Search

CN-122012070-A - Petroleum fracturing sand with multilayer composite structure and preparation method thereof

CN122012070ACN 122012070 ACN122012070 ACN 122012070ACN-122012070-A

Abstract

The invention discloses petroleum fracturing sand with a multilayer composite structure and a preparation method thereof, belonging to the technical field of oil and gas exploitation, the petroleum fracturing sand of the invention is prepared by adopting a three-layer composite structure of a high-strength inner core-interface transition layer-high-toughness shell, the structural design ensures that the product has both high compressive strength (more than or equal to 8000 psi) of the inner core and high toughness and low breaking rate (less than 3 percent) of the outer shell, and the long-term flow conductivity of the fracturing crack is obviously improved. The hydraulic fracturing device is particularly suitable for hydraulic fracturing operation of unconventional reservoirs such as deep wells, ultra-deep wells, shale oil gas and the like.

Inventors

  • WANG DEXIAN
  • SUN FENGFEI
  • LI YUEXIANG

Assignees

  • 临沂鑫海新型材料有限公司

Dates

Publication Date
20260512
Application Date
20251226

Claims (10)

  1. 1. The petroleum fracturing sand with the multilayer composite structure is characterized by comprising a mineral core, an interface transition layer coated on the surface of the mineral core and a modified resin-based shell coated on the surface of the interface transition layer, wherein the mineral core is solid particles formed by rapidly cooling and condensing ferronickel molten slag after water quenching or air quenching.
  2. 2. The oil frac sand of claim 1, wherein the interfacial transition layer is formed by wrapping a mineral core surface with an interfacial transition layer solution, the interfacial transition layer solution being prepared by: And weighing gamma-glycidol ether oxypropyl trimethoxy silane, adding the gamma-glycidol ether oxypropyl trimethoxy silane into absolute ethyl alcohol, dropwise adding a plurality of drops of glacial acetic acid, and stirring until the gamma-glycidol ether oxypropyl trimethoxy silane is completely dissolved to obtain an interface transition layer solution.
  3. 3. The petroleum frac sand of claim 1, wherein the modified resin-based shell is cured from a modified resin-based shell coating solution prepared by: (1) Dissolving aluminum isopropoxide in absolute ethyl alcohol, heating in a water bath, stirring until the aluminum isopropoxide and the ethyl alcohol are completely clarified, obtaining a mixed solution of aluminum isopropoxide and the ethyl alcohol, slowly dripping the mixed solution of aluminum isopropoxide and the ethyl alcohol into the ethyl alcohol solution of phenolic resin, and stirring to obtain a component A; (2) Mixing deionized water and concentrated nitric acid to obtain 0.1 mol/L dilute nitric acid catalytic hydrolysate, slowly dropwise adding the dilute nitric acid catalytic hydrolysate into the component A liquid under continuous high-speed stirring, and dropwise adding the dilute nitric acid catalytic hydrolysate in a water bath at 35-40 ℃ for 1-1.5 hours; (3) And (3) continuously preserving heat and stirring for 2-3 hours at the water bath temperature of 35-40 ℃ to obtain the modified resin matrix shell coating liquid.
  4. 4. A petroleum frac sand according to claim 3, wherein the phenolic resin solids in the phenolic resin ethanol solution are 60-80% by mass.
  5. 5. The petroleum frac sand of claim 1, wherein the ferronickel alloy molten slag comprises, in mass percent ：Ni 0.03-0.04%、Al 2 O 3 3.5-4.5%、Cr 2 O 3 1-2%、TFe 4.5-5.5%、CaO 1-2%、MgO 30-35%、SiO 2 50-55%、MnO 0.5-0.7%、TiO 2 0.1-0.2%、CO 0.005-0.009%、Cu 0.001-0.0034%.
  6. 6. The oil frac sand of claim 1, wherein the interfacial transition layer is 0.1% -0.5% by mass of the mineral core and the modified resin-based shell is 1.5% -4% by mass of the high strength mineral core.
  7. 7. The petroleum frac sand of any of claims 1-6, wherein the petroleum frac sand is 16/30 mesh, 20/40 mesh, 30/50 mesh, 40/70 mesh, or 70/140 mesh.
  8. 8. A method for producing petroleum frac sand according to any one of claims 1 to 7, comprising the steps of: (1) Taking solid particles formed after water quenching or air quenching of ferronickel molten slag as a mineral core, and heating the mineral core to 150-220 ℃; (2) Spraying the interface transition layer solution in the step (2) into the mineral core under high-speed stirring to uniformly wrap the surface of the core to form an interface transition layer; (3) On the basis of the treatment in the step (2), adding the modified resin-based shell coating liquid in the step 3, so that the modified resin-based shell coating liquid is uniformly coated on the surface of the mineral core wrapped with the interface transition layer to form a modified resin-based shell; (4) And (3) cooling the coated product to room temperature on the basis of the treatment in the step (3), and screening to obtain the petroleum fracturing sand with the target particle size.
  9. 9. Use of the petroleum frac sand of any one of claims 1-7 in a hydraulic frac operation of an oil and gas well.
  10. 10. The use according to claim 9, wherein the oil fracturing sand is suitable for the exploitation of deep wells, ultra-deep wells, shale gas, tight sandstone hydrocarbon reservoirs with well depths exceeding 3000 meters.

