METHOD OF GEOCHEMICAL PROSPECTING FOR GEOECOLOGICAL MONITORING OF OFFSHORE OIL-AND-GAS-BEARING ZONES Russian patent published in 2014 - IPC G01N24/08 

FIELD: oil and gas industry.

SUBSTANCE: water area relief survey is performed. Flooded river valleys crossing the continental shelf are determined as per survey results. Bottom deposits are explored with acoustic pulses. Layers of soil and bottom deposits are restored to depths of up to 2-4 km. Structural denudation relief shapes are analysed and terrigenous deposits are determined. When prerequisites of existing oil-gas sections are being determined, soil is sounded with coherent pulse proton spin echo. Tomographic restoration of image of explored geological soil profile is performed on the level of prismatic crystals. At least two bottom seismic stations are installed in addition to record and analyse microseismic waves. Soil resistance and friction coefficients as per which its strength characteristics are determined are defined by means of penetrometers arranged on the above seismic stations. After that, samples of mine rock and plants along water courses are taken. Samples of mine rocks are separated into two fractions - more than 0.1 mm and less than 0.1 mm. The first fraction is analysed for content of Si, Al, Ti, Y, and the second one - for Hg content. Samples of plants are analysed for content of Ba, Cu, Pb, Zn, and Ag. Analysis results of fractions of more than 0.1 mm and samples of plants are recalculated for the corresponding additive characteristics of use concentrations. Distribution charts of the above additive characteristics and Hg are built. Objects characterised by distribution of anomalous values of additive characteristics and Hg are identified in the row of Si, Al, Ti, Y-Ba, Cu, Pb, Zn, Ag-Hg-Ba, Cu, Pb, Zn, Ag-Si, Al, Ti, Y, with oil-gas perspective sections. Water layer is analysed for methane content. Coordinates of gas formation are determined. When overflows of the transported liquid product with formation of oil spot are determined, oil spreading and transfer processes are calculated considering hydrodynamic parameters of water environment. Hydrosphere is sounded additionally during ground sounding by coherent pulse proton spin echo. The tested medium is subjected to simultaneous impact of SHF emission and variable magnetic field within the frequency range of nuclear magnetic resonance, at that SHF emission and constant magnetic field are maintained in resonance conditions. Decrease in intensity of one hyperfine transition is measured at simultaneous saturation due to high power of the respective SHF of the second hyperfine transition; additionally electron paramagnetic resonance is subject to optical detection. Spin state of the radical pair (singlet or triplet) is changed in the forced way that leads to spin transition of the pair partners under action of resonant microwave field in the external magnetic field; at that the range of electron magnetic resonance is registered by change in products output in the radical pair by analytical method.

EFFECT: enlarging functional capabilities of the method; improving detection reliability of perspective oil-gas sections.

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