CN112322265A

CN112322265A - Finger-advancing front edge locking nano-worm and preparation method thereof

Info

Publication number: CN112322265A
Application number: CN202011075208.1A
Authority: CN
Inventors: 施雷庭; 曾媛; 曾志伟; 王路; 芦琪文; 汪超; 朱珊珊
Original assignee: Southwest Petroleum University
Current assignee: Southwest Petroleum University
Priority date: 2020-10-09
Filing date: 2020-10-09
Publication date: 2021-02-05

Abstract

The invention discloses a finger-entering frontier locking nano-worm and a preparation method thereof, which consists of a colloid assembling agent, a polymer, a composite monomer system, a colloid protective agent, a surfactant and an encapsulation coating shell, and is prepared by mixing the components, adding water and stirring at normal temperature. The nano worms wrapped by the wrapping shells reach a certain position when the injected rock core reaches, the wrapping shells on the outermost layers are disintegrated, the core main body nano worms in the wrapping shells are released, the nano worms have certain deformation plugging capability, the viscous fingering phenomenon is generated, the fluidity control is realized on the displacement front edge, the front edge is changed, a new front edge is formed after the water drive front edge is locked, the swept volume of the injected displacement fluid can be enlarged, and the purpose of front edge control is achieved.

Description

Finger-advancing front edge locking nano-worm and preparation method thereof

Technical Field

The invention belongs to the technical field of oilfield chemistry, and particularly relates to a finger-advance front edge locking nano-worm and a preparation method thereof.

Background

After long-term development, the existing partial water-drive old oil field enters a 'dual-high' development stage, and the recovery ratio which can be achieved after primary and secondary oil recovery is only 30% -40%, so that the improvement of the crude oil recovery ratio is the leading research subject and the major problem faced at present. In order to improve the recovery ratio of crude oil, the exploitation of residual oil is an important way for improving the recovery ratio, and the prior art usually adopts chemical, thermal and microbial displacement and mixed displacement of water injection, polymer injection, gas injection and the like. The surfactant flooding oil also attracts the extensive attention and research application in the field of tertiary oil recovery in recent years, however, because the surfactant flooding oil lacks a mobility control agent represented by a polymer, the viscosity of the aqueous solution of the surfactant flooding oil is very low, the viscosity fingering behavior in a heterogeneous oil reservoir is very prominent, and further the problems that the displacement front is not stably propelled in the multi-phase seepage process of a porous medium and the displacement efficiency is directly influenced are caused.

The nanotechnology has long been applied to the aspect of improving the recovery efficiency of crude oil. The nano particles have large surface area, and can generate huge diffusion driving force along with the rise of temperature, and researches show that the nano particles can change the wettability of reservoir rock and reduce the interfacial tension, so that the nano technology has early application in the aspect of improving the recovery ratio of crude oil. Among them, applied include nano metal oxide, nano organic particles, nano inorganic particles, etc.

The shape and appearance of the existing nanoparticle materials applied to the enhanced oil recovery cannot change the size of the adapted pore throat after the external environment such as the pore throat is changed, and the inherent reason of no appearance property change causes the effect of the application of the nanotechnology in the enhanced oil recovery to be reduced. The finger-advance front edge locking nano-insect provided by the invention well overcomes the defect. The appearance shape of the reservoir can be changed at different permeability, the creep property is good, the plugging to a low permeable layer is realized, and the crude oil of a high permeable layer is fully used.

Disclosure of Invention

The invention aims to provide a finger-advancing front edge locking nano worm, wherein the outermost layer of a nano worm colloid system is an encapsulated three-dimensional circular coating shell, and the nano worm can reach a specified position of an oil layer to be released, so that the control on a displacement front edge is well realized, the swept volume is improved, and the recovery ratio is increased.

