Waterflooding swallowing-spitting method for double fracturing horizontal wells through zipper-type crack distributing

Abstract

The invention relates to a waterflooding swallowing-spitting method for double fracturing horizontal wells through zipper-type crack distributing. The waterflooding swallowing-spitting method comprises the following steps that in an initial production stage, the two horizontal wells are simultaneously exploited for a period of time through natural energy; in the horizontal well I, a waterflooding control unit I corresponding to an odd stage crack is started, water is injected into an oil pipe I, the injected water enters the odd stage crack, meanwhile in the horizontal well II, a waterflooding control unit II corresponding to an even stage crack is started, water is injected into an oil pipe III, and the injected water enters the even stage crack; well openings of the two horizontal wells are simultaneously closed to stew the wells, and crude oil and the injected water are imbibed and replaced; and the well openings of the two horizontal wells are simultaneously opened to extract the oil, in the horizontal well I, an oil extracting control unit I corresponding to the even stage crack is opened, the crude oil is extracted out of the even stage crack, in the horizontal well II, an oil extracting control unit II corresponding to the odd stage crack is opened, and the crude oil is extracted out of the add stage crack. The waterflooding and extracting method can effectively displace residual oil between the wells, between the cracks and in a dead oil area, and the swept volume is improved.

Description

technical field [0001] The invention belongs to the technical field of oil and gas reservoir development, and in particular relates to a water injection huff and puff oil production method for double fracturing horizontal wells with zipper type fractures. Background technique [0002] In recent years, due to the drastic reduction in the recoverable resources of conventional oil and gas, the exploration and development of unconventional oil and gas has become a new focus, and tight oil is one of them. Tight oil reservoirs are usually developed by depletion at the initial stage of development, but the natural energy of tight oil reservoirs in my country is generally insufficient, and the depletion recovery method alone will cause a rapid drop in reservoir pressure and a rapid decline in production, so energy supplementation is required after a period of development , such as water injection development, etc. [0003] Due to the low porosity and permeability of tight reservoirs...

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Problems solved by technology

[0003] Due to the low porosity and permeability of tight reservoirs, poor formation connectivity, large seepage resistance, and high heterogeneity, a series of problems may occur when using conventional water injection methods and injection-production well patterns: the injection pressure of water injection wells Usually large, injection is difficult; water channeling is easy to form; and because the seepage resistance of the formation is relatively large, and the flow capacity of the injected water in the formation is poor, resulting in a relatively small swept volume and a relatively limited increase in production of a single well, etc.

Although this invention patent can increase the oil recovery rate, due to the single-well injection and production, for oil and gas reservoirs with a large oil layer area, the swept volume, sweep efficiency and recovery degree will be limited, thereby reducing the oil recovery. Realize the displacement of the dead oil zone in the formation

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