CN113355074A - Modifying and flooding agent and method for improving polymer microsphere plugging efficiency - Google Patents

Modifying and flooding agent and method for improving polymer microsphere plugging efficiency Download PDF

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CN113355074A
CN113355074A CN202110653503.9A CN202110653503A CN113355074A CN 113355074 A CN113355074 A CN 113355074A CN 202110653503 A CN202110653503 A CN 202110653503A CN 113355074 A CN113355074 A CN 113355074A
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agent
profile control
cross
emulsion
water
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刘进祥
谢坤
卢祥国
郝敬滨
邢剑飞
曹伟佳
曹豹
闫坤
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Northeast Petroleum University
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
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    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/50—Compositions for plastering borehole walls, i.e. compositions for temporary consolidation of borehole walls
    • C09K8/516—Compositions for plastering borehole walls, i.e. compositions for temporary consolidation of borehole walls characterised by their form or by the form of their components, e.g. encapsulated material
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
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    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/50—Compositions for plastering borehole walls, i.e. compositions for temporary consolidation of borehole walls
    • C09K8/504—Compositions based on water or polar solvents
    • C09K8/506—Compositions based on water or polar solvents containing organic compounds
    • C09K8/508—Compositions based on water or polar solvents containing organic compounds macromolecular compounds
    • C09K8/5083—Compositions based on water or polar solvents containing organic compounds macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/50—Compositions for plastering borehole walls, i.e. compositions for temporary consolidation of borehole walls
    • C09K8/504—Compositions based on water or polar solvents
    • C09K8/506—Compositions based on water or polar solvents containing organic compounds
    • C09K8/508—Compositions based on water or polar solvents containing organic compounds macromolecular compounds
    • C09K8/512—Compositions based on water or polar solvents containing organic compounds macromolecular compounds containing cross-linking agents
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    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/58—Compositions for enhanced recovery methods for obtaining hydrocarbons, i.e. for improving the mobility of the oil, e.g. displacing fluids
    • C09K8/588—Compositions for enhanced recovery methods for obtaining hydrocarbons, i.e. for improving the mobility of the oil, e.g. displacing fluids characterised by the use of specific polymers

Abstract

The invention provides a profile control agent for improving the plugging efficiency of polymer microspheres, belonging to the technical field of oilfield development. The invention provides a modifying and flooding agent for improving the plugging efficiency of polymer microspheres, which is prepared by a method comprising the following steps: mixing the polymer microspheres with water to obtain a polymer microsphere solution; the polymer microspheres are water-in-oil type emulsion; mixing the polymer microsphere solution with a cross-linking agent or an emulsion of the cross-linking agent to obtain a profile control agent; the emulsion of the cross-linking agent is a water-in-oil type emulsion prepared by mixing the cross-linking agent and an oil phase. The results of the embodiment show that the plugging rate of the profile control agent provided by the invention is 76.59-92.13%; compared with the polymer microspheres with the same concentration under the same core permeability, the injection pressure is the same, and the resistance coefficient and the pressure gradient are basically consistent; in the subsequent water stage, the residual resistance coefficient and the pressure gradient of the profile control agent are obviously higher.

Description

Modifying and flooding agent and method for improving polymer microsphere plugging efficiency
Technical Field
The invention belongs to the technical field of oilfield development, and particularly relates to a profile control and flooding agent and a method for improving polymer microsphere plugging efficiency.
Background
Because the reservoir heterogeneity of most oil fields in China is severe, the water flooding development effect is often poor, the water flooding recovery ratio is usually only 27-40%, the potential for improving the recovery ratio is huge, and chemical flooding is an effective means for improving the heterogeneous reservoir.
