Clean fracturing flowback fluid recovery, oil displacement and blockage removal process

Abstract

The invention relates to a clean fracturing flowback fluid recovery, oil displacement and blockage removal process which comprises the following steps: after clean fracturing flowback fluid is gelout, flocculating agents or loam remover or bactericide is added to the gelout clean fracturing flowback fluid for the sedimentation of suspension and sterilization; initial filtering and recovery are carried out by a flushing truck with a filtering function or a precise filter, and the suspension content after treatment is less than or equal to 10 mg / l; oil content is less than or equal to 15 mg / l; 2 micron-150 micron fine filtering is then carried out by the precise filter according to the quality requirement of water added into each well; and after the fine filtering, chemical agents are added or compounded. The invention has the characteristic of environmental protection, can greatly improve the performance of drill cores, recovers the permeability of stratum, enhances the effects of water wetting, expansion prevention and sand stabilization, prevents dirt from depositing again, reduces oil and water interfacial tension, and increases the recovery ratio of crude oil.

Description

technical field [0001] The invention relates to a waste liquid chemical recovery process, in particular to a process for recovering oil displacement and plugging removal of clean fracturing flowback liquid. Background technique [0002] With the continuous development of hydraulic fracturing, various sand-carrying fluids have emerged. In water-based, emulsified and foam fracturing operations, the most used fracturing fluid is water-based gel fracturing fluid, in which thickeners are some high molecular polymers, such as boron cross-linked guar gum, hydroxypropyl fracturing fluid, etc. Base cellulose, polyacrylamide, etc. These polymers can basically meet the requirements for liquids in current on-site construction. However, due to the high molecular weight of the polymer and the large amount of water-insoluble matter, it is cross-linked with a cross-linking agent to form a supermacromolecule. The completely broken supermacromolecules stay in the cracks, which reduces the ...

AI Technical Summary

Problems solved by technology

However, due to the high molecular weight of the polymer and the large amount of water-insoluble matter, it is cross-linked with a cross-linking agent to form a supermacromolecule. The completely broken supermacromolecules stay in the cracks, which reduces the permeability of the formation and the construction effect is not good

In addition, in the whole fracturing process, there are many kinds of fracturing fluid admixtures, thickeners have slow dispersion and swelling speed, etc., which seriously affect the quality of fracturing fluid.

People have recognized this hazard, and made great improvements in the gel breaking system and additives, but there is still little effect on reducing residues and improving fracturing quality

Although foam fracturing overcomes the above shortcomings, its large-scale use is limited due to the high cost of equipment and liquids