An integrated method of nitrogen-assisted carbon dioxide fracturing and development in shale reservoirs

Abstract

The invention discloses a shale oil reservoir nitrogen-assisted carbon dioxide fracturing and development integrated method, which comprises using nitrogen-assisted carbon dioxide to perform a fracturing operation on a target shale oil reservoir; after the fracturing operation is completed, injecting Carbon dioxide gas, followed by injecting nitrogen gas into the target shale reservoir to push the carbon dioxide gas into the deep part of the reservoir; implement brine operation on the target shale reservoir; after the brine is completed, open the well to implement depletion production; After one cycle of production; in the subsequent production process, the volume of injected gas slug and soaking time are 1.5 times that of the previous cycle, and the operation of step 5-step 7 is repeated for each cycle. The present invention maximizes the recovery rate of shale oil reservoirs; in this way, carbon dioxide gas is used most efficiently, making the development of shale oil reservoirs more economical and efficient; the integrated design of fracturing and development makes on-site operation flow and standardization , Different departments 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...

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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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