Evolution of the Geometry of Coastal Plain Sand Bodies During Transgression (on the Example of Formations of the TP Group of the Tanopchinskaya Suite)

Abstract

The purpose of this work is to improve the predictive ability of the geological model of coastal formations when assessing hydrocarbon reserves and laying production wells. The article presents the results of work on the analysis of the geometry of sand bodies of the formations of the TP group of the Tanopchinskaya suite. To determine the morphology of sandstones, the authors used an integrated approach that takes into account: the results of sedimentological core studies, well logging data, 3D seismic materials. The authors studied in detail the conditions for the formation of these rocks on the basis of actual material (core), and presented photographs with characteristic structural and textural features of the rocks, which make it possible to establish the conditions for their formation. Spectral decomposition sections were analyzed in detail in the studied interval at several license areas of NOVATEK.The reasons for changes in the geometry of sand bodies from the perspective of sequence stratigraphy have been established and explained. In addition, an idea has been formed about the vertical evolution of the coastal zone under conditions of sea transgression. The filtration and reservoir properties of rocks were also analyzed based on measurements of porosity and permeability on more than 700 core samples formed in different sedimentation environments. Recommendations are given for the practical use of established patterns of changes in reservoir properties and the geometry of sand bodies when constructing a geological model of hydrocarbon deposits, which will certainly improve the efficiency of production drilling.

Keywords

• sedimentological analysis
• depositional environments
• flooding surface
• transgression
• geometry of sand bodies