阅读说明：本技术 脂肪醇烯醚羧酸酯作为修复液在油田油藏修复中的应用 (Application of fatty alcohol vinyl ether carboxylate as repairing liquid in oilfield reservoir repair ) 是由 唐雷 姚欣 于 2021-08-13 设计创作，主要内容包括：本发明涉及脂肪醇烯醚羧酸酯的应用,尤其涉及脂肪醇烯醚羧酸酯作为修复液在油田油藏修复中的应用,本发明将脂肪醇烯醚羧酸酯直接用于油田油藏修复中,开辟了新的应用领域,将脂肪醇烯醚羧酸酯直接作为修复液用于油藏修复具有溶解油相并降低流体界面张力、降低表面张力及相圈闭、水润湿在岩石基质中的固相及制备工艺简单、成本低、效果好的优点；本发明脂肪醇烯醚羧酸酯直接作为修复液注入到近井筒地层骨架中去分解乳状液,使非混相流体分离,并使近井筒的地层砂处于亲水状态,有利于油气生产,带来显著的经济效益和社会效益。(The invention relates to the application of fatty alcohol alkene ether carboxylate, especially relate to the application in the oil reservoir of oil field of fatty alcohol alkene ether carboxylate as repairing liquid, the invention uses fatty alcohol alkene ether carboxylate in the oil reservoir of oil field is repaired directly, has opened up the new application field, use fatty alcohol alkene ether carboxylate as repairing liquid to repair oil reservoir directly and have dissolved oil phase and reduce the interfacial tension of the fluid, reduce surface tension and phase trap, water wet the solid phase in the rock substrate and prepare simple technological process, with low costs, effectual advantage; the fatty alcohol alkenyl ether carboxylate is directly used as a repairing liquid to be injected into a near-wellbore stratum skeleton to decompose emulsion, so that non-miscible fluid is separated, and stratum sand near a wellbore is in a hydrophilic state, thereby being beneficial to oil gas production and bringing remarkable economic and social benefits.)

1. The application of fatty alcohol alkene ether carboxylate as a repairing liquid in oilfield reservoir repair is characterized in that the fatty alcohol alkene ether carboxylate has the following structural general formula:

wherein R is-C₁₂H₂₅And n is 5.

2. The use of the fatty alcohol alkenyl ether carboxylate as a remediation fluid in oilfield reservoir remediation according to claim 1 wherein the fatty alcohol alkenyl ether carboxylate has a concentration of 2g/L and the fatty alcohol alkenyl ether carboxylate has a pH of 4.

3. The use of the fatty alcohol alkenyl ether carboxylate as a remediation fluid in oilfield reservoir remediation according to claim 1 or claim 2, wherein the fatty alcohol alkenyl ether carboxylate is prepared according to the following method:

A. weighing maleic anhydride and fatty alcohol polyoxyethylene (5) ether according to a molar ratio of 1.05: 1;

B. and C, adding the maleic anhydride weighed in the step A and fatty alcohol polyoxyethylene (5) ether into a three-neck glass flask together for constant temperature reaction to obtain fatty alcohol alkylether carboxylate.

4. The application of the fatty alcohol alkenyl ether carboxylate as a repairing liquid in oilfield reservoir repair, which is characterized in that in the step B, the temperature of the isothermal reaction is controlled to be 90 ℃, and the time of the isothermal reaction is controlled to be 1 h.

Technical Field

The invention relates to application of fatty alcohol alkenyl ether carboxylate, in particular to application of fatty alcohol alkenyl ether carboxylate serving as a repair liquid in oilfield reservoir repair.

Background

In the domestic oil and gas field, chemical, biological and physical pollution is easily caused in the positions of a near wellbore area, a wellbore and the like due to casing running, well completion perforation, fracturing and other operations, for example, paraffin, asphalt, inorganic scale and emulsion are accumulated in the near wellbore area of a stratum to damage an oil and gas well reservoir, so that smooth flowing of fluid and gas is limited, and the yield of the oil and gas well is reduced or the production (lifting) cost is increased. Therefore, the method continuously improves the oil reservoir restoration work and has important strategic significance on the stable oil production process in China.

