A biomimetic nanofiber network profile control agent, a preparation method and application thereof

Abstract

The present application relates to the technical field of oil field chemicals, and provides a kind of bionic nanofiber network profile control agent and its preparation method and application, bionic nanofiber network profile control agent includes white oil, 1, 4-butanediol, nanofiber membrane memory editing intermediate product and diphenylmethane diisocyanate-polyether prepolymer, the profile control agent has the characteristics of bionic spider web structure and shape memory property, after injection into formation, in situ shape change is realized in formation, changes from granular to nanofiber network structure, accumulates and stays in formation pore and forms nanofiber network blocking zone, when subsequent liquid flow is aqueous phase, the gap between nanofiber in the blocking zone shrinks, hinders water flow through, when subsequent liquid flow is oil phase, the gap between nanofiber in the blocking zone expands, reduces the percolation resistance to oil flow, realizes oil-water selective plugging.

Description

Technical Field

[0001] This invention relates to the field of oilfield chemical reagent technology, and more specifically, to a biomimetic nanofiber network modulator, its preparation method, and its application. Background Technology

[0002] After water injection development in oilfields enters the medium-to-high water-cut stage, the increased heterogeneity of the reservoir leads to the development of dominant seepage channels. Injected water rushes along the high-permeability zone, forming ineffective circulation, which severely reduces waterflood sweep efficiency and oil recovery rate. Chemical modifiers are one of the core technologies for addressing this problem. Currently, commonly used modifiers mainly include polymer gels, polymer microspheres, and pre-crosslinked expanded particles.

[0003] Although existing modulators have achieved a certain degree of plugging effect, they generally suffer from a key drawback: poor oil-water selectivity. When plugging high-permeability water channels, they easily invade oil-bearing pore throats, leading to a decrease in oil phase permeability and even blocking oil-producing sections, resulting in the negative effect of "controlling water but not increasing oil production." In recent years, although some studies have improved selectivity through chemical modification and particle size control, problems such as insufficient response precision to complex reservoirs and poor dynamic plugging matching still exist, making it difficult to achieve a high degree of selective differentiation between oil and water, and the risk of accidentally plugging oil layers remains unresolved. Therefore, developing novel modulators with biomimetic structures and intelligent response characteristics is a key requirement to support the goal of reducing water content and increasing oil production in high water-cut reservoirs. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a biomimetic nanofiber network modulator, its preparation method, and its application. This modulator possesses biomimetic spiderweb structure characteristics and shape memory properties. After injection into the formation, it can undergo in-situ shape changes within the formation, transforming from a granular form into a nanofiber network structure. It accumulates and remains within the formation pores, forming a nanofiber network sealing band. When the subsequent fluid flow is aqueous, the gaps between the nanofibers within this sealing band shrink, hindering water flow. When the subsequent fluid flow is oil, the gaps between the nanofibers within this sealing band expand, reducing the seepage resistance to oil flow and achieving selective oil-water sealing.

[0005] In a first aspect, the present invention provides a biomimetic nanofiber network modulator, comprising white oil, 1,4-butanediol, and a nanofiber membrane memory editing intermediate and a diphenylmethane diisocyanate-polyether prepolymer in a mass ratio of 1:(0.1-0.8); the mass ratio of the nanofiber membrane memory editing intermediate to the white oil is 1:(20-30); the mass ratio of 1,4-butanediol to the diphenylmethane diisocyanate-polyether prepolymer is 1:(12.5-50).

[0006] The intermediate product of nanofiber membrane memory editing is obtained by crushing, sieving and ball milling the nanofiber membrane. The nanofiber membrane is made by multi-layer alternating electrospinning of spinning solution A and spinning solution B.

[0007] Spinning solution A is obtained by dissolving the intermediate product PU in N,N-dimethylformamide, and spinning solution B is an aqueous solution of polyacrylic acid, polyvinyl alcohol and glutaraldehyde;

[0008] The intermediate product PU is obtained by reacting poly(ε-caprolactone) and isoflurone diisocyanate under the catalysis of dibutyltin laurylate, followed by chain extension with 1,4-butanediol.

[0009] The molecular weight of the diphenylmethane diisocyanate-polyether prepolymer is 2000-4000 g / mol.

[0010] Furthermore, the preparation of intermediate products for nanofiber membrane memory editing includes:

[0011] The nanofiber membrane was pulverized using a fine powder mill, passed through an 80-500 mesh sieve, and then transferred to a high-temperature ball mill for further grinding. The high-temperature ball mill grinding time was 30-60 minutes, the grinding speed was 200-400 rpm, and the grinding temperature was 50-60℃ to obtain the nanofiber membrane memory editing intermediate product.

[0012] Furthermore, the preparation of nanofiber membranes includes:

[0013] Nanofiber membranes were obtained by multi-layer alternating electrospinning with spinning solution A as the bottom layer and spinning solution B as the top layer at a temperature of 25℃ and humidity of <30%.

[0014] Furthermore, the concentration of the intermediate product PU in spinning solution A is 9-15%, corresponding to an electrospinning voltage of 10-22kV, a feed rate of 0.8-1.5mL / h, and a receiving distance of 18-24cm.

