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CN-121991666-A - Bag-type wrapped floating temporary plugging agent for fracturing and preparation method and application thereof

CN121991666ACN 121991666 ACN121991666 ACN 121991666ACN-121991666-A

Abstract

The invention provides a capsule-type coated floating temporary plugging agent for fracturing, and a preparation method and application thereof, wherein the temporary plugging agent consists of a capsule core and a coating, and the capsule core consists of 50-70wt% of a lamellar expanding agent, 20-40wt% of an adhesive and 5-15wt% of a structural stabilizer; the coating consists of 20-50wt% of modified starch, 40-70wt% of gelatin and 5-10wt% of mixed solvent, and the coating is coated on the capsule core to obtain the capsule-type coated floating temporary plugging agent. The temporary plugging agent prepared by the invention can enter the inside of a crack along with fluid to realize deep temporary plugging, and simultaneously, the temporary plugging effect is improved through the adhesive and the structural stabilizer.

Inventors

  • ZHU JUHUI
  • ZHOU WENGAO
  • LIU WEI
  • LI JIA
  • YU SHIHU
  • WANG RONG
  • ZHANG XIAOHU
  • GUAN BIN
  • WU YUE
  • SUN YADONG

Assignees

  • 中国石油天然气集团有限公司
  • 中国石油集团川庆钻探工程有限公司

Dates

Publication Date
20260508
Application Date
20241104

Claims (12)

  1. 1. The capsule-type wrapped floating temporary plugging agent for fracturing is characterized by comprising a capsule core and a coating; The capsule core consists of 50-70wt% of lamellar expanding agent, 20-40wt% of adhesive and 5-15wt% of structural stabilizer; the coating is coated on the capsule core and consists of 20-50wt% of modified starch, 40-70wt% of gelatin and 5-10wt% of mixed solvent.
  2. 2. The capsule-type wrapped floating temporary plugging agent for fracturing according to claim 1, wherein the lamellar swelling agent is prepared from the following raw materials, by mass, 10-30wt% of a polymeric monomer, 0.2-0.6wt% of a composite cross-linking agent and the balance of water.
  3. 3. The balloon-coated floating temporary plugging agent for fracturing according to claim 2, wherein the lamellar swelling agent is prepared by the following method: Dissolving the polymerized monomer in the water, introducing nitrogen, stirring, adjusting the pH value to 6-9, heating to 30-70 ℃, adding the composite cross-linking agent, slowly adding an initiator under the conditions of constant temperature and continuous nitrogen introduction, reacting for 2-8 hours under the conditions of constant temperature and continuous nitrogen introduction, taking out, drying and slicing.
  4. 4. The balloon-wrapped flotation temporary plugging agent for fracturing according to claim 2, wherein the polymeric monomers comprise one or more of acrylamide, itaconic acid, acrylic acid and 2-acrylamido-2-methylpropanesulfonic acid.
  5. 5. The capsule-type wrapped floating temporary plugging agent for fracturing according to claim 2, wherein the composite cross-linking agent is prepared from, by mass, 30-80% of N-maleylated chitosan, 0-40% of N, N-methylenebisacrylamide, 0-40% of tetraallylammonium chloride and 0-40% of dimethyldiallylammonium chloride.
  6. 6. The balloon-coated floating temporary plugging agent for fracturing according to claim 1, wherein the adhesive comprises one or more of polyvinyl alcohol, pregelatinized starch and polyvinylpyrrolidone, and the particle size of the adhesive particles is 0.1-0.8 mm; The structure stabilizer comprises degradable fibers, and the length of the degradable fibers is 1-10 mm.
  7. 7. The balloon-wrapped floating temporary plugging agent for fracturing according to claim 1, wherein the mixed solvent comprises one or more of ethylene glycol, glycerin, sorbitol and urea.
  8. 8. The balloon-coated floating temporary plugging agent for fracturing according to claim 1, wherein said modified starch is hydroxypropyl starch modified with 1, 3-propane sultone and 2-amino-1-methylimidazolin-4-one.
  9. 9. The balloon-coated floating temporary plugging agent for fracturing according to claim 8, wherein said modified starch is prepared by the following method: Preparing 20-30wt% of first starch milk from hydroxypropyl starch by using water, keeping the temperature below 35 ℃, adjusting the pH value to 8-9 while stirring, and adding 1-5wt% of 2-amino-1-methylimidazoline-4-one while keeping the stirring state to obtain second starch milk; Heating propane 1, 3-propane sultone to a molten state, slowly dripping the propane 1, 3-propane sultone into second starch milk, keeping the pH value of the second starch milk to 8-9, keeping the temperature below 35 ℃, stirring and reacting for 2-4 hours, and then regulating the pH value to be neutral by using dilute hydrochloric acid to obtain modified third starch milk, wherein the adding amount of the 1, 3-propane sultone is 1-10wt%; washing the third starch milk with water, and drying at the temperature of 40 ℃ to obtain the modified starch.
  10. 10. The method for preparing the capsule-type encapsulated floating temporary plugging agent according to claim 1, which comprises the following steps: Uniformly mixing a lamellar expanding agent, an adhesive and a structural stabilizer, and preparing into a capsule core which is streamline; And uniformly mixing the modified starch, the gelatin and the mixed solvent, and then uniformly spraying the mixture onto the capsule core to obtain the temporary plugging agent.
  11. 11. The method for preparing the capsule-type wrapped floating temporary plugging agent according to claim 10, wherein the size of the capsule core is 3-10 mm; the thickness of the spraying is 0.1-1 mm; The temporary plugging agent is streamline in shape.
  12. 12. The use of the capsule-type wrapped floating temporary plugging agent according to any one of claims 1 to 9, wherein the use comprises adding the temporary plugging agent through a sand mixing vehicle or a ball injection device, pumping by adopting a displacement of 2-6 m 3 /min, and after entering a hole, adopting a displacement of 5-8 m 3 /min to plug a joint end to promote steering, and lifting to a design displacement after the steering to finish construction.