In recent years, chemical flooding mainly based on polymer flooding is widely applied to oil fields in Daqing, Shengli, Henan, Dagang and the like in China, and good oil and water increasing and reducing effects are achieved. The polymer microspheres have narrow particle size distribution, and only enter a high permeability layer under reasonable selection conditions, are hydrated and expanded in the high permeability layer, and effectively block the high permeability layer, so that liquid flow steering is realized, and the polymer microspheres basically cannot enter a medium-low permeability layer, so that the attention of vast technologists is paid, and the oil field application also achieves a certain effect. However, the hydration expansion of the microspheres can be influenced by temperature, formation water mineralization degree, calcium and magnesium ion concentration and the like, and the hydration expansion of the polymer microspheres is only relied on, so that the liquid flow diversion effect is very limited, and the plugging efficiency is reduced.
Therefore, it is necessary to provide a modifying and flooding agent for improving the plugging efficiency of the polymer microspheres, so as to improve the plugging effect of the polymer microspheres.
Disclosure of Invention
The invention aims to provide a modifying and flooding agent and a method for improving the plugging efficiency of polymer microspheres. The profile control agent provided by the invention can obviously improve the plugging effect and the recovery rate after being injected into a rock core.
The invention provides a modifying and flooding agent for improving the plugging efficiency of polymer microspheres, which is prepared by a method comprising the following steps:
(1) mixing the polymer microspheres with water to obtain a polymer microsphere solution; the polymer microspheres are water-in-oil type emulsion;
(2) mixing the polymer microsphere solution obtained in the step (1) with a cross-linking agent or an emulsion of the cross-linking agent to obtain a profile control agent; the emulsion of the cross-linking agent is a water-in-oil type emulsion prepared by mixing the cross-linking agent and an oil phase.
Preferably, the solid content of the polymer microspheres in the step (1) is 20-30 wt%.
Preferably, the polymer in the polymer microsphere in the step (1) contains carboxyl or amide groups.
Preferably, the concentration of the polymer microsphere solution in the step (1) is 1000-30000 mg/L.
Preferably, the concentration of the polymer microsphere solution is 2000-20000 mg/L.
Preferably, the crosslinking agent in the step (2) includes at least one of an organic chromium crosslinking agent, an organic aluminum crosslinking agent, an organic zirconium crosslinking agent and a phenolic crosslinking agent.
Preferably, the concentration of the cross-linking agent in the profile control agent is 50-5000 mg/L.
Preferably, the preparation method of the emulsion of the cross-linking agent in the step (2) comprises the following steps:
1) mixing an emulsifier with the oil phase to obtain an emulsion;
2) mixing the emulsion obtained in the step 1) with a cross-linking agent to obtain an emulsion of the cross-linking agent.
The invention also provides a method for improving the plugging efficiency of the polymer microspheres, and the profile control agent in the technical scheme is injected into the rock core.
Preferably, the injection speed is 0.3-3 mL/min.
The invention provides a modifying and flooding agent for improving the plugging efficiency of polymer microspheres, which is prepared by a method comprising the following steps: mixing the polymer microspheres with water to obtain a polymer microsphere solution; the polymer microspheres are water-in-oil type emulsion; mixing the polymer microsphere solution with a cross-linking agent or an emulsion of the cross-linking agent to obtain a profile control agent; the emulsion of the cross-linking agent is a water-in-oil type emulsion prepared by mixing the cross-linking agent and an oil phase. The polymer microspheres of the water-in-oil type emulsion adopted by the invention are prepared by wrapping a water-soluble polymer in an oil phase, mixing the water-soluble polymer with water to form a water-in-oil-in-water type polymer microsphere solution, and mixing a cross-linking agent or an emulsion of the cross-linking agent with the oil phase to obtain the profile control agent, so that the cross-linking agent can only be dispersed in water or dispersed in water in a water-in-oil form and cannot be contacted with the polymer microspheres, the cross-linking reaction is avoided, the polymer microspheres can gradually hydrate and expand at the oil reservoir temperature when the profile control agent is used to promote the emulsion to crack, and the polymer microspheres are contacted with the cross-linking agent after the crack so as to generate the cross-linking reaction, thereby achieving the purpose of deep profile control, and obviously improving the plugging effect and the recovery ratio of the polymer microspheres. The results of the embodiment show that the plugging rate of the profile control agent provided by the invention is 76.59-92.13%; compared with the polymer microspheres with the same concentration under the same core permeability, the injection pressure is the same, and the resistance coefficient and the pressure gradient are basically consistent, so that the polymer microspheres and the cross-linking agent in the profile control agent provided by the invention do not generate a cross-linking reaction in the injection process, the purpose of deep migration is achieved, and in the subsequent water stage, the residual resistance coefficient and the pressure gradient of the profile control agent are obviously higher, so that the profile control agent generates an obvious cross-linking reaction in the deep part of the core, and the purpose of deep profile control is achieved.
