On detection of gas accumulations in dense sandstones with mobile geophysical methods

Purpose. The results of the application of frequency-resonance technology of remote sensing (RS) data processing and interpretation and geoelectric methods of forming short-pulsed electromagnetic field (FSPEF) and vertical electric-resonance sounding (VERS) for gas accumulations searching in tight sandstones of Dnieper-Donetsk basin (DDB) are analyzed. Design/methodology/approach. Approved methods works within the framework of the "substantial" paradigm of geological and geophysical studies, the essence of which is "direct" searching for a particular substance such as oil, gas, gold, silver, platinum, zinc, iron, water, etc. The FSPEF method and technology of remote sensing data processing allow to detect and map operatively the anomalous zones of the "oil accumulation" and (or) "gas accumulation" type. The bedding depths of the anomalous polarized layers (APL) of gas and gas-condensate type may be determined by VERS sounding within mapped anomalous areas. Mobile technology allows to get a new (additional) and, more importantly, independent information on the petroleum potential of the surveyed areas. Findings. Three prospective areas were examined. Studies show that a drilled Belyaevskaya-400 well falls into the anomalous zone with high reservoir pressure and, consequently, the probability of commercial gas inflows receiving in it is very high. At the same time, the construction site of the Novomechebilovskaya-100 well is not located in an optimal place; it is located on the edge of the mapped anomaly. Seven previously drilled wells within the Slavyanskaya structure does not fall within the contours of the detected anomalies there; the gas inflows were not received in these wells. Practical implications/value. In general, the mobile methods using during prospecting for hydrocarbon accumulations in unconventional reservoirs (carboniferous and crystalline rocks, shales, tight sandstones) allow to optimize the location of exploration and production wells, and, hence, significantly reduce their number and harmful effects on the environment.