Oil extracting method adopting air pre-injecting

Abstract

The invention discloses an oil extracting method adopting air pre-injecting. The method comprises the following steps that a first model used for determining the largest steam-injection volume is built according to the energy balance principle that down hole injected energy is the sum of top-bottom cap rock lost energy and increased energy of an oil layer; a second model used for determining the minimum steam-injection volume is built through the displacement difference between oil and water when thickened oil is flooded by the air under the condition that thickened oil movement is ignored; the model corresponding to oil reservoir exploitation is determined on the basis of obtained designated oil reservoir parameters which comprise the porosity, the permeability, the oil layer thickness and the formation temperature; the obtained oil reservoir parameters are substituted into the determined model, and the needed air pre-injecting quantity is obtained under the standard condition; air is injected into the oil layer at a first preset speed; and after the needed air pre-injecting quantity is achieved, an igniter is dropped to a designated position to conduct igniting. According to the oil extracting method adopting air injecting, fireflood exploiting can be effectively applied to the field of thickened oil reservoirs, so that a thickened oil reservoir, in a water logging state, of a main oil-producing layer is effectively exploited.

Description

technical field [0001] The invention relates to the field of heavy oil production, in particular to an oil recovery method with air pre-injection. Background technique [0002] Heavy oil refers to high-viscosity heavy crude oil with a viscosity greater than 100 mPa.s (milliPa.s) under formation temperature and degassed conditions. According to the size of the viscosity, it can be divided into ordinary heavy oil (100 to 10000mPa.s), extra heavy oil (10000 to 50000mPa.s) and super heavy oil (greater than 50000mPa.s). In the oil extraction of oil fields, due to the special characteristics of high viscosity and high freezing point of heavy oil, the fluidity in the reservoir and the wellbore is poor, and the recovery rate of conventional extraction is low, that is, the normal economic output cannot be guaranteed. In order to ensure a reasonable recovery rate, oil is often recovered by reducing the viscosity of crude oil. [0003] Heavy oil recovery technologies in the prior art...

AI Technical Summary

Problems solved by technology

However, in the above-mentioned method, multiple rounds of production are performed by using steam huff and puff first, and the original main oil-producing layers are mostly in water flooding.

At this time, if an electric igniter is installed for fire-flooding mining, the hot air will heat a large amount of water, which cannot achieve the ideal fire-flooding mining effect

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