Reversible physical crosslinking polymer fracturing fluid and preparation method thereof

Abstract

The invention relates to a reversible physical crosslinking polymer fracturing fluid and a preparation method thereof. The fracturing fluid is composed of 0.3% to 0.6% of a polymer thickening agent, 0.12% to 0.3% of a reversible physical crosslinking agent, 0.1% to 0.5% of a clay stabilizing agent and 0.001% to 0.05% of an ammonium persulfate gel breaking agent, with the balance being water. The reversible physical crosslinking polymer fracturing fluid can be applied in fracturing construction of a reservoir at 120 to 160 DEG C, and does not need addition of a temperature stabilizing agent, a cleanup agent, a defoaming agent and a bactericide, so the cost of the fracturing fluid is saved; meanwhile, the fracturing fluid has a gel breaking liquid viscosity less than 2 mPa-s, a gel breaking liquid surface tension lower than or equal to 28 mN/m, a residue content less than or equal to 100 mg/L, and a damage rate less than 10%.

Description

Technical field [0001] The invention belongs to the technical field of oil and gas field reservoir reconstruction, and specifically relates to a reversible physically crosslinked polymer fracturing fluid and a preparation method thereof. Background technique [0002] At present, the fracturing fluids used in oil fields at home and abroad mainly include natural vegetable gum and its derivatives, viscoelastic surfactant-based fracturing fluids and synthetic polymer-based fracturing fluids. The disadvantages of natural vegetable glue and its derivatives fracturing fluid are easy biodegradation, high water-insoluble content, incomplete gel breaking and great damage; viscoelastic surfactant-based fracturing fluid has low damage to cracks and no damage after gel breaking. Residue, but poor temperature resistance (generally no more than 110℃) and high cost; synthetic polymer fracturing fluid mainly includes chemically cross-linked polymer fracturing fluid and physical cross-linked polym...

AI Technical Summary

Problems solved by technology

Disadvantages of natural plant gum and its derivative fracturing fluids are easy biodegradation, high water-insoluble content, incomplete gel breaking, and large damage; Residue, but poor temperature resistance (generally no more than 110°C) and high cost; synthetic polymer fracturing fluid mainly includes chemical cross-linked polymer fracturing fluid and physical cross-linked polymer fracturing fluid, chemical cross-linked polymer fracturing fluid The fracturing fluid has good temperature resistance, but it takes a long time to completely break the gel, which will cause great damage to the reservoir; the physical cross-linked polymer fracturing fluid has good temperature resistance, salt resistance, shear resistance, and sand suspension performance. and gel breaking performance, etc., this type of fracturing fluid is currently a hot spot in the field of fracturing fluid research at home and abroad.

[0003] Chinese patent CN 103013487A discloses a multi-branched polymer fracturing fluid and its preparation method, which consists of 0.3-0.6 parts of thickener, 0.3-0.6 parts of crosslinking agent, 0.3-0.6 parts of 2 parts of anti-swelling agent, 0.01-0.05 parts of gel breaker, this invention uses chemical cross-linking to prepare polymer fracturing fluid, at 90°C, 170S -1 After shearing for 120 minutes under the same conditions, the tail stickiness is greater than 100mPa s, but no rheological data for temperatures above 90°C

Wang Siyu and others reported a chemically cross-linked polymer fracturing fluid system in the article "Study on the Formulation System of Organic Zirconium Jelly Fracturing Fluid" (Oilfield Chemist

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