A fluorinated surfactant for oil-based foam drilling fluid and a preparation method thereof

Abstract

The present invention provides a fluorinated surfactant for oil-based foam drilling fluid having a structure of formula (I). The specific preparation method is: an amino compound, an acid-binding agent and a fluorinated compound are mixed and reacted to obtain a fluorinated surfactant for oil-based foam drilling fluid having a structure of formula (I). The surfactant for oil-based foam drilling fluid obtained by the present invention can reduce the surface tension of the oil phase, has strong foaming ability and foam stability, and can be used for the preparation of oil-based foam drilling fluid.

Description

Technical Field

[0001] The invention relates to the technical field of drilling fluid, in particular to a fluorine-containing surfactant for oil-based foam drilling fluid and a preparation method thereof. Background Art

[0002] In the process of drilling in low-pressure and leaky formations, the use of conventional drilling fluid systems is very likely to cause drilling fluid leakage, affecting the safety of underground construction. Foam drilling fluid is an effective means to solve the above technical problems. However, for highly water-sensitive formations (such as shale gas formation drilling, etc.), since clay is very easy to hydrate and disperse, the use of water-based foam drilling fluid is very likely to cause wellbore instability. Therefore, when drilling in low-pressure and highly water-sensitive formations, an oil-based foam drilling fluid system must be used.

[0003] Oil-based foam drilling fluid is formed by adding a surfactant with foaming function to the oil-based drilling fluid system, and wrapping air into the oil-based drilling fluid by means of vigorous stirring. Due to the presence of the surfactant, the interfacial tension between the gas and the liquid is significantly reduced, and finally an oil-based foam with good stability is formed. In ZL201210239981.6, a drilling fluid for low-pressure water-sensitive formations is disclosed, and the surfactant used is dehydrated sorbitan fatty acid ester; in ZL201110407297.X, an environmentally friendly high-temperature resistant synthetic foam drilling fluid and a preparation method thereof are disclosed, and the surfactant used is an alkyl sulfonic acid with 18 to 24 carbon atoms. Both of these surfactants are surfactants with long alkyl carbon chain structures. Due to their own large surface tension, it is difficult to reduce the surface tension of diesel, and the foaming ability in diesel is poor, making it difficult to form stable oil-based foam. Summary of the invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a fluorine-containing surfactant for oil-based foam drilling fluid. The fluorine-containing surfactant for oil-based foam drilling fluid provided by the present invention has strong foaming performance and foam stability.

[0005] The present invention provides a fluorinated surfactant for oil-based foam drilling fluid having a structure of formula (I), comprising:

[0006]

[0007] Where R 1 =C m F 2m+1 C n H 2n or m is an integer of 3 to 8, n is an integer of 0 to 1, and x is an integer of 2 to 4; R 2 is a C6-C20 alkyl group, a C6-C20 cycloalkyl group, or a C6-C20 aryl group; preferably, R 2is a C8-C20 alkyl group containing a long chain or aromatic ring structure; R 3 is H, C3-C12 alkyl, C3-C12 cycloalkyl, C6-C12 aryl; Z is

[0008] Preferably, the

[0009] R 1 =C m F 2m+1 C n H 2n or m is an integer of 6 to 8, R 2 It is a C12-C18 alkyl group, a C12-C18 cycloalkyl group, or a C12-C18 aryl group.

[0010] The present invention provides a method for preparing a fluorinated surfactant for oil-based foam drilling fluid of the structure of formula (I) described in the above technical solution, comprising:

[0011] The amino compound, the acid binding agent and the fluorine-containing compound are mixed and reacted to obtain a fluorine-containing surfactant for oil-based foam drilling fluid having a structure of formula (I);

[0012] The fluorine-containing compound is selected from one or more of perfluorobutyryl chloride, perfluorohexanoyl chloride, perfluorooctanoyl chloride, perfluorobutylsulfonyl fluoride, perfluorohexylsulfonyl fluoride, perfluorooctanesulfonyl fluoride, perfluorobutylacetyl chloride, perfluorohexylacetyl chloride, perfluorooctylacetyl chloride, hexafluoropropylene oxide dimer, hexafluoropropylene oxide trimer and hexafluoropropylene oxide tetramer.

