Navegando por Assunto "Seismic reflection method"

Agora exibindo 1 - 4 de 4

Acesso aberto (Open Access)
Uma análise de métodos de supressão de múltiplas de superfície livre aplicados a um dado real
(Universidade Federal do Pará, 2011-10-14) OLIVEIRA, Andrei Gomes de; GOMES, Ellen de Nazaré Souza; http://lattes.cnpq.br/1134403454849660
The seismic record in 2D linear events are common features in the seismograms. These events are overlap with interesting reflections (early reflections) complicating the stages of seismic processing and identification of possible subsurface geological horizons. It possible highlight multiple surface that distinguished from others by a low frequency, high amplitude and low velocity of propagation. The identification and removal of multiple reflflections in seismic data is a real step of great importance in seismic processing, because the attenuation can prevent many of these errors in the interpretation of geological images seismic. This study is the determination of a processing flow for multiple attenuation free surface. Methods of elimination of multiple surface (SRME, Radon filtering, predictive deconvolution domain τ - p and fk filltering) applied to a real data 2D were used in different combinations. These are analyzed and presented the results are the best combinations.
Acesso aberto (Open Access)
Joining diffraction filter and residual diffraction moveout to constructo a velocity model in the depth and time domains: application to a Viking Graben data set
(Universidade Federal do Pará, 2014-08-14) COLLAZOS GONZALEZ, Jaime Andres; FIGUEIREDO, José Jadsom Sampaio de; http://lattes.cnpq.br/1610827269025210
Diffracted seismic waves are generated by unsmooth structures in the subsurface with a size on the order of seismic wavelengths. Because the incident wave field can be significantly affected by these discontinuities, many important properties of the seismic events can be used to improve the velocity model building. In this thesis, we propose a practical approach to construct velocity models in the time and depth domains using diffractions. This methodology applies the plane wave destruction (PWD) filter jointly with the residual diffraction moveout (RDM) method to construct velocity models in time and depth domains. Our method does not depend on any requirements except for identifiable diffractions filtered from reflection events and an arbitrary initial velocity model as input. The post-stack migrated images (in the time and depth domains) are compared with the mi- grated images derived from conventional seismic processing steps. In both cases, we used post-stack Kirchhoff Migration. Beyond the to the need to identify and select the diffraction events in the post-stack migrated sections in the depth domain, the method has a very low computational cost of processing time. To reach an acceptable velocity model was less compared with conventional processing. The applicability of our methodology was verified using a real Viking Graben seismic dataset.
Acesso aberto (Open Access)
Métodos de processamento de sísmica rasa em fundos submersos no baixo curso do rio Amazonas
(Universidade Federal do Pará, 2014-12-02) WATANABE, Fábio Kiyoshi; PINHEIRO, Roberto Vizeu Lima; http://lattes.cnpq.br/3251836412904734; ROLLNIC, Marcelo; http://lattes.cnpq.br/6585442266149471
The study area is located on northeast region of Pará state, it includes the Pará river, Tocantins river’s outfall and Marajó bay. The study is restricted to Amazon estuarine complex, characterized by coastal lowland regions which have been formed during the Holocene marine transgression which flooded vales of rivers. This work aims to improve the knowledge about the shallow seismic methods in the Amazon, specifically on tributary rivers, applying the X-STAR 3200-XS system. The work’s focus is to enable ways to process the information from this geophysical acquisition system, little used in the region, applying methods of treatment in seismic profiles where it’s possible to perceive the horizontal continuity’s distribution and a better morphological identification, besides that is also important locate the depth of acoustic basement. This work intents to present a methodological proposal to investigate the sedimentary unconsolidated covers deposited in submerged areas of different amazonian environments. From these data a processing flow in the region will be made to explain some aspects, related mainly to its limiters, besides more suitable criteria to a better data acquisition.
Acesso aberto (Open Access)
Processamento, inversão e imageamento de dados sísmicos marinhos
(Universidade Federal do Pará, 2012) SILVA, Douglas Augusto Barbosa da; LEITE, Lourenildo Williame Barbosa; http://lattes.cnpq.br/8588738536047617
This work was there on the study and processing, inversion and imaging in time and in depthof Marmousi seismic data, and of the real Jequitinhonha obtained in the Bahia state Brazilian atlantic oriental continental platform. Were applied the NMO and CRS stack methods andthe niptomographic inversion technique of the cinematic attributes of the wave field. Withthe NMO stack was obtained a velocity distribution map throughout the velocity analysis onthe semblance coherence map and straight afterward the stacked and migrated sections in thedomain of the time and depth. The stack method of the common reflection surface (CRS)was applied with the crsstack-511 program to obtain the stacked and migrated sections inthe time domain and to extract the field wave parameters throughout the coherence analysis and of the redundancy obtained on the seismic data of multi-device. The niptomographicinversion phenomena of reflection took place throughout the aplication of the niptomo program,which is an implementation of the inversion method of the cinematic attributes ofthe NIP hypothetic wave, extracted straight from the CRS stack, to obtain an smoothedvelocity model, and subsequently, a migrated section in depth. The migrated sections areof the Kirchhoff kind. The techniques used follow a pre-determined and realized flowchartfollowing a file “makefile”, that works as an stage organizer. These stages were realized in theLinux desktop and in the Seismic Uni*x system of the Center for Wave Phenomena (CWP)of Colorado School of Mines. The results of the three techniques were compared with theaim of illustrating the evolution of the visual quality of the reluctant sections throughout theevents continuity trace-by-trace and the signal/noise relation, to analyze differences and improvementsin the migrated sections expecting a better geologic interpretation and organizebetter terms of processing and imaging, trying to aid possible well succeed drillings.