Low pressure dense oil reservoir supplementary energy fracturing method

Abstract

The invention discloses a low pressure dense oil reservoir supplementary energy fracturing method. The low pressure dense oil reservoir supplementary energy fracturing method comprises the following steps that a plurality of long horizontal wells are deployed in a low pressure dense oil reservoir, long horizontal well shafts are parallel one another, the long horizontal well shafts are perpendicular to the direction of the maximum principal stress of the formation; each long horizontal well is laid through close cutting precision fracturing; through full three-dimensional fracturing software simulation, the amount of ground-entering fluid required for fracturing fractures to completely cover spaces between all long horizontal wells and spaces between sections of each long horizontal well segment is obtained; supplementary ground-entering fluid required when the formation pressure in the range of long horizontal well reaches a preset multiple of the original formation pressure is calculated; and all the long horizontal wells are fractured according to the amount of ground fluid and the supplementary ground fluid. According to the low pressure dense oil reservoir supplementary energyfracturing method, the production decline of the low-pressure dense oil reservoir can be slowed down, the stable production period is prolonged, the recovery degree is improved, and the cumulative production of a single well in a whole life cycle of a single well is increased.

Description

technical field [0001] The invention belongs to the field of oil and gas field exploration and development, and relates to a method for replenishing energy fracturing of low-pressure tight oil reservoirs. Background technique [0002] At present, low-pressure tight oil reservoirs are mainly developed by quasi-natural energy in horizontal wells or by water injection in vertical wells and oil recovery in horizontal wells. [0003] However, under the condition of quasi-natural energy development after volume fracturing in horizontal wells, the initial production is high, but due to lack of energy supplement, the production declines greatly, with an annual decline rate of about 40%, and the final recovery rate generally does not exceed 25%. Under the condition of oil production and development of horizontal wells, although the formation energy has been replenished, the injected water expands radially, the sweep area is limited, the remaining oil area is large, and the horizontal...

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Problems solved by technology

[0003] However, under the condition of quasi-natural energy development after volume fracturing in horizontal wells, the initial production is high, but due to lack of energy supplement, the production declines greatly, with an annual decline rate of about 40%, and the final recovery rate generally does not exceed 25%. Under the condition of oil production and development of horizontal wells, although the formation energy has been replenished, the injected water expands radially, the sweep area is limited, the remaining oil area is large, and the horizontal wells are easy to see water, resulting in high water cut and even violent water flooding. The degree of extraction is only about 30%

It can be seen that the annual decline rate of these two oil recovery development methods is high and the cumulative oil production is low

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