Methodology for determining relative linear deformations in a rock massif of the sedimentary strata

Purpose. To develop a method for predicting fractured zones in a massif of sedimentary rocks formed due to the folding, by determining relative linear deformations that exceed those critical ones for discontinuity of rock massif. Methodology. The task of identifying fractured zones is to determine areas in the rock massif where tensile deformations, under the action of tectonic processes, have exceeded the critical limit. The determination requires the map construction of the researched area with the help of trend analysis and a series of mathematical calculations, namely, finding the distance between the selected points of the direction and along the arc connecting them within the interpolating surface. The length of the last curve is found by integration. The coefficient of relative linear deformation is the result of dividing the found distances (the length of the arc by the length of the line). Findings. A new methodology for predicting fractured zones in a massif of sedimentary rocks formed due to the folding is proposed. The methodology was developed based on an algorithm that involves calculating the relative linear deformations of the bed by constructing maps of local structures of the researched area and a series of mathematical calculations. Using the example of the “Chaikino” minefield, the authors present the concrete result of determining the relative linear deformations of the rock massif. An anticlinal local structure (the 2nd-order structure) was identified within the minefield, the parameters of the structure were determined, and calculations were performed according to the appropriate algorithm. The obtained data indicate that the real values of relative linear deformations (1.011 and 1.034) significantly exceed the critical limit for sandstones (1.003–1.004). This indicates the discontinuity of rock massif and the presence of the fractured zone. Originality. For the first time, the methodology has been developed that allows determining the relative linear deformations of rocks between any individual points within the researched area, based on the coordinates of the points’ location in the plan and the hypsometric marking of the bed. Practical value. The proposed methodology can be used to solve several geological problems directly related to the research and detection of fracturing, which was formed under the action of tectonic forces in the process of folding.