Vol. 332 No. 7 (2021)
DOI https://doi.org/10.18799/24131830/2021/7/3259
EVALUATION OF OIL AND GAS CONTENT OF LOCAL UPLIFTS IN THE NORTH ABSHERON ZONE BASED ON PETROPHYSICAL PARAMETERS (LOCAL UPLIFTS GOSHADASH–AGBURUN-DENIZ–DARWIN KYUPESI–GYURGYAN-DENIZ AS AN EXAMPLE)
The paper considers the properties of changes in the rocks petrophysical parameters of the local Goshadash, Agburun-deniz, Darwin kyupesi and Gyurgyan-deniz uplifts within the 400–2650 m depths interval, and the relevant diagrams were mapped. Analysis of the areal and depth changes in the petrophysical characteristics of rocks makes it possible to determine changes in their reservoir properties, as well as to relatively objectively assess both the fluid content and the prospects for the oil and gas potential of the reservoirs. Changes in the rock petrophysical properties and their impact upon porosity and permeability of the Goshadash, Agburun-deniz, Darwin kyupesi and Gyurgyan-deniz uplifts up to 2650 m deep were individually analyzed. The diagrams drawn based on petrophysical data show that psephitic, psammitic, silt and peliticfacies of terrigenous origin, as well as carbonate facies in the section in various ratios. As a rule, there is inverse relation between carbonate and shale content and reservoir properties and direct relation with grain sorting. This pattern is breached in exceptional cases, when reservoir properties are, probably, associated with increase in rock viscosity and formation of secondary porosity. Formation of secondary porosity at relatively greater depths, therefore, does not exclude the presence of hydrocarbon accumulations. Relevance. The North Absheron uplifts zone, located close to rich oil and gas condensate fields, covers a large territory originating from the northwest of the Absheron peninsula and extending southeastwards. Goshadash, Agburun-deniz, Darwin kyupesi and Gyurgyan-deniz offshore uplifts under study are situated here. Productive series, that are the primary oil and gas bearing complex, are located at a relatively shallow depth, within the reach of modern technology. The construction and analysis of petrophysical models can play an important role in predicting oil and gas potential of the productive series and underlying sediments. This can lead to the discovery of new oil and gas accumulations and increase in oil production. The aim of the research is to study the lithofacies and reservoir properties of rocks along the total depth based on petrophysical models built according to geological and geophysical data and well data. Subject: productive series sediments of the Goshadash, Agburun-deniz, Darwin kyupesi and Gyurgyan-deniz fields. Methods. The reservoir properties of sediments in the 400–2650 m depth interval of the Goshadash, Agburun-deniz, Darwin Kupesi and Gyurgan-deniz areas were researched on the basis of a laboratory study of core samples taken in wells. The above study interval was divided into several short intervals, each 150 m deep, and 20 to 40 core samples were taken from each interval, analysis was carried out, their particle size distribution, carbonate content, porosity and permeability were established. As a result of this analysis, for each of the 150 m intervals, the average values for the above parameters were presented, on the basis of which we built histograms. Results. The inverse relationship is mainly observed between reservoir properties and carbonate and shale content within the depth interval under investigation in the fields of Goshadash, Agburun-deniz, Darwin kyupesi, Gyurgan-deniz. With the exception of some short intervals no pattern (i. e. linearity) is observed in the variation properties of petrophysical parameters of the productive series deposits along the depth in Goshadash, Agburun structures and Darwin kyupesi, Gurgan-deniz fields as well. Based on 42 ton/day flow rate of well 726 from PKS drilled at the Darwin kyupesi field and 20 ton/day flow rate of well 813 from KS oil gushers, 10 ton/day of oil obtained from PKS while testing well 7 drilled at the Gyurgan-deniz field and identical variation degree of rock reservoir properties in the Goshadash and Aghburun-deniz structures located on the same anticlinal line as the field above one can assume the presence of hydrocarbon accumulations in identical deposits of these structures.
Keywords:
Sediments, petrophysical properties, pelites, psammites, silts, carbonate content, porosity, permeability


