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CN-119592002-B - Multiple emulsion with high-precision gas-sensitive fracturing tracing capability and preparation method and application thereof

CN119592002BCN 119592002 BCN119592002 BCN 119592002BCN-119592002-B

Abstract

A multiple emulsion with high-precision gas-sensitive fracturing tracing capability and a preparation method and application thereof belong to the technical field of functional materials. Aiming at the problems that in the prior art, reports on gas phase tracers in unconventional reservoir fracturing effect evaluation are few, and W/O/W emulsion with sensitive response characteristics to hydrocarbon gases in a stratum reservoir does not exist, and further three-phase yield high-efficiency monitoring of underground oil, gas and water is realized, the invention provides a W/O/W type multiple emulsion which is prepared by taking solution with small molecular gaseous hydrocarbon sensitivity as an oil phase, using modified starch particles to replace a traditional small molecular surfactant as a stabilizer to stabilize Pickering emulsion. The multiple emulsion can realize the release of the small molecular rare earth tracer material in fracturing flowback fluid and underground oil gas, and further realize the efficient monitoring of the three-phase yield of underground oil gas and water and the analysis of the fracture network shape and the profile of an oil gas producing layer formed by fracturing construction.

Inventors

  • ZHANG FAN
  • XU KUN
  • CHI HUI
  • HUANG XIAONA
  • BAI YUNGANG
  • DONG XIAOTONG
  • WANG PIXIN

Assignees

  • 中国科学院长春应用化学研究所

Dates

Publication Date
20260508
Application Date
20230907

Claims (8)

  1. 1. A multiple emulsion with gas-sensitive fracturing tracing capability is characterized in that the multiple emulsion is a W/O/W emulsion, the W/O/W emulsion is composed of 70-90% of an oil phase and 10-30% of a water phase based on 100% of the W/O/W emulsion, the oil phase is a stable water-in-oil emulsion, the water phase is prepared by dispersing solid particle surfactants in water, the water-in-oil emulsion is composed of 40-60% of the oil phase and 40-60% of the water phase based on 100% of the water-in-oil emulsion, the oil phase of the water-in-oil emulsion is prepared from an oil phase solvent, an oil phase tracer, a rubber grafting gas-sensitive material and a nonionic surfactant, the water phase of the water-in-oil emulsion is prepared from an aqueous phase tracer and water, and the solid particle surfactants are any one of modified SiO 2 , modified cellulose and modified starch; the preparation method of the rubber grafted gas-sensitive material comprises the following steps: ① Mixing one or more than two of acrylic ester monomer, alkyl olefine acid monomer and styrene monomer with solvent to obtain monomer solution with total monomer mass concentration of 20-40%; ② Swelling nonpolar or weakly polar rubber particles in the monomer solution obtained in the step ① to obtain a prepolymer; ③ And mixing the prepolymer obtained in the step ② with a release agent, performing graft polymerization under the condition of initiating polymerization, and drying and crushing the product to obtain the rubber graft gas-sensitive material.
  2. 2. The multiple emulsion of claim 1, wherein the oil phase tracer is present in the oil phase of the water-in-oil emulsion in an amount of 25% by mass, the rubber graft gas sensitive material is present in an amount of 30% by mass, and the nonionic surfactant is present in an amount of 3% to 10% by mass.
  3. 3. The multiple emulsion of claim 1, wherein the solvent in step ① is any one of benzene, toluene or xylene, and the mass ratio of the prepolymer to the release agent in step ③ is 1:1.
  4. 4. The multiple emulsion of claim 2, wherein the oil phase tracer is one or a combination of two or more liquid hydrocarbon compounds.
  5. 5. The multiple emulsion of claim 2, wherein the nonionic surfactant is span 20 or span 80, or a combination of span 20 and span 80.
  6. 6. The multiple emulsion of claim 1, wherein the water-in-oil emulsion comprises 25% of an aqueous phase tracer by mass and the aqueous phase tracer is one or a combination of more than two of rare earth salt compounds.
  7. 7. A method of preparing a multiple emulsion according to any one of claims 1 to 6, comprising the steps of: (1) Preparation of a water-in-oil emulsion: A) Dispersing a rubber grafted gas-sensitive material, an oil phase tracer and a surfactant in toluene to serve as an oil phase; b) Dissolving an aqueous phase tracer in water as an aqueous phase; C) Mixing the oil phase in the step A) and the water phase in the step B), and homogenizing and emulsifying to obtain water-in-oil emulsion; (2) Preparation of a water-in-oil-in-water emulsion: a) Taking the water-in-oil emulsion obtained in the step (1) as an oil phase; b) Dispersing solid particles with a water contact angle of 15-80 degrees in water as a surfactant to serve as a water phase; c) Mixing the oil phase in the step a) with the water phase in the step b), and homogenizing and emulsifying to obtain the water-in-oil-in-water emulsion.
  8. 8. Use of the multiple emulsion according to any one of claims 1-6 for the realization of the efficient monitoring of the three-phase production of oil, gas and water in the well, the analysis of the shape of the fracture network formed by the fracturing construction and the profile of the oil and gas producing layer.