Drawings
FIG. 1 is a schematic structural view of an experimental apparatus;
FIG. 2 is a graph of injection pressure versus pore volume multiple for the profile control agent prepared in comparative example 1;
FIG. 3 is a graph of injection pressure versus pore volume multiple for profile control agents prepared in examples 1-3 and comparative example 1;
FIG. 4 is a graph showing the relationship between the injection point and the pressure at each pressure measuring point of the profile control agent prepared in comparative example 1 and the PV number;
FIG. 5 is a graph of the injection point and pressure at each pressure measurement point versus PV number for the profile control agent prepared in example 1.
Detailed Description
The invention provides a modifying and flooding agent for improving the plugging efficiency of polymer microspheres, which is prepared by a method comprising the following steps:
(1) mixing the polymer microspheres with water to obtain a polymer microsphere solution; the polymer microspheres are water-in-oil type emulsion;
(2) mixing the polymer microsphere solution obtained in the step (1) with a cross-linking agent or an emulsion of the cross-linking agent to obtain a profile control agent; the emulsion of the cross-linking agent is a water-in-oil type emulsion prepared by mixing the cross-linking agent and an oil phase.
The invention mixes the polymer microsphere with water to obtain the polymer microsphere solution.
In the present invention, the polymer microspheres are water-in-oil emulsions; the solid content of the polymer microspheres is preferably 20-30 wt%, more preferably 24-28%, and even more preferably 24.5-25%; the polymer in the polymer microsphere preferably contains carboxyl or amido, and is more preferably polyacrylamide microsphere or; the polymer microspheres are preferably obtained by inverse emulsion polymerization using acrylic acid monomers and/or acrylamide monomers. The preparation method of the polymer microsphere is not particularly limited in the invention, and the polymer microsphere can be prepared by a preparation method well known to those skilled in the art. The polymer microsphere is a particle dispersion system synthesized by inverse emulsion polymerization, and the polymer microsphere of a water-in-oil type emulsion is prepared by wrapping a water-soluble polymer in an oil phase, and can be prevented from being dissolved after being mixed with water after being mixed with the water.
In the present invention, the water is preferably the target oilfield injection water.
The operation of mixing the polymer microspheres with water is not particularly limited in the present invention, and the technical scheme for preparing the mixed material, which is well known to those skilled in the art, can be adopted. In the invention, the concentration of the polymer microsphere solution is preferably 1000-30000 mg/L, more preferably 2000-20000 mg/L, and more preferably 3000-10000 mg/L.
After the polymer microsphere solution is obtained, the polymer microsphere solution is mixed with a cross-linking agent or an emulsion of the cross-linking agent to obtain the profile control agent. According to the invention, the polymer microsphere solution is mixed with the cross-linking agent or the emulsion of the cross-linking agent, so that the cross-linking agent can only be dispersed in water or can be dispersed in water in oil form and can not contact with the polymer microspheres, thereby avoiding cross-linking reaction.
In the present invention, the crosslinking agent preferably includes at least one of an organic chromium crosslinking agent, an organic aluminum crosslinking agent, an organic zirconium crosslinking agent, and a phenol-based crosslinking agent. The source of the crosslinking agent is not particularly limited in the present invention, and commercially available products known to those skilled in the art may be used.
In the invention, the emulsion of the cross-linking agent is a water-in-oil emulsion prepared by mixing the cross-linking agent and an oil phase. In the present invention, the method for preparing the emulsion of the crosslinking agent preferably comprises the steps of:
1) mixing an emulsifier with the oil phase to obtain an emulsion;
2) mixing the emulsion obtained in the step 1) with a cross-linking agent to obtain an emulsion of the cross-linking agent.
