Method for mining remaining oil in bottom water heavy oil reservoir through non-condensate gas injecting or in-situ combustion

Abstract

The invention discloses a method for mining remaining oil in a bottom water heavy oil reservoir through non-condensate gas injecting or in-situ combustion. The method comprises the following steps: a new horizontal well is drilled in an oil layer between an existing horizontal production well position and a bottom water layer; the new horizontal well is preheated; after the horizontal section of the horizontal well and an upper steam cavity are in heat communication, steam is injected into the horizontal well, and the horizontal well is converted into a continuous production well; then a vertical well is drilled in an unexploited reservoir area; an oil layer between the vertical well and the horizontal well forms flow communication, and air or oxygen is injected into the vertical well; and gas injection is stopped at the later stage of the horizontal well, and the pressure of the steam cavity is gradually decreased till oil mining is completed. The remaining oil near the lower part and the toe tip of an original horizontal well is mined, and thus the ultimate recovery factor of the reservoir is greatly increased.

Description

technical field [0001] The invention relates to a method for exploiting remaining oil in heavy oil reservoirs with bottom water by injecting non-condensable gas or burning in situ. Background technique [0002] Heavy oil reservoirs with bottom water are very common. Currently, most of the oil reservoirs in Liaohe Oilfield that have thermal recovery by steam injection have medium-deep bottom water (such as figure 1 shown) oil reservoir. The earthy red in the picture is the oil layer, and the blue part is the water layer. In these reservoirs, vertical well steam huff and puff development is mainly used. Some reservoirs are also converted to steam flooding or steam assisted gravity drainage (SAGD) production in the later stage of steam huff and puff. Steam huff and puff relies on the steam injected near the wellbore to heat the oil layer, reduce the viscosity of crude oil, and then lift the mixture of crude oil and steam condensate to the surface. When the temperature of th...

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Problems solved by technology

Once the bottom water breaks through to the production layer, the thermal efficiency of steam injection production will be greatly reduced, and in severe cases, production wells will be shut down, and the development efficiency of the entire reservoir will be affected

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