Phase Transitions in the Preparation of Oil Extracted from Oil Rims

Abstract

Abstract Most of the undeveloped reserves in Russia are hard to recover (TRIZ) and are poorly understood (over 65% of undeveloped reserves are classified as C2 reserves) [1]. Hard-to-recover reserves (TRIZ) – reserves of deposits (fields, objects of development) or parts of the Deposit, characterized by relatively unfavorable geological conditions for the extraction of oil and (or) its physical properties, the development of which by existing technologies in the current tax system is economically inefficient [2]. Hard-to-recover reserves include: Deposits with high-viscosity oils;Depleted (depleted) deposits;Thin oil rims;Deposits which are remote from the infrastructure;Deposits with low-permeability reservoirs;Unconventional reserves: Bazhenov, Abalak, Hadum and domanik formation;Gas hydrate deposits. The main feature of the oil rims is a small reservoir capacity: from 2-3 to 15 m above the oil layer located a much bigger gas cap, which is in a hydrodynamic connection with the oil. The development of these deposits is due to the following characteristics: –full hydrodynamic connection of the oil layer with the gas cap and the aquifer and mobility of oil and gas and water contacts in the development of the Deposit;–uniform distribution of reservoir energy over the oil and gas area, equal to the initial reservoir pressure and oil saturation pressure;–relatively close location to the faces of oil and gas wells and water-oil contacts in the drainage of oil rims;–instability of the process of oil displacement by gas, leading to a rapid gas breakthrough to the bottoms of production wells, increase of the gas factor of the produced fluid and ultimately to a significant loss of reservoir energy and a decrease in oil recovery;–the possibility of retrograde condensation due to the pressure reduction in the gas-saturated zone of the formation, which predetermines the formation losses of condensate;–maintaining reservoir pressure (PPD) is ineffective and is not able to keep the gas cap in its original position. As a result, oil recovery does not exceed 10% of the initial reserves [3].