiments for VTI media are presented and discussed.
-
-
-
Thermal and Thermo-chronological Constraints to the Southern Apennines Evolution, Italy
Authors C. Invernizzi, L. Aldega, S. Corrado, C. Giampaolo, M. D‘Errico, S. Mazzoli, M. Schiattarella and M. ZattinA multidisciplinary approach for thermo-baric data acquisition is proposed along the southern Appennines, a key region of the Alpine orogen in the central Mediterranean area, including the remnants of a Cretaceous to Palaeogene accretionary complex. Ophiolite-bearing HP-LT tectonic units occur on top of the thrust pile. The underlying outcropping thrust sheets consist of Mesozoic and Cenozoic rocks derived from the sedimentary cover of the foreland plate (Apennine carbonate platform and Lagonegro pelagic units). These latter suffered, in some parts, HT-LT metamorphic conditions. We integrated independent thermal and thermo-chronological methods such as XRD analyses of clay mineral assemblages, fluid inclusion micro-thermometry, apatite fission tracks and vitrinite reflectance analyses, sampling both metamorphic and non methamorphic low-temperature successions. Our results indicate that a significant part of the sedimentary rocks exposed in the southern Apennines experienced substantial tectonic burial (locally in excess of 5 km), and confirm that, besides kinetics factors, a combination of methods allow to define thermo-cronological and, subordinately, pressure characteristics also for the HP-LT successions. Finally, in the northern sector of the area (Lucania), a break in thermal maturity from the Apennine carbonate platform and Lagonegro pelagic derived units has been documented, and along-strike variations of thermal maturity also emerged.
-
-
-
Structural, Morphotectonic and Thermo-chronological Constraints to the Late Miocene-quaternary Tectonic Evolution and Exhumation in the Southern Apennines, Italy
Authors S. Mazzoli, A. Ascione, M. D‘Errico, L. Allega, S. Corrado, C. Invernizzi, A. Pignalosa, M. Zattin and P. ShinerIn the southern Apennines fold and thrust belt, thermal indicators record exhumation of sedimentary units from depths locally in excess of 5 km. The belt is made of allochthonous sedimentary units that overly a 6–8 km thick, carbonate footwall succession. The latter is deformed by reverse faults involving the underlying basement. Therefore, a switch from thin-skinned to thick-skinned thrusting occurred as the Apulian Platform carbonates - and the underlying continental lithosphere - were deformed during the latest shortening stages. Apatite fission track data, with cooling ages ranging between 9.2 ± 1.0 and 1.5 ± 0.8 Ma, indicate that exhumation marks these late tectonic stages, probably initiating with the buttressing of the allochthonous wedge against the western margin of the Apulian Platform. Pliocene-Pleistocene foreland advancing of the allochthonous units exceeds the total amount of slip that could be transferred to the base of the allochthon from the underlying thick-skinned structures. This suggests that emplacement of the allochthon above the western portion of the Apulian Platform carbonates was followed by gravitational readjustments within the allochthonous wedge, coeval - and partly associated with - thick-skinned shortening at depth. The related denudation processes have played a primary role in tectonic exhumation.
-
-
-
Transmission and Reflection of Mixed Surface Waves on the Vertical Boundaries
Authors N. Y. Kirpichnikova, P. V. Krauklis, A. P. Krauklis, D. Pissarenko, M. Fukuhara and T. ZharnikovMixed Surface Waves are the combination of the whispering gallery waves or creeping waves with the body heterogeneous or inhomogeneous P and S waves. Propagating along the curved surface they pass the boundaries. The transmission and reflection coefficients are calculated. The transmission matrix discribed the conversion of differents modes on this boundary is builded. A lot of synthetic seismograms are presented.
-
-
-
A Comparison between Two GPR Data Processing Techniques for Fracture Detection and Characterization
Authors M. Bavusi, F. Soldovieri, A. Giocoli, S. Piscitelli, L. Crocco, F. Vallianatos, P. Soupios and A. SarrisThe abstract deals with the fracture detection in civil engineering via Ground Penetrating Radar. In particular, we present the comparison between two data processing techniques. The first one is a conventional technique while the second one is a novel m
-
-
-
Vector Migration of Virtual Source VSP Data
Authors M. Lou, F. Doherty and J. JacksonThe virtual source method is becoming a popular technology in VSP data processing for imaging subsurface structures under complex and poorly understood formations. Most virtual source imaging methods currently in use migrate only a single scalar component. VSP data is recorded using three-component (3C) borehole receivers with 3D vector characteristics. Due to both the 3C vector nature and the complexity of wave modes, it is necessary to develop new methods to migrate the full 3C vector wavefield simultaneously. We present a methodology to perform 3C vector migration for virtual source VSP data. First, we redatum each of three components to their virtual receiver positions in a borehole using seismic interferometry. Next we perform a 3C vector Kirchhoff prestack depth migration. The elastic FD modeling suggests that this new vector migration can effectively image steeply dipping structures without the knowledge of the overburden velocity. The image strength and quality is significantly enhanced with the migration of all three components instead of one scalar component alone. A simultaneous 3C migration of the virtual source VSP data also simplifies the VSP pre-processing as it is not necessary to try and maximize the reflection onto a single component prior to migration.
