A system and method for downhole steam generation in ultra-deep heavy oil reservoirs

Abstract

The invention discloses a method for generating steam downhole in an ultra-deep heavy oil reservoir, and relates to the technical field of heavy oil exploitation. The system includes a horizontal well, the horizontal section of which is set at the bottom of the ultra-deep heavy oil layer, and an air injection pipe is arranged in the horizontal well; an injection vertical well is provided, and there are multiple injection vertical wells, and a fuel injection pipe is installed in the horizontal well. pipe, and the end of the injection vertical well is connected to the horizontal section of the horizontal well. The end of the injection vertical well is also equipped with a direct-fired downhole steam generator. When injecting, fuel is injected from the fuel injection pipe, and the fuel pipe and casing Water is injected into the annulus between them, and air enters the steam generator from the bottom of the vertical shaft to generate steam together. The invention designs a brand-new injection method of water, fuel and air, which significantly improves the injection efficiency and the amount of steam that can be generated downhole every day; at the same time, the invention can adjust water, fuel and air according to the development needs of different ultra-deep heavy oil reservoirs. The amount of fuel and air injected realizes timely regulation of the amount of steam generated.

Description

technical field [0001] The invention relates to the technical field of heavy oil recovery, in particular to a thermal recovery system and method for generating steam downhole in an ultra-deep heavy oil reservoir. Background technique [0002] Ultra-deep heavy oil reservoirs refer to heavy oil reservoirs with a burial depth exceeding 2,200 meters and crude oil viscosity greater than 50 mPa·s under formation conditions. For heavy oil reservoirs, due to the high viscosity and poor fluidity of heavy oil, only by reducing the viscosity of heavy oil and improving the fluidity of heavy oil can effective production be realized. [0003] Methods to reduce the viscosity of heavy oil include heating, blending thin oil, chemical viscosity reduction, etc. Among them, the thermal oil recovery method of heating heavy oil to reduce the viscosity of heavy oil is the most widely used. At present, methods for heating heavy oil include downhole electric heating, surface injection of high-tempe...

AI Technical Summary

Problems solved by technology

Therefore, this technology is not applicable in ultra-deep heavy oil reservoirs

[0007] In addition, for ultra-deep heavy oil, the existing method of generating steam by downhole steam generators has the following defects: First, the amount of steam generated every day is limited and the efficiency is low

When the amount of steam generated per day is too low, the heavy oil cannot be heated effectively, which is not conducive to the efficient development of heavy oil

Second, high safety risks such as corrosion

The reason is that there is water and air in the wellbore, which will easily cause corrosion to the wellbore and injection equipment, increase the production cost such as anti-corrosion investment, and reduce the safety of production at the same time

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