Method for improving shale oil recovery ratio and reducing fracturing fluid flowback through pressure-drive integration

Abstract

The invention relates to a method for improving the shale oil recovery ratio and reducing fracturing fluid flowback through pressure-drive integration. The method comprises the steps that (1) autogenous gas fracturing fluid is prepared; (2) the autogenous gas fracturing fluid is used for carrying sand for fracturing construction; (3) after a crack is formed, the reaction time is designed according to the target layer temperature and the gas generating agent reaction rate for well closing and well closing, and an oil reservoir is soaked until the autogenous gas fracturing fluid completely reacts and is fully imbibed on the crack expansion face; and (4) well opening and flowback are carried out on the residual fracturing fluid, and normal oil production is started. The autogenous gas fracturing fluid is prepared by adding 2.5% to 77% of gas generating agent and 0.05% to 0.1% of anti-scaling agent into water-based fracturing fluid. The gas generating agent is a water-soluble compound capable of reacting with water to generate gas. The anti-scaling agent is ethylenediamine tetraacetic acid or sodium polyacrylate or a maleic acid-acrylic acid copolymer. The fracturing fluid flowback amount is reduced while the shale oil recovery ratio is improved, the gas generating speed is controllable, chemical agents are fully utilized, and wide market application prospects are achieved.

Description

technical field [0001] The invention relates to a method for increasing the recovery rate of shale oil in the field of oil field development, in particular to a method for increasing the recovery rate of shale oil through integration of pressure and drive and reducing the flowback of fracturing fluid. Background technique [0002] With the continuous consumption of conventional oil and gas resources in my country, unconventional oil and gas resources have become an important supplement to conventional oil and gas under the background of increasing oil and gas resource exploration. One of the most important types of unconventional oil and gas is shale oil (liquidrich shale oil). ). my country's shale oil recoverable resources rank third in the world, at 322×10 8 barrel, second only to the United States and Russia. Thanks to the maturity of multi-stage fracturing technology for long horizontal wells, the United States has developed shale oil resources on a large scale and has...

AI Technical Summary

Problems solved by technology

The two-fluid method involves multi-slug injection, which increases the complexity of fracturing operations, and the gas reaction will produce salts that are ineffective for enhancing oil recovery, resulting in waste of chemical agents, which has a negative impact on controlling construction costs

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