Conditions for formation of technogenic reservoirs (on the example of the Rudkivske gas field)

Abstract

The practical experience of long-term operation of hydrocarbon deposits con- firms the presence of geomechanical processes and their significant impact on the state of the gas-saturated massif of rocks. In fields that are being operated for a long time, the prospects for industrial hydrocarbon accumulation can be associated with secondary gas traps of non-traditional type, in particular, technogenic ones, which are formed in low-pore collectors. The authors carried out a detailed analysis of the well-known gas and gas condensate fields of Ukraine. The Rudkivske gas field of the Western oil-and-gas bearing region was chosen. The purpose of the study is to clarify the geological conditions for the formation of technogenic collectors and attracting additional volumes of gas under the action of a geomechanical factor while operating the Rudkivske gas field. The quoted results of the research prove the effect of gas extraction from the deposits of the J-h horizon on the formation of secondary technogenic collectors by attracting additional volumes of gas from the of ND-4, ND-5, ND-7 productive horizons and the formation of a new (ND-10) one, which subsequently connected to the gas production. 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 of the Jurassic age (J-h), 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 geomechanical factor management opens 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.