[0015] Furthermore, the concentrations of polyacrylic acid, polyvinyl alcohol, and glutaraldehyde in spinning solution B are 10-13%, 1.5-2.5%, and 0.2-0.5%, respectively, corresponding to an electrospinning voltage of 15-18kV, a feed rate of 0.38-0.9mL / h, and a receiving distance of 20-26cm.

[0016] Furthermore, the preparation of the intermediate product PU includes:

[0017] Poly(ε-caprolactone) and isoflurane diisocyanate were mixed and then purged with nitrogen for 20-30 minutes to remove oxygen. The mixture was then heated to 70-80℃ and stirred for 10-20 minutes. Dibutyltin laurylate was added and reacted for 1-2 hours. 1,4-Butanediol was added and reacted for 1-2 hours. After cooling, the mixture was vacuum dried at 40-50℃ for 45-50 hours to obtain the intermediate product PU.

[0018] Furthermore, the molar ratio of poly(ε-caprolactone) to isoflurane diisocyanate is 1:(2-3); the amount of dibutyltin laurylate added is 0.8-1.0% of the total mass of poly(ε-caprolactone) and isoflurane diisocyanate; and the molar ratio of 1,4-butanediol to isoflurane diisocyanate is 1:(1.2-1.5).

[0019] Secondly, based on the same inventive concept, the present invention provides a method for preparing the biomimetic nanofiber network modulator as described in any one of the first aspects, comprising the following steps:

[0020] The nanofiber membrane memory editing intermediate was dispersed in white oil, and diphenylmethane diisocyanate-polyether prepolymer was added. The mixture was stirred at 300-600 r / min for 20-40 min, 1,4-butanediol was added, and the temperature was raised to 50-60℃ for 4-6 h. After cooling, the mixture was centrifuged to obtain the biomimetic nanofiber network modulator.

[0021] Thirdly, based on the same inventive concept, this invention provides the application of the biomimetic nanofiber network modulator / drive agent described in any of the first aspects or the biomimetic nanofiber network modulator / drive agent prepared by any of the preparation methods described in any of the second aspects in modulator / drive operations in high water-cut reservoirs with a water cut > 90%.

[0022] Furthermore, the biomimetic nanofiber network modulator, in the form of nano-micro particles, is injected into high water-cut reservoirs at a rate of 0.2-0.3 mL / min for oil-water selective plugging.

[0023] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects:

[0024] 1. The biomimetic nanofiber network nano-modifier provided by this invention has controllable particle size and a wide range of adaptability to reservoir properties.

[0025] 2. The biomimetic nanofiber network nano-modifier provided by this invention has strong oil-water sensitivity and higher oil-water selectivity compared with traditional modifiers such as gels, particles, and microspheres.

[0026] 3. The biomimetic nanofiber network nano-modulator provided by this invention has good mechanical properties, is not easily damaged by underground shear, and has good long-term effectiveness after construction. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0029] The mechanism of action of the biomimetic nanofiber network modulator provided by this invention is as follows:

[0030] This biomimetic nanofiber network flood control agent has an initial particle size in the nanometer and micrometer range. It can enter the reservoir with injected water. Under the influence of reservoir temperature, the shape memory function of the polyurethane fibers (formed by spinning solution A) in the flood control agent is triggered, gradually transforming them from curled granules into a stretched network state. Simultaneously, the water-absorbing fibers (formed by spinning solution B) also stretch. Compared to the granular state, the expanded network state has an increased size, causing the biomimetic nanofiber network flood control agent to be retained and accumulated at the pore throat. Subsequently, the water-absorbing fibers gradually absorb water and expand in the formation water state, leading to a reduction or even complete disappearance of the pore size in the nanofiber network, thus blocking the subsequent aqueous phase. When the subsequent fluid flow is the oil phase, the water-absorbing fibers dehydrate and shrink, the pore size in the nanofiber network expands, and the fluid flow resistance decreases, allowing the oil phase to pass through smoothly. Through this selective oil-water blocking effect, the biomimetic nanofiber network flood control agent can effectively regulate the reservoir flow field, expanding the swept volume and oil recovery rate.

[0031] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed according to national standards. If no corresponding national standard exists, then generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0032] Example 1

[0033] This embodiment provides a biomimetic nanofiber network modulator, the preparation method of which includes the following process:

[0034] 11.4 g of poly(ε-caprolactone) and 0.45 g of isoflurane diisocyanate, after being vacuum dried and dehydrated, were added to a flask. Nitrogen gas was purged into the flask for 20 min, and the temperature was raised to 75 °C. After magnetic stirring for 15 min, 0.12 g of dibutyltin laurylate was added, and the reaction was allowed to proceed for 2 h. Then, 0.15 g of 1,4-butanediol was added, and the reaction was allowed to continue for 1 h. The mixture was then cooled to room temperature and vacuum dried at 40 °C for 48 h to obtain the intermediate product PU.