[0013] Preferably, the amino compound is selected from one or more of dodecylamine, tetradecylamine, hexadecylamine, oleylamine, octadecylamine, 2-phenylethylamine, di-n-dodecylamine and 2-octyl-1-dodecylamine. Preferably, the acid binding agent is one of pyridine or triethylamine.

[0014] Preferably, the molar ratio of the amino compound, the acid binding agent and the fluorine-containing compound is 1:(1-2):(0.5-2).

[0015] Preferably, the reaction temperature is 0 to 100° C.; the reaction time is 1 to 3 hours.

[0016] Preferably, after the reaction, the step further comprises washing with distilled water at room temperature until the mixture becomes neutral.

[0017] The present invention provides an oil-based foam drilling fluid, comprising the fluorinated surfactant described in any one of the above technical solutions or the fluorinated surfactant prepared by the preparation method described in any one of the above technical solutions.

[0018] Compared with the prior art, the present invention provides a fluorinated surfactant for oil-based foam drilling fluid having a structure of formula (I). The specific preparation method is: an amino compound, an acid-binding agent and a fluorinated compound are mixed and reacted to obtain a fluorinated surfactant for oil-based foam drilling fluid having a structure of formula (I). The surfactant for oil-based foam drilling fluid obtained by the present invention can reduce the surface tension of the oil phase, has strong foaming ability and foam stability, and can be used for the preparation of oil-based foam drilling fluid. DETAILED DESCRIPTION

[0019] The present invention provides a fluorinated surfactant for oil-based foam drilling fluid and a preparation method thereof. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve the same. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and they all fall within the scope of protection of the present invention. The method and application of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the method and application of this article without departing from the content, spirit and scope of the present invention to achieve and apply the technology of the present invention.

[0020] The present invention provides a fluorinated surfactant for oil-based foam drilling fluid having a structure of formula (I), comprising:

[0021]

[0022] Where R 1 =C m F 2m+1 C n H 2n or m is an integer of 3 to 8, specifically 3, 4, 5, 6, 7 or 8. n is an integer of 0 to 1, and x is an integer of 2 to 4, specifically 2, 3 or 4.

[0023] R 2 is a C6-C20 alkyl group, a C6-C20 cycloalkyl group, or a C6-C20 aryl group; preferably a C8-C20 alkyl group containing a long chain or aromatic ring structure; more preferably a C8-C18 alkyl group, a C8-C18 cycloalkyl group, or a C8-C18 aryl group. Most preferably, R 2 It is a C12-C18 alkyl group, a C12-C18 cycloalkyl group, or a C12-C18 aryl group.

[0024] R 3 It is H, C3-C12 alkyl, C3-C12 cycloalkyl, C6-C12 aryl; preferably H, C5-C10 alkyl, C5-C10 cycloalkyl, C8-C11 aryl.

[0025] Z is

[0026] In some preferred embodiments of the present invention, the fluorinated surfactant for oil-based foam drilling fluid having the structure of formula (I) is specifically:

[0027]

[0028] The present invention provides a method for preparing a fluorinated surfactant for oil-based foam drilling fluid of the structure of formula (I) described in the above technical solution, comprising:

[0029] The amino compound, the acid binding agent and the fluorine-containing compound are mixed and reacted to obtain a fluorine-containing surfactant for oil-based foam drilling fluid having a structure of formula (I);

[0030] The fluorine-containing compound is selected from one or more of perfluorobutyryl chloride, perfluorohexanoyl chloride, perfluorooctanoyl chloride, perfluorobutylsulfonyl fluoride, perfluorohexylsulfonyl fluoride, perfluorooctanesulfonyl fluoride, perfluorobutylacetyl chloride, perfluorohexylacetyl chloride, perfluorooctylacetyl chloride, hexafluoropropylene oxide dimer, hexafluoropropylene oxide trimer and hexafluoropropylene oxide tetramer.

