Viscosity reducer and composition thereof

Abstract

The invention relates to a viscosity reducer and a composition thereof. The viscosity reducer is prepared from the following raw material components: a betaine surfactant, a foaming agent, a fluorocarbon surfactant and a green surfactant, wherein the content of the betaine surfactant is 30%-40% by mass, the content of the foaming agent is 8%-10% by mass, the content of the fluorocarbon surfactant is 3%-6% by mass, and the content of the green surfactant is 10%-15% by mass. The technical problem that the recovery efficiency of an existing single well is low is solved.

Description

Technical Field

[0001] The present application relates to the technical field of petroleum exploration and development, and in particular to a viscosity reducer and a composition thereof. Background Art

[0002] Heavy oil development is mainly thermal recovery, including steam injection. However, during the steam injection development process, on the one hand, due to the difference in viscosity between steam and crude oil and the influence of reservoir heterogeneity, steam overburden and fingering occur, which reduces the volumetric sweep coefficient of steam injection production; on the other hand, due to the influence of the crude oil-rock-water interface characteristics, a large part of the heavy oil cannot be stripped from the rock, and the oil washing efficiency cannot be effectively improved, resulting in a poor effect of heavy oil steam injection production.

[0003] At present, the injection of surfactant system is accompanied by steam injection, and the special properties of surfactant are used to improve the development effect. However, in the process of conventional steam injection of ultra-heavy oil in medium and deep layers, the bottom hole steam injection dryness is low, the thermal sweep range is small, the steam seepage stirring conditions are poor, the crude oil cannot be effectively emulsified and viscosity reduced, and the formed water-in-oil emulsion is not conducive to subsequent treatment. Most of the surfactant systems can only play the role of reducing the viscosity of crude oil, and the single well recovery rate is low. Summary of the invention

[0004] The present application provides a viscosity reducer and a composition thereof to solve the technical problem of low recovery rate of existing single wells.

[0005] In a first aspect, the present application provides a viscosity reducer, wherein the raw material components of the viscosity reducer include: a betaine surfactant, a foaming agent, a fluorocarbon surfactant and a green surfactant; wherein, by mass fraction,

[0006] The content of the betaine surfactant is 30% to 40%, the content of the foaming agent is 8% to 10%, the content of the fluorocarbon surfactant is 3% to 6%, and the content of the green surfactant is 10% to 15%.

[0007] Optionally, the content of the betaine surfactant is 34% to 36%.

[0008] Optionally, the content of the green surfactant is 12% to 15%.

[0009] Optionally, the betaine surfactant includes one of the following: cocoamidopropyl betaine, lauryl amide propyl betaine, and oleamidopropyl betaine.

[0010] Optionally, the foaming agent includes one of the following: sodium dodecylbenzene sulfonate and sodium dodecylbenzene sulfate.

[0011] Optionally, the fluorocarbon surfactant includes one of the following: sodium perfluorononenyloxybenzene sulfonate and perfluoropolyoxyethylene ether.

[0012] Optionally, the green surfactant includes one of the following: alkyl glycoside, alcohol ether carboxylate, phenol ether carboxylate.

[0013] In a second aspect, the present application provides a composition comprising heavy oil and the viscosity reducer described in any one embodiment of the first aspect.

[0014] Optionally, relative to 1 part by weight of the heavy oil, the viscosity reducer is 0.001 part by weight to 0.01 part by weight.

[0015] Optionally, under the condition of a temperature of 300° C., the viscosity reduction rate of the viscosity reducer on the heavy oil is greater than 80%.

