Methods for Estimating the Thickness of Productive Intervals and Water Saturation in Oil Deposits Using Seismic Background Noise

The article presents the results of remote determination of the rock saturation type and estimation of the total thickness of productive intervals based on recordings of natural seismic background noise. Field data were processed using both methods previously proposed by the authors and new ones. These methods are based on the well-known empirical phenomenon—the appearance of a positive spectral anomaly in the seismic background above a hydrocarbon deposit in the 1–10 Hz frequency range. The field data recorded near wells and along the profile in mature fields in the desert of southeastern Kuwait were analyzed. The developed methods were found to be equally effective for analyzing hydrocarbon deposits with both carbonate and terrigenous reservoirs at different stages of development. Empirical mode decomposition allowed for the separation of the oscillating and trend components of the productive interval thickness estimates, which characterize different geological and geophysical features of the study area. The maxima of the trend component mark the position of large oil-bearing geological blocks, while the minima correspond to inter-block boundaries with no oil content. The oscillating modes reflect local features of the degree of rock oil saturation. The proposed methods and techniques are valuable tools in oil and gas exploration for constructing maps of total productive interval thickness and selecting the most promising drilling locations. They can also be applied in the development of mature fields to identify water breakthrough zones, delineate water-flushed compartments, and locate poorly drained, oil-filled areas. The new acoustic method for detecting water saturation of rocks is promising for developing technologies to prospect for underground high-quality drinking water sources in arid and industrial regions, which is an urgent modern problem.