Application of Tectonic-Physical Approach for Construction of Tectonic Model of the Deeply-Buried Complexes

Abstract

Recent publications on oil and gas tectonics note the extreme “eclecticism” of the terminology used in the tectonic zoning of the sedimentary basin and surrounding structures, in describing the stage of formation, tectonic conditions, and typification of different-scale discontinuous and plicate structures. The existing situation makes it difficult for researchers to understand each other and leads to the lack of an unified approach in describing the regional tectonic models. Formation of a unified terminology and a common approach in describing tectonic processes is an important and urgent problem. At present, when studying and describing the prospects of oil and gas bearing capacity in the north of the Volga-Urals province, definitions as the Ural geosyncline, TimanPechora province, Pechora-Kolva avlacogen (palaeorift), deep faults and regmatic fault network may be used in one published work. The study of the history of tectonic elements formation in areas with complex geological structure is complicated by overlapping tectonic structures of different order and age. Based on the tectonicphysical approach, authors carried out the reconstruction of the history of tectonic transformations within the study area. When interpreting seismic data of the internal structure of the fault zone, reconstruction of evolution of the formation, tectonic-physical ideas about structural paragenesis were used as a methodological tool. From the tectonic-physical point of view, the fault zone is considered not only as the uniform displacement plane, but as the whole volume of the section, in which genetically related brittle and plastic deformations are manifested. The internal structure of the fault zone is considered as a set of structural elements that determine its kinematics, stage and duration of formation. Application of modern approaches to geological analysis of shear tectonics areas is illustrated by detail analysis of 3D seismic cube data obtained at the territory of the Pechoro-Kozhva megaval. As a result, a new tectonic model was developed. In the conditions of complex deformation history of shear zones, the structures were dated according to their belonging to different-age paragenesis.