Complex Analysis of Coastal-Continental Geological Formations for the Clarification of Geological Model

Abstract

The main objective of this paper is to increase the efficiency of planning horizontal wells and refine the geological model of formations of coastal origin. Based on a comprehensive analysis of geological and geophysical information and a description of the core, a facies and a 3D geological models of TP16 formations of coastal origin were constructed. These formations are characterized by strong lateral variability and low net to gross. In the course of this research, data from seismic inversion, geophysical studies of wells and production logging were used. Updated seismic correlation and an interval analysis of seismic cubes, together with the data from well test results, made it possible to reliably determine the stratigraphy and chronology of accumulation of the studied formations. As a result of the performed research, seismic attributes describing the geological structure of the deposits, as well as the distribution of productive volumes and reservoir properties were obtained for each formation. Also, the boundaries of tidal-fluvial channels and floodplain areas were identified based on seismic attributes. Taking into account the acquired data, the facies and 3D geological models were updated and the drilling of exploitation wells was planned. The accuracy of the new geological model was confirmed by drilling 8 horizontal wells with an average effective penetration of the reservoir of 1640 meters (82%) and an average permeability coefficient of 108 mD.