S Tabasi; A KamkarRouhani; M.M Khorasani
Abstract
Archie’s equation, which is the most fundamental equation for water saturation calculation,consists of three factors: Cementation factor (m), saturation exponent (n) and tortuosity (a). Cementation factor is a function of the shape of pores. Hence, the study of pore type is important in determining ...
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Archie’s equation, which is the most fundamental equation for water saturation calculation,consists of three factors: Cementation factor (m), saturation exponent (n) and tortuosity (a). Cementation factor is a function of the shape of pores. Hence, the study of pore type is important in determining the Archie’s coefficients. In order to achieve more precise and reliable results in Archie’s coefficient determination and then water saturation accurately, the rocks must be rated based on texture and porosity type, where the coefficients should be constrained for each class. In this paper, fractal method is used to rate the resistivity log data and calculate Archie’s coefficient in an exploration well of a hydrocarbon reservoir in southwest of Iran. The results show three different zones based on porosity type and texture of the rocks. Then the Genetic algorithm method is used to calculate the Archie’s coefficients in each of the zones separately. The results show that this method is able to consider the complex behavior of each of the coefficients in the calculations.
S Parnow; A Kamkar Rouhani; A.R Arab Amiri; N Karimi
Abstract
The method of ground penetrating radar (GPR) has increasingly been used for investigation of surface and internal structures of glaciers within the last few decades. This geophysical method distinguishes different structures of glaciers considering the existence of electrical permittivity contrast between ...
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The method of ground penetrating radar (GPR) has increasingly been used for investigation of surface and internal structures of glaciers within the last few decades. This geophysical method distinguishes different structures of glaciers considering the existence of electrical permittivity contrast between ice, air, sediment debris and water in the glaciers. In this research, the GPR acquired data using unshielded antenna with central frequency of 25 MHz along 3 lines in Alam kuh glacier, Kelardasht, Mazandaran, in June 2012, have been processed and interpreted. In order to remove the effect of low-frequency unwanted reflections overlain on high-frequency reflections from all GPR sections, we have used dewow filter. Moreover, we have used gain function for signal enhancement, especially in late times of the GPR data acquisition. Considering the coarse topography of the study area, we have also applied topography correction on the data, and then, the obtained results have been compared with the obtained results without topography correction to demonstrate the importance of topography correction on GPR data. Moraine materials, covered the surface of the area, are mainly fine-grained granite. The bed rock or basement in the area is also granite. The polarity representing ice-bed rock is clearly seen on the GPR profiles. Furthermore, the results of this research indicate that recognition of moderate and cold ice areas in the glacier, type of the glacier (Multi-thermal), holes and topography of the glacier basement has successfully been possible using only the GPR method. The electrical resistive nature of the glacier has caused large depth of penetration of GPR waves in this research work.