-
-
-
Mapping the structure and depth of sedimentary basins using the magnetic Tilt-Depth method
Authors E. M. Samson, A. Salem, S. E. Williams, A. J. Bourne, C. M. Green and J. D. FairheadThe aim of this contribution is to show that it is possible to transform a magnetic anomaly map using the recently introduced ‘Tilt-Depth’ method, which only uses first order derivatives, into a form that allows an initial and rapid means of evaluating the depth and structure of sedimentary basins. We do this by introducing a new colour mapping method. This method assumes a simple buried vertical contact model such that the 0 degree contour of the Tilt derivative closely follows the edge of the vertical contact whilst the distance between the 0 degree and the +/-45 degree contours providing the depth estimate to the top of the buried contact. The method has been tested on simple 2D and 3D models with success and is used here to illustrate its value at regional (continental) and local (exploration) scales.
-
-
-
Comparison of the Jurassic Reservoirs of the Kara-Yamal Region and the Barents Sea
By M. OgarkovaThe present work is devoted to characterization and distribution of the Jurassic reservoirs of the Barents Sea-Kara Sea and Yamal region. Compilation of literature combined with fieldtrips materials, seismic interpretation and well-logs analysis have been done in order to describe the focused intervals. The study has been carried out in the framework of Russian-Norwegian collaboration between Moscow State University and Tromsø University with scientific contribution and software / financial support of StatoilHydro.
-
-
-
The origin study of the garnets from the tonalities, Susita Valley
By C. F. EneaThis paper contains the chemical analyses of the garnets included in the tonalities from Susita Valley, Romania. This paper represents a premiere, because these garnets were not studied before.
-
-
-
Importance of coloidal iron in mine waters revealed by differential pulse voltammetry
Authors L. K. Mudashiru, B. R. Horrocks and A. C. AplinIn this work we have developed Differential Pulse Voltammetry (DPV) as a rapid and robust method of determining the concentration of truly dissolved iron and colloidal iron in 0.45 μm filtered waters from a series of mine water discharges and remediation sites in NE England.
-
-
-
An approach to Seismic Interpretation based on Cognitive Vision/Seismic Interpretation
By P. VerneyAdvanced seismic interpretation most commonly rests on transforming original data representations by considering more or less numerous seismic attributes, which bear no explicit relation with geology. For this reason, they hardly allow fully solving problems such as reassembling sparse geological surface elements or specifying chronological or topological relationships between surfaces such as unconformity, on lap, interruption by fault. The present work intends to make further progress in geology-based interpretation of seismic data by using artificial intelligence tools based on cognitive vision. We propose a cognitive vision workflow for seismic interpretation based on a visual ontology and on three associated module dealing for data management, visual characterisation and geological correlation. An example of results is given showing the possibilities of the method for easily merging disconnected reflectors within one stratigraphical horizon taking into account simple geological criteria (amplitude, thickness, dip, vertical distance between reflectors).
-
-
-
Accelerometer Versus Geophone Response: A Field Case History
By M. HonsThere has been considerable interest in the geophysical community surrounding the use of MEMS accelerometers as a new sensor in the acquisition of seismic data (Dragoset and Gabitzsch, 2007; Laine and Mougenot, 2007). It has been suggested that accelerometers, with their flat response in acceleration, may have advantages over geophones at low frequencies as well as high frequencies - due to greater sensitivity (Maxwell et al., 2001; Mougenot and Thorburn, 2004). If both sensors’ frequency responses correspond to what the simple harmonic oscillator model would predict, then it should be straightforward to calculate an equivalent output in any domain desired. The output of the sensors could then be compared to show if differences are in evidence and whether either sensor more accurately represents ground motion.
-
-
-
Foraminiferal response to sedimentary cyclicity in the Haymana Basin (Central Anatolia, Turkey)
By E. AmirovThe aim of this research was the determination of the foraminiferal response to sedimentary cyclicity. The results of the field works on exposures of the Cretaceous-Paleocene deposits located in the Haymana basin demonstrated the high-frequency cyclicity in sedimentation, accompanied by rapid lateral and vertical depositional environment change. The sedimentary sequence is mainly characterized by flyschoidal sequence that is composed of alternation of siliciclastic and carbonate units in the Cretaceous-Paleocene age. It is possible to observe several full depositional sequences developed from low stand system tracts to transgressive and high stand system tracts. The depositional setting during accumulation of this succession has changed from pelagic to neritic environments. On the background of these cycles, the depositional series of higher order containing sediments formed during very small scale sea level fall and rise.
