Predicting of oil-gas-water-saturation of rocks of different lithology and geodynamic genesis in open-casts of wells
Journal Title: Геодинаміка - Year 2015, Vol 18, Issue 1
Abstract
Purpose. The aim of the work is developing the methodology of the prediction of oil-gas-water-saturation of rocks in open-casts of wells based on the data of acoustic (seismic) logging (АL, SL) and core research (CR) and its approbation for wells’ geological open-casts research of rocks of different lithology and geodynamic genesis. Methodology. The methodology is based on the theoretical relations between the elastic parameters of rocks, taking into account the influence of operating pressure (depth), porosity, nonlinear elasticity according to the structural and dispersive features of rocks (stratification, microporosity). The empiric dependences between physical and collector properties of rocks with the use of parametric database for rock-collectors of particular territories and geological structures are built. The type of rock pores is predicted by a comparison of the results of speed calculations according to theoretical and empiric dependences with the factual data of АL. In the case of АL (SL) data lack for the investigated wells or separate intervals of their open-casts, a version of the methodology with the establishment and use of correlation relations and gamma logging (GL) data has been developed. The software for the methodology realization is worked out in the Fortran and Excel environment. Results. The developed methodology has been tested on the well’s data of a number of structures of the Western oil-gas bearing region of Ukraine (Zaluzhans’ka, Lishchyns’ka, Buchachs’ka, Ludyns’ka). For separate wells there were detected not fixed by the previous research thin (from 0,1 m) layers with substantial porosity and filled with gas, water or oil, and also layers with practically zero porosity which can serve as screens. Changes of the elastic (the elastic waves’ velocities, the shear modulus, compressibility, the modulus of bulk compression, density, etc.) and collector (porosity) characteristics of the rocks in the open-casts of the investigated wells (clay, marl, siltstone, limestone, sandstone, shale strata) depending on the pressure were studied. On the basis of these data, oil-gas-water-saturation (porosity and the type of the pore filler) of the investigated horizons of the out-casts has been predicted. The differences in elastic and collector characteristics of rocks of different age, type and geodynamic genesis, such as terrigenous-carbonous (Carbonian, Devonian), carbonous (Devonian, Silurian, Cambrian), terrigenous (Devonian, Silurian) were investigated. Originality. The novelty of the research consists in methodical approaches with the use of a compressibility parameter of rocks and empirical correlation relations in the theoretical calculations on the basis of the AL or GL data. New are the empiric correlation relations, linking effective pressure, porosity and compressibility for both types of rocks: dry and saturated by liquid for geological open-casts of particular wells, for rocks of different type and geodynamic genesis. Also the new results are thin oil-gas-water-saturated layers and interlayers which are predicted for the first time in the open-casts of a number of wells. By calculations zones of low velocity also are traced. Practical significance. The methodology ensures a reliable prediction of the physical characteristics and oil-gas-water-saturation of rocks layers of different thickness (including thin layers – from 0,1–0,2 m) by the data of АL (SL, GL) in wells’open-casts: the porosity coefficient, elastic modules; the type of pore saturation and detecting of nonstructural type traps. The expressions are built for the calculation of coefficients for the corresponding empiric relations which are good for any geological region with available parametric database.
Authors and Affiliations
L. V. Skakal’s’ka, A. Nazarevych
Keywords
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- EP ID EP455953
- DOI 10.23939/jgd2015.01.099
- Views 86
- Downloads 0
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