At present, the methods for reservoir restoration mainly comprise physical methods, mechanical methods and chemical methods.

The physical method comprises the following steps: a negative pressure stratum blocking removal technology, a hydraulic vibration blocking removal technology and a high-pressure water jet blocking removal technology; the stratum blocking removal technology by the negative pressure method is realized by means of a suspended packer and a downhole negative pressure generator, and the treatment of a near-wellbore area at the bottom of a well is realized by forming instantaneous, periodic and controllable negative pressure on the stratum; the hydraulic vibration unblocking is realized by means of a special device, namely a hydraulic vibrator to form vibration shock waves and transmit the vibration waves in a pore channel of a stratum, so that a blocking object is loosened or fatigue-cracked and falls off, and the purpose of clearing the blocking object in a rock pore is achieved; the high-pressure water jet flow blockage removing technology is characterized in that a downhole controllable rotary self-vibration cavitation jet flow blockage removing device is utilized to simultaneously generate low-frequency rotary hydraulic waves, high-frequency oscillation jet flow impact waves and cavitation noise (ultrasonic waves), and three physical actions jointly act on a stratum to achieve the aim of blockage removal.

The mechanical method comprises the following steps: the pulse blockage-removing and yield-increasing technology for oil wells mainly comprises the steps of connecting a power supply through professional mechanical equipment, and forming shock waves by using high-strength voltage, so that the blockage problem of the oil wells is solved through corresponding pressure and pressure effects.

The chemical method comprises the following steps: adding a composite surfactant into the repair liquid to form an organic-inorganic emulsified repair system, wherein the inorganic repair liquid can acidify a near-wellbore area and remove inorganic blockage; the organic repairing liquid has strong dispersing and dissolving effects on organic matters such as asphaltene and colloid, and can remove the blockage of the organic matters.

In the prior art, complete blockage removal cannot be realized after one-time operation of a mechanical method at the present stage, technicians are required to operate mechanical equipment to perform circulating operation in an oil well with a blockage problem, the pulse speed and pressure are controlled well, and the oil well is subjected to secondary damage due to overlarge impact force, so that the labor cost and the operation safety risk are increased, and the repair cost is high; the effective period of the physical method for repairing is short, a blind area exists in the energy action, and the physical method is not suitable for easily-lost strata with large stratum pressure drop, strata with serious sand production and deep pollution and stratum blockage; the types and the performances of the repair liquid related in the chemical method are single, the repair effect is poor, the self-diffusion performance in the repair process is poor, and the preparation method of the repair liquid is complex.

The fatty alcohol alkene ether carboxylate is a lipid polymer obtained by esterifying maleic anhydride and fatty alcohol-polyoxyethylene ether, the lipid is generally used as an intermediate product and then is applied after being reacted to generate a lipid salt solution, and at present, no report that the fatty alcohol alkene ether carboxylate is directly applied to oil field reservoir remediation exists.

Disclosure of Invention

The invention provides application of fatty alcohol alkenyl ether carboxylate serving as a repair liquid in oilfield reservoir repair to solve the technical problems.

The technical scheme for solving the technical problems is as follows: the application of fatty alcohol alkene ether carboxylate as a repairing liquid in oilfield reservoir repair is characterized in that the fatty alcohol alkene ether carboxylate has the following structural general formula:

wherein R is-C₁₂H₂₅And n is 5.

Further preferably, the concentration of the fatty alcohol alkenyl ether carboxylate is 2g/L, and the pH of the fatty alcohol alkenyl ether carboxylate is 4.

As a further preferred aspect of the present invention, the fatty alcohol alkenyl ether carboxylate is prepared according to the following method:

A. weighing maleic anhydride and fatty alcohol polyoxyethylene (5) ether according to a molar ratio of 1.05: 1;

B. and C, adding the maleic anhydride weighed in the step A and fatty alcohol polyoxyethylene (5) ether into a three-neck glass flask together for constant temperature reaction to obtain fatty alcohol alkylether carboxylate.

