High-temperature-resistant oil well cement retarder as well as preparation method and application thereof

Abstract

The invention relates to a high-temperature-resistant oil well cement retarder and a preparation method thereof. The problems of poor high temperature resistance and poor adaptability of the existing retarder are mainly solved. The invention is characterized in that the composition comprises the following components in parts by mass: 1-3 parts of a compound molecular emulsifier, 95-99 parts of a hydrophilic monomer, 1-5 parts of a hydrophobic monomer, 1-5 parts of an initiator, 390-470 parts of deionized water, and 45-85 parts of a 30% W / W NaOH solution. The preparation method comprises the following steps: adding a hydrophilic monomer into a first part of deionized water in proportion, after the hydrophilic monomer is completely dissolved, adding a compound molecular emulsifier, dropwise adding a NaOH solution at the temperature of 15-30 DEG C, stirring, adding a hydrophobic monomer, introducing nitrogen, and heating for 30 minutes to obtain a to-be-reacted solution; dissolving the initiator with a second part of deionized water, adding into the to-be-reacted liquid, introducing nitrogen, heating to 60 DEG C, and reacting for 5 hours; the oil well cement retarder can be suitable for well cementation of ultrahigh-temperature wells at 240 DEG C, and has good adaptability to quality fluctuation of oil well cement.

Description

Technical field:

[0001] The invention relates to a cementing admixture in the field of oilfield drilling, and in particular to a high-temperature resistant oil well cement retarder, a preparation method and application thereof. Background technology:

[0002] Cementing construction is the top priority in the entire drilling project. In cementing construction, it is necessary to ensure that the cement slurry has a certain period of pumpability, especially in deep well cementing construction. Retarders must be added to inhibit cement hydration, delay the setting time, change its fluidity, and keep the cement slurry pumpable before reaching the designated location to ensure the safety of cementing construction. In recent years, with the continuous deepening of oil and gas resource exploration and development and the steady advancement of the development plan of gas-to-oil, the depth of drilling wells has continued to increase. At present, the bottom temperature of drilling wells has exceeded 200℃. Retarders face the problems of performance deterioration under high temperature and compatibility under large temperature difference. The comprehensive performance requirements of retarders such as temperature resistance and product stability are high. In addition, in recent years, the components of oil well cement vary greatly, hydration is unstable, the adaptability between cement and admixtures has deteriorated, and the high-temperature retarder has deteriorated or even failed under high temperature conditions. Abnormal gelation of thickening and other phenomena have led to difficulties in adjusting the cement slurry formula; problems such as poor temperature resistance and adaptability of retarders have restricted the exploration and development of deep wells and ultra-deep wells. Summary of the invention:

[0003] The purpose of the present invention is to overcome the problems of poor high temperature resistance and adaptability of existing retarders in the background technology, and to provide a high temperature resistant oil well cement retarder. The high temperature resistant oil well cement retarder can be used for cementing ultra-high temperature wells with a temperature of 240°C, has good adaptability to fluctuations in the quality of oil well cement, forms cement stone with high early strength, reduces the cost of ultra-deep well cementing, and ensures cementing construction safety and cementing quality. The present invention also provides a preparation method and application of a high temperature resistant oil well cement retarder.

[0004] In order to achieve the above-mentioned purpose, the first aspect of the present invention provides a high-temperature resistant oil well cement retarder, whose components and the mass fractions of each component are as follows: 1 to 3 parts of a composite molecular emulsifier, 95 to 99 parts of a hydrophilic monomer, 1 to 5 parts of a hydrophobic monomer, 1 to 5 parts of an initiator, 390 to 470 parts of deionized water, and 45 to 85 parts of a 30% (W / W) NaOH solution.

[0005] Preferably, the compound molecular emulsifier is a mixture of sodium dodecylbenzene sulfonate, sodium dodecyl sulfate and alkylphenol polyoxyethylene ether in a mass ratio of (40-45):(55-40):(5-15).

[0006] Preferably, the compound molecular emulsifier is sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, and alkylphenol polyoxyethylene ether, and the mass ratio is 45:45:10.

[0007] Preferably, the hydrophilic monomers are at least two of other hydrophilic carboxyl-containing monomers such as 2-acrylamido-2-methylpropanesulfonic acid, itaconic acid, sodium styrene sulfonate, and acrylic acid;

[0008] Preferably, the hydrophobic monomer is a long-chain alkene ester monomer, such as at least one of long-chain acrylate monomers such as butyl acrylate, dodecyl acrylate, octadecyl acrylate, etc.;

[0009] Preferably, the initiator is VA044 or APS thermal initiator to initiate monomer polymerization.

