Temperature-resistant, acid-resistant and salt-resistant acid liquid thickening agent and preparation method thereof

Abstract

The invention relates to a temperature-resistant, acid-resistant and salt-resistant acid thickening agent and a preparation method thereof, and belongs to the technical field of oil and gas field exploitation. The method comprises the following steps: (1) dissolving a nonionic water-soluble monomer and a cationic monomer in water to obtain a first mixed solution; (2) dissolving a salt-resistant monomer, a temperature-resistant monomer, a hydrophobic monomer, a penetrant and a cosolvent in the first mixed solution to obtain a second mixed solution; (3) dissolving a chain extender in the second mixed solution to obtain a third mixed solution; (4) introducing nitrogen into the third mixed solution to remove oxygen, and then sequentially adding an azo initiator, a complexing agent, a molecular weight regulator and a redox initiator to initiate a polymerization reaction to obtain polymerization gel; and (5) drying the polymerization gel, and grinding to obtain the temperature-resistant, acid-resistant and salt-resistant acid liquid thickening agent. The acid liquid thickening agent prepared by the invention has the characteristics of strong tackifying ability, small shear influence, acid resistance, stability, good temperature resistance, small secondary damage to strata and the like.

Description

technical field [0001] The invention relates to the technical field of oil and gas field exploitation, in particular to a temperature-resistant, acid-resistant and salt-resistant acid liquid thickener and a preparation method thereof. Background technique [0002] Acidizing treatment technology is one of the main measures for increasing production of oil and gas wells and increasing injection of water wells. It uses acid liquid to dissolve and corrode rock cement or formation pores and plugs in fractures (clay, drilling mud, completion fluid, etc.), to restore or improve the permeability of formation pores and fractures. In the conventional acidizing construction, there are the following disadvantages: (1) The acid-rock reaction speed is fast, and the acid penetration distance is short, which can only eliminate the damage near the wellbore; (2) Increasing the acid concentration can increase the acid penetration distance , but serious silt and emulsion blockage occurs, which...

AI Technical Summary

Problems solved by technology

In the conventional acidizing construction, there are the following disadvantages: (1) The acid-rock reaction speed is fast, and the acid penetration distance is short, which can only eliminate the damage near the wellbore; (2) Increasing the acid concentration can increase the acid penetration distance , but serious silt and emulsion blockages occur, which brings difficulties to anti-corrosion; (3) The effective period of production increase is usually short. After sandstone is treated with soil acid, the oil flow channel is blocked due to the migration of clay and other particles, resulting in the increase of production in the early stage of acidification. Rapid decline in late production

As the construction environment of oil and gas reservoirs becomes more and more complex, the disadvantages of some conventional acid thickeners such as weak viscosity-increasing ability, strong shear influence, poor acid resistance stability and temperature resistance have become more and more prominent.

Existing acid thickeners generally have problems such as poor viscosity at higher temperatures, low shear viscosity retention, long dissolution time, and increased costs.

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