Further preferably, in step B, the isothermal reaction temperature is controlled at 90 ℃ and the isothermal reaction time is controlled at 1 h.

The invention has the beneficial effects that: the invention directly applies the fatty alcohol alkene ether carboxylic ester to the oil reservoir restoration, and provides a more effective restoration and blockage removal method for replacing expensive re-fracturing and re-drilling; the fatty alcohol vinyl ether carboxylate serving as the repair liquid can obviously dissolve an oil phase, reduce the interfacial tension of a fluid, reduce the surface tension and the phase trapping, wet a solid phase in a rock matrix with water, improve the fluidity of a formation fluid, eliminate emulsification damage, remove particles blocking pores to the maximum extent, solve the problem of oil well blockage, ensure the yield of an oil-gas well, control the production (lifting) cost and prolong the production life of a mature oil field aging well, and has good repair effect; the aliphatic alcohol alkenyl ether carboxylate, namely the repair liquid, is synthesized by a green, efficient and economic method, the cost of the repair liquid is low, and economic benefits are realized.

Drawings

FIG. 1 is an infrared spectrum of a repair liquid of the present invention;

FIG. 2 is a nuclear magnetic hydrogen spectrum of the repair liquid;

FIG. 3 is a nuclear magnetic carbon spectrum of the repair fluid;

FIG. 4 is a graph of the contact angle of the healing liquid;

FIG. 5 is a graph of concentration versus emulsification time;

FIG. 6 is a graph showing the relationship between the oil-water ratio and the emulsification time;

FIG. 7 is a graph of pH versus emulsification time;

FIG. 8 is a diagram showing an oil washing rate experiment and a repairing liquid experiment;

FIG. 9 is a diagram of an oil content experiment-fatty alcohol-polyoxyethylene ether experiment;

FIG. 10 is a graph showing the results of a viscosity reduction experiment;

FIG. 11 is a graph of a foam stability experiment for a healing fluid;

FIG. 12 is a graph showing the experimental foam stability of fatty alcohol polyoxyethylene ether;

fig. 13 is a graph of particle suspension performance experiments.

Detailed Description

The principles and features of this invention are described below in conjunction with examples which are set forth to illustrate, but are not to be construed to limit the scope of the invention.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.

The invention provides an application of fatty alcohol alkene ether carboxylate as a repairing liquid in oil field reservoir repairing, wherein the fatty alcohol alkene ether carboxylate has the following structural general formula:

wherein R is-C₁₂H₂₅And n is 5.

Further, the concentration of the fatty alcohol alkenyl ether carboxylate is 2g/L, and the pH of the fatty alcohol alkenyl ether carboxylate is 4.

The reason why the concentration of the fatty alcohol alkenyl ether carboxylate as a repair liquid is controlled to be 2g/L is to achieve excellent emulsifying properties while meeting economic benefits.

Further, the fatty alcohol alkenyl ether carboxylate is prepared according to the following method:

A. weighing maleic anhydride and fatty alcohol polyoxyethylene (5) ether according to a molar ratio of 1.05: 1;

B. and C, adding the maleic anhydride weighed in the step A and fatty alcohol polyoxyethylene (5) ether into a three-neck glass flask together for constant temperature reaction to obtain fatty alcohol alkylether carboxylate.

The fatty alcohol polyoxyethylene (5) ether (MOA-5) is selected because the foam property, the wetting property and the emulsibility of the MOA-5 are better, and the number of EO (ethylene oxide) is increased, so that the emulsifying property and the wetting property are reduced; the oleophylic property is stronger, which is beneficial to oil washing, and the carbon chain is shorter, the molecular weight is smaller, the pollution of waste liquid after reaction is small, and the treatment is easier.

Further, in the step B, the temperature of the isothermal reaction is controlled at 90 ℃, and the time of the isothermal reaction is controlled at 1 h.