[0035] The intermediate product PU was dissolved in N,N-dimethylformamide (DMF) to prepare a spinning solution A with a concentration of 11%. Polyacrylic acid, polyvinyl alcohol, and glutaraldehyde were dissolved in deionized water to prepare a spinning solution B with a certain concentration. The concentrations of polyacrylic acid, polyvinyl alcohol, and glutaraldehyde in spinning solution B were 10%, 1.7%, and 0.5%, respectively. Spinning solution A was spun into the bottom layer under the conditions of temperature 25°C, humidity less than 30%, voltage 22kV, feed speed 1.0mL / h, and receiving distance 19cm. Spinning solution B was spun into the top layer under the conditions of temperature 25°C, humidity less than 30%, voltage 16kV, feed speed 0.5mL / h, and receiving distance 23cm. Multilayer alternating electrospinning was performed to finally obtain the intermediate product nanofiber membrane.

[0036] The nanofiber membrane was pulverized using a fine powder mill. The particle size of the pulverized nanofiber membrane powder was controlled by sieving through an 80-500 mesh sieve. The pulverized nanofiber membrane powder was then transferred to a high-temperature ball mill and ground under the conditions of 40 min grinding time, 300 rpm grinding rate, and 55 ℃ grinding temperature. After completion, the nanofiber membrane memory editing intermediate product was obtained.

[0037] The nanofiber membrane memory editing intermediate was dispersed in white oil, and then 22g of diphenylmethane diisocyanate-polyether prepolymer was added to the white oil. The mixture was stirred at room temperature for 30 minutes at 500r / min, followed by the addition of 1.76g of 1,4-butanediol and the temperature was raised to 55℃ for 5h. The mixture was then cooled to room temperature, and the solid product was separated by centrifugation to obtain biomimetic nanofiber network modulator product 1.

[0038] Example 2

[0039] This embodiment provides a biomimetic nanofiber network modulator, the preparation method of which includes the following process:

[0040] 12.5 g of poly(ε-caprolactone) and 0.68 g of isoflurane diisocyanate, after being vacuum dried and dehydrated, were added to a flask. Nitrogen gas was purged into the flask for 20 min, and the temperature was raised to 75 °C. After magnetic stirring for 15 min, 0.13 g of dibutyltin laurylate was added, and the reaction was allowed to proceed for 2 h. Then, 0.2 g of 1,4-butanediol was added, and the reaction was continued for 1 h. The mixture was then cooled to room temperature and vacuum dried at 40 °C for 48 h to obtain the intermediate product PU.

[0041] Intermediate product PU was dissolved in DMF to prepare a 15% spinning solution A. Polyacrylic acid, polyvinyl alcohol, and glutaraldehyde were dissolved in deionized water to prepare a spinning solution B of a certain concentration. The concentrations of polyacrylic acid, polyvinyl alcohol, and glutaraldehyde in spinning solution B were 11%, 2.5%, and 0.35%, respectively. Spinning solution A was spun into a bottom layer under the conditions of 25°C, humidity less than 30%, 22kV voltage, 1.0mL / h feed speed, and 19cm receiving distance. Spinning solution B was spun into a top layer under the conditions of 25°C, humidity less than 30%, 16kV voltage, 0.5mL / h feed speed, and 23cm receiving distance. Multilayer alternating electrospinning was performed to finally obtain the intermediate product nanofiber membrane.

[0042] The nanofiber membrane was pulverized using a fine powder mill. The particle size of the pulverized nanofiber membrane powder was controlled by sieving through an 80-500 mesh sieve. The pulverized nanofiber membrane powder was then transferred to a high-temperature ball mill and ground under the conditions of 40 min grinding time, 300 rpm grinding rate, and 55 ℃ grinding temperature. After completion, the nanofiber membrane memory editing intermediate product was obtained.

[0043] The nanofiber membrane memory editing intermediate was dispersed in white oil, and then 131g of diphenylmethane diisocyanate-polyether prepolymer was added to the white oil. The mixture was stirred at room temperature for 30 minutes at 500r / min, followed by the addition of 2.62g of 1,4-butanediol and the temperature was raised to 55℃ for 5h. The mixture was then cooled to room temperature, and the solid product was separated by centrifugation to obtain biomimetic nanofiber network modulator product 2.

[0044] Example 3

[0045] This embodiment provides a biomimetic nanofiber network modulator, the preparation method of which includes the following process:

[0046] 10.3 g of poly(ε-caprolactone) and 0.6 g of isoflurane diisocyanate, after being vacuum dried and dehydrated, were added to a flask. Nitrogen gas was purged into the flask for 20 min, and the temperature was raised to 75 °C. After magnetic stirring for 15 min, 0.09 g of dibutyltin laurylate was added, and the reaction was allowed to proceed for 2 h. Then, 0.16 g of 1,4-butanediol was added, and the reaction was continued for 1 h. The mixture was then cooled to room temperature and vacuum dried at 40 °C for 48 h to obtain the intermediate product PU.

