Seismic signal processing—A new millennium perspective

Geophysics ◽  
2001 ◽  
Vol 66 (1) ◽  
pp. 18-20 ◽  
Author(s):  
Peter Cary
Keyword(s):  
Seismic Data ◽  
Seismic Signal ◽  
First Century ◽  
Vast Number ◽  
Seismic Processing ◽  
Almost Everywhere ◽  
The People ◽  
Conference Presentations ◽  
And Migration ◽  
Seismic Signal Processing

In the introduction to his comprehensive SEG textbook, Seismic Data Processing, Oz Yilmaz selects deconvolution, common‐midpoint stacking and migration as being the three principal processes that are applied during routine seismic processing. Since Yilmaz’s tome was first published in 1987, a vast number of papers have been published and conference presentations have been given on virtually every aspect of seismic processing. However, I think it is still accurate to say that the same three processes dominate the processing flow of the vast majority of seismic data that is processed now, at the beginning of the twenty‐first century. This is not to say that important progress has not been made in many aspects of seismic processing and that much more sophisticated processing flows are now applied to some datasets. But it is a great tribute to the real pioneers of our profession—the people who advanced our ideas of seismic processing from examining raw analog records in the field to creating crisp computer‐generated images of the subsurface with processes such as deconvolution, stack and migration—that the very same, or similar, algorithms that they invented still form the backbone of everyday processing that is done around the world today. In fact, there are times when it seems that the last great geophysicist was Carl Friedrich Gauss, because the method that he published back in 1823 of minimizing the sum of the squared errors seems to be used almost everywhere one looks in seismic processing, from deconvolution to migration.

scholarly journals Optimized Characterization of Gas Chimneys Based on Special Seismic Processing

2019 ◽  
Vol 37 (4) ◽  
Author(s):  
José Paulo Goulart ◽  
David Castro ◽  
Wander Amorim
Keyword(s):  
Seismic Data ◽  
Seismic Signal ◽  
Low Frequencies ◽  
Important Indicator ◽  
Seismic Processing ◽  
Gas Chimney ◽  
Seismic Acquisition ◽  
Seismic Sections ◽  
Gas Chimneys ◽  
Parnaíba Basin

ABSTRACT A new computational methodology was developed to facilitate the interpretation of gas chimneys in seismic sections by analyzing the frequency spectrum of the seismic signal in the Hilbert Domain. Gas chimneys are structures associated with the migration of hydrocarbons or free gas, causing vertical chaotic disturbances in the seismic data. Its occurrence in oil reservoirs is considered an important indicator of the presence of an active petroleum system and its mapping is useful to reduce exploratory risks, increasing the probability of success of the pioneer wells. Standard seismic processing does not favor the recognition of gas chimneys, since their characteristic seismic signature is treated as noise and the low frequencies are strongly attenuated already in the period of the seismic acquisition. The set of reflections is calculated to enhance the low frequencies, making the gas chimneys easily identifiable in the seismic sections where they were not previously even perceived. The special processing flow was applied to seismic data from the Parnaíba Basin “(NE Brazil). This Paleozoic basin is especially rich in gas chimneys, which were favored by transcurrent tectonics associated with the Transbrasiliano Lineament. The gas chimneys interpretation could be validated by the observation of correlated seismic, topographic and geochemical features.KEYWORDS: special processing, gas chimney, exploratory risk, Parnaíba Basin. RESUMO. Uma nova metodologia computacional foi desenvolvida para facilitar a interpretação de chaminés de gás em seções sísmicas por meio da análise do espectro de frequência do sinal sísmico no Domínio de Hilbert. Chaminés de gás são estruturas associadas à migração de hidrocarbonetos ou gás livre, provocando perturbações caóticas verticais no dado sísmico. Sua ocorrência em reservatórios petrolíferos é considerada um importante indicador da presença de um sistema petrolífero ativo e seu mapeamento é útil para reduzir os riscos exploratórios, aumentando a probabilidade de sucesso dos poços pioneiros. O processamento sísmico padrão não favorece o reconhecimento das chaminés de gás, uma vez que a sua assinatura sísmica característica é tratada como ruído e as baixas frequências são fortemente atenuadas já no período da aquisição sísmica. O conjunto de reflexões é calculado para realçar as baixas frequências, tornando as chaminés de gás facilmente identificáveis nas seções sísmicas onde antes não eram nem percebidas. O processamento especial foi aplicado em dados sísmicos da Bacia do Parnaíba. Esta bacia paleozoica é especialmente rica em chaminés de gás, cuja presença foi favorecida pela tectônica transcorrente associada ao Lineamento Transbrasiliano. As chaminés de gás interpretadas puderam também ser validadas pela observação de feições sísmicas, topográficas e geoquímicas correlatas.Palavras-chave: processamento especial, chaminé de gás, risco exploratório, Bacia do Parnaíba.

