Department of geochemistry of sedimentary series of oil- and gas-bearing provinces

Department of geochemistry of sedimentary series of oil- and gas-bearing provinces

The head of the department  – S. V. Vovnyuk, PhD

The deprtment was founded in 1969 and titled “Department of salt structures of oil- and gas-bearing provinces”.The first head of the department was professsor V. I. Kityk, Dr. Sc., a corresponding member of Ukrainian Academy of Science. From 1984 to 2007 the department was headed by prof. Petrychenko O. Yo, Dr. Sc. From 2007 to 2015 the duties of the head were executed by I. V. Dudok PhD, and from 2015 – by S. V. Vovnyuk, PhD.

The main fields of department’s research work are:

– geology and geochemistry of evaporites of Ukraine and World and related deposits of gypsum, rock salt, potash salts, native sulphur, celestite;

– evolution of Phanerozoic seawater chemistry evaluated by means of fluid inclusion study in halite from marine evaporites;

– vein mineralogy of different structural and facial zones of Ukrainian Carpathians.

The significant attention in studies is paid to problems of the nature of relations between evaporites and oil- and gas-bearing sedimentary series.

Mineralogical and geochemical research is aimed to comprehensive study of evaporite formation – physical and chemical parameters of environment of precipitation and recrystallization of salts, seawater chemistry evolution in the framework of Earth’s history, the evaluation of criteria for searching of mineral deposits related to evaporites in general and salt structures in particular.

The scientific school for fluid inclusion study in salt minerals was founded in the department by prof. O. Yo. Petrychenko. The study of individual fluid inclusions chemistry is conducted by means of unique method (developed by   O. Yo. Petrychenko) – inclusion brine is extracted by microcapillars and then analyzed for major solutes. The researchers have conducted large amount of studies of individual fluid inclusion chemistry from World’s evaporate formations of different age, which made it possible to discover two megacycles of seawater chemistry changes during Phanerozoic – from Ca-rich to SO4-rich chemical type. Today the results of novel contribution of prof. O. Yo. Petrychenko, prof V. M. Kovalevych and their students are recognized by scientists worldwide.

The main recent achievements of the department’s researchers are:

For the first time for terrigenous and evaporate deposits of Carpathian region it was discovered that the presence of organic matter in interlayer spaces slows down the clay minerals transformation (from smectite through mixed-layer minerals to illite)

The method of ancient evaporate depth determination is developed. In particular, the depth in Ordos basin (Ordovician, Central China) at the halite precipitation stage was 60 m.

For the first time the chemistry of primary inclusions brines in Ordovician evaporate basin (Central China) was studied. It is determined that sedimentary brines of this age belong to Ca-rich type with elevated potassium content.

The indications of oil and gas saturation of Earth’s depth (fields of anomalous hydrocarbons concentrations) were determined in near-surface sediments. This made possible to locate the fields of potential hydrocarbon accumulation.

The geochemical studies showed that capturing of organic compounds by interlayer spaces of clay minerals impacts the gas productivity of low permeable clay deposits. There are 13 employees working at the department, including 5 PhDs. The X-ray diffractometric laboratory and the analytical chemistry laboratory are functioning at the department.