The invention preferably mixes the emulsifier with the oil phase to obtain an emulsion.
In the invention, the dosage of the emulsifier is preferably 17.8-19.4% of the mass of the oil phase, and more preferably 18-19% of the mass of the oil phase; the kind of the emulsifier is preferably at least one of Span-60 and Tween-60, and more preferably Span-60 and Tween-60; when the emulsifier is Span-60 and Tween-60, the mass ratio of the Span-60 to the Tween-60 is preferably 9: 1 or 8: 2. the source of the emulsifier is not particularly limited in the present invention, and a commercially available product known to those skilled in the art may be used.
In the present invention, the oil phase is preferably liquid paraffin; the dosage of the oil phase is preferably 50-80% of the total volume of the oil phase and the cross-linking agent, and more preferably 60-70%. The source of the liquid paraffin is not particularly limited in the present invention, and commercially available products known to those skilled in the art may be used.
The operation of mixing the emulsifier and the oil phase is not particularly limited in the invention, and the technical scheme for preparing the mixed material, which is well known to the technical personnel in the field, can be adopted.
After obtaining the emulsion, the present invention preferably mixes the emulsion with the crosslinking agent to obtain an emulsion of the crosslinking agent.
In the invention, the dosage of the cross-linking agent is preferably 20-50% of the total volume of the oil phase and the cross-linking agent, and more preferably 30-40%; the mixing of the emulsion and the cross-linking agent is preferably carried out under stirring conditions; the stirring time is preferably 20-40 min, and more preferably 30 min. The rotation speed of the stirring is not particularly limited in the present invention, and it is sufficient to ensure that the emulsion and the crosslinking agent are uniformly dispersed in the above time.
The cross-linking agent emulsion adopted by the invention is formed by wrapping the cross-linking agent in the oil phase to form a water-in-oil structure, and compared with the method of directly adopting the cross-linking agent, the cross-linking can be carried out at a deeper part of an oil reservoir, so that the aim of deep profile control is fulfilled.
The operation of mixing the polymer microsphere solution with the crosslinking agent or the emulsion of the crosslinking agent is not particularly limited in the present invention, and the technical scheme for preparing the mixed material which is well known to those skilled in the art can be adopted. In the invention, the concentration of the cross-linking agent in the profile control agent is preferably 50-5000 mg/L, more preferably 150-2000 mg/L, and even more preferably 600-1200 mg/L.
The polymer microspheres of the water-in-oil type emulsion adopted by the invention are prepared by wrapping a water-soluble polymer in an oil phase, mixing the water-soluble polymer with water to form a water-in-oil-in-water type polymer microsphere solution, and mixing a cross-linking agent or an emulsion of the cross-linking agent with the oil phase to obtain the profile control agent, so that the cross-linking agent can only be dispersed in water or dispersed in water in a water-in-oil form and cannot be contacted with the polymer microspheres, the cross-linking reaction is avoided, the polymer microspheres can gradually hydrate and expand at the oil reservoir temperature when the profile control agent is used to promote the emulsion to crack, and the polymer microspheres are contacted with the cross-linking agent after the crack so as to generate the cross-linking reaction, thereby achieving the purpose of deep profile control, and obviously improving the plugging effect and the recovery ratio of the polymer microspheres.
The invention also provides a method for improving the plugging efficiency of the polymer microspheres, and the profile control agent in the technical scheme is injected into the rock core. The polymer microspheres in the profile control agent provided by the invention gradually hydrate and expand at the oil reservoir temperature to promote emulsion fracture, and the broken polymer microspheres are contacted with the cross-linking agent to generate a cross-linking reaction, so that the purpose of deep profile control is achieved, and the plugging effect and the recovery ratio of the polymer microspheres are obviously improved.
