Известия Томского политехнического университета: Инжиниринг георесурсов (May 2019)

Features of processing and interpretation of magnetic and lithochemical data while exploring oil and gas fields in Siberian platform conditions (by the example of Imbinskaya gasvbearing area)

  • Igor Sobolev,
  • Nikolay Bredikhin,
  • Vitaliy Merkulov,
  • Aleksandr Orekhov

Journal volume & issue
Vol. 326, no. 4

Abstract

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The relevance of the discussed issue is caused by the necessity to develop the effective ways of processing and approaches to interpretation of magnetic and lithochemical data in the search for hydrocarbon deposits in geological conditions of the Siberian platform. One of the features of Siberian platform geological section is the extensive development of products of late Permian-Triassic basaltic magmatism. Against the background of sedimentary formations the effusive rocks and intrusive bodies of the basic structure are differentiated by sharp differences in magnetic properties and levels of accumulation of some chemical elements. In general, the areas of epigenetic influence of hydrocarbon deposits are characterized by high contrast in the change of chemical elements content and magnetic characteristics of sedimentary sequence. Rocks of trap formation contribute significantly to the fluctuations of magnetic field and geochemical anomalies and form their own ones, preventing isolation and identification of magnetic and lithochemical irregularities associated with oil and gas accumulations. Therefore, the application of the developed procedures for oil and gas areas with purely terrigenous cover for processing magnetic and lithochemical data requires the changes in division anomalies of epigenetic and magmatic origin. The main aim of the research is to develop the algorithm for processing magnetic and lithochemical data to allocate the areas of epigenetic influence of hydrocarbon accumulations in conditions of wide development of products of the Triassic magmatism in Siberian platform. Research methods. The authors have used the results of high-resolution magnetic survey and lithochemical sampling of surface sediments in Imbinskaya gas-bearing area of the Angara folds area. Results. The authors developed special procedures when applying bandpass filtering of magnetic data by the method of Saxov-Nygaard and differentiating lithochemical field by indicators of dispersion and variance of geochemical spectrum for identification of anomalous variations caused by the influence of dolerite bodies.

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