The temperature of the isothermal reaction is controlled at 90 ℃ to ensure that the MOA-5 and the maleic anhydride are fully reacted and the generation of byproducts is avoided; the constant temperature reaction temperature is higher than 90 ℃, ether bonds in MOA-5 are easy to break, and byproducts are generated; the constant temperature reaction temperature is lower than 90 ℃, so that the reaction is insufficient, and the raw material waste is caused;

the constant temperature reaction time is controlled to be 1h, so that the MOA-5 and maleic anhydride are fully reacted, and the conversion rate is ensured; the constant temperature reaction time is more than 1h, and the change of the conversion rate is not obvious; the constant temperature reaction time is less than 1h, the reaction is insufficient, and the conversion rate is low; the conversion rate and the time cost are comprehensively considered, and the constant-temperature reaction time is selected to be 1 h.

The constant temperature reaction temperature and time are matched to ensure that MOA-5 and maleic anhydride are fully reacted, the conversion rate is high, byproducts are avoided, no catalyst is needed in the whole reaction process, the preparation process is simple, and the cost is low.

Examples

A. Weighing 3.00g of maleic anhydride and 16.98g of MOA-5;

B. and B, adding the maleic anhydride weighed in the step A and MOA-5 into a three-neck glass flask together, regulating the temperature of the raw materials in the three-neck flask to 90 ℃ through a constant-temperature water bath, and reacting for 1h at a constant temperature to finally obtain a light yellow viscous liquid to obtain a product fatty alcohol alkenyl ether carboxylate, namely the repair liquid.

The fatty alcohol alkenyl ether carboxylate prepared in the above example, i.e., the repair liquid, was subjected to the following tests:

1. infrared characterization

Taking a small amount of dried KBr, and tabletting by using an infrared tabletting machine; coating the repair liquid (fatty alcohol alkenyl ether carboxylate) prepared in the embodiment on a KBr sheet, and drying; infrared spectrum scanning is carried out by a WQF-520 type infrared spectrometer, the background of the instrument is collected, and an infrared spectrogram of the repair liquid is shown in figure 1.

FIG. 1 is an infrared spectrum of a repairing liquid, which can be obtained from FIG. 1, at 3470cm^-1The nearby absorption peak is a characteristic peak of hydroxyl;at 2940cm^-1，2870cm^-1The nearby absorption peak is a characteristic peak of methylene; at 1730cm^-1The absorption peak in the vicinity is a characteristic peak of a carbonyl group; at 1120cm^-1The nearby absorption peak is the characteristic peak of the ether group, and the characteristic absorption peak of each monomer is shown in the map, which proves that the target product is synthesized.

2. Nuclear magnetic resonance analysis

(1) Hydrogen spectroscopy

Adding the repairing liquid prepared in the embodiment into a nuclear magnetic tube; adding deuterated chloroform into the nuclear magnetic tube, and standing until the deuterated chloroform is completely dissolved; and thirdly, scanning the hydrogen spectrum of the repairing liquid by using a Bruker AC-E200 nuclear magnetic resonance spectrometer, wherein the frequency is 400Hz, and the hydrogen spectrum of the repairing liquid is respectively shown in figure 2.

FIG. 2 is a hydrogen spectrum of the repairing solution, which is obtained from FIG. 2, with chemical shift/ppm as abscissa and absorption peak intensity as ordinate, and 4.38ppm is-CH₂＝CH₂-proton chemical shift of; 4.30ppm is-CH₂Proton chemical shift of COO-; 3.66ppm is-CH₂-proton chemical shift of O-; 1.59ppm is-CH₂-CH₂-proton chemical shift of; 1.27ppm is- (CH)₂)₁₀-proton chemical shift of; 0.89ppm is CH₃-proton chemical shift of; 7.28ppm is the proton chemical shift of the solvent deuterated chloroform.

(2) Carbon spectrum analysis

Adding the repairing liquid prepared in the embodiment into a nuclear magnetic tube; adding deuterated chloroform into the nuclear magnetic tube, and standing until the deuterated chloroform is completely dissolved; thirdly, the carbon spectrum of the repairing liquid is scanned by a Bruker AC-E200 nuclear magnetic resonance spectrometer, the frequency is 100Hz, and the carbon spectrum of the repairing liquid is respectively shown in figure 3.