We also carried out the microfaunal analysis, which displays significant presence of foraminifers and an insignificant presence of ostracoda shells represented by genera Leptocythere, Caspiella, Xestoleberis and etc. The foraminiferal assemblages of this sequence were determined in detail and quantitative analysis of them was carried out. By detail investigation of microfauna and determination of foraminifer species under the microscope, we also pinpointed the C/T boundary in the section, which is indicating the mass extinctions of Cretaceous foraminifers represented by genera Planoglobulina, Globotruncana, Globorotalia, Heterohelix and appearance of new genera such as Globoconusa, Igorina, Globanomalina in the Tertiary time. Diversity and abundance of the assemblages was analyzed in order to demonstrate the response of the foraminifers to sedimentary cyclicity.
-
-
-
Sedimentary and structural features of the Late Tertiary from the western Moesian Platform – constrains on Dacic Basin evolution
Authors A. Mirea and I. MunteanuThis study aims to provide some tectonic and sedimentary constrains on the evolution of the Dacic Basin (fig. 1, 2) based on structural and stratigraphic interpretation of several seimic lines from the western part of the Moesian Platform (fig. 1, 3). The study area is located in the fordeep of the South Carpathian orogen and the interpretation regards the last stage postcollisional evolution of the system. Although the tectonic framework of the area is far from a simple orogen/foreland system, in general the classical definition of the foreland basin as formed in front of an active orogenic system by flexure of lower plate driven by orogenic loading (Beaumont, 1981) may be applied for the foredeep of the South Carpathians. The basin's stratigraphy and geometry depend on the tectonic processes taking place in the adjacent orogen and within the foreland.
-
-
-
Accounting the Fracture to Wellbore Connection for Design and Pressure Transient Testing of Hydraulically Fractured Wells-A Gulf of Mexico Challenge
By A. AnchliyaWells drilled from pads on shore and from platforms or drill ships offshore use extended reach drilling to reach the target reservoir location. Often drillers prefer to keep the same angle through the productive zone even when the intent is to hydraulically fracture the well. Because the hydraulic fracture is usually a vertical plane, frequently the wellbore trajectory is not aligned with the far field plane of the hydraulic fracture, leading to a choked fracture skin. A recent paper characterized the choked fracture skin by the number of perforations connecting the hydraulic fracture to the wellbore.
This paper provides a new model for the hydraulic fracture pressure transient response taking into account the fracture to wellbore connection. The model for the fracture skin accounts for the well deviation angle, the angle between the wellbore trajectory and hydraulic fracture plane azimuths, the perforation tunnel diameter and length, the hydraulic fracture half length and conductivity, and fracture face skin.
Sensitivity studies show the pressure transient behavior for a wide range of model inputs. The results are significant because they help determine the mechanical skin used for flux analysis.
-
-
-
Effect of phase variations of the signal to noise ratio of seismic data/ seismic modelling
More LessThe signal-to-noise ratio of the seismic data depends on the way how the data acquisition is done and on the amplitude of the perturbing factors that occur due to the field conditions, for example the phase variations. Some of the effects of the phase variations can be removed/attenuated by using static corrections in the processing flow and some of them not. The later is the case of the effect of irregular geometry, where the extra-times introduced by the receiver positions cannot be removed during the data processing.
In this abstract, we will analyze the effect of irregular geometry on the processing results. Analyzing the synthetic seismic data, we will show that the signal (the reflected waves) can be affected by the irregular geometry used during the data acquisition; the modeling of the seismograms was done using the parameters extracted from the field data geometry in the absence of other perturbing factors, in order to have a control on the effect of irregular geometry. Next, we will analyze a field dataset and we will show how important is the effect of irregular geometry on the signal-to-noise ratio of seismic data.
-
-
-
Datuming of multi-channel deept-tow acoustic data in the shallow water conditions
By D. KalmykovHigh frequency seismic profiling is one of the most important methods of study of sea-floor sediments. At the present time numerous instrumental and methodological modifications are developed and broadly used. In most cases using of one-channel profiling is quite enough for water areas with simple structure of sea-floor sediments. However, for certain sea-floor sediments characterized complex structure, identification of reliability horizons configuration and increasing their traceability are problems of today. One way around these problems is application of the deep-towed acoustic system with multichannel tow.
In the present work, travel time processing features are discussed. These data were collected at the Kandalaksha Gulf (White Sea, Kola Peninsula, Russia), 2005-2006. Author anticipated in this geophysical survey. We used a sparker as a marine seismic impulsive source and 16-channel piezoelectric seismograph. Data were processed by means of standard procedure which is called the CMP method.
-