In order to achieve the technical purpose, the invention is specifically realized by the following technical scheme:

a finger-entering frontier locking nano-worm is composed of a colloid assembling agent, a polymer, a composite monomer system, a colloid protective agent, a surfactant and an encapsulation coating shell, wherein the colloid assembling agent comprises 0.55-2.56% of sodium alginate, 8.7-10.2% of gelatin, 15-16% of guar gum, 2.3-5.8% of polyvinyl alcohol, 6.9-15% of carrageenan and 2.5-5% of acrylic acid, the polymer comprises 0.05-2% of polyacrylamide, the composite monomer system comprises 4.5-6.2% of laboratory self-made branched monomer P, 2-8% of acrylamide, 0.3-5% of 2-acrylamide-2-methylpropanesulfonic Acid (AMPS) and 5-8.2% of methacrylamide ethyl tetramethylammonium chloride, the protective agent comprises 1.2-2% of colloid hydroxyethyl cellulose, and the surfactant comprises 2.1-3.5% of sodium lignosulfonate, the encapsulation coating shell is 8 to 10 percent of carbon nano tube, and the balance is complemented by water; the monomer P is:

preferably, the advancing front edge locking nano-insect comprises the following components in percentage by mass: 2.33% of sodium alginate, 9.372% of gelatin, 15.02% of guar gum, 3.86% of polyvinyl alcohol, 11.25% of carrageenan, 3.65% of acrylic acid, 5.23% of monomer P, 4.12% of acrylamide, 2.65% of 2-acrylamide-2-methylpropanesulfonic Acid (AMPS), 5.14% of methacrylamide ethyl tetramethylammonium chloride, 1.35% of hydroxyethyl cellulose, 2.45% of sodium lignin sulfonate, 9.05% of carbon nanotubes and water for balancing.

The carbon nanotube structure is obtained by modifying the following method: the carbon nano tube is treated for 2 days at the high temperature of 800-1000 ℃, and is put into the tannin and Pd solution to remove impurities after being completely cooled.

According to the invention, carrageenan plays a main adhesion and wrapping role in the whole colloid system aggregation, the viscosity of the acrylic emulsion in the whole colloid system is increased, a branched monomer P self-made in a laboratory has amphipathy, the wettability of the rock surface can be changed timely, the control of the fluidity is increased in an auxiliary manner, a colloid protective agent plays a role in suspension and dispersion in the colloid system, all components in the whole colloid system are dispersed more uniformly, and the colloid formed after assembly is firmer.

In the invention, the finger-advance front edge locking nano-insect also comprises 0.4-1.2% of polyhydroxy compound according to mass fraction, wherein the polyhydroxy compound is selected from one or more of 1, 3-propylene glycol, ethylene glycol, 1, 2-propylene glycol or 5-hydroxymethyl furfural.

In another aspect of the present invention, there is provided a method for preparing the finger-advanced leading edge locked nanobud, comprising the steps of:

1) mixing the prepared colloid assembling agent, the polymer, the composite monomer system, the colloid protective agent, the surfactant and the three-dimensional circular coating shell in sequence according to a certain mass fraction;

2) adding water into the mixture, and stirring at normal temperature.

After the finger advance front edge locks the nano-insects to be injected into the rock core (or a proper stratum), the generated viscous finger advance phenomenon realizes fluidity control on the displacement front edge to change the front edge, and a new front edge is formed after the water drive front edge is locked, so that the purpose of front edge control is achieved.

After the finger-advance front edge locks the nano-worms in the injected rock core (or in a proper stratum), the coating shell on the outermost layer is disintegrated to release the core main body nano-worms in the core main body, and the nano-worms have certain deformation plugging capability and can enlarge the swept volume of the injected displacement fluid.

The invention has the beneficial effects that:

compared with the traditional nanotechnology, the finger-advance front-edge locking nanobud has better throat adaptability, can change the form of the nanobud along with the size of the throat, can optimize the swept area under the conditions of different sizes of throats and reservoirs with different permeabilities, and has more advantages in the aspect of improving the recovery ratio than the traditional nanotechnology.