Description

Bag-type wrapped floating temporary plugging agent for fracturing and preparation method and application thereof Technical Field The invention relates to a temporary plugging and steering transformation process of an unconventional reservoir, which is used for the construction design and implementation of deep coal gas, compact oil-gas fields and shale oil-gas field reservoir transformation sites, belongs to the field of energy and technical science, and particularly relates to a bag-type wrapped floating temporary plugging agent for fracturing and a preparation method and application thereof. Background Temporary plugging steering measures are commonly adopted in the process of modifying unconventional reservoirs in China so as to promote the steering of artificial cracks. Because of the influence of factors such as uncertainty of the flowing space in the artificial crack, density of temporary plugging agent, morphology and the like, the temporary plugging material is difficult to realize deep temporary plugging steering in the crack, and even after the temporary plugging material is put in, the net pressure in the crack is not increased. In order to increase temporary plugging effect, the method of increasing the using amount of temporary plugging agent or performing secondary temporary plugging is generally adopted at present, so that not only is the cost increased, but also the problem of temporary plugging at the far end of a crack cannot be solved. Disclosure of Invention The present invention aims to address at least one of the above-mentioned deficiencies of the prior art. For example, one of the purposes of the invention is to provide a preparation method of the bag-type wrapped floating temporary plugging agent for fracturing, the other purpose of the invention is to provide the bag-type wrapped floating temporary plugging agent for fracturing, and the other purpose of the invention is to provide an application process of the bag-type wrapped floating temporary plugging agent for fracturing. In order to achieve the above purpose, the invention provides a preparation method of the capsule-type wrapped floating temporary plugging agent for fracturing. The temporary plugging agent is prepared by uniformly mixing a lamellar expanding agent, an adhesive and a structural stabilizer, preparing a capsule core which is streamline, uniformly mixing modified starch, gelatin and a mixed solvent, and uniformly spraying the mixture onto the capsule core. Optionally, the size of the capsule core is 3-10 mm, and the size of the capsule core can be adjusted according to the size of the hole, the adding mode and the like. The thickness of the spraying is 0.1-1 mm, and the spraying can be adjusted according to temperature, dissolution time and the like. Optionally, the temporary plugging agent is streamlined in shape, including but not limited to spherical, jujube-pit, oval. Optionally, the lamellar swelling agent, the adhesive and the structural stabilizer are respectively used in the mass percent of 50-70wt%, 20-40wt% and 5-15wt%. Optionally, the dosages of the modified starch, the gelatin and the mixed solvent are respectively 20-50wt%, 40-70wt% and 5-10wt% according to mass percent. Optionally, the lamellar swelling agent is prepared from the following raw materials, by mass, 10-30wt% of a polymer monomer, 0.2-0.6wt% of a composite cross-linking agent and the balance of water. Alternatively, the flake-form swelling agent may be prepared as follows: Dissolving the polymerized monomer in the water, introducing nitrogen, stirring, adjusting the pH value to 6-9, preferably 7-8, heating to 30-70 ℃, preferably 40-60 ℃, adding the composite cross-linking agent, slowly adding an initiator under the conditions of constant temperature and continuous nitrogen introduction, reacting for 2-8 hours, preferably 3-6 hours under the conditions of constant temperature and continuous nitrogen introduction, taking out, drying and slicing. The initiator can comprise ammonium sulfate, wherein the flake-shaped material has a thickness of 0.1-1 mm, a width of 0.5-2 mm and a length of 1-3 mm. Alternatively, the polymeric monomer includes one or more of acrylamide, itaconic acid, acrylic acid, and 2-acrylamido-2-methylpropanesulfonic acid. Optionally, the composite cross-linking agent is prepared from the following raw materials, by mass, 30-80% of N-maleylated chitosan, 0-40% of N, N-methylenebisacrylamide, 0-40% of tetra-allyl ammonium chloride and 0-40% of dimethyl diallyl ammonium chloride. Optionally, the adhesive comprises one or more of polyvinyl alcohol, pregelatinized starch and polyvinylpyrrolidone, and the particle size of the adhesive particles is 0.1-0.8 mm. Optionally, the structural stabilizer comprises degradable fibers, and the length of the fibers is 1-10 mm. Alternatively, the modified starch is hydroxypropyl starch modified with 1, 3-propane sultone and 2-amino-1-methylimidazolin-4-one. Alternatively, the modified sta