[0031] The fluorinated surfactant for oil-based foam drilling fluid of formula (I) provided by the present invention first mixes an amino compound and an acid binding agent, stirs, and then adds a fluorinated compound to mix. The present invention does not limit the specific method of stirring, which is well known to those skilled in the art. The reaction of the present invention is preferably carried out in a reactor.

[0032] The amino compound of the present invention is preferably selected from one or more of dodecylamine, tetradecylamine, hexadecylamine, oleylamine, octadecylamine, 2-phenylethylamine, di-n-dodecylamine and 2-octyl-1-dodecylamine.

[0033] The acid binding agent is preferably one of pyridine or triethylamine.

[0034] The fluorine-containing compound of the present invention is preferably selected from one or more of perfluorobutyryl chloride, perfluorohexanoyl chloride, perfluorooctanoyl chloride, perfluorobutylsulfonyl fluoride, perfluorohexylsulfonyl fluoride, perfluorooctanesulfonyl fluoride, perfluorobutylacetyl chloride, perfluorohexylacetyl chloride, perfluorooctylacetyl chloride, hexafluoropropylene oxide dimer, hexafluoropropylene oxide trimer and hexafluoropropylene oxide tetramer; more preferably one or more of perfluorohexanoyl chloride, perfluorooctanoyl chloride, perfluorobutylsulfonyl fluoride, perfluorohexylsulfonyl fluoride, perfluorooctanesulfonyl fluoride, perfluorobutylacetyl chloride, perfluorohexylacetyl chloride, perfluorooctylacetyl chloride, hexafluoropropylene oxide trimer and hexafluoropropylene oxide tetramer.

[0035] The present invention does not limit the sources of the amino compound, acid binding agent and fluorine-containing compound, and those known to those skilled in the art are sufficient.

[0036] According to the present invention, the molar ratio of the amino compound, the acid binding agent and the fluorine-containing compound is preferably 1: (1-2): (0.5-2); more preferably 1: (1-1.8): (0.5-1.8).

[0037] The reaction temperature of the present invention is preferably 0-100°C; more preferably 0-90°C; most preferably 0-80°C; particularly preferably 0-70°C.

[0038] The reaction time is preferably 1 to 3 hours; specifically, it can be 1 hour, 2 hours or 3 hours.

[0039] The reaction of the present invention further comprises washing with distilled water at room temperature until the mixture is neutral, thereby obtaining a surfactant.

[0040] The surfactant for oil-based foam drilling fluid obtained by the invention can reduce the surface tension of the oil phase, has strong foaming ability and foam stability, and can be used for preparing oil-based foam drilling fluid.

[0041] The present invention provides an oil-based foam drilling fluid, comprising the fluorinated surfactant described in any one of the above technical solutions or the fluorinated surfactant prepared by the preparation method described in any one of the above technical solutions.

[0042] The fluorinated surfactant provided by the present invention can be used to prepare oil-based foam drilling fluid, and has good technical effects. The present invention does not limit the other components for preparing the oil-based foam drilling fluid, and those familiar to those skilled in the art are sufficient.

[0043] The present invention provides a fluorinated surfactant for oil-based foam drilling fluid having a structure of formula (I). The specific preparation method is: an amino compound, an acid-binding agent and a fluorinated compound are mixed and reacted to obtain a fluorinated surfactant for oil-based foam drilling fluid having a structure of formula (I). The surfactant for oil-based foam drilling fluid obtained by the present invention can reduce the surface tension of the oil phase, has strong foaming ability and foam stability, and can be used for the preparation of oil-based foam drilling fluid.

[0044] In order to further illustrate the present invention, a fluorinated surfactant for oil-based foam drilling fluid and a preparation method thereof provided by the present invention are described in detail below in conjunction with examples.

