ACCOUNTING THE PARAMETER OF ANISOTROPY OF PERMEABILITY IN GEOLOGICAL AND HYDRODYNAMIC MODELS OF CARBONATE OBJECTS (ON THE EXAMPLE OF THE GAGARIN DEPOSIT)

Abstract

The relevance of the research. A significant share of the developed oil assets, confined to carbonate complex objects, has increased markedly both in Russia and in the Perm Krai. Reliable knowledge of the parameters of a fracture-porous reservoir type allows selecting a rational development system, controlling development, ensuring optimal geological and technical measures for a given reservoir, clarifiesthe existing geological and hydrodynamic models. When building and adapting geological and hydrodynamic models of oil fields, especially those related to complex carbonate reservoirs, knowledge of both horizontal and vertical permeability (anisotropy parameter) is important. In practice, the vertical permeability in geological and hydrodynamic models is often assumed to be zero, although this is far from the case. Determining the vertical permeability (anisotropy parameter), its dynamics when changing reservoir and bottomhole pressures, and use in geological and hydrodynamic models is an important task that will improve the quality and accuracy of using digital models for calculating and predicting oil production. The main aim of the study is toimprove the geological and hydrodynamic model, taking into account the use of permeability anisotropy index. Object: carbonate Famennian deposit of the Gagarinsky field. Methods: processing of geological research data; use of the Tempest hydrodynamic simulator version 8.3.1 from Roxar. The results. According to the method for determining the anisotropy parameter proposed in the article, 252 studies were carried out at production and injection wells in the Famennian deposit of the Gagarinsky field. For each lithofacial zone, the dependence of the permeability anisotropy index on the bottomhole pressure was constructed. For forecasting and evaluating the effectiveness of the applied geological and technical measures and technological indicators of development, the authors modified the geological and hydrodynamic model taking into account the dependencies obtained on the change in the anisotropy parameter. With the help of a modified hydrodynamic model, we managed to significantly improve the adaptation of both production and injection wells. Thus, it was possible to improve the quality and reliability of the digital model of the Famennian reservoir of the Gagarinsky field for calculating and forecasting oil production.

Keywords

• well testing
• vertical permeability
• horizontal permeability
• lithologic-facies zones
• modified hydrodynamic model