[0047] Intermediate product PU was dissolved in DMF to prepare a 9% spinning solution A. Polyacrylic acid, polyvinyl alcohol, and glutaraldehyde were dissolved in deionized water to prepare a spinning solution B of a certain concentration. The concentrations of polyacrylic acid, polyvinyl alcohol, and glutaraldehyde in spinning solution B were 12%, 1.5%, and 0.3%, respectively. Spinning solution A was spun into the bottom layer under the conditions of 25°C, humidity less than 30%, 22kV voltage, 1.0mL / h feed speed, and 19cm receiving distance. Spinning solution B was spun into the top layer under the conditions of 25°C, humidity less than 30%, 16kV voltage, 0.5mL / h feed speed, and 23cm receiving distance. Multilayer alternating electrospinning was performed to finally obtain the intermediate product nanofiber membrane.

[0048] The nanofiber membrane was pulverized using a fine powder mill. The particle size of the pulverized nanofiber membrane powder was controlled by sieving through an 80-500 mesh sieve. The pulverized nanofiber membrane powder was then transferred to a high-temperature ball mill and ground under the conditions of 40 min grinding time, 300 rpm grinding rate, and 55 ℃ grinding temperature. After completion, the nanofiber membrane memory editing intermediate product was obtained.

[0049] The nanofiber membrane memory editing intermediate was dispersed in white oil, and then 55g of diphenylmethane diisocyanate-polyether prepolymer was added to the white oil. The mixture was stirred at room temperature for 30 minutes at 500r / min, followed by the addition of 2.48g of 1,4-butanediol and the temperature was raised to 55℃ for 5h. The mixture was then cooled to room temperature, and the solid product was separated by centrifugation to obtain the biomimetic nanofiber network modulator product 3.

[0050] Example 4

[0051] This embodiment provides a biomimetic nanofiber network modulator, the preparation method of which includes the following process:

[0052] 11.9 g of poly(ε-caprolactone) and 0.58 g of isoflurane diisocyanate, after being vacuum dried and dehydrated, were added to a flask. Nitrogen gas was purged into the flask for 20 min, and the temperature was raised to 75 °C. After magnetic stirring for 15 min, 0.11 g of dibutyltin laurylate was added, and the reaction was allowed to proceed for 2 h. Then, 0.18 g of 1,4-butanediol was added, and the reaction was allowed to continue for 1 h. The mixture was then cooled to room temperature and vacuum dried at 40 °C for 48 h to obtain the intermediate product PU.

[0053] Intermediate product PU was dissolved in DMF to prepare a 12% spinning solution A. Polyacrylic acid, polyvinyl alcohol, and glutaraldehyde were dissolved in deionized water to prepare a spinning solution B of a certain concentration. The concentrations of polyacrylic acid, polyvinyl alcohol, and glutaraldehyde in spinning solution B were 12.5%, 2.0%, and 0.2%, respectively. Spinning solution A was spun into the bottom layer under the conditions of 25°C, humidity less than 30%, 22kV voltage, 1.0mL / h feed speed, and 19cm receiving distance. Spinning solution B was spun into the top layer under the conditions of 25°C, humidity less than 30%, 16kV voltage, 0.5mL / h feed speed, and 23cm receiving distance. Multilayer alternating electrospinning was performed to finally obtain the intermediate product nanofiber membrane.

[0054] The nanofiber membrane was pulverized using a fine powder mill. The particle size of the pulverized nanofiber membrane powder was controlled by sieving through an 80-500 mesh sieve. The pulverized nanofiber membrane powder was then transferred to a high-temperature ball mill and ground under the conditions of 40 min grinding time, 300 rpm grinding rate, and 55 ℃ grinding temperature. After completion, the nanofiber membrane memory editing intermediate product was obtained.

[0055] The nanofiber membrane memory editing intermediate was dispersed in white oil, and then 102g of diphenylmethane diisocyanate-polyether prepolymer was added to the white oil. The mixture was stirred at room temperature for 30 minutes at 500r / min, followed by the addition of 2.9g of 1,4-butanediol and the temperature was raised to 55℃ for 5h. The mixture was then cooled to room temperature, and the solid product was separated by centrifugation to obtain biomimetic nanofiber network modulator product 4.

[0056] Example 5

[0057] This embodiment provides a biomimetic nanofiber network modulator, the preparation method of which includes the following process:

[0058] 10.8 g of poly(ε-caprolactone) and 0.47 g of isoflurane diisocyanate, after being vacuum dried and dehydrated, were added to a flask. Nitrogen gas was purged into the flask for 20 min, and the temperature was raised to 75 °C. After magnetic stirring for 15 min, 0.1 g of dibutyltin laurylate was added, and the reaction was allowed to proceed for 2 h. Then, 0.16 g of 1,4-butanediol was added, and the reaction was allowed to continue for 1 h. The mixture was then cooled to room temperature and vacuum dried at 40 °C for 48 h to obtain the intermediate product PU.

[0059] Intermediate product PU was dissolved in DMF to prepare a 14% spinning solution A. Polyacrylic acid, polyvinyl alcohol, and glutaraldehyde were dissolved in deionized water to prepare a spinning solution B of a certain concentration. The concentrations of polyacrylic acid, polyvinyl alcohol, and glutaraldehyde in spinning solution B were 13%, 2.2%, and 0.4%, respectively. Spinning solution A was spun into the bottom layer under the conditions of 25°C, humidity less than 30%, 22kV voltage, 1.0mL / h feed speed, and 19cm receiving distance. Spinning solution B was spun into the top layer under the conditions of 25°C, humidity less than 30%, 16kV voltage, 0.5mL / h feed speed, and 23cm receiving distance. Multilayer alternating electrospinning was performed to finally obtain the intermediate product nanofiber membrane.