Drawings

FIG. 1 is a structural shape of a modified carbon nanotube according to the present invention;

FIG. 2 is a graph of a trace of the change of a displacement front edge after locking a nano-worm on the front edge after the core is injected with a water content of 20% according to the invention;

FIG. 3 is a trace diagram of the change of the displacement front edge after locking the nano-insects at the injection front edge of the core with 21% of water content according to the invention;

FIG. 4 is a graph of a trace of the change of a displacement front edge after locking a nano-worm on the front edge after the rock core with water content of 22% is injected;

FIG. 5 is a trace diagram of the change of the displacement front edge after locking the nano-worms on the front edge after the rock core with 23% of water content is injected;

FIG. 6 is a trace diagram of the variation of the displacement front edge after locking the nanobud with the injected front edge under the condition that the water content of the rock core is 24 percent;

FIG. 7 is a trace diagram of the change of the displacement front edge after locking the nano-insects at the injection front edge of the core with water content of 25% according to the invention.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to specific embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The embodiment provides a finger-feeding frontier locked nano-worm, which consists of a colloid assembling agent, a polymer, a composite monomer system, a colloid protective agent, a surfactant and an encapsulated coating shell. The method comprises the steps of sequentially adding a prepared colloid assembling agent, a polymer, a composite monomer system, a colloid protective agent, a surfactant and a three-dimensional circular coating shell into a 250ml beaker, pouring a certain amount of clear water into the beaker, turning on an electric stirrer, stirring for 2 hours at regular time, and stirring uniformly the components. Wherein the beaker was kept at a normal temperature of 25 ℃ while stirring.

The nano-insect composite material comprises the following components by mass percent, wherein a colloid assembling agent is 0.55% of sodium alginate, 10.2% of gelatin, 15% of guar gum, 5.8% of polyvinyl alcohol, 6.9% of carrageenan and 5% of acrylic acid, a polymer is 0.05% of polyacrylamide, a composite monomer system is 6.2% of a laboratory self-made branched monomer P, 2% of acrylamide, 5% of 2-acrylamide-2-methylpropanesulfonic Acid (AMPS) and 5% of methacrylamide ethyl tetramethylammonium chloride, a colloid protective agent is 2% of hydroxyethyl cellulose, a surfactant is 2.1% of sodium lignosulfonate, an encapsulated shell is 10% of modified carbon nano-tubes, and the balance of water is supplemented; the monomer P is:

wherein the structural shape of the modified carbon nano tube is shown in figure 1, and the modified carbon nano tube is prepared by the following method:

1) placing the carbon nano tube at the high temperature of 800-1000 ℃ for 2 days to make the structure thereof regular;

2) after the carbon nano tube treated at high temperature is completely cooled, the carbon nano tube is put into tannin and Pd solution to remove impurities, and an additional functional group structure is added, so that the adhesion between the modified carbon nano tube and other components of the nano worm is stronger.

Example 2

The implementation provides a finger-advance leading edge locking nano-worm which comprises a colloid assembling agent, a polymer, a composite monomer system, a colloid protective agent, a surfactant and an encapsulation coating shell. The preparation method is the same as example 1, except that:

the nano-insect composite material comprises the following specific components in percentage by mass, wherein a colloid assembling agent is 0.55% of sodium alginate, 8.7% of gelatin, 16% of guar gum, 2.3% of polyvinyl alcohol, 15% of carrageenan and 2.5% of acrylic acid, a polymer is 2% of polyacrylamide, a composite monomer system is a 4.5% laboratory self-made branched monomer P, 8% of acrylamide, 0.3% of 2-acrylamide-2-methylpropanesulfonic Acid (AMPS), 8.2% of methacrylamide ethyl tetramethylammonium chloride, a colloid protective agent is 1.2% of hydroxyethyl cellulose, a surfactant is 3.5% of sodium lignosulfonate, an encapsulated coating shell is 8% of modified carbon nano-tubes, and the balance of water is supplemented; the monomer P is:

example 3

the nano-insect colloid assembling agent comprises, by mass, 2.33% of sodium alginate, 9.372% of gelatin, 15.02% of guar gum, 3.86% of polyvinyl alcohol, 11.25% of carrageenan, 3.65% of acrylic acid, 5.23% of monomer P, 4.12% of acrylamide, 2.65% of 2-acrylamide-2-methylpropanesulfonic Acid (AMPS), 5.14% of methacrylamide ethyl tetramethylammonium chloride, 1.35% of hydroxyethyl cellulose, 2.45% of sodium lignosulfonate and 9.05% of modified carbon nanotubes, and water is used for balancing.

