A drag reducing agent for carbon dioxide dry fracturing and its application

Abstract

The invention provides a drag-reduction agent for carbon dioxide dry-process fracturing and application thereof. The drag-reduction agent mainly comprises a fluorinated acrylate-styrene-sulfonated styrene block copolymer prepared by carrying out polymerization reaction on a fluorinated acrylate polymer, sulfonated styrene and styrene, wherein the mass ratio of the fluorinated acrylate polymer to the sulfonated styrene to the styrene is (55 to 65) to (20 to 30) to (10 to 20). The drag-reduction agent has relatively good compatibility with carbon dioxide; the drag-reduction agent is dissolved into a carbon dioxide fracturing solution and the friction resistance in a fracturing process can be reduced, so that the ground pump pressure is reduced and the pressure bearing capability of a pipeline is reduced, and furthermore, carbon dioxide dry-process fracturing engineering is safer and the pipeline can meet working requirements better; the speed of injecting liquid-state carbon dioxide is improved, and the carbon dioxide dry-process fracturing can be used in deeper reservoir stratums with more extreme conditions; the drag-reduction effect still can be kept under the more extreme conditions; the drag-reduction effect can reach 30 percent to 40 percent in carbon dioxide work.

Description

technical field [0001] The invention relates to the technical field of oil field chemistry, in particular to a drag reducer for carbon dioxide dry fracturing and an application thereof. Background technique [0002] The use of carbon dioxide fracturing fluid can greatly reduce or eliminate the chance of contact between water and the formation during fracturing construction, thereby greatly reducing the formation damage caused by water lock and water sensitivity. Dry carbon dioxide fracturing technology has broad prospects in the development of shale gas, tight oil reservoirs and strong water-sensitive formations. Compared with conventional fracturing technology, dry carbon dioxide fracturing technology has many advantages, mainly including: (1) No water phase, eliminating the damage caused by water sensitivity and water lock; (2) The fracturing fluid has extremely low interfacial tension, and can be directly flowed back without breaking the gel after being heated and vaporiz...

AI Technical Summary

Problems solved by technology

[0003] However, the carbon dioxide fracturing fluid also faces the problem of high friction during fracturing, which limits the scope of application of the carbon dioxide fracturing fluid, making some deeply buried low-permeability and strong water-sensitive reservoirs have to use conventional water base fracturing fluid, caused permanent damage to the reservoir, and developed poorly