Eliminate P-wave Direction in Application of Exploration Seismology

Exploration seismology has substantially contributed to finding and developing giant field worldwide. The technology has evolved in single to two, three dimensional methods, and later added a fourth dimension for reservoir monitoring [1]. In land seismic acquisition, a variety of innovative single, three or multiple geophone has been developed by some manufacturer. In this project, the experiment will demonstrate numerous applications for single component geophone (SM – 24) using different composition of sand and rock proportion. The source vibration will generate by a geophone (SM-24) which supplied external frequency from the function generator. The resulting output by single component geophone only provides the output voltage of the propagating elastic wave in one directio

Seismic Waves

The importance of seismic wave research lies not only in our ability to understand and predict earthquakes and tsunamis, it also reveals information on the Earth's composition and features in much the same way as it led to the discovery of Mohorovicic's discontinuity. As our theoretical understanding of the physics behind seismic waves has grown, physical and numerical modeling have greatly advanced and now augment applied seismology for better prediction and engineering practices. This has led to some novel applications such as using artificially-induced shocks for exploration of the Earth's subsurface and seismic stimulation for increasing the productivity of oil wells. This book demonstrates the latest techniques and advances in seismic wave analysis from theoretical approach, data acquisition and interpretation, to analyses and numerical simulations, as well as research applications. A review process was conducted in cooperation with sincere support by Drs. Hiroshi Takenaka, Yoshio Murai, Jun Matsushima, and Genti Toyokuni

Eliminate P-wave Direction in Application of Exploration Seismology

Exploration seismology has substantially contributed to finding and developing giant field worldwide. The technology has evolved in single to two, three dimensional methods, and later added a fourth dimension for reservoir monitoring [1]. In land seismic acquisition, a variety of innovative single, three or multiple geophone has been developed by some manufacturer. In this project, the experiment will demonstrate numerous applications for single component geophone (SM – 24) using different composition of sand and rock proportion. The source vibration will generate by a geophone (SM-24) which supplied external frequency from the function generator. The resulting output by single component geophone only provides the output voltage of the propagating elastic wave in one directio

Petroleum Play Study of the Keathley Canyon, Gulf of Mexico

Beneath Keathley Canyon (KC) off the Southern Coast of Louisiana and Texas, allochthonous salt bodies have attained thicknesses of over 7620 m (25000 feet), providing excellent seals and migration pathways for hydrocarbons produced by post-rift sedimentary deposition. This study analyzes a small portion of the KC area, utilizing Petrel Seismic software and well information from the KC102 (Tiber) well. An intra-Miocene wedge, expressed beneath salt, may provide information about movement of allochthonous salt over Wilcox sands, sediment compaction, and hydrocarbon pathways. Progradational sedimentation is the driving force which leads to faulting in the early Miocene, allowing Jurassic salt to rise, spreading laterally and upwards towards the surface, scarring the sediments beneath it in glacier-like form. This intrusion helped to create the proper conditions for formation of a petroleum play system, maintain reservoir quality sands and temperatures, and create a four way closure in the Eocene for prospective well location

Petroleum Play Study of the Keathley Canyon, Gulf of Mexico

Beneath Keathley Canyon (KC) off the Southern Coast of Louisiana and Texas, allochthonous salt bodies have attained thicknesses of over 7620 m (25000 feet), providing excellent seals and migration pathways for hydrocarbons produced by post-rift sedimentary deposition. This study analyzes a small portion of the KC area, utilizing Petrel Seismic software and well information from the KC102 (Tiber) well. An intra-Miocene wedge, expressed beneath salt, may provide information about movement of allochthonous salt over Wilcox sands, sediment compaction, and hydrocarbon pathways. Progradational sedimentation is the driving force which leads to faulting in the early Miocene, allowing Jurassic salt to rise, spreading laterally and upwards towards the surface, scarring the sediments beneath it in glacier-like form. This intrusion helped to create the proper conditions for formation of a petroleum play system, maintain reservoir quality sands and temperatures, and create a four way closure in the Eocene for prospective well location

METODOLOGÍA DE REDUCCIÓN DE SOMBRA DE FALLA: APLICADA EN UNA ZONA DE LA CUENCA LLANOS – DEPARTAMENTO DE CASANARE, COLOMBIA

La sombra de falla distorsiona la imagen sísmica del bloque yacente de una falla normal o inversa, lo cual se debe a fuertes cambios de velocidad lateral que desvían la trayectoria de los rayos. En la Cuenca Llanos este efecto crea en las imágenes sísmicas falsas estructuras de anticlinales (“pull-up”) y sinclinales (“push down o sag”). En este artículo se estudian los factores que generan este efecto y su impacto en las imágenes sísmicas mediante el modelado numérico. Se define una metodología para identificar la sombra y los factores que la causan, y crear el modelo apropiado para la migración PSDM. La metodología se probó en sismogramas sintéticos y se aplicó a una línea sísmica de un sector del Departamento de Casanare-Colombia. Como resultado se obtuvo una imagen en profundidad confiable libre de sombra de falla. Aunque la metodología se usó en un sector con falla normal ésta es aplicable a zonas con fallas inversas.    The shadow fault distorts the image of the hanging block of normal and inverse faults, caused by strong lateral velocity changes that deviates the ray path of waves. In the Llanos basin, this effect creates in the seismic images false structures like anticlines (pull up) and synclines (push down or sag). In this paper, the factors that generate this effect and its impact on the seismic images are studied through numerical modeling. It is defined a methodology to identify the fault shadow and its causing factors, and to create the appropriate model for the pre stack depth migration – PSDM. The methodology was tested with synthetic seismograms and applied to a seismic line recorded in a sector of the Departamento de Casanare-Colombia. As a result, a reliable image in depth free of fault shadow was obtained. Even the methodology was used in a sector with normal fault it is applicable to zones with inverse faults. &nbsp