Description

Multiple emulsion with high-precision gas-sensitive fracturing tracing capability and preparation method and application thereof Technical Field The invention belongs to the technical field of functional materials, and particularly relates to a multiple emulsion with high-precision gas-sensitive fracturing tracing capability, and a preparation method and application thereof. Background At present, the exploration amount of unconventional oil gas resources such as domestic shale oil gas, compact oil gas and the like is increased year by year, the development demand amount of natural gas, shale gas and the like is huge, and multistage hydraulic fracturing is gradually becoming a common technical means for the development of the oil field. The characterization of the fracturing fracture is an important link in the horizontal well fracturing development process, and the method for evaluating the fracturing effect at the present stage is mainly described and predicted according to geological data, a numerical simulation method, certain ion concentration change of flowback fluid and the like, and is mainly an empirical method or a semi-empirical method, and has poor universality and certain limitation. The fracturing tracing technology is used as a fracturing effect evaluation means, and the concentration change of the tracer in the flowback fluid of each fracturing layer section can be monitored to indirectly obtain and analyze flowback conditions of fracturing fluid of each layer section, capacity conditions of each reservoir in different periods, fluid production sections in the initial stage of production and fluid production contribution rates of each layer section in the fracturing process, and meanwhile, the fracturing measure effect is rapidly and effectively evaluated, so that the fracturing effect evaluation method has an important effect on unconventional oil and gas development and has huge application potential. The types of tracers in the fracturing tracing technology mainly comprise an aqueous phase tracer, an oil phase tracer and a gas phase tracer. But few reports are currently reported for evaluation of gas phase tracers in unconventional reservoir fracturing effects. The W/O/W emulsion is used as a good carrier for controlling release, and the outermost water phase has good compatibility with a cement paste system, and can be used as a protective layer to play a certain role in protecting the water phase and oil phase tracers wrapped in the internal phase. Therefore, if a W/O/W emulsion with sensitive response characteristic to hydrocarbon gas in a stratum oil reservoir can be developed, a polymer network is increased, so that the release rate of a tracer is increased, the purpose of transmitting information is achieved, and the method has important significance in realizing the efficient monitoring of underground oil-gas-water three-phase yield, the analysis of the fracture network shape formed by fracturing construction and the analysis of the profile of an oil-gas production layer. Disclosure of Invention In order to solve the problems that in the prior art, reports on gas phase tracers in unconventional reservoir fracturing effect evaluation are few, W/O/W emulsion with sensitive response characteristics to hydrocarbon gases in a stratum reservoir does not exist, and further the three-phase yield of underground oil-gas-water is effectively monitored, and the like, the invention provides a method for stabilizing Pickering emulsion by taking a material with small molecular gaseous hydrocarbon sensitivity as an oil phase and utilizing modified starch particles to replace a traditional small molecular surfactant as a stabilizer, wherein the prepared W/O/W type multiple emulsion is used for realizing release of a small molecular rare earth tracer material in fracturing flowback fluid and underground oil-gas bodies and analyzing the shapes of fracture networks and sections of oil-gas producing layers formed by underground oil-gas-water three-phase yield efficient monitoring and fracturing construction. In order to achieve the technical effects, the invention provides the following technical scheme: The first object of the invention is to provide a multiple emulsion with gas-sensitive fracturing tracing capability, wherein the multiple emulsion is a W/O/W emulsion, the W/O/W emulsion is composed of 70-90% of oil phase and 10-30% of water phase based on 100% of the W/O/W emulsion, the oil phase is a stable water-in-oil emulsion, the water phase is prepared by dispersing solid particle surfactant in water, the water-in-oil emulsion is composed of 40-60% of oil phase and 40-60% of water phase based on 100% of the water-in-oil emulsion, the oil phase of the water-in-oil emulsion is prepared from an oil phase solvent, an oil phase tracer, a rubber grafting gas-sensitive material and a nonionic surfactant, and the water phase of the water-in-oil emulsion is prepared from an aqueous phase tracer and wate