Geology, geography and global energy

Scientific and Technical Journal

Optimization of oil and gas prospecting and exploration based on the study of peculiarities of territory’s structure, geomorphology and gas component of the underground geosphere caspian depression

2015. №4, pp. 25-35

Zotov A.N. - Chief Geologist, Ltd "LukBelOil", 42 Ulyanovskaya st., Saratov, 410056, Russian Federation,

Navrotskiy O.K. - D.Sc. in Geology and Mineralogy, Chief Researcher, Lower Volga Research Institute of Geology and Geophysics, 70 Moskovskaya st., Saratov, 410012, Russian Federation,

Bondarenko V.V. - Geologist, Lower Volga Research Institute of Geology and Geophysics, 70 Moskovskaya st., Saratov, 410012, Russian Federation,

The article presents the results of integration of structural and geomorphological investigations and gasometric surveying, which contributed to oil field discovery. It views the role of fault tectonics and sedimentary cover jointing in formation and distribution of oil and gas deposits. Structural deciphering was performed with photo materials of various scale. The study defines the nature of jointing (including planetary jointing) and oil and gas content. Gasometric surveying was carried out within the territory under study on the structures, which were identified through seismic surveying. Gasometric surveying has long been one of the cheapest and relatively informative methods in oil prospecting practice. Gasometric surveying involved drilling shallow holes (up to two meters deep) and taking gas samples with their further chromatographic analysis. Gases contained methane and its homologs, helium, hydrogen, oxygen, carbon dioxide, nitrogen. Lineament network was taken as a main characteristic of the geodynamic density, as it reflected fault tectonics and decompression zones, denudation and erosion scraps, captures of upper erosion cuts. Analysis of geodynamic density within discovered deposits showed that all oil and gas deposits are located in geodynamically smooth blocks. Gasometric surveying was performed on the sample zone (deposit), it was then compared with gasometric characteristics of other zones. It was found out that geodynamically smooth blocks are characterized by minimal atmogeochemical background. Structures ranking according to their geodynamic density and atmogeochemical background allowed selecting the priority location for prospect well placement. The drilled well resulted in inflow of commercial oil from Bobrikovian age deposits.

Key words: дешифрирование, структурно-геоморфологический анализ, линеаментная сеть, геодинамическая напряженность, газометрическая съемка, газогеохимический фон, эталонный участок, ранжирование, нефтегазоносность, deciphering, structural and geomorphological analysi