[0016] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0017] The viscosity reducer provided in the embodiment of the present application comprises a betaine surfactant which plays an oil displacement role, a foaming agent which plays a foaming role, a fluorocarbon surfactant which plays a role in temperature resistance and reducing the surface tension of water, and a green surfactant which plays a role in accelerating the solubility of the betaine surfactant. The above-mentioned agents have a synergistic effect. When the viscosity reducer encounters formation water during injection from an oil well, the foaming agent plays a role in generating foam, which plays a temporary plugging role, and the foam bursts when encountering oil. The betaine surfactant, the fluorocarbon surfactant and the green surfactant are selectively injected into the bottom layer, and the green surfactant accelerates the solubility of the betaine surfactant. Several surfactants preferentially enter the water layer and play an effective plugging role. The subsequent viscosity reducer can enter the oil layer and mix with the crude oil to reduce the viscosity of the crude oil, thereby improving the single well recovery rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0020] Figure 1 A viscosity reducing effect diagram of a viscosity reducing agent provided in an embodiment of the present application on heavy oil;

[0021] Figure 2A schematic diagram of a process for reducing the viscosity of heavy oil using a viscosity reducer provided in an embodiment of the present application. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0023] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0024] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present specification, the terms "including", "comprising", etc. refer to "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of the associated objects, indicating that there may be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A, B can be singular or plural. In this article, "at least one" refers to one or more, and "plural" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b, or c", or "at least one of a, b and c", can both mean: a, b, c, ab (i.e. a and b), ac, bc or abc, where a, b, c can be single or plural, respectively.

[0025] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0026] In a first aspect, the present application provides a viscosity reducer, wherein the raw material components of the viscosity reducer include: a betaine surfactant, a foaming agent, a fluorocarbon surfactant and a green surfactant; wherein, by mass fraction,

[0027] The content of the betaine surfactant is 30% to 40%, the content of the foaming agent is 8% to 10%, the content of the fluorocarbon surfactant is 3% to 6%, and the content of the green surfactant is 10% to 15%.

[0028] In some embodiments, the content of the betaine surfactant is 34% to 36%.

[0029] In some embodiments, the content of the green surfactant is 12% to 15%.

[0030] In the embodiment of the present application, betaine surfactant plays an oil displacement role, foaming agent plays a foaming role, fluorocarbon surfactant plays a role in temperature resistance and reducing the surface tension of water, and green surfactant plays a role in accelerating the solubility of betaine surfactant; the above-mentioned agents have a synergistic effect, and the foaming agent plays a role in generating foam after the viscosity reducer encounters formation water during the injection process from the oil well, which plays a temporary plugging role, and the foam breaks when encountering oil, betaine surfactant, fluorocarbon surfactant and green surfactant are selective after being injected into the bottom layer, and green surfactant accelerates the solubility of betaine surfactant, several surfactants preferentially enter the water layer, play an effective plugging role, and subsequent viscosity reducers can enter the oil layer, meet crude oil mixing to reduce the viscosity of crude oil, thereby improving the single well recovery rate. The compounding of several agents makes the viscosity reducer have the effects of high temperature resistance, foaming, viscosity reduction, stripping, and oil displacement at the same time.

[0031] At the same time, the content of the above-mentioned agents is controlled, and an appropriate amount of betaine surfactant is used to control the oil-water interfacial tension value to form an ultra-low interfacial tension of ≤10 -3 mN / m. If the content of the betaine surfactant is too much, it will increase the cost to a certain extent, increase the viscosity of the surfactant, and deteriorate the fluidity, which is not conducive to field application; if the content of the betaine surfactant is too little, it will be impossible for the oil and water to achieve ultra-low interfacial tension to a certain extent. Specifically, the content of the betaine surfactant can be 30%, 32%, 34%, 36%, 38%, 40%, etc. Preferably, the content of the betaine surfactant can be 34% to 36%.

[0032] An appropriate amount of foaming agent is used to control the foaming volume. If the content of the foaming agent is too much, it will cause more foam to be generated during the compounding process, and the defoaming process will be long, which is not conducive to environmental protection; if the content of the foaming agent is too little, the foaming volume will not meet the requirements of on-site use to a certain extent. Specifically, the content of the foaming agent can be 8%, 9%, 10%, etc.

[0033] An appropriate amount of fluorocarbon surfactant is used to control the surface tension to ≤28mN / m. If the content of the fluorocarbon surfactant is too much, it will increase the cost to a certain extent, because the price of fluorocarbon surfactant is about 10-20 times that of other surfactants; if the content of the fluorocarbon surfactant is too little, the surface tension will not reach the ideal value to a certain extent. Specifically, the content of the fluorocarbon surfactant can be 3%, 5%, 6%, etc.

