Physical-Chemical Investigation of the Recent Soils as a New Method of Detection in Oil and Gas Deposits

Polivtsev, Anatoliy V., Lesia A. Buzhuk, Svyatoslav V. Kushnir, Myroslava B. Yakovenko, Ukrainian State Geological Research Institute, Kyiv, Ukraine

The investigation objects were patterns from various units of chernozems and darkish­grey soils (podzolised, salted etc.) from the flanks of Dnieper-Donets Depression covering oil and gas-bearing and non-productive structures. The research was aimed to ascertain optimal circumstances for laboratory measurements to reveal the specific physical-chemi-cal conditions made up by hydrocarbons microseepage effect.

The feature of investigations is their supplement by new procedures (Polivtsev, 1999):

a.                    o Eh-pH of soil solutions were measured during various periods – from several minutes to several weeks at different temperature. So, we obtain more reliable data than those obtained from ordinary static measurements.

b.                    o Regulation of biochemical activity by adding various liquids and gases enable inhibit or catalyse redox reactions and restrict the effect of oxygen system.

c.                    o Eh-pH dynamic measurements performed in different phases of system “solid soil–solution”. That enabled observe the effect of principal for equilibrium adjustment reac­tions between the compounds of various phases. Hence, we determine the dominant at the moment Eh-pH-conditions with their gradients from one phase to another and obtain more helpful information.

The results. The feature of soils covering hydrocarbons fields and zones of faults is anomalous character of redox reactions caused by hydrocarbons microseepage. That reflects in anomalous Eh-pH dynamics. The optimal time of soil solutions preparatory expo­sition was determined. Employment the specific additions to solutions enable sensibly reduce the biochemical activity fluctuations and get more typical experiment conditions for patterns with different storage time. The reagents increasing hydrocarbons microseepage effect in soils should be employed in geochemical exploration.