In the present invention, the injection rate is preferably 0.3 to 3mL/min, more preferably 0.5 to 2mL/min, and still more preferably 0.9 to 1.5 mL/min. The present invention is not limited to the other operations of the implantation, and the implantation operation known to those skilled in the art may be used. The dosage of the mixed emulsion is not specially limited, and the mixed emulsion can be adjusted according to actual conditions.
The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. 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 profile control agent is prepared by the following method:
(1) mixing polyacrylamide microspheres with the solid content of 24.5% with experimental water to obtain a polymer microsphere solution with the concentration of 3000 mg/L;
wherein, the polyacrylamide microspheres are water-in-oil type emulsion; the water for the experiment is Bohai sea QHD32-6 oilfield simulation injection water, and the water quality analysis result is shown in table 1;
TABLE 1 Water quality analysis results
Figure BDA0003112785860000061
(2) Mixing the polymer microsphere solution obtained in the step (1) with an organic chromium crosslinking agent (Cr)3+The content is 1.2%) to obtain a profile control agent;
wherein, the concentration of the cross-linking agent in the mixed profile control agent is preferably 150 mg/L; the emulsion of the cross-linking agent is a water-in-oil emulsion prepared by mixing the cross-linking agent and an oil phase, and the method comprises the following steps:
1) mixing Tween-60, surfactant Span-60 and liquid paraffin to obtain emulsion;
wherein the dosage of the emulsifier is 17.8 percent of the mass of the oil phase, and the mass ratio of Span-60 to Tween-60 is 9: 1; 2/3 liquid paraffin accounts for the total volume of the liquid paraffin and the cross-linking agent;
2) adding the emulsion into one dropping funnel of the three-neck flask, adding the organic chromium crosslinking agent into the other dropping funnel, and stirring for 30min to form the water-in-oil emulsion, wherein the organic chromium crosslinking agent accounts for 1/3 of the total volume of the liquid paraffin and the crosslinking agent.
Example 2
The concentration of the cross-linking agent in the profile control agent in the step (2) of the example 1 is changed to 600mg/L, and other conditions are not changed.
Example 3
The concentration of the cross-linking agent in the profile control agent in the step (2) of the example 1 is changed to 1200mg/L, and other conditions are not changed.
Comparative example 1
The polymer microsphere solution prepared in example 1 was used as a profile control agent.
Performing performance test on the profile control agent provided in examples 1-3 and comparative example 1 by using an experimental core;
wherein, the experiment rock core is quartz sand epoxy resin cemented artificial column rock core, and geometric dimension: the diameter x length is 2.5cm x 10 cm;
1. experimental equipment
The core displacement experimental equipment mainly comprises a constant flow pump, a pressure sensor (pressure gauge), a core holder, a middle container and the like, and other components except the constant flow pump and a hand pump are arranged in a constant temperature box. The schematic structure of the experimental facility is shown in FIG. 1.
2. Experimental procedure
1) Experimental procedures for injectability and plugging property
Core evacuating saturated formation water, injecting simulated water and recording pressure delta P1；
② injecting the modifying and driving agent 5PV of examples 1-3 and comparative example 1 respectively, recording the pressure delta P2；
Thirdly, cutting off the length of the core injection end to be about 0.2cm, implementing subsequent water drive of 4 PV-5 PV after slowly expanding for 7d, and recording the subsequent water stable pressure delta P3；
Resistance coefficient I: fR1＝δP2/δP1Coefficient of residual resistance FRR＝δP3/δP1。
The injection rate for the above experimental procedure was 0.9 mL/min.
2) Injection and transport migration experiment steps:
firstly, evacuating saturated simulated water from a rock core at normal temperature, and calculating porosity;
measuring permeability under reservoir temperature, recording pressure P between pressure points0Calculating the total pressure difference DeltaP0；
Thirdly, injecting the profile control and flooding agent of the examples 1 to 3 and the comparative example 1 into a rock core (1.2PV) from a first injection port respectively, and recording the pressure P of each pressure measuring point1Calculating the pressure difference delta P between the pressure measurement points1Calculating the pressure gradient and the resistance coefficient of each interval;
fourthly, respectively carrying out water seepage experiments after injection when the rock core is placed to the 3 rd, 5d and 7d at the oil reservoir temperature until the pressure is stable, and recording the pressure P of each pressure measuring point when the water seepage experiments after injection are finished2Calculating the pressure difference delta P between the pressure measurement points2；
Fifthly, calculating the pressure gradient ratio of each stage.