[0060] The nanofiber membrane was pulverized using a fine powder mill. The particle size of the pulverized nanofiber membrane powder was controlled by sieving through an 80-500 mesh sieve. The pulverized nanofiber membrane powder was then transferred to a high-temperature ball mill and ground for 40 minutes at a grinding rate of 300 rpm and a grinding temperature of 55°C. After the grinding was completed, the nanofiber membrane memory editing intermediate product was obtained.

[0061] The nanofiber membrane memory editing intermediate was dispersed in white oil, and then 113g of diphenylmethane diisocyanate-polyether prepolymer was added to the white oil. The mixture was stirred at room temperature for 30 minutes at 500r / min, followed by the addition of 2.81g of 1,4-butanediol and the temperature was raised to 55℃ for 5h. The mixture was then cooled to room temperature, and the solid product was separated by centrifugation to obtain the biomimetic nanofiber network modulator product 5.

[0062] Comparative Example 1

[0063] This comparative example provides a biomimetic nanofiber network modulator, the preparation method of which includes the following process:

[0064] 13.8 g of poly(ε-caprolactone) and 0.23 g of isoflurane diisocyanate, after being vacuum dried and dehydrated, were added to a flask. Nitrogen gas was purged into the flask for 20 min, and the temperature was raised to 75 °C. After magnetic stirring for 15 min, 0.08 g of dibutyltin laurylate was added, and the reaction was allowed to proceed for 2 h. Then, 0.19 g of 1,4-butanediol was added, and the reaction was allowed to continue for 1 h. The mixture was then cooled to room temperature and vacuum dried at 40 °C for 48 h to obtain the intermediate product PU.

[0065] Intermediate product PU was dissolved in DMF to prepare a 14% spinning solution A. Polyacrylic acid, polyvinyl alcohol, and glutaraldehyde were dissolved in deionized water to prepare a spinning solution B of a certain concentration. The concentrations of polyacrylic acid, polyvinyl alcohol, and glutaraldehyde in spinning solution B were 9.5%, 2.0%, and 0.2%, respectively. Spinning solution A was spun into a bottom layer under the conditions of 25°C, humidity less than 30%, 21kV voltage, 1.3mL / h feed speed, and 22cm receiving distance. Spinning solution B was spun into a top layer under the conditions of 25°C, humidity less than 30%, 16kV voltage, 0.6mL / h feed speed, and 20cm receiving distance. Multilayer alternating electrospinning was performed to finally obtain the intermediate product nanofiber membrane.

[0066] The nanofiber membrane was pulverized using a fine powder mill. The particle size of the pulverized nanofiber membrane powder was controlled by sieving through an 80-500 mesh sieve. The pulverized nanofiber membrane powder was then transferred to a high-temperature ball mill and ground for 50 minutes at a grinding rate of 350 rpm and a grinding temperature of 55°C. After the grinding was completed, the nanofiber membrane memory editing intermediate product was obtained.

[0067] The nanofiber membrane memory editing intermediate was dispersed in white oil, and then 60g of diphenylmethane diisocyanate-polyether prepolymer was added to the white oil. The mixture was stirred at room temperature for 30 minutes at 500r / min, followed by the addition of 2.4g of 1,4-butanediol and the temperature was raised to 55℃ for 5h. The mixture was then cooled to room temperature, and the solid product was separated by centrifugation to obtain comparative product 1.

[0068] Comparative Example 2

[0069] This comparative example provides a biomimetic nanofiber network modulator, the preparation method of which includes the following process:

[0070] 14.5 g of poly(ε-caprolactone) and 0.21 g of isoflurane diisocyanate, after being vacuum dried and dehydrated, were added to a flask. Nitrogen gas was purged into the flask for 20 min, and the temperature was raised to 75 °C. After magnetic stirring for 15 min, 0.09 g of dibutyltin laurylate was added, and the reaction was allowed to proceed for 2 h. Then, 0.17 g of 1,4-butanediol was added, and the reaction was allowed to continue for 1 h. The mixture was then cooled to room temperature and vacuum dried at 40 °C for 48 h to obtain the intermediate product PU.

[0071] Intermediate product PU was dissolved in DMF to prepare a 13% spinning solution A. Polyacrylic acid, polyvinyl alcohol, and glutaraldehyde were dissolved in deionized water to prepare a spinning solution B of a certain concentration. The concentrations of polyacrylic acid, polyvinyl alcohol, and glutaraldehyde in spinning solution B were 5%, 1.0%, and 0.1%, respectively. Spinning solution A was spun into the bottom layer under the conditions of 25°C, humidity less than 30%, 20kV voltage, 1.1mL / h feed speed, and 18cm receiving distance. Spinning solution B was spun into the top layer under the conditions of 25°C, humidity less than 30%, 18kV voltage, 0.38mL / h feed speed, and 26cm receiving distance. Multilayer alternating electrospinning was performed to finally obtain the intermediate product nanofiber membrane.

