The borehole geochemistry methods are conducted for a more rapid and in-depth study of borehole sections, forecasting, and evaluation of oil and gas saturation of potentially productive horizons, as well as studies of formation fluids. One of the most effective methods for assessing oil and saturation in borehole sections is geochemical research, including gas and bituminological logging by drilling fluid (DF), sludge, and core, the resolving power of which allows performing real-time analysis and evaluation of sedimentary deposits unsealed by drilling, in terms of gas saturation and component composition of hydrocarbon gases and bitumen rocks (water and DF). The geochemical studies in boreholes conducted by the company include:

  • a sampling of drilling liquid (sludge) and core, if necessary;
  • a sampling of edge water and gases;
  • express analysis of gas samples of drilling liquid (sludge) and edge water;
  • thermal desorption of gases of deep sorption by core and sludge;
  • thermal vacuum degassing of samples of drilling liquid (sludge) and edge water;
  • mechanical degassing (MD) of the core and sludge;
  • identification of the component composition of DF gases, sludge, core and formation fluids;
  • identification of chemical composition and physical and chemical properties of edge water;
  • luminescent and bituminological analysis of sludge and core;
  • identification of organic carbon in the core (sludge);
  • pyrolysis of core (sludge) samples to determine oil-generating and productive properties of the section;
  • identification of lithological and geochemical indicators-physicochemical properties (pH, Eh), secondary carbonate content, heavy metals, etc.

 The borehole geochemistry methods solve the following tasks:

  • geochemical characteristics of the sedimentary section and formation fluids are studied;
  • productive intervals of the section are identified with an estimate of their phase saturation;
  • physicochemical properties of formation fluids are identified;
  • oil-generating and productive properties of rocks of oil and gas-promising complexes and thermodynamic maturity of hydrocarbon fluids are assessed;
  • conservation degree of hydrocarbon accumulations is identified;
  • Contacts: water-gas, water-oil, water-oil-gas, boundaries of reservoir pinch out boundaries are delineated.
Geological and geochemical model of ALS

Geological and geochemical model of ALS

Geological and geochemical section of the sedimentary cover of Angara–Ilim interfluve

Geological and geochemical section of the sedimentary cover of Angara–Ilim interfluve

Dispersion halos of HC gases in sedimentary section of the Bratsk gas condensate field

Dispersion halos of HC gases in sedimentary section of the Bratsk gas condensate field