The injection rate was 0.9 mL/min.
3. Experimental results of injectability and plugging property
1) Coefficient of drag and residual coefficient of drag
Drag coefficients (F) of examples 1 to 3 and comparative example 1R) And residual drag coefficient (F)RR) The experimental data are shown in table 2.
TABLE 2 drag coefficient and residual drag coefficient
Figure BDA0003112785860000081
As can be seen from Table 2, in the injection stage, the resistance coefficient increases with the decrease of the rock permeability, because the pore throat size increases with the increase of the rock core permeability, the compatibility between the microspheres and the pore throat of the rock core becomes better, the retention amount decreases, the seepage resistance decreases, and the resistance coefficient decreases; in the subsequent water flooding process, the residual resistance coefficient presents a tendency of increasing first and then decreasing along with the increase of the permeability of the rock core, because when the permeability of the rock core is too low, the end face effect generated in the process of injecting the polymer microspheres is serious, only a few microspheres enter the porous medium to slowly expand, and the residual resistance coefficient and the plugging rate are small. When the permeability limit is reached, most microspheres can be injected into the porous medium, the plugging effect is the best after the microspheres slowly expand, and when the permeability of the rock core continues to increase, the plugging effect of the polymer microspheres is reduced, the residual resistance coefficient is reduced, and the plugging rate is reduced.
It can also be seen from table 2 that the resistance coefficients of the profile control agent prepared in examples 1 to 3 at the injection stage are substantially the same as those of the comparative example, which indicates that the profile control agent prepared in examples 1 to 3 does not undergo a crosslinking reaction during the injection process, the residual resistance coefficient and the plugging rate are significantly increased after 7 days of slow swelling, and the greater the concentration of the crosslinking agent is, the greater the residual resistance coefficient and the plugging rate are, which indicates that the profile control agent prepared in examples 1 to 3 undergoes an obvious crosslinking reaction in the deep part of the core.
2) Dynamic curve
The profile control agent injection pressure versus pore volume multiple curve prepared in comparative example 1 is shown in fig. 2.
As can be seen from FIG. 2, during the injection, the injection pressure gradually increased with the increase of the permeability, when the permeability increased to 200X 10-3μm2When the chemical flooding is finished, a horizontal section appears in the latter half section, which indicates that the injection production reaches the balance, namely the permeability limit of the polymer microspheres is 200 multiplied by 10-3μm2. The reason is that the pressure is greatly reduced due to the fact that the end face effect is eliminated in the subsequent water process, and the microspheres injected into the rock core have a certain plugging effect after being slowly expanded, so that the subsequent water drive pressure is increased; the core permeability is more than 200 multiplied by 10-3μm2The injection pressure of the subsequent water stage is greater than the pressure at the end of the polymer microspheres, which indicates that the polymer microspheres in the profile control agent are hydrated and expanded in the rock core.
The injection pressure versus pore volume multiple curves for the profile control agents prepared in examples 1-3 and comparative example 1 are shown in FIG. 3.
As can also be seen from fig. 3, in the chemical flooding stage, the injection pressure rises first and then becomes stable, which indicates that the injection-production balance can be achieved in the water flooding process, the injection pressure of the profile control agent prepared in examples 1 to 3 is substantially the same as that of the profile control agent prepared in comparative example 1, and indicates that the profile control agent prepared in examples 1 to 3 does not undergo a crosslinking reaction in the injection process; in the subsequent water stage, the injection pressure of the profile control and flooding agent prepared in examples 1 to 3 is gradually increased along with the increase of the concentration of the cross-linking agent, and the injection pressure is greater than that of the profile control and flooding agent prepared in comparative example 1 with the same PV number, which indicates that the profile control and flooding agent prepared in examples 1 to 3 is obviously cross-linked, and the cross-linking effect is stronger when the concentration of the cross-linking agent is higher.
