Viscoelastic acid-resisting clean fracturing fluid and preparation method thereof

Abstract

The invention provides a viscoelastic acid-resisting clean fracturing fluid. The acid-resisting clean fracturing fluid is suitable for a stratum of 60-100 DEG C, and the acid-resisting clean fracturing fluid is characterized by comprising, by mass, 0.2-0.4% of a hydrophobic associating polymer thickening agent, 2-3% of a viscoelastic surface active agent, 3-6% of inorganic salt, 0.02-0.2% of a gelbreaker and the balance water. The preparation method comprises the steps of (1), preparation of a base solution, wherein according to the ratio in the formula, the hydrophobic associating polymer thickening agent is prepared into powder and carried by water via negative pressure into a liquid preparation tank, stirring is conducted for about 20-40 minutes, so that the hydrophobic associating polymer thickening agent is swelled, the inorganic salt is added, stirring is conducted to make the inorganic salt completely dissolved, and standing is conducted for 2-3 hours for use; (2), preparationof a surface active agent crosslinking solution, wherein according to the ratio in the formula, the surface active agent and the water are added, and stirring is conducted until the active agent is dissolved completely; (3), preparation of the viscoelastic acid-resisting clean fracturing fluid, wherein the prepared base solution and the prepared surface active agent crosslinking solution are obtained, prepared in a weight ratio of (8-12):1 and significantly stirred to be uniform to obtain the viscoelastic acid-resisting clean fracturing fluid. After 1-3% of HCl is added into a fracturing fluidsystem, the viscosity is reduced by 5% or below.

Description

Technical field [0001] The invention relates to a viscoelastic acid-resistant cleaning fracturing fluid and a preparation method thereof. Background technique [0002] Conventional fracturing fluids usually use guar gum fracturing fluid systems that are cross-linked in an alkaline environment. This type of system has a high cost, and when applied to low-permeability reservoirs, the residual gel will cause greater damage to the formation, and the reservoir will not break the gel. The shortcomings of being thorough, unable to work with acidification and acid fracturing. Although the current clean fracturing fluids on the market have reduced reservoir damage, they still have disadvantages such as poor temperature resistance, high use cost, and acid resistance. Summary of the invention [0003] The technical problem to be solved by the present invention is to provide a formulation of viscoelastic acid-resistant cleaning fracturing fluid prepared by using hydrophobically associating p...

AI Technical Summary

Problems solved by technology

[0002] Conventional fracturing fluids usually use guar gum fracturing fluid systems cross-linked in alkaline environments. Disadvantages of being thorough and unable to work in conjunction with acidification and acid fracturing

Although the clean fracturing fluids currently on the market have reduced reservoir damage, they still have disadvantages such as poor temperature resistance, high cost of use, and acid resistance.