Exploitation method of horizontal SAGD well pair and SAGD oil well system

Abstract

The invention discloses an exploitation method of a horizontal SAGD well pair and a SAGD oil well system. The exploitation method includes following steps: injecting gas into a gas injection well of the horizontal SAGD well pair; when a steam cavity ascends to the top of an oil layer and enters a transverse expansion stage, connecting high-voltage high-frequency alternating current to a conductive cable arranged in a U-shaped horizontal well to heat the oil layer, wherein a horizontal section of the U-shaped horizontal well is arranged between two adjacent horizontal SAGD well pairs or arranged in one horizontal SAGD well pair; according to transverse expansion parameters of the SAGD steam cavity, adjusting the alternating current, and continuing heating the oil layer; when the SAGD steam cavity descends to a preset height, disconnecting the conductive cable in the U-shaped horizontal well so as to stop heating the oil layer. The exploitation method further increase recovery ratio and has economic benefit obviously better than common steam injection SAGD.

Description

technical field [0001] The invention relates to the field of oil reservoir exploitation, in particular to a method for exploiting a horizontal SAGD well pair and a SAGD oil well system. Background technique [0002] Steam-assisted gravity drainage technology (abbreviation: SAGD) was invented by Canada's Buter in 1978, and has been successfully applied in heavy oil reservoirs in Canada's oil sands mining area, my country's Liaohe Oilfield, Xinjiang Oilfield and other places. [0003] The principle of SAGD is to deploy upper and lower horizontal well pairs in the same oil layer, inject high-dryness steam into the upper steam injection well, and the steam will overlap upwards in the formation to form a steam cavity because the density is much lower than that of crude oil. After injection, the steam chamber expands upwards and laterally, and exchanges heat with the crude oil in the oil layer. The viscosity of the heated crude oil is reduced, and the condensed water flows downwa...

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Problems solved by technology

[0004] However, since the heavy oil reservoirs in my country belong to the sedimentary environment of fluvial facies, and the reservoir heterogeneity is strong, in the development process of steam-assisted gravity drainage technology, when the well spacing between adjacent SAGD well pairs is large, The heterogeneity between wells often varies greatly, or there are discontinuously distributed interlayers, which prevent the uniform expansion of the steam chamber, and it is difficult for the injected steam to effectively reach and utilize the reserves in the middle between adjacent well pairs; and because The well spacing is large, the flow path of crude oil in the middle position to the production well is too long, and the flow resistance is too large, which affects the effective production of the oil layer at this position to a certain extent, resulting in low recovery under the condition of large well spacing SAGD, economical Poor benefit

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