Method for mining tight oil reservoir by nanometer fluid

Abstract

The invention relates to a method for mining a tight oil reservoir by nanometer fluid. The method comprises the following steps that a nanometer fluid segment plug is injected into the tight oil reservoir, then, water is injected into the oil reservoir through an injecting well, and the exploitation is carried out, and the water injecting speed needs to be smaller than 1.4m / d. According to the method provided by the invention, the nanometer fluid segment plug can invert the oil-wet tight oil reservoir into the water-wet reservoir, and the subsequently injected water can enter a substrate in a dialysis way under the effect of capillary force, so that rest oil in the substrate is used. The sudden water flooding due to fast fluid channeling of the injected water along the cracks can be avoided through low-speed water injection, and the stratum energy after the once oil production of the tight oil reservoir can be supplemented through the water injection.

Description

technical field [0001] The invention belongs to the technical field of tight oil reservoir exploitation, and relates to a method for exploiting tight oil reservoirs by nanofluid. Background technique [0002] With the continuous development of oil and gas exploration and development, unconventional oil and gas such as tight gas, shale gas, coalbed methane, and tight oil have shown great potential under the current economic and technological conditions, and global oil and gas resources will usher in a second expansion. Tight oil refers to the oil that occurs in the source rocks in an adsorbed or free state, or interbeds with source rocks, or in tight sandstones, tight carbonate rocks, and other reservoir rocks that have not undergone large-scale long-distance migration. gather. Tight oil reservoirs in my country are characterized by low porosity, low permeability, and low pressure, and their effective development faces many challenges. The oil production of tight oil reserv...

AI Technical Summary

Problems solved by technology

In the initial stage of depletion-type development, the oil production is generally relatively high, but due to the influence of poor reservoir properties, low formation pressure and small single well controlled reserves, the natural energy is very limited, and the production generally declines rapidly. Industrial oil was obtained by conventional fracturing in the Chang 7 Member The average single-well production test production of the wells that flow is 5.8t / d, while the test production production is only 0.6-0.9t / d

Even with large-scale fracturing of horizontal wells, the primary oil recovery rate of tight oil reservoirs is only 5% to 10%.

However, after the large-scale fracturing of tight oil forms a fracture system, the injected water for waterflooding development is likely to rush rapidly along the fractures, resulting in violent water flooding, the crude oil in the matrix cannot be effectively produced, and the waterflooding development effect is poor. Adopting the combined well pattern development of vertical well water injection and horizontal well oil production, the risk of water injection in horizontal wells is high, and the proportion of water breakthrough reaches 65%.

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