scholarly journals Efficient selective filtering of seismic data using multiscale decomposition

2013 ◽  
Vol 20 (2) ◽  
pp. 207-211 ◽  
Author(s):  
F. E. A. Leite ◽  
M. V. C. Henriques ◽  
V. C. Gurgel ◽  
J. M. S. Filho
Keyword(s):  
Seismic Data ◽  
Multiple Scales ◽  
Relevant Information ◽  
Seismic Signal ◽  
Geological Structure ◽  
Petroleum Exploration ◽  
Discrete Wavelet ◽  
Physical Information ◽  
Ground Roll ◽  
Seismic Signal Processing

Abstract. Seismic signal processing is an important task in geophysics sounding and represents a permanent challenge in petroleum exploration. Although seismograms could in principle give us a picture of a geological structure, they are very contaminated by spurious signals and the ground roll noise is a strongly undesired signal present in the seismograms – it does not carry physical information about the deep geological structures. This fact demands a big effort in developing new filtering methodologies. Using discrete wavelet transform, an efficient filtering for suppression of the ground roll is presented. In this method, seismic data is decomposed in multiple scales. We can remove the noise as a surgical operation in each scale, just from the regions where they are present or strong, allowing us to preserve the maximum of relevant information.

APPLICATION OF THE EMPIRICAL MODE DECOMPOSITION METHOD TO GROUND-ROLL NOISE ATTENUATION IN SEISMIC DATA

2013 ◽  
Vol 31 (4) ◽  
pp. 619 ◽  
Author(s):  
Luiz Eduardo Soares Ferreira ◽  
Milton José Porsani ◽  
Michelângelo G. Da Silva ◽  
Giovani Lopes Vasconcelos
Keyword(s):  
Empirical Mode Decomposition ◽  
Seismic Data ◽  
Low Frequency ◽  
High Amplitude ◽  
Seismic Line ◽  
Seismic Processing ◽  
Mode Decomposition ◽  
Ground Roll ◽  
Fortran 90 ◽  
Emd Method

ABSTRACT. Seismic processing aims to provide an adequate image of the subsurface geology. During seismic processing, the filtering of signals considered noise is of utmost importance. Among these signals is the surface rolling noise, better known as ground-roll. Ground-roll occurs mainly in land seismic data, masking reflections, and this roll has the following main features: high amplitude, low frequency and low speed. The attenuation of this noise is generally performed through so-called conventional methods using 1-D or 2-D frequency filters in the fk domain. This study uses the empirical mode decomposition (EMD) method for ground-roll attenuation. The EMD method was implemented in the programming language FORTRAN 90 and applied in the time and frequency domains. The application of this method to the processing of land seismic line 204-RL-247 in Tacutu Basin resulted in stacked seismic sections that were of similar or sometimes better quality compared with those obtained using the fk and high-pass filtering methods.Keywords: seismic processing, empirical mode decomposition, seismic data filtering, ground-roll. RESUMO. O processamento sísmico tem como principal objetivo fornecer uma imagem adequada da geologia da subsuperfície. Nas etapas do processamento sísmico a filtragem de sinais considerados como ruídos é de fundamental importância. Dentre esses ruídos encontramos o ruído de rolamento superficial, mais conhecido como ground-roll . O ground-roll ocorre principalmente em dados sísmicos terrestres, mascarando as reflexões e possui como principais características: alta amplitude, baixa frequência e baixa velocidade. A atenuação desse ruído é geralmente realizada através de métodos de filtragem ditos convencionais, que utilizam filtros de frequência 1D ou filtro 2D no domínio fk. Este trabalho utiliza o método de Decomposição em Modos Empíricos (DME) para a atenuação do ground-roll. O método DME foi implementado em linguagem de programação FORTRAN 90, e foi aplicado no domínio do tempo e da frequência. Sua aplicação no processamento da linha sísmica terrestre 204-RL-247 da Bacia do Tacutu gerou como resultados, seções sísmicas empilhadas de qualidade semelhante e por vezes melhor, quando comparadas as obtidas com os métodos de filtragem fk e passa-alta.Palavras-chave: processamento sísmico, decomposição em modos empíricos, filtragem dados sísmicos, atenuação do ground-roll.