Fig. 3 is a carbon spectrum of the repair liquid, wherein chemical shifts/ppm are plotted as abscissa and absorption peak intensity is plotted as ordinate, and 165.98ppm are chemical shifts of-COO-, -COOH, and 131.72ppm and 128.32ppm are chemical shifts of-CH-, as can be obtained from fig. 3; 77.08ppm is-CH₂-chemical shift of O-; 22.5ppm is-O-CH₂-chemical shift; 29.45ppm is- (CH)₂)₁₀-chemical shift of (a).

The above results show that the target product is synthesized by combining FIG. 2 and FIG. 3.

3. Wetting Properties

Wettability: when two immiscible fluids are present, there is a tendency for one of the fluids to spread or adhere to the surface of the solid. The contact angle is also called wetting angle, so the wetting property can be judged by measuring the contact angle. The contact angle is the angle between the tangent line of the liquid drop surface passing through the three intersection points of gas, liquid and solid and the liquid-solid interface.

The operation method comprises the following steps: the repairing liquid prepared in the embodiment is dripped on the surface of a solid sample (glass slide, the material of the repairing liquid is glass), the outline image of the liquid drop is obtained through a microscope lens and a camera, the contact angle of the liquid drop in the image is marked by digital image processing, the result is shown in fig. 4, and the judgment basis is shown in table 1.

TABLE 1 basis for judging wettability by contact angle

Fig. 4 is a graph showing the contact angle of the repair liquid, and it can be seen from fig. 4 that the contact angle of the repair liquid is 65.31 °, and the wettability is good.

4. Emulsifying Property

(1) Effect of concentration on emulsification Properties

Respectively taking 0.1g, 0.15g, 0.2g, 0.25g and 0.3g of the repairing solution prepared in the embodiment, dissolving in 100mL of distilled water, and fully dissolving to obtain repairing solution solutions with the concentrations of 1g/L, 1.5g/L, 2g/L, 2.5g/L and 3 g/L; dissolving 0.1g, 0.15g, 0.2g, 0.25g and 0.3g of fatty alcohol-polyoxyethylene ether in 100mL of distilled water, and fully dissolving to obtain fatty alcohol-polyoxyethylene ether solutions with the concentrations of 1g/L, 1.5g/L, 2g/L, 2.5g/L and 3g/L, which serve as a control group;

respectively taking 40mL of the prepared repair solution with the concentration of 1g/L, 1.5g/L, 2g/L, 2.5g/L and 3g/L, 40mL of the fatty alcohol-polyoxyethylene ether solution and 40mL of the oil phase, mixing and pouring the mixture into a 100mL measuring cylinder with a plug, wherein the temperature is 70 ℃, uniformly shaking the mixture for 5 times every 60s, repeating the steps for 5 times, starting to press a stopwatch for timing, and obtaining the time for 10mL of water to appear at the bottom of the measuring cylinder, namely the emulsifying time, and the results are shown in Table 2:

TABLE 2 concentration vs. emulsification time Table

The contents of table 2 are plotted as a line graph, with the results shown in fig. 5.

Fig. 5 is a graph showing the relationship between concentration and emulsification time, and it can be seen from table 2 and fig. 5 that, on one hand, with the increase of concentration, the effective content of the repair liquid is increased, the emulsification time of the crude oil of the repair liquid and fatty alcohol-polyoxyethylene ether is gradually increased, and the emulsification stability is enhanced, and on the other hand, at the same concentration, the repair liquid of the present invention has a longer crude oil emulsification time than fatty alcohol-polyoxyethylene ether, which indicates that the activity of the repair liquid is higher than fatty alcohol-polyoxyethylene ether, and the emulsification stability is stronger. The emulsification time is increased along with the increase of the concentration, when the concentration exceeds 2g/L, the increase amplitude of the emulsification time is not obvious along with the increase of the concentration, and the concentration is selected to be 2g/L in consideration of the emulsification time and the economic benefit.

