Mining method for heavy oil reservoir and well network thereof

Abstract

The invention relates to a mining method for a heavy oil reservoir and a well network used in the same. The mining method comprises a well network arrangement stage, a preheating stage, a gravity fire flooding stage and a steam flooding stage; the gravity fire flooding stage comprises an ignition stage and a fire wire propulsion stage. The well network comprises a plurality of mining well groups. Each mining well group comprises a horizontal well, a middle vertical well and a plurality of side vertical wells, wherein the plurality of side vertical wells are arranged in two lines; the first line of the side vertical wells and the second line of the side vertical wells are symmetrical about the horizontal well; each line of side vertical wells are arranged at intervals in the direction from the tiptoe to the heel of the horizontal well and are in parallel to the horizontal well. According to the invention, combination of gravity fire flooding and steam flooding is adopted, so that utilization of heat after fire flooding is improved; thermal communication of injection and production wells is established by steam huff and puff auxiliary gravity fire flooding, so that a steam flooring mining effect is improved; well completion cost and drilling cost are reduced.

Description

technical field [0001] The invention relates to a mining method of a heavy oil reservoir and a well pattern used in the mining method. Background technique [0002] In the production technology of heavy oil, the thermal recovery method of gravity fire flooding belongs to the cutting-edge technology, and the recovery method of gravity fire flooding is an oil recovery method that uses fire flooding to achieve the purpose of gravity drainage. That is, the vertical well is located at the toe position of the horizontal well, and air is injected into the vertical well, and the oil layer is heated through the advance of the fire line, and the crude oil is released into the horizontal well for production. However, it was found during gravity fire flooding that even if side wells are provided to pull the fire line by discharging exhaust gas, the lateral sweep range of the front edge of the fire line is very narrow. If the wells are densely arranged, there will be two problems. One i...

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Problems solved by technology

However, during the operation process, the thermal communication between injection and production wells has not been established, and the steam stimulation development method has reached the limit of economic development (the operating cost of steam injection is greater than the income of heavy oil production), so it is transferred to steam flooding in advance. Production wells have not yet established heat communication. During steam flooding, the heat conduction speed is slow. In addition to steam overburden, the water content of production wells rises rapidly, which greatly shortens the life of steam flooding.

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