scholarly journals Prospects of Using Hydrocarbon Deposits from the Autochthonous Miocene Formation (Eastern Carpathian Foredeep, Poland) for Geothermal Purposes

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3102
Author(s):  
Anna Chmielowska ◽  
Anna Sowiżdżał ◽  
Barbara Tomaszewska
Keyword(s):  
Oil And Gas ◽  
Geothermal System ◽  
Vast Number ◽  
Hydrocarbon Traps ◽  
Oil And Gas Fields ◽  
Geothermal Potential ◽  
Carpathian Foredeep ◽  
And Migration ◽  
Gas Fields ◽  
Geothermal Parameters

There are many oil and gas fields around the world where the vast number of wells have been abandoned or suspended, mainly due to the depletion of reserves. Those abandoned oil and gas wells (AOGWs) are often located in areas with a prospective geothermal potential and might be retrofitted to a geothermal system without high-cost drilling. In Poland, there are thousands of wells, either operating, abandoned or negative, that might be used for different geothermal applications. Thus, the aim of this paper is not only to review geothermal and petroleum facts about the Eastern Carpathian Foredeep, but also to find out the areas, geological structures or just AOGWs, which are the most prospective in case of geothermal utilization. Due to the inseparability of geological settings with both oil and gas, as well as geothermal conditionings, firstly, the geological background of the analyzed region was performed, considering mainly the autochthonous Miocene formation. Then, geothermal and petroleum detailed characteristics were made. In the case of geothermal parameters, such as formation’s thickness, temperatures, water-bearing horizons, wells’ capacities, mineralization and others were extensively examined. Considering oil and gas settings, insights into reservoir rocks, hydrocarbon traps and migration paths issues were created. Then, for evaluating geothermal parameters for specific hydrocarbon reservoirs, their depths were established based on publicly available wells data. Thereafter, the average temperatures for selected reservoirs were set. As the effect, it turned out that most of the deposits have average temperatures of 40/50 °C, nonetheless, there are a few characterized by higher (even around 80 °C) temperatures at reasonable depths.

scholarly journals Family planning program under low fertility: where to go

2021 ◽  
Author(s):  
Baochang Gu
Keyword(s):  
Family Planning ◽  
Reproductive Health ◽  
Unmet Needs ◽  
Family Planning Program ◽  
Population Control ◽  
First Century ◽  
Low Fertility ◽  
Planning Program ◽  
The People ◽  
The Family

AbstractThis commentary is intended to take China as a case to discuss the mission of the family planning program under low fertility scenario. After a brief review of the initiation of family planning program in the 1970s, as well as the reorientation of family planning program since ICPD in 1994, it will focus on the new mission for the family planning program under low fertility scenario in the twenty-first century, in particular concerning the issue of induced abortion among the others. Given the enormous evidence of unmet needs in reproductive health as identified in the discussion, it is argued that family planning programmes are in fact even more needed than ever before under low-fertility scenario, and should not be abandoned but strengthened, which clearly has nothing to do to call back to the program for population control in the 1970s–1980s, and nor even go back to the program for “two reorientations” in the 1990s, but to aim to serving the people to fulfill their reproductive health and reproductive rights in light of ICPD and SDGs, and to become truly integral component of “Healthy China 2030” Strategy.