[0034] An appropriate amount of green surfactant can accelerate the solubility of betaine surfactants. If the content of the green surfactant is too much, the viscosity of the system will increase and the fluidity will deteriorate to a certain extent; if the content of the green surfactant is too little, the solubility of betaine will deteriorate to a certain extent. Specifically, the content of the green surfactant can be 10, 11, 12, 13, 14, 15, etc. Preferably, the content of the green surfactant can be 12% to 15%.

[0035] In some embodiments, the betaine surfactant includes one of the following: cocoamidopropyl betaine, lauramidopropyl betaine, and oleamidopropyl betaine.

[0036] In the examples of the present application, cocoamidopropyl betaine, lauryl amide propyl betaine and oleyl amide propyl betaine are selected as betaine surfactants. These betaine surfactants are easy to obtain and have excellent performance.

[0037] In some embodiments, the foaming agent includes one of the following: sodium dodecylbenzene sulfonate and sodium dodecylbenzene sulfate.

[0038] In the examples of the present application, sodium dodecylbenzene sulfonate and sodium dodecylbenzene sulfate are selected as foaming agents. As traditional foaming surfactants, they have large production and low prices.

[0039] In some embodiments, the fluorocarbon surfactant includes one of the following: sodium perfluorononenyloxybenzene sulfonate and perfluoropolyoxyethylene ether.

[0040] In the examples of the present application, sodium perfluorononenyloxybenzene sulfonate and perfluoropolyoxyethylene ether are selected as fluorocarbon surfactants. Such fluorocarbon surfactants have excellent temperature resistance.

[0041] In some embodiments, the green surfactant includes one of the following: alkyl glycoside, alcohol ether carboxylate, phenol ether carboxylate.

[0042] In the examples of the present application, alkyl glycosides, alcohol ether carboxylates, and phenol ether carboxylates are selected as green surfactants. These green surfactants are easy to obtain, have excellent performance, and can improve the solubility of betaine.

[0043] In the embodiment of the present application, a viscosity reducer formula for heavy oil steam stimulation wells is developed by compounding. During the steam stimulation process, the initial temperature of the superheated steam in the formation is about 280-300°C, and the agent must first withstand one of the high temperature indicators. On the premise of meeting this indicator, the agent is compounded from a variety of agents so that the agent has the effects of temperature resistance, oil displacement, stripping, penetration and viscosity reduction at the same time, which can effectively reduce the oil-water interfacial tension, change the wettability of the oil layer rock, and change the rock from oil-wet to hydrophilic. At the same time, it has the effects of penetration, stripping, and viscosity reduction, effectively stripping the heavy oil, reducing the viscosity of the heavy oil, and improving the fluidity of the heavy oil, thereby increasing the recovery rate of the heavy oil steam stimulation wells. Specifically, as one of the indicators of the viscosity reducer, it is as follows: the appearance is a colorless viscous liquid with a density of 1.06g / cm 3 , pH value (1% aqueous solution) is 7, surface tension (0.3% aqueous solution) is 25.67mN / m, and interfacial tension (0.3% aqueous solution) is 1.57mN / m.

[0044] Preparation of the above viscosity reducer: Compound the above betaine surfactant, foaming agent, fluorocarbon surfactant and green surfactant in proportion, add water and stir for 30 minutes to obtain a high-performance composite surfactant. Figure 2 .

[0045] In the embodiments of the present application, multiple agents are used in combination to give the viscosity reducer a complex function. Compared with the prior art, the advantage is that traditional viscosity reducers can only reduce crude oil viscosity and increase crude oil fluidity, but do not have comprehensive properties such as foaming and oil displacement.

[0046] In a second aspect, the present application provides a composition comprising heavy oil and the viscosity reducer described in any one embodiment of the first aspect.

[0047] In some embodiments, the viscosity reducer is in an amount of 0.001 to 0.01 parts by weight relative to 1 part by weight of the heavy oil.

[0048] In some embodiments, under the condition of a temperature of 300° C., the viscosity reduction rate of the heavy oil by the viscosity reducer is greater than 80%.