(2) Influence of oil-water ratio on emulsification

Preparing a repair liquid and a fatty alcohol-polyoxyethylene ether solution with the concentration of 2g/L by using distilled water, respectively mixing an oil phase with the prepared repair liquid and the fatty alcohol-polyoxyethylene ether solution according to the volume ratio (the volume ratio of the oil phase to the repair liquid/the fatty alcohol-polyoxyethylene ether) of 2:8, 3:7, 4:6, 5:5, 6:4, 7:3 and 8:2, pouring the mixture into a 100mL measuring cylinder with a plug, uniformly shaking the mixture for 5 times every 60s at the temperature of 70 ℃, and starting to time according to a lower second meter after repeating the steps for 5 times to obtain the time for 10mL of water to appear at the bottom of the measuring cylinder, namely the emulsifying time, wherein the oil-water ratio refers to the volume ratio of the oil phase to the repair liquid/the fatty alcohol-polyoxyethylene ether, and the result is shown in Table 3:

TABLE 3 oil-water ratio versus emulsification time Table

The contents of table 3 are plotted as a line graph, with the results shown in fig. 6.

Fig. 6 is a graph showing the relationship between the oil-water ratio and the emulsification time, and it can be seen from table 3 and fig. 6 that the oil-water ratio has an obvious influence on the emulsification time of the crude oil of the repair liquid and the fatty alcohol-polyoxyethylene ether, and as the oil-water ratio decreases, the emulsification stability decreases first and then increases, and the emulsification rate increases obviously, because as the water content increases, the emulsification system gradually approaches to the O/W type from the W/O type, so the stability decreases. When the oil-water ratio is reduced to a certain degree, on one hand, an O/W type emulsification system is formed, the stability is gradually enhanced, and on the other hand, the effective content of the surface activity is improved, so that the effective content is favorable for being attached to an oil-water interface to reduce the interfacial tension, and the emulsification rate is improved. Meanwhile, the crude oil emulsification time of the repair liquid is longer than that of fatty alcohol-polyoxyethylene ether under the same oil-water ratio. The emulsification time of the oil-water ratio is 2:8 and 8:2 is almost the same, for 2:8, the using amount of the repairing liquid is more, and for 8:2, the using amount of the repairing liquid is less, so that the cost is saved, and therefore the oil-water ratio is 8: 2.

(3) Effect of pH on emulsification

The repairing liquid prepared in the example, a fatty alcohol-polyoxyethylene ether solution (with the concentration of 2g/L) and an oil phase are mixed, the pH of the solution is adjusted to 4, 5, 6, 7, 8, 9 and 10 by HCl, the solution is poured into a 100mL measuring cylinder with a plug, the temperature is 70 ℃, the solution is uniformly shaken for 5 times every 60s, after 5 times of the shaking, a stopwatch is pressed for counting, and the time for 10mL of water to appear at the bottom of the measuring cylinder with the plug, namely the emulsifying time is obtained, and the results are shown in a table 4:

TABLE 4 pH vs. emulsification time Table

The contents of table 4 are plotted as a line graph, with the results shown in fig. 7.

FIG. 7 is a graph showing the relationship between pH and emulsification time, and it can be seen from Table 4 and FIG. 7 that, on the one hand, as the pH increases, the emulsification time of the crude oil emulsion of the repairing liquid and fatty alcohol-polyoxyethylene ether of the present invention is shortened and then increased, and the emulsification time of the repairing liquid is longer than that of fatty alcohol-polyoxyethylene ether at the same pH; on the other hand, the pH value should be controlled under the condition of peracid or overbasing, so that the stability of the emulsifier is better and the demulsification is more difficult. From this, it is found that the emulsion stability of the repair liquid is optimal when the pH is selected to be 4.

5. Decontamination experiment

Weighing 4.0g of oil, adding the oil into 50.0g of quartz sand, placing the quartz sand in a constant-temperature water bath at 70 ℃ for stirring, uniformly mixing, adding 108.0g of fatty alcohol-polyoxyethylene ether and a repair solution (the concentration is 2g/L) into oil sand, cleaning the oil sand for half an hour under the constant temperature condition when the solution reaches 70 ℃, standing, separating the oil from the sand, placing the separated oil sand in an oven for drying, weighing the separated oil sand after drying, calculating the oil washing efficiency by using a gravimetric method, and performing three-group parallel experiments. The oil washing efficiency represents the elution capacity of the oil washing agent on the thick oil on the surface of the oil sand, and the larger the value of the oil washing efficiency is, the stronger the elution capacity is. Currently, the oil washing rate of oil sand is generally calculated by a mass method, see formula (1):

in formula (1): η is the oil wash efficiency,%; and m1 and m2 are respectively the oil mass g before and after the oil sand cleaning agent washes the oil.

