Small-molecular liquid anti-swelling agent, clay anti-swelling agent for fracturing and preparation method

[0037] Embodiment 1-6: the synthesis of alkyl hydroxypropyl quaternary ammonium salt

[0038] In a 500mL three-necked flask equipped with a thermometer, a condensing reflux device, and an agitator, add tertiary amine and concentrated hydrochloric acid in equal amounts to react for 4 hours to obtain tertiary amine hydrochloride; mix tertiary amine, tertiary amine hydrochloride, epoxy chloride Propane is added to a certain amount of alcohol and water mixture according to a certain proportion of substances, slowly heated to a certain temperature, and reacted for a period of time to obtain a product solution; the solution is subjected to vacuum distillation, recrystallized with acetone, and dried to obtain an alkyl hydroxyl Propyl quaternary ammonium salt. The specific reaction conditions are shown in Table 1.

[0039] The synthetic condition of table 1 alkyl hydroxypropyl quaternary ammonium salt

[0040]

[0041] Embodiment 6-12: the preparation of anti-swelling agent

[0042] A certain amount of alkyl hydroxypropyl quaternary ammonium salt, guanidine hydrochloride, and non-ionic surfactants are sequentially added to water according to a certain mass ratio, and the anti-swelling agent is obtained by fully stirring. The distribution ratio of each group is shown in Table 2.

[0043] The distribution ratio of each component of the clay stabilizer in table 2

[0044]

[0045] Embodiment 13: Evaluation of anti-swelling rate of anti-swelling agent

[0046] Referring to the eccentricity method in the standard SY / T 5971-94 "Clay Stabilizer Performance Evaluation Method for Water Injection", the anti-swelling rate is evaluated by measuring the volume expansion increment of bentonite powder in the anti-swelling agent solution and clear water.

[0047] Use the anti-swelling agent prepared in Examples 6-12 and clear water (tap water) or drag-reducing water fracturing fluid to prepare an anti-swelling agent solution with a mass fraction of 0.3%, and weigh 0.50 g of bentonite powder (100-200 mesh, dried) , into a dry and clean 10mL centrifuge tube, add 10mL clay stabilizer solution, shake well, let stand at room temperature for 2h, centrifuge at 1500r / min for 15min, and read the volume of bentonite after swelling. Replace the anti-swelling agent solution with 10mL of tap water and 10mL of anhydrous kerosene, respectively measure the swelling volume of...