Perm Journal of Petroleum and Mining Engineering (Sep 2019)
Petrophysical aspects of deep reservoirs in the Absheron and Baku Archipelagos
Abstract
Based on the recent information about oil and gas production potential in Azerbaijan, a geological and geophysical assessment of deep formations has been made. Scientific criteria have been prepared in order to use them as a basis for new researches. It has been highlighted that the main oil and gas fields are associated with the South Caspian and Kura basins, which were subjected to intense sinking during the Mesozoic Era. The high production potential of the central part and deep formations has not been sufficiently shown in terms of quality and quantity. It is known that the exploration, production and assessment of oil and gas field potential strongly depend on the information collected about petrophysical parameters of the formation. Researches shall be conducted concerning the oil and gas regions in the Absheron and Baku archipelagos, where Mesozoic and Cenozoic sediments are widely spread. Various geological, geophysical and physical aspects that had been influencing the reservoir potential of oil, gas, and gas condensate fields in that region have been studied. The conducted researches demonstrate that there is a thin layer of Pliocene anthropogenic deposits of 100 to 200 m in the paleoprofiles formed along the Kurdakhan – Shah Deniz offshore field in the northwest. The thickness increases towards Kum Adasi up to 3600 m and reaches 6000 m in Shah Deniz. Along the edges of the synclinal folds, the thickness of the abovementioned deposits reaches 3000 m in the northwest and about 10,000 m in Shah Deniz. Therefore, without sufficient knowledge about reservoir properties of the layer, it is impossible to assess the hydrocarbon accumulations and production volumes and change the exploration direction. In addition to geological and geophysical researches conducted in the area, lithologic, petrographic and reservoir properties have been studied in order to identify changes in the correspondence of carbon content, porosity, permeability, density, grain size distribution and sound wave velocity along the area to the properties of the abovementioned layer. For this reason, a table with the field reservoir properties has been prepared. It contains upper, intermediate and lower boundaries of physical characteristics, analyses the reservoir property interdependences and determines the formation depth and other physical aspects. The researches show that physical characteristics of coeval and homonymous rock change due to geological and physical processes and lead to different results. The reservoir characteristics of productive strata have been studied. A table has been prepared to show physical parameters of the area depending on time and place and to display different types and frequency of geological characteristics pertaining to the reservoir rock.
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