Geological features of gas-condensate

Abstract

The purpose of the work is to elucidate general peculiarities and characteristic features of geological conditions for the occurrence and development of gas-condensate fields of the Dniprovsko-Donetskyi depression (DDD), on which the growth for the gas reserves is obtained with the further use of these indicators as forecast-estimated. The methods. The age of industrial horizons, a type of reservoir, a type of deposit, the presence of salt deposits, a depth of deposit roof, a deposit regime, levels of gas-bearingness, calculated thickness of reservoirs and their total thickness at the field, the initial formation pressure, initial gas reserves, volumes of excess of initial gas reserves were determined; the maximum geostatic pressure was calculated, the minimum reservoir gas pressure until its growth jump or stabilization was established; the value of the compression pressure for the reservoir of deposits was calculated and the relationship between the effective pressure in the deposit and the strength of the porous sandstone-reservoir was established; the common features and characteristics for the geological conditions of gas condensate field (GCF) with additional resources were undertaken, among which the predictive and estimated indicators were selected. Findings. The authors carried out a detailed analysis of the well-known gas and gas condensate fields of Ukraine. Gas-condensate deposits of the Mashivsko-Shebelynskyi gas-bearing area of the Dniprovsko-Donetskyi depression (DDD) are chosen as an object of the research. It has been established that the power of the gas column, the structure area, and the total power of productive horizons characterize the promising volume of the gas-bearing structure, which allows approximately give a predictive quantitative assessment of the production of additional gas reserves. Attracting additional gas volumes is due to the gas influx from newly made technogenic collectors, which were formed under the action of a geomechanical factor in the process of long-term development of the field. The formation of technogenic collectors occurred due to the compression of the main reservoir, the deformation of the rock strata, and the decomposition of the overlying rocks, the development of the crack propagation, permeability increase and gas recovery rising. The originality. It has been established that the power of the gas column, the structure area, and the total power of productive horizons characterize the promising volume of the gas-bearing structure, which allows approximately give a predictive quantitative assessment of the production of additional gas reserves. Practical implimintation. The geomechanical factor management opens up the prospect of obtaining additional industrial gas influx in the late stages of the development of gas and gas-condensate fields, by predicting the geological conditions for the formation of improved secondary filtration and capacitive properties favorable to form technogenic gas deposits.