SU1723314A1 - Method for thermal treatment of hydrocarbon pool - Google Patents

Abstract

The invention relates to the oil industry, in particular to methods for extracting high viscosity hydrocarbons. Chain - increasing the efficiency of the method when exposed to a reservoir containing high-viscosity or bituminous oil. For this purpose, injection is carried out into the reservoir. solvent or solvent mixture. At the same time, the formation is treated with a high-frequency electromagnetic field. After reaching the temperature at the bottom of the injection well, at which the oil viscosity does not exceed the viscosity of the solvent more than ten times, the treatment is stopped. 1 hp ff.

Description

The invention relates to the oil industry, in particular to methods for extracting high viscosity hydrocarbons.

Known methods for the development of hydrocarbon deposits, including the injection of mixing agents, such as solvents /:.

The disadvantage of these methods is their low efficiency in the development of deposits with highly viscous oils and bitumens due to the low mobility or immobility of the latter, due to their high viscosity, as a result of which the solvent breaks in the form of tongues to production wells and does not displace most of them. reservoir hydrocarbons.

There is also a known method of thermal exposure of deposits containing high-viscous oils and bitumens, in combination with the injection of any agent or without it (injection of hot water or steam, the creation of a source of combustion and various types of heating

reservoirs, usually through production wells to increase oil flow).

However, this method has a common drawback that inhibits their use: the heat loss is so great that the impact does not extend to more than the bottom hole areas.

Closest to the present invention is a method that pruduyuschem injection into the reservoir of a solvent or mixture of solvents in combination with thermal effects. At the bottom of the injection well, water is first pumped, and after it, the solvent is above its level. As a result, a two-layer fluid system is formed in the wellbore. After the introduction of metallic sodium into water, a chemical reaction occurs with the evolution of heat, which is used to heat the solvent. In this case, the latter serves as a diluting agent, and its preheating enhances the effect of reducing the viscosity of the oil.

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The disadvantage of this method is its low efficiency in carrying out an exothermic chemical reaction and the low recovery rate of hydrocarbons due to the need to simultaneously use water injection. In addition, the heat generated, localized by the downhole area, is quickly absorbed by the nnacja skeleton due to thermal conductivity, and some is immediately lost by the inevitable heating of the water and the wellbore. A less effective method is known for deposits containing high viscosity or bituminous oils.

The aim of the invention is to increase the efficiency of the heat treatment method for deposits containing high viscosity or bituminous oil.

The goal is achieved by the fact that in the method of thermal impact on the hydrocarbon reservoir, which involves the injection of a solvent or solvent mixture, simultaneously with the injection of the solvent, the formation is treated with a high-frequency electromagnetic field until the bottom hole of the injection well, at which the viscosity of the oil does not exceed solvent viscosity more than ten times. , /

This goal is also achieved in that the treatment with a high-frequency electromagnetic field is carried out cyclically after the temperature has decreased not lower than the formation one.

The method is carried out as follows.

In a hydrocarbon reservoir containing high-viscosity or bituminous oil, a high-frequency electromagnetic field is created by means of a radiator located in the injection well (or surface) in a wide frequency range from 500 kHz to 3 MHz. At the same time, a solvent is pumped into the well, which displaces hydrocarbons from the bottom of the well into the formation and mixes with them. As a result of exposure to the formation by extraction of electromagnetic energy, the formation is heated and the viscosity of the saturated hydrocarbon is reduced. The treatment of the high-frequency electromagnetic field is carried out until the bottom-hole temperature reaches a value at which the oil viscosity corresponds (becomes one order, i.e. does not exceed more than ten times) the viscosity of the solvents . This temperature value is determined previously by experiment or by calculation. Then the exposure to the RF electromagnetic field is stopped, continuing the injection of the solvent in volume,

necessary for complete recovery of oil from the reservoir. At the same time, the temperature at the bottom of the well becomes lower and when it drops to the reservoir, the treatment of the high-frequency field is resumed. The number of cycles depends on the volume of the solvent to be completed, which can later be replaced by another, cheaper agent, for example, associated petroleum gas.

Example 1. A reservoir containing high-viscosity oil with a viscosity at a reservoir temperature of 15 ° C within 710 PA s was subjected to a high-frequency electromagnetic (HF EM) effect in the 13.56 MHz frequency range by introducing HF EM energy into the reservoir through the injection well. The effective thickness of the layer is 6-8 m, the depth is 80-100 m, the porosity is 0.25, the permeability is 0.43. The power of the RF generator is 3060 kW. At the same time, a solvent was pumped into the well — a broad fraction of light hydrocarbons (CA Ce) with a viscosity of 2.3 MPa-s. Preliminary experiments have shown that a temperature of 120-125 ° C is required to reduce the viscosity of oil to 3-8 MPa.

EXAMPLE 2. Experimentally and by calculation, it was found that the most optimal volume (from the point of view of profitability at achieving a given efficiency) of the solvent for injection into the reservoir (see example 1) is 12-15% of the gross volume . The treatment with the high-frequency electromagnetic field was carried out before reaching the bottom hole temperature of 125 ° C. At the same time about one third of the planned volume of solvent was pumped. With further injection of the latter, the temperature at the bottom of the well decreased and after it fell to the initial reservoir (15 ° C), the treatment was restored. Just spent three such cycles. During this time, 1200 m of solvent was pumped into the formation, which amounted to 15% of the pore volume of the reservoir. After that, associated gas was injected into the formation until oil was completely removed. The recovery rate of hydrocarbons was 73%.

The use of the proposed method in comparison with the known ones will allow to increase the recovery rate of hydrocarbons by 10-12%, increase the coverage ratio of the reservoir by the displacing agent by equalizing the viscosity of the oil and solvent at the displacement front, after injection of 10-15% of the pore volume of the solvent, switch to displacement of more cheap agent, for example, associated petroleum gas or water.

In addition, the proposed method will maximize the use of thermal energy, including the heating of the solvent injected into the well, to develop in fields with slow-moving (and stationary at reservoir temperatures and recovered pressure drops) hydrocarbons due to the simultaneous effects of warming the reservoir and fluids and dissolving hydrocarbons at the extrusion front, significantly reduce the loss of heat introduced into the reservoir due to miscible displacement of the solvent and convective iffuzionnogo heat transfer.

Formula 1 of the invention 1. Method of thermal effect on a hydrocarbon reservoir, provided for

injection of a solvent or solvent mixture into the reservoir, characterized in that, in order to increase the efficiency of the process, when a reservoir containing high-viscosity or bituminous oil is applied, the reservoir is treated with a high-frequency electromagnetic field simultaneously with the injection of the solvent until the bottom hole temperature of the injection well is reached the viscosity of the oil does not exceed the viscosity of the solvent more than ten times.

2. The method of claim 1, wherein the processing with the high-frequency electromagnetic field is carried out cyclically after the temperature has decreased not lower than the formation one.

Claims (2)

Claim 1, A method of thermal exposure of a hydrocarbon deposit, which involves injecting a solvent or mixture of solvents into the formation, characterized in that, in order to increase the efficiency of the method when acting on a reservoir containing high-viscosity or bituminous oil, the formation is treated simultaneously with a high-frequency electromagnetic field until the temperature at the bottom of the injection well is reached, at which the viscosity of the oil does not exceed the viscosity of the solvent by more than ten times. 2. The method according to claim 1, with the fact that the treatment with a high-frequency electromagnetic field is carried out cyclically after lowering the temperature not below the reservoir.