Example 4

In this example, the water content of the experimental displacement core was set to 20%, and other experimental simulation conditions were conventional reservoir conditions. And injecting the prepared front edge locking nano worms into the rock core, sampling and preparing specimens at intervals of 5 days, 25 days, 45 days and 65 days respectively, carrying out microscopic observation, and roughly drawing the flow shift shape of the displacement front edge.

The results of this example show (fig. 2) that after the injection of the nanobud, the shift distance increases from about 95m to 500m as viewed from the X-axis direction with a change in the shape of the displacement front observed by plotting a plane using a scale-reduction; the moving distance increases from 30m to 100m as viewed in the Y-axis direction. Both are propelled with a conventional saw tooth wavy leading edge, eventually forming a stable new displacement leading edge with a wider swept area.

Example 5

In this example, the water content of the experimental displacement core was set to 21%, and other experimental simulation conditions were conventional reservoir conditions. And injecting the prepared front edge locking nano worms into the rock core, sampling and preparing specimens at intervals of 5 days, 25 days, 45 days and 65 days respectively, carrying out microscopic observation, and roughly drawing the flow shift shape of the displacement front edge.

The results of this example show (fig. 3) that after the injection of the nanobud, the shift distance increases from about 120m to about 480m as viewed in the X-axis direction with a change in the shape of the displacement front observed by scaling to plot a plane; the moving distance increases from about 25m to about 85m as viewed in the Y-axis direction. Likewise, both are propelled with a conventional sawtooth wavy front, eventually forming a stable new displacement front with a wider swept area.

Example 6

In this example, the water content of the experimental displacement core was set to 22%, and other experimental simulation conditions were conventional reservoir conditions. And injecting the prepared front edge locking nano worms into the rock core, sampling and preparing specimens at intervals of 5 days, 25 days, 45 days and 65 days respectively, carrying out microscopic observation, and roughly drawing the flow shift shape of the displacement front edge.

The results of this example show (fig. 4) that after the injection of the nanobud, the shift distance increases from around 110m to around 410m as viewed from the X-axis direction with a change in the shape of the displacement front observed by scaling to plot a plane; the moving distance increases from about 20m to about 65m as viewed in the Y-axis direction. Likewise, both are propelled with a conventional sawtooth wavy front, eventually forming a stable new displacement front with a wider swept area.

Example 7

In this example, the water content of the experimental displacement core was set to 23%, and other experimental simulation conditions were conventional reservoir conditions. And injecting the prepared front edge locking nano worms into the rock core, sampling and preparing specimens at intervals of 5 days, 25 days, 45 days and 65 days respectively, carrying out microscopic observation, and roughly drawing the flow shift shape of the displacement front edge.

The results of this example show (fig. 5) that after the injection of the nanobud, the shift distance increases from around 110m to around 280m as viewed from the X-axis direction with a change in the shape of the displacement front as viewed by a scale-reduced rendering plane; the moving distance increases from about 12m to about 40m as viewed in the Y-axis direction. Likewise, both are propelled with a conventional sawtooth wavy front, eventually forming a stable new displacement front with a wider swept area.

Example 8

In this example, the water content of the experimental displacement core was set to 24%, and other experimental simulation conditions were conventional reservoir conditions. And injecting the prepared front edge locking nano worms into the rock core, sampling and preparing specimens at intervals of 5 days, 25 days, 45 days and 65 days respectively, carrying out microscopic observation, and roughly drawing the flow shift shape of the displacement front edge.