The results are shown in tables 5, 6, 8 and 9.

TABLE 5 oil wash rate of repair fluids (fatty alcohol alkenyl ether carboxylates)

TABLE 6 oil washout Rate of fatty alcohol polyoxyethylene ethers

As can be seen from tables 5 and 6, under the condition of the agent-to-sand ratio of 2:1, the oil washing efficiency of the remediation liquid is 67.42%, the oil washing efficiency of the fatty alcohol-polyoxyethylene ether is 47.67%, the data show that the oil washing effect of the remediation liquid is much higher than that of the fatty alcohol-polyoxyethylene ether, and the results prove that the oil washing efficiency of the remediation liquid is higher, the requirements of the oil field on oil reservoir remediation can be met, and the remediation effect is good.

Fig. 8 is a diagram of an oil washing rate experiment and a repairing solution experiment, and fig. 9 is a diagram of an oil washing rate experiment and a fatty alcohol-polyoxyethylene ether experiment.

6. Viscosity reduction test

Preparing the repairing liquid and the fatty alcohol-polyoxyethylene ether with the concentration of 2g/L, weighing 90mg, 120mg, 150mg, 180mg and 210mg of the fatty alcohol-polyoxyethylene ether and the repairing liquid, mixing the repairing liquid and 100mg of crude oil (with the viscosity of 491.4mpa.s), stirring the mixture for 15min at the temperature of 70 ℃, and testing the viscosity, wherein the results are shown in Table 7:

TABLE 7 viscosity reduction test results table

The contents of table 7 are plotted as a line graph, with the results shown in fig. 10.

Fig. 10 is a viscosity reduction experiment result diagram, and as can be seen from table 7 and fig. 10, as the mass of the fatty alcohol-polyoxyethylene ether and the repair liquid increases, the viscosity gradually decreases, the viscosity reduction rate gradually increases, and the viscosity reduction rate of the repair liquid is higher than that of the fatty alcohol-polyoxyethylene ether under the same solution mass, which indicates that the viscosity reduction effect of the repair liquid is good.

7. Foam performance

Surfactants with different foam properties are required in different fields of application, and the foam properties can be roughly judged from two aspects (foamability and foam stability). In the experiment, an oscillation method is selected, 40mL of test solution (repair solution with the concentration of 2g/L and fatty alcohol-polyoxyethylene ether) is filled into a container with scales, the container is oscillated in a certain mode, the foam volume in the container is recorded after oscillation is stopped, and the foamability of the test solution (V30s/V0) is explained by the volume; the foam half-life was recorded and demonstrated the stability of the foam by half-life (V3min/V30s), and the results are shown in Table 8:

table 8 experimental results of foam properties table

Fig. 11 is a foam stability experimental graph of the repair liquid, fig. 12 is a foam stability experimental graph of fatty alcohol-polyoxyethylene ether, as can be seen from table 8, fig. 11, and fig. 12, the foaming performance of the repair liquid and fatty alcohol-polyoxyethylene ether is overall better, both have substantially no liquid separated out when forming foam, but both have different half-lives (3min), the half-life foam of the repair liquid is stabilized at about 50mL, and the half-life foam of fatty alcohol-polyoxyethylene ether is stabilized at about 40mL, it is found from the experimental picture that compared with fatty alcohol-polyoxyethylene ether, the repair liquid has better foaming capacity, denser foam, more uniform distribution, and more excellent foam stabilizing performance.

8. Suspension properties of particles

Respectively preparing a repairing solution and fatty alcohol-polyoxyethylene ether with the concentration of 2g/L, generating a certain amount of foam through stirring, adding quartz sand grains with the grain size of 0.45-0.90 mm into the solution, and judging the small grain capacity of a cleaning channel by observing the settling time of the sand grains, wherein the result is shown in figure 13.