METODOLOGÍA DE REDUCCIÓN DE SOMBRA DE FALLA: APLICADA EN UNA ZONA DE LA CUENCA LLANOS – DEPARTAMENTO DE CASANARE, COLOMBIA

La sombra de falla distorsiona la imagen sísmica del bloque yacente de una falla normal o inversa, lo cual se debe a fuertes cambios de velocidad lateral que desvían la trayectoria de los rayos. En la Cuenca Llanos este efecto crea en las imágenes sísmicas falsas estructuras de anticlinales (“pull-up”) y sinclinales (“push down o sag”). En este artículo se estudian los factores que generan este efecto y su impacto en las imágenes sísmicas mediante el modelado numérico. Se define una metodología para identificar la sombra y los factores que la causan, y crear el modelo apropiado para la migración PSDM. La metodología se probó en sismogramas sintéticos y se aplicó a una línea sísmica de un sector del Departamento de Casanare-Colombia. Como resultado se obtuvo una imagen en profundidad confiable libre de sombra de falla. Aunque la metodología se usó en un sector con falla normal ésta es aplicable a zonas con fallas inversas.    The shadow fault distorts the image of the hanging block of normal and inverse faults, caused by strong lateral velocity changes that deviates the ray path of waves. In the Llanos basin, this effect creates in the seismic images false structures like anticlines (pull up) and synclines (push down or sag). In this paper, the factors that generate this effect and its impact on the seismic images are studied through numerical modeling. It is defined a methodology to identify the fault shadow and its causing factors, and to create the appropriate model for the pre stack depth migration – PSDM. The methodology was tested with synthetic seismograms and applied to a seismic line recorded in a sector of the Departamento de Casanare-Colombia. As a result, a reliable image in depth free of fault shadow was obtained. Even the methodology was used in a sector with normal fault it is applicable to zones with inverse faults. &nbsp

Effects of geophysical parameters on the seismic expression of the Maghlaq Fault, Malta: insights from outcrop-based 2D seismic modeling

Faults are heterogenous zones comprising highly complex geometries, which can be studied in detail from field outcrops. The internal complexity of a fault zone is however difficult to interpret from seismic images, due to resolution and illumination limitations of the data. To improve the seismic interpretation of subsurface structures, synthetic seismic can be simulated from outcrop-derived geological models. Such seismic modeling reveals the potential seismic expression of structural and stratigraphic features observed in the field. In this study, a 2D Point-Spread Function based modeling approach is applied to investigate the seismic expression of the Maghlaq Fault, Malta, which is a carbonate-hosted normal fault zone comprising complex hanging wall geometries. Geological models of the fault zone are created based on both geological interpretations of virtual outcrop models of the hanging wall of the fault as well as conceptual extrapolations. The geological models are divided into lithostratigraphic units, which are further assigned realistic elastic properties (i.e. seismic velocities and density) in order to create reflectivity models. Pre-stack Depth Migration images are simulated from the seismic modeling, predicting the seismic characteristics of the Maghlaq Fault. The study further analyzes the effects of various geophysical survey parameters on the seismic images, by systematically varying each individual parameter, such as the dominant frequency, level of noise, angle of maximum illumination, incident angle and wavelet type. The resulting 2D seismic sections generated in this study show that the seismic expression of the Maghlaq Fault differs to some extent for the four different geological models, due to the significant variation in hanging wall geometry of the four geological input models. Nevertheless, some consistent seismic characteristics are found in all seismic images, regardless of the variation in structural and stratigraphic input. Furthermore, the obtained results from the sensitivity analyses highlight the geophysical parameter dependency of both the detectability and the seismic expression of the fault zone. The dominant frequency, noise level and angle of maximum illumination are the parameters which have the greatest impact on the seismic images of the Maghlaq Fault zone. This thesis is a contribution to improve the understanding of seismic imaging of normal fault zones within carbonates, which hopefully can aid seismic interpretation of similar structures in the subsurface.Masteroppgave i geovitenskapGEOV399MAMN-GEO

Static Load Balancing using Non-Uniform Mesh Partitioning based on Ray Density Prediction for the Parallel Wavefront Construction Method

The Wavefront Construction (WFC )method, which was developed based on ray theory, is one of the most efficient tools in seismic modeling. The main idea of this method is to propagate a wavefront represented by rays in a computational mesh that is interpolated whenever an accuracy criterion is violated. Recently, a parallel WFC was developed using the Standard Template Adaptive Parallel Library. However, due to wavefront density adaptivity, the parallel implementation exhibits inefficient performance owing to load imbalances between multiple processors.This paper applies a static load balancing approach based on a method for predicting future loads for a synthetic salt dome model, in order to improve the performance.The approach utilizes a preliminary conventional ray simulation to estimate the cost (future load) of each cell in the WFC's initial wavefront mesh.Then it applies a non-uniform mesh decomposition that results in a more efficient parallel WFC. Our implementation shows better and stable scalability in most WFC simulations. Overall, this paper contributes to understanding the behavior of wavefront mesh adaptability and predicting earth model complexities, and it serves as a guide for achieving the ultimate goal, a fully load-balanced parallel WFC