Unconventional oil reservoir recovery ratio increasing method and system

Abstract

The invention discloses an unconventional oil reservoir recovery ratio increasing method and system. The method comprises the steps of deploying horizontal well rows in the middle of an unconventionaloil reservoir in the direction of the maximum principal stress, and carrying out the reservoir reconstruction of the horizontal well rows to obtain a fractured horizontal well group as a production well; deploying a horizontal well between the horizontal well rows in the direction perpendicular to the production well at the upper part of the unconventional oil reservoir as a gas injection well; deploying a vertical well at the root of the fractured horizontal well group as a water injection well, wherein the perforation position of the water injection well is positioned at the lower part of the unconventional oil reservoir; and after one-time production of the production well is finished, gas injection of the gas injection well and water injection of the water injection well are conductedsimultaneously, and the production well conducts production simultaneously. According to the method and system, by the adoption of the modes of gas injection from the top, water injection from the bottom and oil extraction from the middle, the longitudinal swept volume can be effectively increased, water injection and gas injection are combined, the advantages of two displacement media can be effectively played, gas injection and water injection complement each other and do not interfere with each other, and the recovery ratio can be increased.

Description

technical field [0001] The invention relates to the technical field of oil field development, in particular to a method and a system for increasing the recovery rate of unconventional oil reservoirs. Background technique [0002] This section is intended to provide a background or context to embodiments of the invention that are recited in the claims. The descriptions herein are not admitted to be prior art by inclusion in this section. [0003] my country is rich in unconventional resources such as shale oil and tight oil, but due to low matrix permeability, poor flow capacity, and small drainage radius, volume fracturing formed by long horizontal wells and large-scale hydraulic fracturing techniques can be formed near the wellbore In the volume fracturing stimulation area, the oil drainage area is greatly increased and the seepage resistance is greatly reduced. It has become the main production capacity construction method of this type of reservoir. And the characteristics...

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Problems solved by technology

[0005] The embodiment of the present invention provides a method for improving the recovery of unconventional oil reservoirs, which is used to solve the problems in the prior art that the unconventional oil and gas reservoir horizontal wells have a fast fracturing production decline, low recovery, and easy channeling in traditional energy supplement methods. technical issues, the method includes:

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