[0010] The second object of the present invention is to provide a method for preparing a high temperature resistant oil well cement retarder by emulsion polymerization, comprising the following steps:

[0011] Add hydrophilic monomer to the first portion of deionized water in proportion, stir until completely dissolved, add compound molecular emulsifier, slowly drop 30% (W / W) NaOH solution, control the temperature at 15-30°C, stir, add hydrophobic monomer, pass nitrogen and heat for 30 minutes to obtain a reaction solution;

[0012] The initiator is dissolved in the second portion of deionized water, added into the reaction solution, heated to 60° C. by nitrogen, and reacted for 5 hours to obtain the high temperature resistant oil well cement retarder of the present invention.

[0013] Preferably, the mass ratio of the first portion of deionized water to the second portion of deionized water is (42-46):1.

[0014] The third object of the present invention is to provide an application of a high temperature resistant oil well cement retarder prepared by emulsion polymerization in deep well and ultra-deep well cementing.

[0015] Preferably, the applicable temperature range for deep well and ultra-deep well cementing is 150-240° C.; the retarder dosage is 6% under the conditions of 240° C. and 120 MPa.

[0016] Compared with the above background technology, the present invention has the following beneficial effects:

[0017] (1) The retarder of the present invention adopts emulsion polymerization in the synthesis process, and the molecular weight of the polymer is significantly better than that of other polymerization methods, and the molecular weight distribution is narrow, which is helpful to improve the stability of the product; the introduction of long-chain olefin acid ester sulfhydryl monomers and compound molecular emulsifiers, through the hydrophilic monomer and the sulfhydryl monomer in the mass ratio range of (95-99): (5-1), the long-chain hydrophobic structural unit in the polymer structure, due to the difference in hydrophilic and hydrophobic properties during the synthesis process, is dispersed and solubilized by the compound molecular emulsifier, and the ratio and length of the two complementary regions of hydrophilic and hydrophobic are adjusted, and a micro-block structure is formed in the polymer chain segment; the presence of this micro-block structure can significantly improve the hydrophobic association of the polymer, thereby forming micro-cross-linked structures of different scales through the association and assembly of the hydrophobic micro-block structure, improving the temperature resistance of the product, and preventing the occurrence of abnormal thickening and gelation, thereby improving the adaptability.

[0018] (2) The retarder has good retarding effect and excellent ultra-high temperature resistance, and can meet the requirements of cementing at a temperature of 240°C.

[0019] (3) The thickening curve of the retarder at 240°C and 120 MPa has a stable temperature and pressure curve, no abnormal gelation phenomenon, and a right-angle thickening. The cement paste formed by preparing cement slurry with the retarder has the characteristic of high early strength.

[0020] (4) A new type of retarder is provided, which expands the range of oil well cement retarders for ultra-deep well cementing, and the dosage is relatively low. Under the conditions of 240°C and 120MPa, the retarder dosage is 6%, which can make the thickening time reach more than 300 minutes, which is beneficial to reduce production costs. Description of the drawings:

[0021] Attached Figure 1 This is the thickening curve of the retarder prepared in Example 1 of the present invention with a dosage of 6% (BWOC) at 240°C and 120 MPa. Specific implementation method:

[0022] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0023] A high temperature resistant oil well cement retarder, the components and the mass fractions of each component are as follows: 1-3 parts of compound molecular emulsifier, 95-99 parts of hydrophilic monomer, 1-5 parts of hydrophobic monomer, 1-5 parts of initiator, 390-470 parts of deionized water, and 45-85 parts of 30% (W / W) NaOH solution.

[0024] The compound molecular emulsifier is a mixture of sodium dodecylbenzene sulfonate, sodium dodecyl sulfate and alkylphenol polyoxyethylene ether in a mass ratio of (40-45):(55-40):(5-15). A mixture with a mass ratio of 45:45:10 is preferred;

[0025] The hydrophilic monomers are at least two of other hydrophilic carboxyl-containing monomers such as 2-acrylamido-2-methylpropanesulfonic acid, itaconic acid, sodium styrene sulfonate, acrylic acid, etc.;

[0026] The hydrophobic monomer is a long-chain alkene ester monomer, such as at least one of long-chain acrylate monomers such as butyl acrylate, dodecyl acrylate, and octadecyl acrylate;

[0027] The initiator is VA044 or APS thermal initiator to initiate monomer polymerization.