[0072] The nanofiber membrane was pulverized using a fine powder mill. The particle size of the pulverized nanofiber membrane powder was controlled by sieving through an 80-500 mesh sieve. The pulverized nanofiber membrane powder was then transferred to a high-temperature ball mill and ground under the conditions of 50 min grinding time, 400 rpm grinding rate, and 60 ℃ grinding temperature. After completion, comparative product 2 was obtained.

[0073] Comparative Example 3

[0074] This comparative example provides a biomimetic nanofiber network modulator, the preparation method of which includes the following process:

[0075] 5.6 g of poly(ε-caprolactone) and 0.47 g of isoflurane diisocyanate, after being vacuum dried and dehydrated, were added to a flask. Nitrogen gas was purged into the flask for 20 min, and the temperature was raised to 75 °C. After magnetic stirring for 15 min, 0.06 g of dibutyltin laurylate was added, and the reaction was allowed to proceed for 2 h. Then, 0.1 g of 1,4-butanediol was added, and the reaction was continued for 1 h. The mixture was then cooled to room temperature and vacuum dried at 40 °C for 48 h to obtain the intermediate product PU.

[0076] Intermediate product PU was dissolved in DMF to prepare a 12% spinning solution A. Polyacrylic acid, polyvinyl alcohol, and glutaraldehyde were dissolved in deionized water to prepare a spinning solution B of a certain concentration. The concentrations of polyacrylic acid, polyvinyl alcohol, and glutaraldehyde in spinning solution B were 9.0%, 1.3%, and 0.2%, respectively. Spinning solution A was spun into a bottom layer under the conditions of 25°C, humidity less than 30%, 18kV voltage, 0.8mL / h feed speed, and 19cm receiving distance. Spinning solution B was spun into a top layer under the conditions of 25°C, humidity less than 30%, 15kV voltage, 0.55mL / h feed speed, and 23cm receiving distance. Multilayer alternating electrospinning was performed to finally obtain the intermediate product nanofiber membrane.

[0077] The nanofiber membrane was pulverized using a fine powder mill. The particle size of the pulverized nanofiber membrane powder was controlled by sieving through an 80-500 mesh sieve. The pulverized nanofiber membrane powder was then transferred to a high-temperature ball mill and ground under the conditions of 35 min grinding time, 300 rpm grinding rate, and 55℃ grinding temperature. After completion, the nanofiber membrane memory editing intermediate product was obtained.

[0078] The nanofiber membrane memory editing intermediate was dispersed in white oil, and then 40g of diphenylmethane diisocyanate-polyether prepolymer was added to the white oil. The mixture was stirred at room temperature for 30 minutes at 500r / min, followed by the addition of 1.6g of 1,4-butanediol and the temperature was raised to 55℃ for 5h. The mixture was then cooled to room temperature, and the solid product was separated by centrifugation to obtain comparative product 3.

[0079] Comparative Example 4

[0080] This comparative example provides a biomimetic nanofiber network modulator, the preparation method of which includes the following process:

[0081] 5.8 g of poly(ε-caprolactone) and 0.55 g of isoflurane diisocyanate, after being vacuum dried and dehydrated, were added to a flask. Nitrogen gas was purged into the flask for 20 min, and the temperature was raised to 75 °C. After magnetic stirring for 15 min, 0.07 g of dibutyltin laurylate was added, and the reaction was allowed to proceed for 2 h. Then, 0.1 g of 1,4-butanediol was added, and the reaction was continued for 1 h. The mixture was then cooled to room temperature and vacuum dried at 40 °C for 48 h to obtain the intermediate product PU.

[0082] Intermediate product PU was dissolved in DMF to prepare a 13% spinning solution A. Polyacrylic acid, polyvinyl alcohol, and glutaraldehyde were dissolved in deionized water to prepare a spinning solution B of a certain concentration. The concentrations of polyacrylic acid, polyvinyl alcohol, and glutaraldehyde in spinning solution B were 9.0%, 1.8%, and 0.35%, respectively. Spinning solution A was spun into the bottom layer under the conditions of 25°C, humidity less than 30%, 15kV voltage, 1.1mL / h feed speed, and 21cm receiving distance. Spinning solution B was spun into the top layer under the conditions of 25°C, humidity less than 30%, 17kV voltage, 0.46mL / h feed speed, and 22cm receiving distance. Multilayer alternating electrospinning was performed to finally obtain the intermediate product nanofiber membrane.

[0083] The nanofiber membrane was pulverized using a fine powder mill. The particle size of the pulverized nanofiber membrane powder was controlled by sieving through an 80-500 mesh sieve. The pulverized nanofiber membrane powder was then transferred to a high-temperature ball mill and ground under the conditions of 45 min grinding time, 200 rpm grinding rate, and 60 ℃ grinding temperature. After completion, comparative product 4 was obtained.

[0084] To better understand the present invention, the following tests were performed on the products obtained in the embodiments and comparative examples.

