Physical and reservoir properties of potential oil and gas bearing intervals at the bottom of productive thickness onshore in Azerbaijan (at the example of Kalamaddin field)

Abstract

During the last years drilling exploration works in the Republic of Azerbaijan have been moved from east regions to less studied central and west regions. Besides, generalization of available geological and geophysical data, evaluation of potential of certain lithologic and stratigraphic complexes and forecast of deep oil and gas reservoirs are of particular importance. The paper shows an analysis of complex petrophysical data. An analysis considers interpretation of reservoir and petrophysical properties of rocks of Mesozoic and Cenozoic deposits taken from drilled wildcat and appraisal wells and geological data of Kalamaddin oil and gas bearing region where sediments of productive thickness (PT) such as Lower Pliocene are widely spread. As a result of an analysis and interpretation of geological, geophysical and petrophysical material it was established that oil and gas bearing reservoirs are represented mostly by naturally fractured igneous-sedimentary and carbonate rocks. Petrophysical properties of rocks of a section of the earth’s crust of Kalamaddin oil and gas bearing region are given in short. Based on the generalized data a schematic graph that reflects change in rock porosity along a section is built. According to a graph the deeper is the formation the lower rock porosity and the higher the density and propagation velocity of ultrasonic waves are. Obtained generalizations allow to conclude that change in reservoir properties in a wide range on the territory of Kalamaddin is connected to lithological heterogeneity of rock complexes, diversity of their burial depths and as a result with diversity of pressure and temperature conditions and complexity of tectonic conditions. Results of different petrophysical study methods show that reservoir properties of rocks become worse if depth is increased. Nevertheless, in certain cases reservoir properties of clay and carbonate rocks can be improved due to secondary porosity under relatively rough pressure and temperature conditions. Besides, relations between physical parameters and matter composition for certain rock types are established. Studies were performed in atmosphere and thermodynamic conditions.

Keywords

• ocks
• set
• porosity
• depth
• well
• density
• petrophysics
• interval
• drilling
• geophysics
• oil and gas deposition