[0045] Example 1

[0046] 1 mol of dodecylamine and 1.5 mol of triethylamine were added to the reactor and stirred evenly, then 1.2 mol of perfluorobutyryl chloride was added to the reactor, reacted at 20°C for 1 hour, and then washed with distilled water at room temperature until neutral to obtain a surfactant sample. Its structural formula is as follows:

[0047]

[0048] Example 2

[0049] 1 mol of octadecylamine and 2 mol of triethylamine were added to the reactor and stirred evenly, then 1.8 mol of perfluorohexylsulfonyl fluoride was added to the reactor, reacted at 60°C for 3 hours, and then washed with distilled water at room temperature until neutral to obtain a surfactant sample. Its structural formula is as follows:

[0050]

[0051] Example 3

[0052] 1 mol 2-phenylethylamine and 1 mol pyridine were added to the reactor and stirred evenly, then 0.5 mol hexafluoropropylene oxide dimer was added to the reactor, reacted at 0°C for 2 hours, and then washed with distilled water at room temperature until neutral to obtain a surfactant sample. Its structural formula is as follows:

[0053]

[0054] Comparative Examples 1-2 and Examples 4-12 have the same steps as Example 1, and the reaction substances and their amounts are shown in Table 1:

[0055] Table 1 Reaction substances and dosage

[0056]

[0057]

[0058] The performance of the surfactants synthesized in Examples 1 to 12 and Comparative Examples 1 and 2 was evaluated.

[0059] (1) Surface tension

[0060] 1.0 g of surfactant was added to 100 mL of diesel, and the mixture was stirred evenly. The surface tension of the diesel was measured using a BZY-101 surface tension meter.

[0061] Table 2 Surface tension values ​​of surfactants in Examples 1 to 12

[0062]

[0063]

[0064] It can be seen from Table 2 that, compared with general surfactants such as SP-80, the surfactant prepared in the present invention can significantly reduce the surface tension of diesel.

[0065] (2) Foaming performance

[0066] 2 g of cis-1,2-butadiene rubber was added to 100 mL of diesel, and the mixture was fully dissolved and uniformly prepared into a base slurry. The sample and SP-80 in the embodiment were added to the base slurry and stirred uniformly. The mixture was stirred at 10,000 r / min for 3 min using a high-speed stirrer. The foam slurry formed was then poured into a measuring cylinder. The foam volume and the time taken for the foam slurry to separate 50 mL of foaming base liquid were recorded as the foam half-life. The results are shown in Table 3.

[0067] Table 3 Evaluation of surfactant performance

[0068] Surfactant Type Foaming volume / mL Half-life / min Example 1 140 6.5 Example 2 165 7.5 Example 3 180 8.4 Example 4 180 9.1 Example 5 200 9.7 Example 6 190 8.8 Example 7 165 8.0 Example 8 140 5.6 Example 9 170 8.3 Example 10 160 7.2 Embodiment 11 175 8.9 Example 12 160 7.7 SP-80 115 1.5

[0069] It can be seen from Table 3 that, compared with general surfactants such as SP-80, the surfactant prepared in the present invention has good foaming performance and the formed foam has better stability.

[0070] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. Use of a compound having a structure of formula (I) in a fluorinated surfactant for an oil-based foam drilling fluid, comprising: Formula (I); Where R1= , x is an integer of 3 to 4; R2 is a C14 or C16 alkyl group; R3 is H, and Z is .

2. A method for preparing a fluorinated surfactant for oil-based foam drilling fluid of formula (I) according to claim 1, characterized in that: include: The amino compound, the acid-binding agent and the fluorine-containing compound are mixed and reacted to obtain a fluorine-containing surfactant for oil-based foam drilling fluid having a structure of formula (I); The fluorine-containing compound is selected from one or more of hexafluoropropylene oxide trimer and hexafluoropropylene oxide tetramer; The amino compound is selected from tetradecylamine or hexadecylamine; The acid binding agent is pyridine; The molar ratio of the amino compound, the acid binding agent and the fluorine-containing compound is 1:(1-2):(0.5-2).

3. The preparation method according to claim 2, characterized in that: The reaction temperature is 0-100°C; the reaction time is 1-3h.

4. The preparation method according to claim 2, characterized in that: After the reaction, the method further comprises washing with distilled water at room temperature until the mixture is neutral.

5. An oil-based foam drilling fluid, characterized in that: The invention comprises the fluorinated surfactant according to claim 1 or the fluorinated surfactant prepared by the preparation method according to any one of claims 2 to 4.

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