[0085] Test Example 1

[0086] This test example applies a shape memory test to the products obtained in the above embodiments and comparative examples. The test results are as follows:

[0087] The shape memory agent was dispersed in a sodium chloride solution with a mineralization of 10000 mg / L. The prepared solution was then sealed and placed in ovens at different temperatures. After 5 days in the ovens, the product was removed and its morphology was observed under a microscope to analyze its shape memory properties.

[0088] The results are shown in Table 1:

[0089]

[0090] Table 1 shows that Comparative Example 3 exhibits partial fiber stretching at 90℃, while Example 3 is fully stretched into a network structure at 90℃, with a lower shape recovery temperature than Comparative Example 3. The comparison indicates that the main component affecting the shape memory capability of the biomimetic nanofiber network modulator is poly(ε-caprolactone). An increase in the proportion of poly(ε-caprolactone) leads to an increase in the soft segment content, resulting in a lower shape recovery temperature for the modulator. Comparative Example 2 is fully stretched into a network structure at 50℃, while Comparative Example 4 exhibits partial fiber stretching at 50℃, with a higher shape recovery temperature than Comparative Example 2. This indicates that the main component affecting the shape memory capability of the biomimetic nanofiber network modulator is isoflurane diisocyanate. An increase in the proportion of isoflurane diisocyanate leads to an increase in the hard segment content, resulting in a higher shape recovery temperature for the modulator.

[0091] Because the addition of white oil and diphenylmethane diisocyanate-polyether prepolymer during the preparation process causes a polyurethane film to form on the outermost layer of the modulator product, the outermost polyurethane film begins to decompose when the temperature reaches 55-60℃. This triggers the shape memory function of the internal fiber network of the modulator, which gradually transforms from a curled granular state to a stretched network state. Modulator products without this step will directly undergo the shape memory change process of gradually transforming from a curled granular state to a stretched network state.

[0092] Test Example 2

[0093] This test example examines the erosion resistance of the products obtained in the above embodiments and comparative examples. The test results are as follows:

[0094] An artificial core with a length of 10.5 cm, a diameter of 2.48 cm, and a permeability of 127 mD was placed in a core holder. The modulator product was placed at the temperature in Test Example 1 above, where each part was fully expanded into a network structure, for ten days to allow it to fully expand. Then, it was removed from the oven and the modulator product was injected at an injection rate of 0.2 mL / min. Subsequently, 20 PV of water was injected, and the permeability of the core after plugging was measured. The plugging rate = (permeability before plugging - permeability after plugging) / permeability before plugging. The scour resistance performance of the modulator was evaluated by the plugging rate.

[0095] The results are shown in Table 2:

[0096]

[0097] Table 2 shows that Example 3 achieved a blocking rate of 95.37%, indicating good blocking performance, while Comparative Example 2 achieved a blocking rate of 78.15%, indicating poor blocking performance. Comparative Example 2 increased the proportion of poly(ε-caprolactone) compared to Example 3, indicating that poly(ε-caprolactone) is the main component affecting the erosion resistance of the biomimetic nanofiber network modulator. The increased proportion of poly(ε-caprolactone) leads to an increase in the soft segment content, making the soft segments more prone to hydrolysis and thus reducing the erosion resistance of the modulator.

[0098] Example 2 showed a blocking rate of 94.08%, indicating good blocking performance, while Comparative Example 1 showed a blocking rate of 80.58%, indicating poor blocking performance. Example 2 increased the content of isoflurone diisocyanate compared to Comparative Example 1, indicating that isoflurone diisocyanate is the main component affecting the erosion resistance of the biomimetic nanofiber network modulator. The increased proportion of isoflurone diisocyanate leads to an increase in the hard segment content, which enhances the mechanical strength of the material and thus improves the erosion resistance of the modulator.

[0099] Test Example 3

[0100] This test example performs an oil-water selectivity test on the products obtained from the above embodiments and comparative examples. The test results are as follows:

[0101] Artificial cores were placed in a core displacement device, and the oil phase permeability (Ka) of the cores before injection of the displacement modifier was measured. o1 ) and water phase permeability (K w1 The prepared modifier system was injected at a confining pressure of 5 MPa and an injection rate of 0.3 ml / min. The oil phase permeability (Ka) after modifier injection was measured using oil displacement cores. o2 ); water displacement core was used to determine the water phase permeability (K) after injection of the modulator. w2 The oil phase plugging rate and the water phase plugging rate are shown in Equations 1 and 2.

[0102] Formula 1;

[0103] Equation 2.

[0104] The results are shown in Table 3:

[0105]

[0106] Table 3 shows that Examples 1-5 and Comparative Examples 1, 3, and 4 exhibit high blocking rates for the aqueous phase but very low blocking rates for the oil phase, demonstrating excellent oil-water selectivity. Comparative Example 2, however, shows a higher blocking rate for the oil phase (58.36%) and a lower blocking rate for the aqueous phase (46.87%), indicating poor oil-water selectivity. Comparative Example 2 has a lower polyacrylic acid content compared to Examples 1-5 and Comparative Examples 1, 3, and 4, suggesting that polyacrylic acid is the main component affecting the oil-water selectivity of the biomimetic nanofiber network modulator. The water-absorbing fibers formed by polyacrylic acid gradually absorb water and swell in the formation water state, leading to a reduction or even complete disappearance of the pore size in the nanofiber network, thus blocking the subsequent formation of the aqueous phase.