scholarly journals “We have never been public:” Continuity and change in the policy production of “the public” in education in England

2021 ◽  
pp. 147490412199047
Author(s):  
Matthew Clarke ◽  
Martin Mills
Keyword(s):  
Public Education ◽  
Progressive Education ◽  
Central Government ◽  
First Century ◽  
Government Control ◽  
The Public ◽  
Continuity And Change ◽  
The People ◽  
Future Potential ◽  
Education And Society

Recent educational reforms in England have sought to reshape public education by extending central government control of curriculum and assessment, while replacing local government control of schools with a quasi-private system of academies and multi academy trusts. In this paper, we resist reading this as the latest iteration of the debate between “traditional” and “progressive” education. Instead, we note how, despite the mobilisation of the rhetoric of the public and public education, schooling in England has never been public in any deeply meaningful sense. We develop a genealogical reading of public education in England, in which ideas of British universalism – “the public” – and inequality and exclusion in education and society have not been opposed but have gone hand-in-hand. This raises the question whether it is possible to envisage and enact another form of collective – one that is based on action rather than fantasy and that is co-authored by, comprising, and exists for, the people. The final part of this paper seeks to grapple with this challenge, in the context of past, present and future potential developments in education, and to consider possibilities for the imaginary reconstitution of public education in England in the twenty-first century.

The Social Challenges of Involving the General Publics in Garbage Separation and Recycling in Chinese Cities

2014 ◽  
Vol 878 ◽  
pp. 831-839 ◽  
Author(s):  
Keng Hang Fan
Keyword(s):  
Collection System ◽  
Social Challenges ◽  
Social Surveys ◽  
The Public ◽  
Informal Recycling ◽  
Almost Everywhere ◽  
The People ◽  
The Social ◽  
Environmental Technologies ◽  
Waste Separation

Waste separation bins that are mainly categorized into recyclable and non-recyclable are being installed almost everywhere in China. It is notable that China is pushing hard to get the public involved in garbage separation and recycling. As an ethnographic research, this paper provides social and cultural explanations of why the roles of these newly designed bins are extremely limited. Explanation of such limitation is deeply concerned with, first, the beliefs and knowledge about recycling of the general publics, and more importantly, the history and hard-to-be-changed culture of informal recycling involving garbage pickers in China. As a foreign Chinese, the author has been running around Beijing and other cities in China to explore into the behind the scene Chinese informal garbage collection system. Using a series of informative social surveys, interviewing the public and personal observation, the paper illustrates and discusses the social challenges and current dilemmas China is facing in attempts to formalize its garbage separation and recycling. The aim of the paper is to address the importance of integrating the existing culture and knowledge of the people with the making of future environmental technologies and policies.

Drowning Not Waving: The ‘Children Overboard’ Event and Australia's Fear of the other

2003 ◽  
Vol 109 (1) ◽  
pp. 93-108 ◽  
Author(s):  
Kate Slattery
Keyword(s):  
Media Coverage ◽  
Asylum Seekers ◽  
News Coverage ◽  
National Identities ◽  
Global Village ◽  
Print News ◽  
The People ◽  
Identity Based ◽  
And Migration ◽  
Selection Of

The last few years have been an awakening time for the people, communities and governments of the global village. Escalating problems in the Middle East, global economic uncertainty and an increase in asylum seekers, refugees and migration worldwide have reignited tensions involving boundaries and borders, both geographical and cognitive. One event which highlighted these tensions in Australia, and which was given much media coverage, was the ‘children overboard’ event in October 2001. Utilising a selection of print news coverage of the event, this paper explores how the ‘children overboard’ event demarcated national identities and spaces through the construction and representation of ‘good’ Australian citizens and ‘bad’ asylum seeker ‘others’. Specifically referring to ‘children overboard’ as an ‘event’, I seek to highlight the constructed and representational nature of ‘children overboard’ as a media story and political tool, one which promoted a continuing threat of ‘others’ to the nation in order to gain support for government policy and legitimize national security, and in so doing creating a model of Australian citizenship and identity based upon fear.

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