Гɟɨфɢɡɢчɟɫɤɢɟ ɦɟɬɨɞɵ ɪɚɡɜɟɞɤɢ ɜ ɩɨɡɧɚɧɢɢ ɪɟɝɢɨɧɚɥɶɧɨɝɨ ɝɟɨɥɨɝɢчɟɫɤɨɝɨ ɫɬɪɨɟɧɢя Зɚɩɚɞɧɨ-Сɢɛɢɪɫɤɨɣ ɧɢɡɦɟɧɧɨɫɬɢ

Geophysical methods of prospecting play an important role in so lving problems of the oil-bearing capability of the West Siberia n Lowland. The importance of these methods is particularly great in the study of the regional geology. Aero-magnetic surveying occupies a significant place in the integrated geophysical operations. This ensues from its inherent technical potentialities w hich permit rapid coping with areas of diff icult access. The aero-magnetic surveys were conducted on two scales: 1:1,000,000 and 1:200,000. The 1:1,000,000 survey was made along traverses fixed at a distance of 10 km. from one another; for the 1:200,000 survey this distance was reduced to 2 km. At the present time th e 1:1,000,000 survey has been completed for all the territory o f the Lowland; in the next 2 - 3 years the 1:200,000 survey will be completed. The aero-magnetic survey shows that the West Siberian Lowland has a very differentiated magnetic field. Anomolies of the magnetic field are caused by the heterogeneous petrographic comp osition of the basement, by the tectonics of the basement, and also in part by the relief of the surface of the basement. Qualitative analysis of magnetic maps and of maps of axes of magneti c anomolies by means of comparing them with the known geologic structure of the basement permits revealing of existing regularities and their extrapolation into the buried part of the Lowland. Quantitative calculations supplement the interpretati on of magnetic anomolies: determination of the depth of occurrence of the upper boundary of a disturbing magnetic body, and calculati on of the intensity of its magnetization. These quantitative computat ions permit construction of schematic maps of the relief of t he hypothetical surface of the basement and of maps of the distribution of rocks of the basement according to composition. Up to the present time mostly gravity surv eying has been used in West Siberia. In the southern regions this surveying was carri ed out with excessive accuracy for the study of the regional plan, but with insufficient accuracy for revealing local uplifts. In the future, one of the important tasks in this area is the increase of the accuracy of gr avity observations, which with use of spec ial procedures of interpretation permits local uplifts to be distinguished. Use of these operations in the northern regions of the West Siberian Lowland, which appear now to be the most favorable for oil and gas, permits better use of seismic investigations for revealing and mapping structures of the second and third order.