The results of this example show (fig. 6) that after the injection of the nanobud, the shift distance increases from about 59m to about 170m as viewed in the X-axis direction with a change in the shape of the displacement front observed by scaling to plot a plane; the moving distance increases from about 9m to about 28m as viewed in the Y-axis direction. Likewise, both are propelled with a conventional sawtooth wavy front, eventually forming a stable new displacement front with a wider swept area.

Example 9

In this example, the water content of the experimental displacement core was set to 25%, and other experimental simulation conditions were conventional reservoir conditions. And injecting the prepared front edge locking nano worms into the rock core, sampling and preparing specimens at intervals of 5 days, 25 days, 45 days and 65 days respectively, carrying out microscopic observation, and roughly drawing the flow shift shape of the displacement front edge.

The results of this example show (fig. 7) that after the injection of the nanobud, the shift distance increases from about 32m to about 75m as viewed from the X-axis direction with a change in the shape of the displacement front observed by scaling to a drawing plane; the moving distance increases from about 7m to about 18m as viewed in the Y-axis direction. Likewise, both are propelled with a conventional sawtooth wavy front, eventually forming a stable new displacement front with a wider swept area.

From the results of examples 4 to 9, it was found that when the water content was increased from 20% to 25%, the amount of the frontal locked nanoballs was kept constant, and the higher the water content was, the smaller the morphological change of the newly formed displacement front was, and the spread range was also gradually reduced, indicating that the increase in the water content in the range of 20% to 25% had a certain inhibitory effect on the frontal locked nanoballs.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A finger-advancing frontier locked nano-worm is characterized by comprising the following components in percentage by mass: 0.55 to 2.56 percent of sodium alginate, 8.7 to 10.2 percent of gelatin, 15 to 16 percent of guar gum, 2.3 to 5.8 percent of polyvinyl alcohol, 6.9 to 15 percent of carrageenan, 2.5 to 5 percent of acrylic acid, 0.05 to 2 percent of polyacrylamide, 4.5 to 6.2 percent of monomer P, 2 to 8 percent of acrylamide, 0.3 to 5 percent of 2-acrylamide-2-methylpropanesulfonic acid, 5 to 8.2 percent of methacrylamide ethyl tetramethylammonium chloride, 1.2 to 2 percent of hydroxyethyl cellulose, 2.1 to 3.5 percent of sodium lignin sulfonate and 8 to 10 percent of carbon nano tube, and the balance of water is complemented; the monomer P is:

2. the finger-feeding leading edge locking nano-worm as claimed in claim 1, characterized by comprising the following components by mass percent: 2.33% of sodium alginate, 9.372% of gelatin, 15.02% of guar gum, 3.86% of polyvinyl alcohol, 11.25% of carrageenan, 3.65% of acrylic acid, 5.23% of monomer P, 4.12% of acrylamide, 2.65% of 2-acrylamide-2-methylpropanesulfonic acid, 5.14% of methacrylamide ethyl tetramethylammonium chloride, 1.35% of hydroxyethyl cellulose, 2.45% of sodium lignin sulfonate, 9.05% of carbon nanotubes and water for balancing.

3. The finger-feeding front edge locked nano-worm according to claim 1 or 2, characterized in that the finger-feeding front edge locked nano-worm further comprises 0.4-1.2% of polyhydroxy compound according to mass fraction.

4. The finger-fed epizootic locking nano-worm as claimed in claim 1 or 2, wherein the carbon nanotube structure is modified by the following method: the carbon nano tube is treated for 2 days at the high temperature of 800-1000 ℃, and is put into the tannin and Pd solution to remove impurities after being completely cooled.

5. The finger-feeding front edge locking nano-worm according to claim 3, characterized in that the polyhydroxy compound is selected from one or more of 1, 3-propylene glycol or ethylene glycol or 1, 2-propylene glycol or 5-hydroxymethylfurfural.

6. The method for preparing a finger-advanced leading edge locked nano-worm according to claim 1, comprising the steps of:

2) adding water into the mixture, and stirring at normal temperature.