Conditions for the formation of non-anticlinal hydrocarbon traps in zones around salt stocks of the south-eastern part of the Dnepr-Donetsk depression

Abstract

Formulation of the problem. The southeastern part of the Dnieper-Donetsk depression has a large-scale formation of underground salt structures (stocks). The stocks are the reason for the formation of many layer structures. The authors divide these layer structures near the stocks into three types - above-stock, inter-stock, and near-stock. The most promising targets for exploration drilling are anticlinal structures (of the first and second types). Many industrial accumulations of hydrocarbons (Shebelinskoe, West-Krestishchenskoe, Efremovskoe) were found in anticlinal structures. The aim of the work is to determine the genetic relationship between lithological structures and hydrocarbon traps. This is the basis for the search for a non-anticlinal form of hydrocarbon traps. Presentation of the main research material. On the territory of the Dnieper-Donetsk depression, different models of structure of salt stock zones were found. The most promising for the search for hydrocarbon deposits are areas with satellite blocks near the underground salt stock. These blocks were formed concurrently with the process of breaking through the rock stock. In this study, salt stocks have been divided into activity types. Only active stocks have satellite blocks. This makes it possible to make predictions in trough zones (stock compensation troughs). The authors have divided found traps for hydrocarbons into: plumes from salt stocks in P1sl - C33 rock formations; rocks raised by salt stocks at the time of formation P1 - C3; tectonic satellite blocks from rocks of age C3, C2b, C1s; carbonate structures of organisms P1. These structures can be hydrocarbon deposits themselves with personal water contact. Often these structures share a common water contact. This is the basis for the allocation of the entire area around the stock for hydrocarbon prospecting. To search for hydrocarbons near stocks, you need to use special techniques. The detailed description of the theory of the search method have been given in the work. Conclusions. Prospective objects for the search for hydrocarbons are located near the salt shafts with the greatest activity. This conclusion was made on the basis of the reconstruction of salt tectonics in the research area. Hydrocarbon traps are non-vaulted forms near the salt object. The objects of the first rank for the search are uprooted blocks, satellite blocks and plume formations. The authors single out Novosanzharsk-Malopereshchepinska, Tarasivska, Elizavetivska, West-Chutivska, Lannivska, South-Khrestishchenska (Berestovenkivska), West-Efremivska, Oleksiivska, Kopylivska and some other areas as promising.