Method for using combustion and vapor combination flooding to exploit thick oil

Abstract

The invention discloses a method for using combustion and stream combination flooding to exploit thick oil. The method comprises the following steps of: carrying out vapor huff and puff exploitation in a heavy crude oil reservoir; carrying out in-situ combustion exploitation after forming thermal linkage; and changing single air charging to be simultaneous charging of air and water vapor in certain proportion to carry out combination flooding exploitation. A proper optimal configuration relationship of air / vapour charging speed is selected, so as to improve combustion wave and volume of the oil reservoir and improve exploitation effects of in-situ combustion and the ultimate recovery factor.

Description

technical field [0001] The invention relates to a technology for enhancing oil recovery of heavy oil reservoirs, which is applicable to a method for enhancing oil recovery by burning oil layers in heavy oil reservoirs, and specifically relates to a method for exploiting heavy oil by combining burning and steam flooding Methods. Background technique [0002] my country's heavy oil reservoirs have the characteristics of continental deposits, with serious heterogeneity, complex geological structures, multiple types of reservoirs, and deep burial of reservoirs. Heavy oil reserves with a reservoir depth greater than 800m account for more than 80% of the proven reserves, and about half of the reservoirs are buried at a depth of 1300-1700m. At present, it has entered the late stage of steam stimulation development, and is in the stage of low production and low efficiency. It is urgent to change the development method. [0003] Steam flooding refers to injecting steam into one or ...

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Problems solved by technology

[0006] (1) The implementation process of forward dry combustion is very difficult. From the combustion front (fire line) to the production well, the temperature gradient is large, and effective thermal communication cannot be formed, so it is difficult to control underground combustion

[0007] (2) The combustion front (line of fire) is a narrow high-temperature area, and the driven fluid must flow to the production well through the low-temperature area of ​​the reservoir. The viscosity of crude oil is high, especially for extra-heavy crude oil, which may cause fluid blockage

[0008](3) As the combustion front (line of fire) advances, the gas injection pressure and gas injection volume must be gradually increased, resulting in severe gas channeling, which is manifested as gas channeling in the vertical direction Overlapping, uneven sweeping on the plane, reducing the sweeping volume, seriously affecting the development effect

This technology is to generate a high-temperature area above 400°C by burning oil formation slugs after steam huff and puff. The injected steam is heated through the high-temperature area to increase the dryness of the injected steam. However, with the subsequent steam injection, the temperature in the high-temperature area will drop. To be consistent with the temperature of the injected steam, the high dryness of the steam in the steam flooding process cannot be guaranteed

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