IDENTIFICATION OF RESERVOIR ROCKS IN THE GEOLOGICAL SECTION OF THE STRYI DEPOSITS OF THE VERKHNEMASLOVETSKE FIELD

Abstract

To reliably solve the problem of identifying reservoir rocks in the geological section of a well, a large amount of diverse information about them is required. However, well logging (e.g., hydrodynamic, core material) and testing is rarely performed for one reason or another. In such conditions, one has to rely only on geophysical information from the study of the well section. Geophysical methods of well logging solve the problem quite clearly: in geological sections filled with so-called «pure quartz sandstones». In the case of complex rock structure, it is difficult to solve the problem of reservoir identification in a well section, which often leads to the omission of productive formations. In this paper, in order to distinguish sandy varieties (sandstone, clayey sandstone, carbonate sandstone, compacted sandstone, siltstone) in the geological section of wells of the Stryi Formation of the Verkhnemaslovetske oil field, the authors proposed to use the parameter D which characterizes the proportion of the dispersed fraction that accounts for the total hydrogen content of the rock and is numerically equal to the ratio of the double difference parameter from neutron gamma ray logging to the double difference parameter from gamma ray logging. The rock is classified as sandy if the value of the D parameter is equal to or greater than 0.5. To divide sandy types into collectors (sandstones with Kp≥7 %) and non-collectors (other sandy types with

Kp<7 %), the authors proposed to compare the value of the parameter Dfact, calculated from actual data of geophysical surveys of wells, with the reference value Ddetail, calculated by the dependence equation of the D=f(ΔIγ) type.