Microemulsion type imbibition agent, and preparation method thereof and oil displacement type fracturing fluid system

Abstract

The invention provides a microemulsion type imbibition agent, and a preparation method thereof and an oil displacement type fracturing fluid system. The microemulsion type imbibition agent is of a core-shell structure, the diameter of the microemulsion type imbibition agent ranges from 9 nm to 500 nm, and the microemulsion type imbibition agent is prepared from, by weight, 20%-35% of a solvent, 15%-25% of an emulsifier, 1%-2.5% of a complexing agent and the balance water; the emulsifier comprises the following components in percentage by weight: 35-60% of a fatty alcohol ether grafted comb-shaped polymer, 25-35% of a zwitterionic surfactant, 2-5% of perfluoroalkyl polyoxyethylene ether and the balance of water. The perfluoroalkyl polyoxyethylene ether interacts with the fatty alcohol ether grafted comb-shaped polymer active agent and the zwitterionic surfactant to form a whole, namely a shell of a core-shell structure, so that the surface tension is effectively reduced. The surface tension of a 0.3% aqueous solution of the microemulsion imbibition agent with the core-shell structure is less than 20mN / m, and the interfacial tension is less than 0.5 mN / m. The fracturing fluid system containing the microemulsion imbibition agent with the core-shell structure is high in displacement capacity, and compared with a conventional oil displacement agent, the oil displacement efficiency is higher.

Description

technical field [0001] The invention belongs to the field of petroleum exploitation, and in particular relates to a microemulsion type osmotic agent, a preparation method thereof and an oil displacement type fracturing fluid system. Background technique [0002] Many oil reservoirs in China belong to the conditions of low permeability, ultra-low permeability, shale, high temperature and deep layers. Moreover, with the deepening of unconventional block mining, the exploration and development of these areas have become more and more important. What follows is the modification of these reservoirs to enable them to develop effective production capacity. Fracturing is the most effective and commonly used stimulation measure for reservoir stimulation. [0003] So far, the main purpose of all fracturing operations is to open a fracture in the reservoir, and then fill it with proppant to form an artificial high-permeability channel in the formation. With the flowback of the fract...

AI Technical Summary

Problems solved by technology

However, the residual fracturing fluid in the formation is considered to have a bad effect on the fracturing effect

Because of this, it is required to flow back the fracturing fluid as soon as possible after fracturing, so as to reduce the result of low oil well production and poor fracturing effect caused by the damage to the formation caused by the existence of fracturing fluid.

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