Low-permeability oil reservoir non-mixed-phase gas-water alternate injection and fluctuation depressurization augmented injection device and method

Abstract

The invention discloses a low-permeability oil reservoir non-mixed-phase gas-water alternate injection and fluctuation depressurization augmented injection device and method. The device mainly comprises a gas-liquid injection device on the ground and a gas-water alternate injection and fluctuation depressurization augmented injection device in a downhole. The gas-liquid injection device mainly comprises a low-temperature high-pressure liquid storage tank, a liquid distribution tank and a plunger pump on the ground. The gas-water alternate injection and fluctuation depressurization augmented injection device comprises a mixed fluid acceleration inlet segment, a collision body, a shell and a mixed fluid outlet segment. According to the device, the effects of the elasticity modulus difference and gravitational differentiation of gas and liquid are utilized to achieve mutual conversion between gas-water alternate injection, injected liquid fluctuation depressurization augmented injection and non-mixed-phase gas bubble anti-channeling functions, and therefore injection efficiency is enhanced, and the phenomenon of gas channeling is eliminated. The device is simple in structure, the construction method is simple, and operation cost is low; the operation process can be adjusted in real time according to injection pressure, the effect of gas (liquid) absorption is effectively improved, and the production efficiency of the low-permeability oil reservoir non-mixed-phase gas drive is substantially enhanced.

Description

technical field [0001] The invention relates to the technical field of oil and gas field development engineering, in particular to the process of low-permeability reservoir immiscible gas-water cross-injection fluctuating pressure-reducing and increasing-injection process, which is a principle of utilizing the difference in elastic modulus of gas and liquid fluids and gravity differentiation , A device and method for realizing the mutual conversion of gas-water cross-injection, liquid injection fluctuating depressurization and increasing injection, and immiscible gas-foam anti-channeling in the process of immiscible gas flooding in low-permeability reservoirs. Background technique [0002] Immiscible gas flooding is an effective and widely used development technology for enhancing oil recovery in low permeability oilfields. However, due to the large differences in the pore-throat structure characteristics of low-permeability reservoirs, mainly fine pores and thin throats, an...

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Problems solved by technology

[0004] However, immiscible gas-water injection in low-permeability reservoirs will also face the following problems: on the one hand, the low-permeability reservoirs have high gas injection pressure or high water injection pressure in the early stage of production; Channeling” phenomenon, these problems make it difficult to achieve the ideal development effect in the development of immiscible gas-water alternate injection

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