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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
541 - 556 of 556 results
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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.
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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.
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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.
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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
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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.
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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.
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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.
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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.
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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.
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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).
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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.
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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.
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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.
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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.
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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.
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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.
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