Method for achieving interval waterflood swallowing-spitting oil exploitation among multi-stage fracturing horizontal well fractures

Abstract

The invention relates to a method for achieving interval waterflood swallowing-spitting oil exploitation among multi-stage fracturing horizontal well fractures.The method comprises the following steps that staged fracturing is performed on a horizontal well shaft to form multiple fracturing fractures perpendicular to the horizontal well shaft; a one-way valve is arranged at the position of each odd-stage fracture, and an injection allocation valve is arranged at the position of each even-stage fracture; exploitation is performed through natural energy for a period of time, then waterflood swallowing-spitting through the interval fractures, the one-way valves are automatically switched off, the injection allocation valves are automatically switched on, water is injected into an annular space of an oil jacket for displacement, and the injected water enters the even-stage fractures; the well is opened for oil exploitation after being shut for soaking, the one-way valves are automatically switched on, crude oil is output from the odd-stage fractures and enters an oil pipe, and a mixture of the displaced crude oil and the injected water is output from the even-stage fractures, enters the annular space of the oil jacket and then enters the oil pipe to be output.According to the method, the yield of the oil well is increased, the operation cost is reduced, and the wide application prospect is achieved.

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 at intervals between multistage fracturing horizontal well fractures. Background technique [0002] Multi-stage fracturing horizontal wells are generally used to stimulate production in low-permeability and tight oil reservoirs. However, the formation pressure of such wells generally drops rapidly after being exploited with natural energy for a period of time, and effective energy supplementation must be carried out for them. The conventional well pattern for supplementing energy is vertical well water injection and multi-stage fracturing horizontal well oil production. Vertical wells are arranged around the horizontal wells, and the injected water is easy to rush along the fractures, leading to early water breakthrough in some fractures, resulting in water flooding of horizontal wells and ...

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Problems solved by technology

This technical solution is relatively complicated. In a horizontal well, only three fractures can be injected with water and oil produced at a time. After these three fractures have completed water injection and oil production, the other three adjacent fractures can be injected with water and produced oil. It can be seen that there are many production processes. The production efficiency is low; moreover, water can only be injected from the crack in the middle, and oil is produced from the cracks on both sides adjacent to it. The cracks in the middle cannot produce oil at the same time, so all the cracks are not used to produce oil, and the oil production needs to be improved; In addition, this technical solution cannot quantitatively evaluate the total oil production and the oil production of each fracture

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