Steam assisted gravity drainage method

Abstract

The invention provides a steam assisted gravity drainage method. The steam assisted gravity drainage method includes the following steps: a first step, arranging a first well and a second well, wherein the first well is a horizontal well, and the second well is a vertical well; a second step, performing steam injection and oil extraction, wherein steam injection is performed on the first well, and oil extraction is performed on the second well; a third step, performing supplementary reversed steam injection and oil extraction, perforating an upper part of an oil layer of the second well, putting a dual-pipe well structure in the second well, setting a supplementary steam injection point on the upper part of the oil layer, and setting an oil extraction point on a lower part of the oil layer, wherein the supplementary steam injection point and the oil extraction point are separated from each other by an isolator, continuous steam injection is performed on the second well, and oil extraction is performed on the second well and the first well. The steam assisted gravity drainage method can improve the efficiency and the quality.

Description

technical field [0001] The invention relates to the field of petroleum drilling, in particular to a method for steam-assisted gravity drainage. Background technique [0002] The current Steam Assisted Gravity Drainage (SAGD) technology is mainly used in the completion of two parallel horizontal wells. The upper horizontal well injects steam and the lower horizontal well produces oil. Due to the heterogeneity of the oil layer, the distance between the two horizontal wells Recently, the temperature of the produced fluid is high, the oil-steam ratio is low, and the energy loss is large. In order to solve the problems in the SAGD process, some SAGD variants have appeared one after another. For example, drill a horizontal well in the lower part of the oil layer, and drill several vertical wells to inject steam in the upper part of the horizontal section. In this way, the horizontal well produces oil and the vertical well injects steam; A horizontal well is drilled between two ve...

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Problems solved by technology

[0003] 1. Double horizontal wells, two parallel wells with an interval of 5-10m, steam injection in the upper well and oil production in the lower well. Due to the heterogeneity of the oil layer, the temperature of the produced fluid is high, the oil-steam ratio is low, and the energy consumption is large. Pressure control technology It is relatively complicated, and its subsequent production fluid treatment technology is also relatively complicated, but the injection and production are continuous operations, and the process management is relatively simple;

[0004] 2. Drill a horizontal well in the lower part of the oil layer, and drill several vertical wells to inject steam in the upper part of the horizontal section. In this way, the horizontal well produces oil and the vertical well injects steam. This process can control the steam injection volume and steam injection pressure of each vertical well to a certain extent. Overcome the difficulties brought about by the heterogeneity of the oil layer, but the lifting in horizontal wells is more complicated, and at the same time, it is more complicated for one lifting well to control the pressure of multiple steam injection wells;

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