--> Abstract: Spatially Constrained Inversion of Transient Electromagnetic Data for Near Surface Characterization, by D. Rovetta, D. Colombo, G. McNeice, and T. Yousuf, #90188 (2014)
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Spatially Constrained Previous HitInversionNext Hit of Transient Electromagnetic Previous HitDataNext Hit for Near Surface Characterization

D. Rovetta1, D. Colombo1, G. McNeice1, and T. Yousuf1

1Saudi Aramco

Abstract

Complementary geophysical measurements and their joint interpretation and Previous HitinversionNext Hit into a coherent velocity model can provide effective solutions for seismic exploration. Electromagnetic Previous HitmethodsNext Hit can improve the characterization of the complex subsurface by enhancing resolution in poor signal-to-noise seismic areas and by adding sensitivity to low velocity zones and hidden layers. For land/airborne acquisition, the loop-based magnetic source transient EM technique represents a robust methodology for obtaining high resolution images of the near surface. The high sensitivity of the method to conductors allows resolving shallow velocity inversions otherwise invisible to refracted seismic energy. Acquisition of transient EM Previous HitdataNext Hit can be performed by ground-based magnetic loops or more efficiently by using helicopters and suspended loops, which enable the acquisition of large areas with spatial sampling comparable with that of seismic. Fast and robust Previous HitinversionNext Hit of such Previous HitdataNext Hit is needed to impact the seismic processing chain during the evaluation of the near surface corrections. To achieve this goal, a new algorithm for spatially constrained Previous HitinversionNext Hit of EM Previous HitdataNext Hit was developed, where the 1D Previous HitinversionNext Hit of the observations is regularized in a 3D sense by means of spatial constraints introduced by the model covariance matrix. The Previous HitinversionNext Hit of each model cell is correlated to the Previous HitinversionNext Hit of the cells of nearby vertical profiles occurring within a radius of influence. Both the spatial extension of the influence and the percentage correlations to be applied to the model cells are explicitly defined by the user. This scheme is effective in terms of computing time and quality of results. The developed algorithm was successfully demonstrated on synthetic and real Previous HitdataNext Hit. The application of the spatially constrained Previous HitinversionNext Hit to transient EM soundings acquired over a subsurface deltaic structure in Saudi Arabia provides unprecedented resolution in the imaging of the shallow near surface. The developed Previous HitinversionNext Hit scheme can be optimally embedded in a simultaneous joint Previous HitinversionNext Hit procedure with seismic Previous HitdataTop to enhance near surface velocity models.

 

AAPG Search and Discovery Article #90188 ©GEO-2014, 11th Middle East Geosciences Conference and Exhibition, 10-12 March 2014, Manama, Bahrain