Published May 2010
Reservoir properties of sediments in Alat-deniz field
L.A.SultanovOne of the principal properties characterizing exploitation of oil-gas deposit is porosity and permeability of reservoir bed. Series of factors influence the reservoir porosity and permeability. One of these factors is gradation composition of rock. As a rule porosity and permeability of clayey rock terrigene sediments is comparatively less than porosity and permeability of homogeneous pure sand reservoir. In the article is investigated alteration by area and section porosity and permeability of bed reservoirs in Alat-deniz field. Alat-deniz field is situated in the north-west of Baku archipelago. This deposit as a structure is discovered as a result of mapping-drilling work from the middle of the last century, later it has been studied via seismic exploration, structural and deep exploration drilling. Principal exploration object – VII horizon by lithology it is presented alteration of sand, sandstone and shale. General thickness of horizon in separate tectonic blocks change within 80-120 m. Average by VII horizon porosity of reservoirs change within 14-20%, permeability 100-800∙10-3 mkm2, carbonate 14-15% and clayiness 22-24%. With aim investigation of alteration by area porosity and permeability of VII horizon of Alat-deniz field it is used core and well-logging materials. For this purpose were collected and analyzed materials conducted with production investigation in drilling wells in given area. In every well it is selected beds distinguished by reservoir characteristics, it is determined their porosity, permeability and clayiness. After this for each well was determined average value indicated parameters and constructed map of distribution by area indicated parameters. It is marked increase of porosity and permeability from north-west to south-east which connected with alteration lithological composition. In comparison core and well-logging materials was determined accordance between them. Taking into account this in interval where volume of materials by core is insufficiently dimension of porosity is determined according to well-logging materials. Estimation of permeability is conducted in the basis of correlated connection. In construction diagrams according to dependence of porosity and permeability from depth investigated sedimentary rock is divided into two groups: prevailing fine grained fraction argillo-aleurite sediments and prevailing coarse-grained fraction sandy-psammitic sediments. Analysis of alteration porosity and permeability of reservoirs in lateral and vertical direction in Alat-deniz area show that these parameters change by area and also by section. At a time in different tectonic blocks dimensions of porosity and permeability distinguish from each other. In greater depth, 5500-6000 m interval is observed preservation of reservoir property of rock. In south-west direction in spite of depth increase reservoir property of VII horizon rock improve. Recent years results of conducted exploration-drilling and geophysical exploration work in Alat-deniz area and in its neighborhood show that there is sufficiently hydrocarbon reserve.
