Gravity inversion of basement relief and estimation of density contrast variation with depth

Silva, João B. C.; Costa, Denis Carlos Lima; Barbosa, Valéria C. F.

doi:10.1190/1.2236383

Cited by 84 publications

(51 citation statements)

References 16 publications

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“…The size of the moving average operator is equivalent to a regularization parameter and should be selected as the smallest value leading to a stable solution (Silva et al, 2006). The solutions displayed in Figure 6a and 6c fit the data within the experimental errors with a residual rms of 0.006, 0.087, and 0.098 mGal, respectively.…”

Section: Stability Of the Proposed Methodsmentioning

confidence: 98%

“…Among the geophysical methods directed at oil prospecting, the gravity method proved to be efficient and economic (Bott, 1960;Corbató, 1965;Tanner, 1967;El-Batroukh and Zentani, 1980;Kieniewicz and Luyendyk, 1986;Barbosa et al, 1997;Silva et al, 2006;Barbosa et al, 2007;Gimenez et al, 2009). In the past six decades, the gravity interpretation of sedimentary basins has evolved in a winding trajectory in response to the ability of the current computer speed and memory to handle an ever increasing quality and quantity of data and meet the ever increasing geologists' demand of information.…”

Section: Introductionmentioning

confidence: 98%

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Fast gravity inversion of basement relief

2014

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Gravity interpretation of large sedimentary basins requires a large number of observations and of parameters estimations, so the development of very efficient gravity inversion methods applicable to such environments is of utmost importance. We found that the highly efficient Bott's method can be cast in the framework of Gauss-Newton's method for minimizing nonlinear functions. Also, we extended Bott's method to (1) be applicable to sedimentary basins with density contrast between the sediments and the basement decreasing with depth according to different laws, (2) optimize the modulus of the parameter correction vector, (3) stabilize the solution by imposing that it be smooth, and (4) quit the iteration according to an objective and effective criterion. To keep up the efficiency of Bott's method, stable solutions were obtained by applying a moving average to the usually unstable solution obtained at the last iteration. Solutions as efficacious as those obtained by the usual nonlinear method were produced by the present extension at a much smaller computation time. Nonlinear methods, with different implementations for solving a linear system of equations, required between one and two orders of magnitude more time to produce similar solutions using between 2000 and 3000 parameters and observations, for example.

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Section: Stability Of the Proposed Methodsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 98%

Fast gravity inversion of basement relief

2014

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“…The gravity method is a powerful tool to estimate the depth to the basement of a sedimentary basin (Silva et al, 2006;Barbosa et al, 2007). Among the information that can be retrieved with the gravity method is the presence of smooth uplifts and depressions and highangle faults in the basement.…”

Section: Introductionmentioning

confidence: 99%

Efficient gravity inversion of discontinuous basement relief

et al. 2015

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We have developed a gravity inversion method to estimate a discontinuous basement relief based on an extended version of Bott's method that allows variable density contrasts between sediments and basement, optimizes the modulus of the solution correction at each iteration, and provides for solution stabilization. Initially, we obtain a linear approximation stabilized by the total variation functional that correctly maps the horizontal positions of the existing high-angle faults but produced poor estimates of the basin depths. Subsequent iterations update the depth estimates toward the correct values, at the same time preserving the correct fault horizontal positions. Additionally, we stabilize each solution correction by the smoothness constraint without inverting any matrix. The method was substantially more efficient than the nonlinear method, which solves a system of linear equations by the conjugate gradient method at each iteration. For 3000 parameters, it is almost four times faster than the conjugate gradient, and this ratio increased with the number of parameters.

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“…Many research papers have been published over the past decade on this subject (e.g., Barbosa et al, 1997Barbosa et al, , 1999aBarbosa et al, , 1999bSilva et al, 2001Silva et al, , 2006Silva et al, , 2007Silva et al, , 2010aSilva et al, , 2010bGallardo-Delgado et al, 2003;Martins et al, 2010Martins et al, , 2011aMartins et al, , 2011b. The conventional approach to solving depth-to-basement gravity inverse problems is based on parameterization of the earth's subsurface, containing the sedimentary pack, into prismatic cells with known horizontal dimensions and known density contrast, and on estimation of the cell's thicknesses.…”

Section: Introductionmentioning

confidence: 99%

Application of Cauchy-type integrals in developing effective methods for depth-to-basement inversion of gravity and gravity gradiometry data

Cai

Zhdanov

2015

GEOPHYSICS

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One of the most important applications of gravity surveys in regional geophysical studies is determining the depth to basement. Conventional methods of solving this problem are based on the spectrum and/or Euler deconvolution analysis of the gravity field and on parameterization of the earth's subsurface into prismatic cells. We have developed a new method of solving this problem based on 3D Cauchy-type integral representation of the potential fields. Traditionally, potential fields have been calculated using volume integrals over the domains occupied by anomalous masses subdivided into prismatic cells. This discretization can be computationally expensive, especially in a 3D case. The technique of Cauchy-type integrals made it possible to represent the gravity field and its gradients as surface integrals. In this approach, only the density contrast surface between sediment and basement needed to be discretized for the calculation of gravity field. This was especially significant in the modeling and inversion of gravity data for determining the depth to the basement. Another important result was developing a novel method of inversion of gravity data to recover the depth to basement, based on the 3D Cauchy-type integral representation. Our numerical studies determined that the new method is much faster than conventional volume discretization method to compute the gravity response. Our synthetic model studies also showed that the developed inversion algorithm based on Cauchy-type integral is capable of recovering the geometry and depth of the sedimentary basin effectively with a complex density profile in the vertical direction.

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Gravity inversion of basement relief and estimation of density contrast variation with depth

Cited by 84 publications

References 16 publications

Fast gravity inversion of basement relief

Fast gravity inversion of basement relief

Efficient gravity inversion of discontinuous basement relief

Application of Cauchy-type integrals in developing effective methods for depth-to-basement inversion of gravity and gravity gradiometry data

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