Displacement developing method for artificial foamed oil of heavy oil reservoir

Abstract

The invention provides a displacement developing method for artificial foamed oil of a heavy oil reservoir. The method comprises the following steps: adopting a vertical well or a horizontal well to displace a well pattern; injecting an oil soluble viscosity reducer and a solvent based foaming agent in an injection well repeatedly and alternatively, or injecting an oil-in-water emulsified viscosity reducer solution and a high oil-resisting foaming agent in an injection well repeatedly and alternatively, wherein during the injection process, a producing well produces continuously. With the adoption of the method, the purposes that the heavy oil reservoir mined through steam injection and the heavy oil reservoir difficulty produced by a conditional mining method can be effectively produced and developed, heavy oil is economically and efficiently developed and the recovery efficiency is improved greatly are achieved.

Description

technical field [0001] The invention relates to a mining method for heavy oil reservoirs, in particular to a mining method for artificial foam oil displacement in heavy oil reservoirs, and belongs to the technical field of petroleum mining. Background technique [0002] my country's heavy oil reservoirs are widely distributed in oilfields such as Xinjiang, Liaohe, and Shengli. The main mining technology is steam injection thermal mining technology. According to incomplete statistics, 70% of the proven reserves have been commercially developed. However, there are still some hard-to-recover heavy oil reserves. Due to their special reservoir conditions, the current conventional steam injection production technology is difficult to be effectively produced. [0003] (1) Heavy oil reservoirs refer to heavy oil reservoirs with a crude oil viscosity greater than 50,000 centipoise under reservoir conditions. Due to the high viscosity of underground crude oil in such heavy oil reservo...

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Problems solved by technology

However, there are still some hard-to-recover heavy oil reserves. Due to their special reservoir conditions, the current conventional steam injection production technology is difficult to effectively produce

[0003] (1) Heavy oil reservoirs refer to heavy oil reservoirs with a crude oil viscosity greater than 50,000 centipoise under reservoir conditions. Due to the high viscosity of underground crude oil in such heavy oil reservoirs, when steam injection is developed, the resistance of steam entering the oil layer is relatively low. large, resulting in a small effective radius of steam huff and puff, the effect of multiple rounds of huff and puff drops sharply, and the recovery rate of steam huff and puff is only about 10%; some heavy oil reservoirs have carried out steam flooding development tests, but due to the high viscosity of crude oil, the resistance is large , it is difficult to establish a driving pressure difference between the injection well and the production well, affected by the heterogeneity inside the oil layer, the injected steam front will rush forward along the strip with high permeability and low resistance, resulting in serious steam channeling , the steam swept volume is small, the recovery factor is low, less than 25%, the oil-steam ratio is low, and the economic benefit is poor

Steam-assisted gravity drainage (SAGD) tests have also been carried out in some heavy oil reservoirs. However, in a SAGD well group, the horizontal distance between the injection well and the production well is only 5 meters. The steam injected from the upper injection well will go down along the high-permeability layer to the horizontal section of the production well, resulting in a low production degree of the horizontal section, less than 50% on average, which seriously affects the production level, the production range of the oil layer and the recovery factor

[0004] (2) Deep and ultra-deep heavy oil reservoirs. Deep heavy oil reservoirs refer to heavy oil reservoirs whose burial depth is greater than 2000m. Because the burial depth of the reservoir is too deep and the heat loss along the steam injection is too large, conventional Steam injection development technology cannot be effectively developed at present

[0005] (3) Thin-layer heavy oil reservoirs refer to heavy oil reservoirs with continuous oil layers less than 5 meters in effective thickness. Due to the thin oil layers of such heavy oil reservoirs, during the steam injection development process, the heat loss of steam to the top and bottom cap layers is large , resulting in low oil-steam ratio and poor economic benefits, it is difficult to realize economical and efficient development of such reservoirs