[0049] In the embodiment of the present application, the amount of the viscosity reducer is controlled, and the viscosity reducer has good performance while controlling the cost. If the content of the viscosity reducer is too much, it will cause a large amount of surfactant to be contained in the produced fluid to a certain extent, affecting the crude oil dehydration and water treatment of the back-end joint station; if the content of the viscosity reducer is too little, it will not achieve the viscosity reduction effect on the heavy oil to a certain extent, and the viscosity reduction rate will become smaller. Specifically, the viscosity reducer can be 0.001 parts by weight, 0.002 parts by weight, 0.004 parts by weight, 0.006 parts by weight, 0.008 parts by weight, 0.01 parts by weight, etc.

[0050] In the examples of this application, a viscosity reducer formula for heavy oil steam huff and puff wells is developed by means of synthesis and compounding technology. Under the condition of a temperature of 300°C, the viscosity reduction rate of heavy oil in the oil field can reach more than 80%. For details, please refer to Figure 1 , indicating that the crude oil viscosity decreases, the fluidity is good, and the viscosity of the composition is low. As the amount of viscosity reducer increases, the viscosity reduction rate can reach 99%.

[0051] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0052] The present application example provides a viscosity reducer, and the specific raw material components thereof are shown in Tables 1-2.

[0053] Table 1 Raw materials of viscosity reducer

[0054]

[0055] Table 2 Raw material ratio of viscosity reducer (wt%), the balance is water

[0056] Serial number Betaine surfactants Foaming agent Fluorocarbon surfactants Green surfactant Example 1 30 8 3 10 Example 2 35 9 4 12 Example 3 37 9 5 13 Example 4 40 10 6 15

[0057] The viscosity reducers of Examples 1 to 4 were applied to heavy oil for testing, that is, the combination of the viscosity reducer and heavy oil. Please see Table 3 for the results.

[0058] Table 3 Viscosity reducer test results on heavy oil

[0059]

[0060]

[0061] For a specific analysis of the single well recovery rate, please refer to Table 4. The traditional viscosity reducer was used in the pre-measures period, and its main component was sodium dodecylbenzene sulfonate; the implementation plan of this application was used in the post-measures period. It can be seen from Table 4 that the single well recovery rate was significantly improved in the post-measures period.

[0062] Table 4 Analysis results of single well recovery before and after measures

[0063]

[0064] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A viscosity reducer, characterized in that: The raw material components of the viscosity reducer include: betaine surfactant, foaming agent, fluorocarbon surfactant and green surfactant; wherein, by mass fraction, The content of the betaine surfactant is 30% to 40%, the content of the foaming agent is 8% to 10%, the content of the fluorocarbon surfactant is 3% to 6%, and the content of the green surfactant is 10% to 15%.

2. The viscosity reducer according to claim 1, characterized in that The content of the betaine surfactant is 34% to 36%.

3. The viscosity reducer according to claim 1, characterized in that The content of the green surfactant is 12% to 15%.

4. The viscosity reducer according to any one of claims 1 to 3, characterized in that The betaine surfactant includes the following: cocamide betaine, lauramide propyl betaine, oleamide propyl betaine.

5. The viscosity reducer according to any one of claims 1 to 3, characterized in that: The foaming agent includes one of the following: sodium dodecylbenzene sulfonate and sodium dodecylbenzene sulfate.

6. The viscosity reducer according to any one of claims 1 to 3, characterized in that: The fluorocarbon surfactant includes the following: sodium perfluorononenyloxybenzene sulfonate and perfluoropolyoxyethylene ether.

7. The viscosity reducer according to any one of claims 1 to 3, characterized in that: The green surfactant includes one of the following: alkyl glycoside, alcohol ether carboxylate, phenol ether carboxylate.

8. A composition comprising thick oil and the viscosity reducer according to any one of claims 1 to 7.

9. The composition according to claim 8, characterized in that The viscosity reducer is present in an amount of 0.001 to 0.01 parts by weight relative to 1 part by weight of the heavy oil.

10. The composition according to claim 8 or 9, characterized in that Under the condition of a temperature of 300° C., the viscosity reduction rate of the heavy oil by the viscosity reducer is above 80%.

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