Plugging agent with characteristic of controlled and delayed expansion, and preparation method thereof

[0019] First weigh 6g of sodium bentonite, 20g of acrylic acid, 10g of 2-acrylamido-2-methylpropanesulfonic acid, 0.03g of N,N-methylenebisacrylamide and 0.015g of initiator ammonium persulfate into the reactor, Add 150g of distilled water, stir in an ice-water bath until completely dissolved, pass N 2 Protection; when the temperature drops to about 5°C, slowly add 10g of initiator sodium sulfite solution (sodium sulfite 0.015g) dropwise; after dropping, continue to stir for 20min, stop stirring, slowly raise the temperature to 45°C, and statically react for 3h to obtain an elastic gel body; take it out, dry it in vacuum at 70°C, and shear it to obtain a water-absorbing swellable resin; weigh 5g of the resin and put it into a reactor, add 20g of n-butanol and 0.025g of solid acid catalyst in turn, react at 120°C for 4h, and filter and drying to obtain the No. 1 product of controllable delayed expansion plugging agent.

[0021] First weigh 5g of sodium bentonite, 25g of acrylic acid, 10g of 2-acrylamido-2-methylpropanesulfonic acid, 0.04g of N,N-methylenebisacrylamide and 0.015g of initiator ammonium persulfate into the reactor, Add 200g of distilled water, stir in an ice-water bath until completely dissolved, pass N 2 Protection; when the temperature drops to about 5°C, slowly add 10g of initiator sodium sulfite solution (sodium sulfite 0.015g) dropwise; after dropping, continue to stir for 20min, stop stirring, slowly raise the temperature to 50°C, and statically react for 2h to obtain an elastic gel body; take it out, dry it in vacuum at 70°C, and shear it to obtain a water-absorbing swellable resin; weigh 5g of the resin and put it into a reactor, add 20g n-octanol and 0.025g solid acid catalyst in turn, react at 150°C for 3h, and filter and drying to obtain the No. 2 product of controllable delayed expansion plugging agent.

[0023] First weigh 5g of sodium bentonite, 30g of acrylic acid, 18g of 2-acrylamido-2-methylpropanesulfonic acid, 0.05g of N,N-methylene bisacrylamide and 0.02g of initiator ammonium persulfate into the reactor, Add 200g of distilled water, stir in an ice-water bath until completely dissolved, pass N 2 Protection; when the temperature drops to about 5°C, slowly add 10g of initiator sodium sulfite solution (sodium sulfite 0.02g) dropwise; after dropping, continue to stir for 20min, stop stirring, slowly raise the temperature to 50°C, and statically react for 3h to obtain an elastic gel body; take it out, dry it in vacuum at 70°C, and shear it to obtain a water-absorbing swellable resin; weigh 5g of the resin and put it into a reactor, add 15g of dodecanol and 0.02g of solid acid catalyst in turn, react at 150°C for 4h, and filter and drying to obtain the No. 3 product of controllable delayed expansion plugging agent.

[0024] The above three products were tested for water-swellin