Nitrogen-assisted carbon dioxide fracturing and developing integrated method for shale oil reservoir

Abstract

The invention discloses a nitrogen-assisted carbon dioxide fracturing and developing integrated method for a shale oil reservoir. The nitrogen-assisted carbon dioxide fracturing and developing integrated method comprises the steps that nitrogen-assisted carbon dioxide is used for conducting fracturing operation on a target shale oil reservoir; after the fracturing operation is completed, carbon dioxide gas is injected into the target shale oil reservoir, and nitrogen gas is subsequently injected into the target shale oil reservoir for pushing the carbon dioxide gas into the deep part of the oil reservoir; soaking operation is conducted on the target shale oil reservoir; after well soaking is finished, the well is opened to implement depletion production; production is conducted in a firstperiod; and in the subsequent production process, the volume of an injected gas slug and the soaking time are 1.5 times those of the previous period, and the operation of the step 5 to the step 7 is repeated in each period. According to the method, the recovery ratio of the shale oil reservoir is increased to the maximum extent; the carbon dioxide gas is utilized to the maximum extent, so that thedevelopment of the shale oil reservoir is more economical and efficient; and fracturing and development are integrally designed, so that field operation is processized and standardized, and differentdepartments can establish closer cooperation.

Description

technical field [0001] The invention relates to the technical field of shale oil reservoir exploitation, in particular to an integrated method for nitrogen-assisted carbon dioxide fracturing and development of shale oil reservoirs. Background technique [0002] my country has huge shale oil reserves, and the efficient development of this part of crude oil will become an important guarantee to meet the energy demand of my country's economic development. The reserves of shale oil resources are huge, and the development and utilization of such resources is the key to solving my country's energy crisis. However, due to the extremely low permeability of shale reservoirs, accompanied by a certain degree of water sensitivity, the conventional development method (water injection development) of this type of crude oil is not applicable (water injection cannot enter, and the injected water damages the formation). In order to improve the development of shale oil, the commonly used met...

AI Technical Summary

Problems solved by technology

Although it can achieve multiple rounds of huff and puff, it can effectively maintain the formation pressure and improve the recovery of tight oil reservoirs; however, it consumes a lot of carbon dioxide, and the mixed nitrogen hinders the diffusion efficiency of carbon dioxide into the reservoir to a certain extent, making it difficult to Maximize enhanced tight oil recovery

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