GIS-based stratigraphical models of the oil and gas bearing provinces

Abstract: The model integrates the lithology, stratigraphy, and tectonic data in Volga-Ural oil & gas bearing province and gives the opportunity to make an operative data analysis using geoinformation technologies for the purposes of oil and gas bearing perspective studying. All data has been visualized as a set of graphic images arranged on a vertical according to the geochronnological scale, and across according to the tectonic and oil & gas bearing patterns. Attribute tables of images contain the essential thematic data and have been connected one with each other so that to provide the optimum informative response to necessary logical inquiry.
The information model of the stratigraphy and geochronology of the Paleozoic deposits in Volga-Ural oil and gas bearing province (Fig.1), which was chosen as a research prototype, is developed In Gecon Ltd. The stratigraphical and geochronological scheme in a general view is a kind of "table": on a vertical - the geochronological scale (millions years), and across - the set of columns which represents certain informative parameters, such as elements of tectonic, oil and gas bearing or other patterns. In geology the schemes are used to analyze the evolution of sedimentary pools, especially oil and gas bearing pools.
The creation of a series of stratigraphical and geochronological schemes which consistently describes lithology, tectonic, sedimentation evolution and stages of oil and gas formation for investigated regions is the useful tool for oil and gas bearing perspective studies. Earlier we offered for naming such series of schemes as formalized information models (FIM)[5].
Till now FIMs are mainly made with the help of the software providing graphic display of the data and storage of the information as files of graphic formats. We are the first who used GIS technologies (ArcView 3.2) for creation and conducting such kind of information models. In spite of the fact that components FIM in themselves are not the spatial data, they are suitable for loading in GIS as they are formalized by a uniform principle and structured in system of groups of mutually represented parameters, in this case - a geochronology, lithology of deposits of oil and gas bearing pool, elements of tectonic zonation and administrative division (Fig.2). The use of GIS technologies simplifies not only the creation FIM (through legends, automatic construction, etc.), but also gives new opportunities of the analysis, transforming graphic forms in the information systems providing with the help of standard functions of GIS technologies search, visualization, formation of categories, the analysis on combinations of the required inquiries using territorial, geochronological, stratigraphical, lithological and other characteristics of components of system.
Components of FIM:
•Map of Volga-Ural oil and gas bearing province. The map represents the province s boundary, oil and gas bearing areas within the province, concentration ranks of initial total recoverable resources of oil, gas and condensate, administrative division.
•Two stratigraphical models of Devonian-Perm deposits along sections AA and BB (Fig. 1) trough the province. Lithology data formalized and transformed into sets of polygonal, linear and dot objects which in aggregate designate homogeneous in lithology and indivisible in stratigraphy volume of deposits or sedimentation break. Shapes of adjacent polygonal objects reflect deposits interbedding patterns. Sets of objects are integrated in columns which are the elements of tectonic referred to oil and gas bearing areas within the province.
•Lithology, stratigraphy, geochronology, tectonic, oil and gas bearing data base contained in set of attribute tables and external documents. Application of GIS analytical functions is achieved by connection and linkage of all project tables and documents so that we can define, for example, what is the tectonic of carbonate collectors of thickness less than 200 m (Fig. 3).
The created information model of Volga-Ural bearing province evidently shows stratigraphical patterns of oil and gas complex (composition of a collector and a tire cover), spatial variability of the complex, and levels of oil and gas bearing in the different areas within province. The system of inquiries of the general{common} character is realized. The further development of model is carried out in a direction of widening of its information fund. The similar FIM are still created for other regions with deposits of hydrocarbons, in particular, for Timan-Pechora province.
Appendixes

Fig.1. Map of Volga-Ural oil and gas bearing province.

Fig.2. The GIS-based stratigraphical model. The Vew presents one of the formalized stratigraphical sections; linked attribute tables provide multicomponental analysis of integrated data.

Fig.3 Response to the injury to select carbonate collectors of thickness not less than 200 m in Vershnekamskaya depression (lighted objects).
References
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