Modeling studies of interference reflections in thin‐layered media bounded by coal seams

Geophysics ◽  
1992 ◽  
Vol 57 (9) ◽  
pp. 1209-1216 ◽  
Author(s):  
Lawrence M. Gochioco
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
Oil And Gas ◽  
Close Correlation ◽  
Destructive Interference ◽  
Modeling Studies ◽  
Velocity Information ◽  
Interpretation Process ◽  
Ricker Wavelet ◽  
Sonic Logs

High‐resolution seismic data collected over a major U.S. coal basin indicated potential complex problems associated with interference reflections. These problems differed from those normally encountered in the exploration of oil and gas because of differences in the geologic boundary conditions. Modeling studies were conducted to investigate the effects of overlapping primary reflections and the composite reflection that result from stacking individual wavelets. A modified empirical formula of Lindseth’s linear relationship between acoustic impedance and velocity is used to extrapolate velocity information from density logs to provide appropriate geophysical properties for modeling. The synthetic seismograms generated from density and synthetic sonic logs correlated well with the processed seismic data. A 150-Hz Ricker wavelet is used to convolve with the computer models, and the models showed that certain anomalous composite reflections result from the superposition of overlapping primary reflections. Depending on the traveltime delay of latter primary reflections, constructive or destructive interference could significantly alter the signature of the initial reflection associated with the bed of interest, which may lead to misinterpretations if not properly identified. The stratigraphic modeling technique further enhances the interpretation process and shows a close correlation with the seismic data, suggesting that more precise analytical methods need to be used to interpret, sometimes complex, high‐resolution seismic data.

Hydrocarbon identification using the AVO response correction method based on high-resolution complex spectral decomposition

2020 ◽  
Vol 8 (1) ◽  
pp. SA49-SA61
Author(s):  
Huihuang Tan ◽  
Donghong Zhou ◽  
Shengqiang Zhang ◽  
Zhijun Zhang ◽  
Xinyi Duan ◽  
...  
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
Spectral Decomposition ◽  
Oil And Gas ◽  
Low Frequency ◽  
Seismic Signal ◽  
Correction Method ◽  
Bohai Bay ◽  
Oil And Gas Exploration ◽  
Response Correction

Amplitude-variation-with-offset (AVO) technique is one of the primary quantitative hydrocarbon discrimination methods with prestack seismic data. However, the prestack seismic data are usually have low data quality, such as nonflat gathers and nonpreserved amplitude due to absorption, attenuation, and/or many other reasons, which usually lead to a wrong AVO response. The Neogene formations in the Huanghekou area of the Bohai Bay Basin are unconsolidated clastics with a high average porosity, and we find that the attenuation on seismic signal is very strong, which causes an inconsistency of AVO responses between seismic gathers and its corresponding synthetics. Our research results indicate that the synthetic AVO response can match the field seismic gathers in the low-frequency end, but not in the high-frequency components. Thus, we have developed an AVO response correction method based on high-resolution complex spectral decomposition and low-frequency constraint. This method can help to achieve a correct high-resolution AVO response. Its application in Bohai oil fields reveals that it is an efficient way to identify hydrocarbons in rocks, which provides an important technique for support in oil and gas exploration and production in this area.

scholarly journals Prediction of reservoir sand in Miocene deltaic deposits in Denmark based on high-resolution seismic data

2007 ◽  
Vol 13 ◽  
pp. 17-20 ◽  
Author(s):  
Erik S. Rasmussen ◽  
Thomas Vangkilde-Pedersen ◽  
Peter Scharling
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
Seismic Reflection ◽  
Oil And Gas ◽  
Lower Miocene ◽  
Sequence Stratigraphic ◽  
Deep Aquifers ◽  
Gas Bearing

Intense investigations of deep aquifers in Jylland, western Denmark, during the last seven years have resulted in de tailed mapping of Miocene sand-rich deposits laid down in fluvial channels, delta lobes, shoreface and spit complexes (Fig. 1; Rasmussen 2004). Detailed sedimentological and paly nol ogical studies of outcrops and cores, and interpretation of high-resolution seismic data, have resulted in a well-founded sequence-stratigraphic and lithostratigraphic scheme (Fig. 1) suitable for prediction of the distribution of sand. The Miocene succession onshore Denmark is divided into three sand-rich deltaic units: the Ribe and Bastrup sands and the Odderup Formation (Fig. 2). Prodeltaic clayey deposits of the Vejle Fjord and Arnum Formations interfinger with the sand-rich deposits. Most of the middle and upper Mio- cene in Denmark is composed of clayey sediments referred to the Hodde and Gram Formations (Fig. 2). This paper presents examples of seismic reflection patterns that have proved to correlate with sand-rich deposits from lower Miocene deltaic deposits and that could be applied in future exploration for aquifers and as analogues for oil- and gas-bearing sands in wave-dominated deltas.