[0107] When the subsequent liquid flow is an oil phase, the absorbent fibers dehydrate and shrink, the pore size in the nanofiber network expands, the liquid flow resistance decreases, and the oil phase passes through smoothly. A comparison of Example 4 and Example 1 shows that increasing the polyacrylic acid content enhances the water absorption and swelling capacity of the formed absorbent fibers, thereby increasing the oil-water selectivity of the modulator product.

[0108] Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible subranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the range referred to.

[0109] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A biomimetic nanofiber network modulator, characterized in that, The biomimetic nanofiber network modulator comprises white oil, 1,4-butanediol, and a nanofiber membrane memory editing intermediate and a diphenylmethane diisocyanate-polyether prepolymer in a mass ratio of 1:(0.1-0.8); the mass ratio of the nanofiber membrane memory editing intermediate to the white oil is 1:(20-30); the mass ratio of the 1,4-butanediol to the diphenylmethane diisocyanate-polyether prepolymer is 1:(12.5-50). The nanofiber membrane memory editing intermediate product is obtained by crushing, sieving and ball milling the nanofiber membrane. The nanofiber membrane is made by multi-layer alternating electrospinning of spinning solution A and spinning solution B. The spinning solution A is obtained by dissolving the intermediate product PU in N,N-dimethylformamide, and the spinning solution B is an aqueous solution of polyacrylic acid, polyvinyl alcohol and glutaraldehyde; The intermediate product PU is obtained by reacting poly(ε-caprolactone) and isoflurone diisocyanate under dibutyltin laurylate catalysis, followed by chain extension with 1,4-butanediol; the molar ratio of poly(ε-caprolactone) to isoflurone diisocyanate is 1:(2-3). The diphenylmethane diisocyanate-polyether prepolymer has a molecular weight of 2000-4000 g / mol.

2. The modulator / redirector according to claim 1, characterized in that, The preparation of the nanofiber membrane memory editing intermediate product includes: The nanofiber membrane is pulverized using a fine powder mill, passed through an 80-500 mesh sieve, and then transferred to a high-temperature ball mill for grinding. The grinding time in the high-temperature ball mill is 30-60 minutes, the grinding speed is 200-400 rpm, and the grinding temperature is 50-60°C to obtain the nanofiber membrane memory editing intermediate product.

3. The modulator according to claim 1, characterized in that, The preparation of the nanofiber membrane includes: The nanofiber membrane is obtained by multi-layer alternating electrospinning with the spinning solution A as the bottom layer and the spinning solution B as the top layer at a temperature of 25°C and a humidity of <30%.

4. The modulator according to claim 3, characterized in that, The intermediate product PU in the spinning solution A has a concentration of 9-15%, corresponding to an electrospinning voltage of 10-22kV, a feed rate of 0.8-1.5mL / h, and a receiving distance of 18-24cm.

5. The modulator according to claim 3, characterized in that, The concentrations of polyacrylic acid, polyvinyl alcohol, and glutaraldehyde in the spinning solution B are 10-13%, 1.5-2.5%, and 0.2-0.5%, respectively, corresponding to an electrospinning voltage of 15-18kV, a feed rate of 0.38-0.9mL / h, and a receiving distance of 20-26cm.

6. The modulator / redirector according to claim 1, characterized in that, The preparation of the intermediate product PU includes: Poly(ε-caprolactone) and isoflurane diisocyanate were mixed and then purged with nitrogen for 20-30 minutes to remove oxygen. The mixture was then heated to 70-80°C and stirred for 10-20 minutes. Dibutyltin laurylate was added and reacted for 1-2 hours. 1,4-Butanediol was added and reacted for 1-2 hours. After cooling, the mixture was vacuum dried at 40-50°C for 45-50 hours to obtain the intermediate product PU.

7. The modulator according to claim 6, characterized in that, The amount of dibutyltin laurylate added is 0.8-1.0% of the total mass of poly(ε-caprolactone) and isoflurone diisocyanate; the molar ratio of 1,4-butanediol to isoflurone diisocyanate is 1:(1.2-1.5).

8. A method for preparing a biomimetic nanofiber network modulator according to any one of claims 1-7, characterized in that, The preparation method of the biomimetic nanofiber network modulator includes the following steps: The nanofiber membrane memory editing intermediate was dispersed in white oil, and diphenylmethane diisocyanate-polyether prepolymer was added. The mixture was stirred at 300-600 r / min for 20-40 min, 1,4-butanediol was added, and the temperature was raised to 50-60℃ for 4-6 h. After cooling, the mixture was centrifuged to obtain the biomimetic nanofiber network modulator.

9. The application of any one of the biomimetic nanofiber network modulators according to claims 1-7 in modulator operations of high water-cut reservoirs with a water cut > 90%.

10. The application according to claim 9, characterized in that, The biomimetic nanofiber network modulator is injected into the high water-cut reservoir in the form of nano-micro particles at a rate of 0.2-0.3 mL / min for oil-water selective plugging.

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