About rocks’ deformations (based on the study of core of deposits of Surgutneftegas PJSC)

UDK: 550.822.3
DOI: 10.24887/0028-2448-2018-8-10-13
Key words: West Siberia, core, deformation, injective body, tectonic melange, milonite, system of joints, boudinage, turbuient-vortical formations
Authors: E.N. Trofimova (SurgutNIPIneft, Surgutneftegas PJSC, RF, Surgut), E.V. Artyushkina (SurgutNIPIneft, Surgutneftegas PJSC, RF, Surgut), O.A. Bikova (SurgutNIPIneft, Surgutneftegas PJSC, RF, Surgut), A.V. Dyakina (SurgutNIPIneft, Surgutneftegas PJSC, RF, Surgut), U.A. Travina (SurgutNIPIneft, Surgutneftegas PJSC, RF, Surgut), I.L. Tsesarzh (SurgutNIPIneft, Surgutneftegas PJSC, RF, Surgut), I.L. Shesteryakova (SurgutNIPIneft, Surgutneftegas PJSC, RF, Surgut)

The study of the core of rock formations of the West Siberian sedimentary cover shows a wide development of various deformation textures. In continuation of the earlier themes there are examples of some types of deformations in the article, defined today by specialists of the scientific-research laboratory of lithology in complex and multi-level study of core. All types are interrelated. They indicate the magnitude of strike-slip tectonics in the context of the West Siberian oil and gas regions. The results of the study of injective deformations are presented. Among those deformations a special place is reserved for clastic intrusions, turbulent-vortex formations, zones of melange and blending deposits. Also in the sections revealed the following: connection between separate turbulent-vortex formations and spotted zones of their concentration (type as «ryabchik» or «hazel-grouse»); connection between the anomalous sections of bituminous upper Jurassic sediments and injective tectonics. Separate sections highlight new data on the character of bituminous argillite fracturing and tectonic dislensing of bituminous competent rocks of the upper Jurassic sediments. It has been revealed that the subhorizontal curvilinearly intersecting fracturing is similar to anastomosing lines in the strike-slip fault systems. Among sub-vertical cracks have been detected leading (advanced) ones, which are disrupted by subhorizontal displacement. The structural reconstruction has been made and on its basis the characteristic of the medium-small and large “budinoid like” formations has been given. Besides, it has been discovered that diverging of argillite fracturing in different directions indicates the presence of budinoid outside the column of core. Similarity between budinoides and mylonite porphyroclasts has been noted. In the border area budinoid-argillite have been identified: the zone of crushing, mixing; intensive exfoliation of mudstones; surfaces of slip, sometimes with brown raids HC; mylonitization zone. The final section addresses rocks mylonitization. There is an example of dynamometamorphit with striped pseudorhyolite image and superimposed curved pseudoperlite micro-cracks contributing to the division of rocks into small oval components to their further tectonization, textural reorientation, mineral transformations in porous medium. In the article the following questions are mentioned: convergence in Geology; the emergence of dissipative or highly ordered structures; evolutionary self-organization and reorganization of rock-forming material. In conclusion the necessity of core studying at different levels and from positions of differing scientific directions is expressed, for example from the point of vortex geodynamics or physical mesomechanics of materials of academician V.E. Panin.

References

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