Behavior of Stresses and Hydrodynamics From Multicomponent Seismic Data

Sibiryakov, Boris; Leite, Lourenildo W. B.; Vieira, Wildney W. S.

doi:10.22564/rbgf.v33i1.601

Cited by 7 publications

(9 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The orthogonal paths of pressure isolines (for zones much thinner than the horizontal extent of the structure) coincide with possible fluid flow paths (Sibiryakov et al, 2004). The zones of highly dense lines of low pressure are natural sinks of fluids.…”

Section: Implications For Well Placementmentioning

confidence: 80%

“…Seismic inversion resolves mostly the boundaries of geologic structures but fails to constrain stress and strain patterns. Meanwhile, shear stress (second stress tensor invariant) correlates with porosity and permeability, and tangent stress highs may be indicator for porous rocks; the stress tensor also has implications for preferable orientations of fractures (Sibiryakov et al, 2004). Of course, stress can be only tentative guides to the distribution of fluids because flow requires some transport system.…”

Section: Introductionmentioning

confidence: 99%

“…Approximate estimates of stress in low-angle anticlinal structures can be obtained with an algorithm presented by Sibiryakov et al (2004). Note that stress in these structures is not hydrostatic even in the case of horizontal layering (Sibiryakov et al, 2004): vertical stress equals the overburden pressure P, while horizontal stress is much lower, being P(1 -2γ 2 ), where γ = v S /v P or the S-to-P velocity ratio. P-wave interval velocities are evaluated from 3D seismic data, while densities and S velocities are extrapolated from well logs.…”

Section: Introductionmentioning

confidence: 99%

“…In this study we estimate stress in a way even simpler than in (Sibiryakov et al, 2004): approximate values are obtained via interface pressure change for low-angle anticlines, and boundary integral equations are used for high-angle structures.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Local pressure lows as possible sinks of fluids in geologic structures

Sibiryakov

2015

Russian Geology and Geophysics

View full text Add to dashboard Cite

Local pressure lows in layered sections perturbed by anticlinal structures are studied analytically using equations for pressure change across interfaces. They are simple equations of pressure difference for low-angle structures and boundary integral equations for steeply dipping anticlines. Pressure may decrease locally near the crests of anticlines, as well as away from them at distances commensurate to the anticline height. Predicting stress patterns, which are specific for different groups of geologic structures, is a difficult task. However, some components of the stress field, such as low-pressure zones which may act as sinks for fluids, are relatively easy to constrain. Stress in these zones depends on the dip of anticlines and their curvature at each surface point. Negative curvature causes additional lateral extension and promotes further decrease of overburden pressure around the crests.

show abstract

Section: Implications For Well Placementmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Local pressure lows as possible sinks of fluids in geologic structures

Sibiryakov

2015

Russian Geology and Geophysics

View full text Add to dashboard Cite

show abstract

“…The main physical parameter governing pressure prediction is given by the measure of discontinuity represented by the velocity ratio γ = v S /v P along the interfaces. Sibiryakov et al (2015) deals with different aspects of this special method, where is described that, as a result of the γ ratio behavior, an anticline is not necessarily the only structural condition for potentiating a zone to be an oil and gas accumulator (reservoir).…”

Section: Pressure Predictionmentioning

confidence: 99%

Modeling and Pressure Prediction of a Block of the Jequinhonha Basin

Vieira¹,

Leite²,

Sibiryakov

2017

Rev. Bras. Geof.

View full text Add to dashboard Cite

ABSTRACT. We present in this paper a seismic-stratigraphical framework for pressure prediction for oil and gas exploration in sedimentary basins, that is based on seismic information, with application to a marine part of the Jequitinhonha basin (east of the State of Bahia, Brazil). For this purpose it is necessary the knowledge of velocity distributions (compressional vP and shear vS), that can be obtained from seismic sections, petrophysical information and empirical models, and the distribution of density (ρ). We show some details of the theoretical modeling method, with an example that shows how pressure varies in the subsurface. We highlight that pressure that does not necessarily increase linearly with depth, but in a complex way that requires specific numerical calculations to be able to see important details related to a reservoir and surroundings. The model considers the vertical gravity load as the source of pressure in the geological formations, and in the present case we do not take into account the effects of formation curvatures, faulting, diagenesis and lateral tectonic events. We show that the meaning of cap rock of a reservoir is not to be related to lithology, but directly to the physics of high and low pressure zones that results from the mechanics of solid bodies under a stress-strain system; in this direction, and as a curiosity, we also show how a basement rock can become a reservoir. It is important to emphasize that an accurate prediction needs a 3D model for a meaningful and complete practical application, in the other hand, it requires handling large matrices. Keywords: basin modeling, seismic velocity analysis, pressure prediction, empirical models. RESUMO. Este artigo tem como objetivo compor uma estratégia sismo-estratigráfica onde se visa a predição de pressão na exploração de gás e óleo em bacias sedimentares com base em informação sísmica, com aplicação a uma parte marinha da bacia de Jequitinhonha (leste do estado da Bahia, Brasil). Para esta finalidade ´e necessário o conhecimento das distribuições de velocidades (compressiva vP e cisalhante vS) que podem ser obtidas a partir de seções sísmicas, informações petrofísicas e modelos empíricos, e da distribuição de densidade (ρ). Apresentamos alguns detalhes da modelagem teórica, e um exemplo para mostrar como a pressão varia na subsuperfície, onde destacamos que a predição de pressão não aumenta necessariamente linearmente, mas de uma forma complexa que requer cálculos numéricas específicos para poder obter detalhes relacionados a um reservatório. O modelo apresenta a carga vertical da gravidade como a fonte de pressão nas formações geológicas, e neste caso não se leva em consideração os efeitos de curvaturas das camadas, falhas, diagênese e eventos tectônicos laterais. Mostramos que o significado de uma rocha selante de um reservatório não deve estar relacionado `a litologia, mas simplesmente à física de zonas de alta e baixa pressão como resultado da mecânica dos corpos sólidos sob o sistema de tensão-deformação; neste sentido, e como curiosidade, mostramos também como uma rocha do embasamento pode se tornar um reservatório de óleo e gás. É importante observar que uma predição com precisão necessita de um modelo 3D para uma aplicação prática significativa e completa, mas que requer o manuseio de matrizes grandes. Palavras-chave: modelagem de bacia, análise de velocidade sísmica, predição de pressão, modelos empíricos.

show abstract