Improving the distribution methodology for oil and gas-bearing local structures into con- and post-sedimentation

Purpose. Improving the means of dividing oil- and gas-bearing formations into post- and con-sedimentation. Methodology. Construction and analysis of unique maps characterizing local oil- and gas-bearing structures and deviations in the thickness of productive horizons. Application of trend and correlation analysis. Generalization of information from the geological fund and published special literature. Findings. The classical geotectonic method of facies and thicknesses, even today, remains relevant in dividing folds into post-sedimentation and con-sedimentation. However, it has a series of restrictions. In particular, it can be applied to sufficiently large tectonic structures. Thickness analysis should be performed only when paired with facies analysis, which is often impossible for local structures. In real conditions of fields, there are a large number of local folds that significantly affect the redistribution of hydrocarbon raw materials. We propose a methodology with the following main steps to divide local structures into post-sedimentation and con-sedimentation. They include construction and analysis of a set of special maps that characterize the structure and thickness of the horizon under research. The structural map of the horizon, the approximate surface map, the map of local structures, the isopach map, the thickness trend map, the map of the thickness deviation from the approximate value, and other maps are the main analyzed maps, if necessary. The simultaneous analysis of the set of maps and correlation analysis makes it possible to distinguish local structures and determine the conditional age of their formation. Originality. Using the new methodology, it was proven that the local structures of the Berezivskyi gas condensate field in the Upper Serpukhiv time (С1s2) of the Carboniferous were formed con-sedimentatively. Practical value. Based on a combination of thickness methods and trend analysis, a methodology for dividing the local structures of oil and gas fields into post-sedimentation and con-sedimentation has been developed.