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IMPROVEMENT VELOCITY MODEL USING SONIC LOG DATA Fadhila N Yeru

Scientific advisers: Galina G Nomokonova and Nadeyna Luiza V. National Research Tomsk Polytechnic University, Tomsk

Abstract Migration needs an accurate velocity model otherwise reflector can be replaced

in the right position. But it is difficult to get accurate velocity model. The focus of this study is improvement of quality velocity model. The method

that we used is adjustment well data into velocity model. Introduction Lateral and vertical accuracy is the most important thing in seismic imaging. But

migration still makes mistake when putting reflector at the wrong place. This mistake becomes worst when lateral and vertical more varieties. Migration can put the reflector well as long as high quality velocity is used. But getting that is difficult (Yeru, 2008) [1]. The sonic or acoustic log measures the travel time of an elastic wave through the formation. This information can also be used to derive the velocity of elastic waves through the formation.

Data This study used synthetic 2D acoustic model Marmousi, synthetic sonic log data

that contain of actual velocity and velocity model of Marmousi was used for checking accuracy.

Fig. 1. Velocity model by velocity analysis Fig. 2. Marmousi Velocity Model

V Университетская научно-практическая конференция «Коммуникация иностранных студентов, магистрантов и аспирантов в учебно-профессиональной и научной сферах»

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Fig. 3. Velocity model using sonic data

The Marmousi model was created in 1988 by the Institut Francais du Petrole (IFP) in 1988. The geometry of this model is based on a profile through the North Quenguela trough in the Cuanza basin, Angola.

Processing

Result. Adjustment wells (CDP 200; CDP 700; CDP 1500) in the depth interval

showed increased accuracy in all areas except in anticline area (CDP 1000-CDP 2000) errors increased although no significantly.

For pre stack depth migration, the result showed that velocity model plays an important rule. Poor quality of velocity model, such as in fig.1 delivered a bad seismic section fig. 5.

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Fig. 4. Seismic section using velocity analysis as input velocity

Fig. 5. Seismic section using velocity analysis and sonic log as input velocity

Conclusion This case requires converting the time migration velocity to a velocity model in

depth. In the case of a laterally homogeneous medium, the conversion from time to

V Университетская научно-практическая конференция «Коммуникация иностранных студентов, магистрантов и аспирантов в учебно-профессиональной и научной сферах»

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depth is provided by the classic Dix method (Dix, 1955)[2]. However, the Dix conversion is not sufficient in the general case. The theoretical connection between time migration velocities and true depth velocity models is provided by the concept of image rays, (Hubral, 1977)[3]. Image rays are seismic rays arriving normal to the surface of the earth. Hubral’s theory explains how to model time migration velocities given the depth velocity model. However, it does not provide a convenient form for developing an accurate inversion algorithm.

This study showed that using sonic log in velocity model totally improved velocity model quality. But sintethic model was used, for further development, we should use real model. However, the tool works at a higher frequency than seismic waves, therefore one must be careful with the direct comparison and application of sonic log data with seismic data. (Glover )[4].

Fig.6 Seismic section using Marmousi model velocity as input velocity

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Reference

1. Yeru, F.N., 2008, Model Kecepatan menggunaan Horizon Velocity Analysis dan Penyelarasan dengan Data Sumur, Bandung, p.9-11

2. Dix, C. H., 1955, Seismic velocities from surface measurements: Geophysics, California, p.68–86.

3. Hubral, P., 1977, Time migration - Some ray theoretical aspects: Geophys.Prosp.,Hannover, p.738–745.

4. Glover P., Petrophysics Course Note, Quebec, p. 176

THE TECHNOLOGIES TO SAVE EARTH FROM GLOBAL WARMING Gopanenko Roman

Scientific adviser: Kobzeva N.A. National Research Tomsk Polytechnic University

Anyone who has closely followed the science news does not lack evidence global warming. Almost weekly there are reports of studies in this area. British naturalist reported bias toward the north areas of some species of birds. Canadians say that the northern rivers remain frozen in an average of two weeks less than half a century ago. In Greenland in recent years has sharply accelerated movement of glaciers, descending to the sea. Arctic ice retreat in summer is much further north than ever before. Broad consensus among climate scientists about the continued growth in global temperatures has led to the fact that a number of states, corporations and individuals are trying to prevent global warming or adapt to it. This study presents some technologies to save Earth from Global Warming.

Global warming is a gradual increase in average temperature of Earth's atmosphere and oceans. Climate change on earth occurs as a result of natural internal processes or in response to external influences, both anthropogenic and non-anthropogenic. Changes in the Earth's orbit, solar activity, volcanic emissions and the greenhouse effect are the main external factors. Automobile exhausts, smoke stacks and other sources of pollution created by mankind emit about 22 billion tons of carbon dioxide and other greenhouse gases a year [1]. The temperature dependence on dioxide content of oxygen is shown below [Fig.1]. Despite these horrific numbers of human impact, the reason for raising the temperature on Earth is controversial. And