4. Experimental results of transport capacity and retention distribution
The results of the resistance coefficient of the profile control agent prepared in the comparative example 1 and the profile control agent prepared in the example 1 in the injection stage and the residual resistance coefficient of the profile control agent prepared in the subsequent water stage are shown in table 3, the results of the delta P test of the pressure gradient in each interval of each stage of the profile control agent prepared in the comparative example 1 and the profile control agent prepared in the example 1 in each interval of each stage are shown in table 4, the relationship curve of the injection point and the pressure of each pressure measuring point of the profile control agent prepared in the comparative example 1 and the PV number is shown in fig. 4, and the relationship curve of the injection point and the pressure of each pressure measuring point of the profile control agent prepared in the example 1 and the PV number is shown in fig. 5.
TABLE 3 coefficient of resistance and coefficient of residual resistance
Figure BDA0003112785860000091
Figure BDA0003112785860000101
TABLE 4 pressure gradient δ P in each interval
Figure BDA0003112785860000102
As can be seen by combining tables 3 and 4 and FIGS. 4 and 5, the pressure of the profile control agent prepared in example 1 is basically the same as that of the profile control agent prepared in comparative example 1 in the injection stage, and the resistance coefficient and the pressure gradient are basically consistent, so that the profile control agent prepared in example 1 is not subjected to a crosslinking reaction in the injection process, and the purpose of deep migration is achieved; in the subsequent water stage, the residual resistance coefficient and the pressure gradient of the profile control agent prepared in example 1 are obviously higher, which indicates that the profile control agent prepared in example 1 generates an obvious crosslinking reaction in the deep part of the rock core, and the purpose of deep profile control is achieved.
The embodiment shows that the profile control agent provided by the invention can obviously improve the plugging effect of the polymer microspheres and realize deep profile control.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (10)

1. A modifying and flooding agent for improving the plugging efficiency of polymer microspheres is prepared by a method comprising the following steps:
(1) mixing the polymer microspheres with water to obtain a polymer microsphere solution; the polymer microspheres are water-in-oil type emulsion;
(2) mixing the polymer microsphere solution obtained in the step (1) with a cross-linking agent or an emulsion of the cross-linking agent to obtain a profile control agent; the emulsion of the cross-linking agent is a water-in-oil type emulsion prepared by mixing the cross-linking agent and an oil phase.
2. The profile control agent according to claim 1, wherein the solid content of the polymer microspheres in the step (1) is 20-30 wt%.
3. The profile control agent according to claim 1, wherein the polymer in the polymeric microspheres of step (1) contains carboxyl or amide groups.
4. The profile control agent according to claim 1, wherein the concentration of the polymer microsphere solution in the step (1) is 1000-30000 mg/L.
5. The profile control agent according to claim 4, wherein the concentration of the polymer microsphere solution is 2000-20000 mg/L.
6. The profile control agent according to claim 1, wherein the crosslinking agent in step (2) comprises at least one of an organic chromium crosslinking agent, an organic aluminum crosslinking agent, an organic zirconium crosslinking agent and a phenolic crosslinking agent.
7. The profile control agent and displacement agent according to claim 1, wherein the concentration of the cross-linking agent in the profile control agent and displacement agent is 50-5000 mg/L.
8. The profile control agent according to claim 1, wherein the emulsion of the cross-linking agent in the step (2) is prepared by a method comprising the following steps:
1) mixing an emulsifier with the oil phase to obtain an emulsion;
2) mixing the emulsion obtained in the step 1) with a cross-linking agent to obtain an emulsion of the cross-linking agent.
9. A method for improving the plugging efficiency of polymer microspheres, wherein the profile control agent as claimed in any one of claims 1 to 8 is injected into a rock core.
10. The method of claim 9, wherein the injection rate is 0.3-3 mL/min.
CN202110653503.9A 2021-06-11 2021-06-11 Modifying and flooding agent and method for improving polymer microsphere plugging efficiency Pending CN113355074A (en)

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