Fig. 13 is an experimental graph of particle suspension performance, and it can be seen from fig. 13 that the added quartz sand is suspended in the foam for more than 60min, which shows that the foam formed by the repair liquid and the fatty alcohol-polyoxyethylene ether solution has good foam strength, stability and good sand carrying capacity, and the 60min picture shows that the repair liquid has higher foam strength and stability than the fatty alcohol-polyoxyethylene ether solution.

9. Permeability recovery test

Firstly, respectively preparing a repairing liquid and fatty alcohol-polyoxyethylene ether with the concentration of 2g/L, and measuring by using a columnar homogeneous rock coreThe core permeability is 1200X 10^-3μm²Filling the core into a core holder, injecting water at a constant speed (0.5ml/min) until the pressure is stable, and calculating the water phasePermeability, i.e. the initial permeability is obtained;

respectively injecting the repair liquid and the fatty alcohol-polyoxyethylene ether prepared in the step I into the rock core at a constant speed which is the same as the water injection speed in the step I, and injecting 2 pv;

injecting simulated water at the same speed and constant speed until the pressure is stable;

fourthly, testing and calculating the permeability of the rock core after the rock core is placed for 500min, and obtaining the permeability after well washing;

and fifthly, calculating the recovery rate of the core permeability to judge the damage effect on the stratum, wherein the recovery rate of the core permeability is (permeability after well flushing/initial permeability) 100%.

Three sets of experiments were tested in parallel and the results are shown in table 9.

TABLE 9 permeability recovery test experiment

As can be seen from table 9, for artificial cores with different permeabilities, the recovery rate of the permeability of the core is about 90% by reversely injecting the 2PV repairing solution, while the recovery rate of the permeability of the core of the fatty alcohol-polyoxyethylene ether is about 80%, the recovery rate of the permeability of the repairing solution is improved by about 10% compared with that of the fatty alcohol-polyoxyethylene ether, and thus the reservoir is well protected by the repairing solution.

The fatty alcohol alkenyl ether carboxylate prepared by the invention is used as a repair liquid, and the specific properties are as follows:

(1) the wettability is good;

(2) the emulsion stability is high;

(3) the oil washing efficiency is high, and the requirement on oil reservoir restoration in an oil field can be met;

(4) the viscosity reduction effect is good;

(5) the foaming capacity is better, the foam is denser, the distribution is more uniform, and the foam stabilizing performance is more excellent;

(6) the foam has high strength, good stability and good sand carrying capacity;

(7) the protective property to the reservoir is good.

The fatty alcohol alkene ether carboxylate is directly used as a repairing liquid to be applied to oil reservoir repairing, and has the advantages of dissolving an oil phase, reducing fluid interfacial tension, reducing surface tension and phase trapping, wetting a solid phase in a rock matrix by water, simple preparation process, low cost and good effect;

the fatty alcohol vinyl ether carboxylate serving as a repair liquid can obviously dissolve an oil phase, reduce the interfacial tension of a fluid, reduce the surface tension, trap the phase and wet a solid phase in a rock matrix by water, improve the fluidity of a stratum fluid, eliminate emulsification damage, remove particles blocking pores to the maximum extent, solve the problem of oil well blockage, ensure the yield of an oil-gas well, control the production (lifting) cost, prolong the production life of a mature oil field aging well and provide a more effective repair and blockage removal method for replacing expensive re-fracturing and drilling; the aliphatic alcohol alkenyl ether carboxylate, namely the repair liquid, is synthesized by a green, efficient and economic method, the cost of the repair liquid is low, and remarkable economic benefits are realized.

The repairing liquid, namely the fatty alcohol vinyl ether carboxylate is injected into the near-wellbore stratum skeleton to decompose the emulsion, so that the non-miscible fluid is separated, and the stratum sand near the wellbore is in a hydrophilic state, thereby being beneficial to oil gas production and bringing remarkable economic and social benefits.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.