A method for artificial foam oil huff and puff recovery in heavy oil reservoirs

Abstract

The invention provides an artificial foaming-oil huff and puff oil production method for a heavy oil reservoir. The method comprises the following steps: filling aqueous solution of foaming oil accelerant and nitrogen into the heavy oil reservoir, wherein the foaming oil accelerant comprises a foaming oil accelerant A, a foaming oil accelerant B and a foaming oil accelerant C of which the mass ratio is 1:1:1; soaking for 1 to 5 days; opening a well to produce oil in a certain production differential pressure range and stopping producing oil when the single-well daily oil production reaches single-well economic limit; repeating the step 1 to the step 3 and stopping production until the single-well cyclic oil production reaches cyclic economic limit, wherein the heavy oil reservoir has a reservoir thickness of over 2m, reservoir permeability of over 10*10<-3> mu<m2>, a reservoir temperature of lower than 120 DEG C, viscosity of crude oil of over 50mPas, oil saturation of over 30 percent and water saturation of over 50 percent. According to the artificial foaming-oil huff and puff oil production method for the heavy oil reservoir, which is provided by the invention, the viscosity of crude oil can be reduced and elastic energy of fluid can be increased so as to increase single-well productivity and a recovery ratio of an oil field.

Description

technical field [0001] The invention relates to an oil recovery method for heavy oil reservoirs, in particular to a huff and puff oil recovery method for artificial foam oil in heavy oil reservoirs, and belongs to the technical field of petroleum exploitation. Background technique [0002] Domestically proven reserves of heavy oil (usually referring to crude oil with a viscosity exceeding 50 mPa·s under formation conditions) have reached 1.3 billion tons, accounting for about 25wt%-30wt% of the total domestic oil reserves. However, due to the high density, high viscosity and poor fluidity of heavy oil, the development effect of conventional water flooding is poor. The key to heavy oil production is to reduce viscosity and improve its rheology. [0003] At present, the commonly used methods for viscous reduction of heavy oil are: heating, diluting, modifying and emulsification. Heating to reduce viscosity is the most commonly used method, but this method has high energy cons...

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Problems solved by technology

However, this technology is only designed for the surfactant huff and puff oil recovery scheme for thin oil reservoirs after water flooding, without nitrogen injection, so its production stimulation effect is limited to the oil washing and plugging removal characteristics of surfactants, and there is no nitrogen in supplementing formation pressure Moreover, this technology cannot achieve the advantage of improving the rheology of crude oil due to the formation of foam oil when it is implemented in thin oil reservoirs

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