Analysis on the well Constraint Inversion of the Jason-Based Layer Flattening Seismic Data under the High-Resolution Isochronous Framework

2013 ◽  
Vol 416-417 ◽  
pp. 1135-1141
Author(s):  
Shi Fang ◽  
Xin Rong Zhang ◽  
Jin Ping Liu ◽  
Chun Lai Xie
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
Oil And Gas ◽  
Absolute Error ◽  
Oil Field ◽  
Obvious Effect ◽  
Sand Body ◽  
The Absolute ◽  
Plane Distribution ◽  
Sand Bodies

The later-period structure of Fuyang oil layer is very complex, and its reservoir mainly consists of riverway sand bodies; the oil and gas reservoir is significantly concealed, so it is greatly difficult to identify. In order to accurately predict sand bodies by using seismic data, a well constrained inversion is made to the layer flattening seismic data using Jason software under the high-resolution sequence framework. Through a comprehensive analysis on seismic and geological data, the absolute error is within ±500, the relative error is within 10%; the predicted sand body plane distribution is reasonable, and the absolute error of 82% sand bodies is less than 10%. This proves that well constrained inversion for the Jason-based layer flattening seismic data under the high-resolution isochronous framework has an obvious effect on the areas of complex later-period structure, and thin and complex changed sand bodies. Therefore, it can meet the needs of the oil field exploration and development to a certain extent.

scholarly journals PROCESSING OF HIGH-RESOLUTION, SHALLOW SEISMIC PROFILES, GUANABARA BAY – RIO DE JANEIRO STATE, BRAZIL

2013 ◽  
Vol 31 (4) ◽  
pp. 579 ◽  
Author(s):  
Igor Kestemberg Marino ◽  
Marco Antonio Cetale Santos ◽  
Cleverson Guizan Silva
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
Oil And Gas ◽  
Single Channel ◽  
Guanabara Bay ◽  
Sea Level Changes ◽  
Seismic Profiles ◽  
Shallow Seismic ◽  
Signal Improvement

ABSTRACT. This paper presents a proposal for implementing a processing flowchart for high-resolution single-channel seismic data acquired in Guanabara Bay, followed by its interpretation. Geologically, it consists of mapping the Guanabara Bay Quaternary deposits relative to the drowning of a fluvial paleochannel that resulted from recent sea level changes. So far, high-resolution seismic data have been interpreted without any signal improvement, while the development of a processing flowchart for this is hardly addressed in the literature. The parameters were selected based on the processing applied to conventional seismic prospecting for oil and gas in order to compose a less extensive and more applicable flowchart. The results confirmed the efficacy of the processing applied to shallow seismic data, with noise and multiples attenuation and better lateral continuity of reflectors in subsurface, thus increasing the quality of the final seismic record.Keywords: Processing, shallow seismic, Guanabara Bay, high-resolution seismic. RESUMO. O presente trabalho apresenta uma proposta de aplicação de um fluxo de processamento para dados de sísmica monocanal de alta resolução adquiridos na Baía de Guanabara e, posteriormente, sua interpretação. O objetivo geológico consiste no mapeamento dos depósitos Quaternários da Baía de Guanabara relativos ao afogamento de um paleocanal fluvial como consequência das variações recentes do nível do mar. Até o momento os dados de sísmica de alta resolução vêm sendo interpretados sem a aplicação de nenhuma melhoria e a elaboração de um fluxo de processamento para tal é raramente abordada na literatura. Os parâmetros foram selecionados para a elaboração do fluxo com base no processamento aplicado à sísmica convencional na prospecção de hidrocarbonetos de forma a compor um fluxo mais sucinto e aplicável. Os resultados obtidos nos perfis analisados comprovaram a eficácia do processamento de dados de sísmica rasa, com a atenuação de ruídos, das múltiplas de fundo e maior continuidade lateral dos refletores em subsuperfície, aumentando assim a qualidade do registro sísmico.Palavras-chave: Processamento, sísmica rasa, baía da Guanabara, alta resolução sísmica.

