Issues of the journals Геофизика 2018 y. issue 3

Testing a new program for profile inversion of tem data on the example of studying paleovalleys in the kaluga region

(Kulikov V.A. Aleksanova E.D. Shustov N.L. Solovieva A.V. Kaminskiy A.E. )

Interpretation of data of the near-field time-domain electromagnetic sounding (TEM) suggests the possibility of using different approaches to solving the inverse problem. In most cases, the interpretation stage uses a one-dimensional selection within a thick-layered model using a priori information or automatic transformations, during which a multilayered model is formed, providing a minimum residual between theoretical and observed curves. The paper discusses the features and benefits of the two-dimensional inversion algorithm implemented in the program ZondTEM2D. The sample field data and synthetic models have shown the possibility of reconstruction of the cross section containing the objects of «paleovalley» type - high resistance lenses against the host horizontally layered subsurface.......

  • 2018  № 3, pp. 61-69

Consistent three-stage AVA inversion

(Myatchin K.M. Tokarev M.Yu. Novoyavchev A.V. Kleimenov A.A. )

Sequential AVA inversion has several benefits over Simultaneous AVA inversion. Sequential AVA inversion with the separate consistent stages allows the use of more intelligent minimization functions as well as solving some problems caused by ambiguities and lack of the correct information (accounting for the ratio of amplitudes at the boundaries of reflection, the weak contrasts and regular noise separation, accounting for the, identify and compensate for regular phase changes, take into account the nonstationarity of seismic traces, apply the correct algorithms for the integration of low-frequency models etc.).......

  • 2018  № 3, pp. 70-80

Anisotropic true amplitude pre-stack migration of 3D seismic data based on gaussian beams: from theory to practice

(Protasov M.I. Cheverda V.A. Gadyl'shin K.G. Lukashov A.V. Pravduhin A.P. Suppes O.V. )

The paper presents the implementation of true amplitude pre-stack migration of 3D seismic data based on Gaussian beams, which allows to process large 3D seismic data in the production mode. The functionality of this development is highlighted. Numerical examples for synthetic data are presented. A comparative analysis of the results of the developed migration with the results of the industrial version of the Kirchhoff migration is done on the real data from Kara sea.......

  • 2018  № 3, pp. 81-90

Methodological approaches to the evaluation of oil resources in the bazhenov formation

(Kopilevich E.A. Surova N.D. Skvortsov M.B. Kuznetsov G.V. Nemova D.V. Kirsanov A.M. Mozhegova S.V. Dachnova M.V. )

In the article, on the example of Bazhenov formation in Western Siberia, methodical approaches to assessing its resource potential are considered. Methods of allocation of effective oil-saturated thicknesses with involvement of Rock-Eval data and geophysical researches of wells, identification of perspective objects in Bazhenov formation, the principles of the differentiated assessment of resources and ranking of the territory of researches on various structure of saturating hydrocarbons are offered.......

  • 2018  № 3, pp. 91-100

Recovery of a depth velocity model by multiscale full waveform unversion

(Cheverda V.A. Gadyl'shin K.G. )

The construction of deep seismic images is currently one of the main trends in seismic research and development. A necessary step for this is construction of a deep velocity model, which ensures the correct travel times. Hence, an erroneous depth velocity model leads to a wrong positioning of target geological objects in space. At present, the process of constructing a depth velocity model is one of the most time and resource consuming procedure in seismic data processing, which heavily relies on the human interactive involvement. The paper develops numerical technique to reconstruction of this velocity model on the base of Full Waveform Inversion (FWI). Our approach is based on the deep modification of the data misfit functional. The key item of this modification is decomposition of velocity model onto two constituents: smooth propagator and highly oscillating reflector. This reflector is changed later to the reflectivity in the data space by application of the demigration procedure.......

  • 2018  № 3, pp. 101-105