Description

Petroleum fracturing sand with multilayer composite structure and preparation method thereof Technical Field The invention belongs to the technical field of oil and gas field exploitation engineering, and particularly relates to petroleum fracturing sand with a multilayer composite structure and a preparation method thereof. Background Petroleum fracturing sand is a key material used for supporting underground rock cracks in hydraulic fracturing technology, and the performance of the petroleum fracturing sand directly determines the diversion capacity of the cracks and the recovery ratio of an oil and gas well. With the shift of oil and gas exploration and development to deep and compact reservoirs, the performance requirements on fracturing sand are increasingly severe. The traditional single natural quartz sand or ceramsite propping agent has the obvious defects that the natural quartz sand has low strength, is easy to break in a deep well with high closing pressure, causes the rapid reduction of the flow conductivity, and the ceramsite has high strength, high density, high cost and high brittleness. In the prior art, although resin is adopted to coat the fracturing sand to improve the performance, most of the fracturing sand is only used for realizing sand prevention or improving dispersibility, and the coating layer is usually thin and has single function, so that the contradiction that the strength and the toughness are difficult to be compatible cannot be fundamentally solved. Under the high-pressure environment of the deep well, the single rigid structure is still easy to generate brittle fracture, and the single flexible structure cannot effectively support cracks. Therefore, there is a strong need in the art for a new type of frac sand that can withstand extremely high closure pressures, yet has excellent toughness and low fracture rate to maintain long term high conductivity of the fracture. Disclosure of Invention Aiming at the prior art, the invention aims to provide petroleum fracturing sand with a multilayer composite structure and a preparation method thereof. The invention provides the petroleum fracturing sand which realizes high compressive strength and high toughness through innovative rigid-flexible combined structural design. In order to achieve the above purpose, the invention adopts the following technical scheme: The invention provides petroleum fracturing sand with a multilayer composite structure, which comprises a mineral inner core, an interface transition layer coated on the surface of the mineral inner core, and a modified resin-based shell coated on the surface of the interface transition layer, wherein the mineral inner core is solid particles formed by rapidly cooling and condensing ferronickel molten slag after water quenching or air quenching. The term petroleum fracturing sand is a key supporting material for hydraulic fracturing operation of oil and gas wells, and has the main functions of filling cracks and maintaining the opening of stratum cracks so as to improve the oil and gas flowing efficiency. The interface transition layer is formed by wrapping the surface of the mineral core with an interface transition layer solution, and the preparation method of the interface transition layer solution comprises the following steps: weighing gamma-glycidol ether oxypropyl trimethoxy silane (KH-560), adding into absolute ethanol, dropwise adding a plurality of drops of glacial acetic acid (0.5-1 g), and stirring until completely dissolving to obtain interface transition layer solution. Preferably, the formulated interfacial transition layer solution is used within 4 hours. The modified resin-based shell is formed by curing a modified resin-based shell coating liquid, and the modified resin-based shell coating liquid is a phenolic resin/alumina organic-inorganic hybrid material prepared from phenolic resin and aluminum isopropoxide by a sol-gel method. The hybrid material has both toughness of resin and rigidity and heat resistance of inorganic matters. The preparation method of the modified resin-based shell coating liquid comprises the following steps: (1) Dissolving aluminum isopropoxide in absolute ethyl alcohol, heating in a water bath, stirring until the aluminum isopropoxide and the ethyl alcohol are completely clarified, obtaining a mixed solution of aluminum isopropoxide and the ethyl alcohol, slowly dripping the mixed solution of aluminum isopropoxide and the ethyl alcohol into the ethyl alcohol solution of phenolic resin, and stirring to obtain a component A; (2) Mixing deionized water and concentrated nitric acid to obtain 0.1 mol/L dilute nitric acid catalytic hydrolysate, slowly dropwise adding the dilute nitric acid catalytic hydrolysate into the component A liquid under continuous high-speed stirring, and dropwise adding the dilute nitric acid catalytic hydrolysate in a water bath at 35-40 ℃ for 1-1.5 hours; (3) And (3) continuously preserving heat and stirring