scholarly journals Structural Interpretation of Seismic Data of Mishrif Formation in East Abu-Amoud Field, South-eastern Iraq

2021 ◽  
pp. 3612-3619
Author(s):  
Mohammed H. Al-Aaraji ◽  
Hussein H. Karim
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
Well Logs ◽  
Seismic Section ◽  
Reflected Waves ◽  
South Eastern ◽  
Vertical Variations ◽  
Structural Image ◽  
Seismic Sections ◽  
Sonic Logs

      The seismic method depends on the nature of the reflected waves from the interfaces between layers, which in turn depends on the density and velocity of the layer, and this is called acoustic impedance. The seismic sections of the East Abu-Amoud field that is located in Missan Province, south-eastern Iraq, were studied and interpreted for updating the structural picture of the major Mishrif Formation for the reservoir in the Abu-amoud field. The Mishrif Formation is rich in petroleum in this area, with an area covering about 820 km2. The seismic interpretation of this study was carried out utilizing the software of Petrel-2017. The horizon was calibrated and defined on the seismic section with well-logs data (well tops, check shot, sonic logs, and density logs) in the interpretations process for identifying the upper and lower boundaries of Mishrif Formation. As well, mapping of two-way time and depth structural maps was carried out, to aid in understanding the lateral and vertical variations and to show the formation of the structural surfaces. The study found that Mishrif thickness increases toward the east, which means that it increases from the Abu-Amoud field in Nasiriyah towards the East Abu-Amoud field in Missan province.       The aim of the study is to draw a high-resolution structural image of the East Abu Amoud field in southeast Iraq and to show the types of the existing faults and structures in the study area.

Find the rocks and the fluids will follow — AVO as a tool for lithology classification

2014 ◽  
Vol 2 (2) ◽  
pp. SC77-SC91 ◽  
Author(s):  
Kester D. Waters ◽  
Michael A. C. Kemper
Keyword(s):  
Case Studies ◽  
Seismic Data ◽  
Oil And Gas ◽  
Rock Physics ◽  
Amplitude Variation With Offset ◽  
Primary Means ◽  
Interpretation Process ◽  
Close Cooperation ◽  
Key Steps

Full-stack seismic interpretation continues to be the primary means of subsurface interpretation. However, the underlying impact of amplitude variation with offset (AVO) is effectively ignored or overlooked during the full-stack interpretation process. Recent advances in well-logging and rock physics techniques highlight the fact that AVO is a useful tool not only for detection of fluid anomalies, but also for the detection and characterization of lithology. We evaluated an overview of some of the key steps in the rock physics assessment of well logs and seismic data, and highlight the potential to move toward a new convention of interpretation on so-called lithology stacks. Lithology stacks may come in a variety of forms but should form the focus of interpretation efforts in the early part of the exploration and appraisal cycle. Several case studies were used to highlight that subtle fluid effects can only be extracted from the seismic data after careful assessment of the lithology response. These case studies cover a wide geography and variable geology and demonstrate that the techniques we tested are transferable and applicable across many different oil and gas provinces. The use of lithology stacks has many benefits. It allows interpretation on a single stack rather than many different offset or angle stacks. A lithology stack provides a robust, objective framework for lithostratigraphic interpretation and can be calibrated to offset wells when available. They are conceptually simple, repeatable, and transferable, allowing close cooperation across the different subsurface disciplines.

Mathematical Substantiation of a New Electromagnetic Tool with Toroidal Coils for High-Resolution Logging of Oil and Gas Wells

2018 ◽  
Vol 16 (1) ◽  
pp. 113-129
Author(s):  
M. I. Epov ◽  
◽  
M. N. Nikitenko ◽  
V. N. Glinskikh ◽  
◽  
...  
Keyword(s):  
High Resolution ◽  
Oil And Gas ◽  
Gas Wells ◽  
Oil And Gas Wells
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