ANALYSIS OF THE EFFECTIVENESS OF STEAM TREATMENT DURING CYCLIC STEAM SIMULATED

Vollständiger Abstract

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Cyclic steam simulated (CSS) is the most common technology of thermal impacton the formation of high-viscosity oil. The CSS technology is the injection of steam into a well, followed by the soaking stage (stopping the injection of steam to condense), followed by switching to the operating mode of the producing well. After the production wells are put into operation, production is carried out to a certain level of water cut floating oil or a cost-effective flow rate. The duration of the effect of the CSS can be both long and relatively short due to possible complications caused by the geological and physical parameters of the developed high-viscosity oil deposit or the technical condition of the production wells.When performing CSS, the same processes occur in the formation as when using areal steam injection or steam assisted gravity drainage. A distinctive feature of CSS in comparison with other thermal methods of increasing oil recovery of highly viscous oils is capillary soaking due to the stage of condensation of the steam. During steam condensation, the heated oil in the reservoir is redistributed from less permeable zones (pores, matrix) to more permeable ones (cracks, cavities, highly permeable layers). During the soaking stage, the heated zone cools down, leading to a decrease in the volume of the coolant and its «steam-hot water» phase transition. The pressure drop that occurs during the phase transition is an additional factor in the flow of oil to the well.At all stages of the CSS, field and geophysical studies are conducted aimed at evaluating the effectiveness of steam injection during reservoir heating and determining the current permeability reservoir at the stage of oil-containing liquid production. The paper presents the results of geophysical studies of wells in the permo-carbon deposit of the Usinsk field at the stage of steam injection stage. According to the analysis of the research results, additional factors have been found that may reduce the efficiency of the CSS in the conditions of the development of a fractured-pore reservoir. A comprehensive analysis of the results of geophysical studies of wells with an assessment of the relative pickup profile of the steam at the permo-carbon deposit development sites has been carried out.