[0028] The present invention provides a method for preparing a high temperature resistant oil well cement retarder by emulsion polymerization, comprising the following steps:

[0029] Add hydrophilic monomer to the first portion of deionized water in proportion, stir until completely dissolved, add compound molecular emulsifier, slowly drop 30% (W / W) NaOH solution, control the temperature at 15-30°C, stir, add hydrophobic monomer, pass nitrogen and heat for 30 minutes to obtain a reaction solution;

[0030] The initiator is dissolved in the second portion of deionized water, added into the reaction solution, heated to 60° C. by nitrogen, and reacted for 5 hours to obtain the high temperature resistant oil well cement retarder of the present invention.

[0031] Preferably, the mass ratio of the first portion of deionized water to the second portion of deionized water is (42-46):1.

[0032] The invention discloses an application of a high temperature resistant oil well cement retarder prepared by emulsion polymerization in deep well and ultra-deep well cementing. The applicable temperature range in deep well and ultra-deep well cementing is 150-240°C; under the conditions of 240°C and 120MPa, the retarder dosage is 6%, and the thickening time can reach more than 300 minutes.

[0033] Evaluation method of retarder and test method of cement application performance in the following embodiments: The evaluation method of retarder in all the following embodiments refers to the existing standard for oil well cement - Petroleum and Natural Gas Industry Standard of the People's Republic of China SY / T5504.1-2013 "Evaluation Method for Oil Well Cement Admixtures Part 1: Retarder".

[0034] In the following examples, the cement slurry evaluation test instruments containing retarders used are the 3170-type Waring agitator of the American Centella Instrument Company, the 8240-type high-temperature and high-pressure thickener of the American Centella Instrument Company, and the 1910-type high-temperature and high-pressure curing kettle of the American Centella Instrument Company.

[0035] The preparation method of the cement slurry containing the retarder in the following embodiments is: weigh a certain amount of oil well cement, quartz sand, suspending agent, liquid high temperature retarder, and mixing water respectively, and then mix them evenly to obtain cement slurry. Other requirements for cement slurry preparation refer to the provisions of GB / T 19139-2012 "Test Methods for Oil Well Cement".

[0036] The test scheme of cement slurry containing retarder in the following examples is: 600g oil well cement + 300g quartz sand (200 mesh) + 18g suspending agent + Xg retarder + (342-X)g water, wherein the suspending agent is the suspension stabilizer WH-2 produced by Weihui Chemical Co., Ltd., and oil well cement and quartz sand are both commercially available products.

[0037] The compound molecular emulsifier in the following examples is prepared by mixing sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, and alkylphenol polyoxyethylene ether at a mass ratio of 45:45:10 to obtain the compound molecular emulsifier.

[0038] Embodiment 1:

[0039] Add 446.99g of deionized water, 70.32g of 2-acrylamido-2-methylpropanesulfonic acid, 15.42g of itaconic acid and 12.23g of sodium styrene sulfonate into a stirring kettle, turn on the cooling water circulation and stir, stir until completely dissolved, add 2g of compound molecular emulsifier, slowly drop 53.77g of 30% NaOH, control the temperature at 15-30°C, add into the stirring kettle, add 2.82g of dodecyl acrylate, pass nitrogen and heat for 30 minutes, dissolve 3.20g of APS with 10g of deionized water, put into the reactor, pass nitrogen and heat to 60°C for reaction for 5 hours to obtain the retarder.

[0040] Embodiment 2:

[0041] Add 446.99g of deionized water, 70.32g of 2-acrylamido-2-methylpropanesulfonic acid, 15.42g of itaconic acid and 12.23g of sodium styrene sulfonate into a stirring kettle, turn on the cooling water circulation and stir, stir until completely dissolved, add 2g of compound molecular emulsifier, slowly drop 53.77g of 30% NaOH, control the temperature at 15-30°C, add into the stirring kettle, add 2.82g of dodecyl acrylate, pass nitrogen and heat for 30 minutes, dissolve 3.20g of VA044 with 10g of deionized water, put into the reactor, pass nitrogen and heat to 60°C for reaction for 5 hours to obtain the retarder.

[0042] Embodiment 3:

[0043] Add 448.57g of deionized water, 82.55g of 2-acrylamido-2-methylpropanesulfonic acid and 15.42g of itaconic acid into a stirring kettle, turn on the cooling water circulation and stir, stir until completely dissolved, add 2g of compound molecular emulsifier, slowly drop 59.28g of 30% NaOH, control the temperature at 15-30°C, add into the stirring kettle, add 4.24g of octadecyl acrylate, pass nitrogen and heat for 30 minutes, dissolve 3.20g of APS with 10g of deionized water, put into the reactor, pass nitrogen and heat to 60°C for reaction for 5 hours to obtain the retarder.

[0044] Embodiment 4:

[0045] Add 454.73g of deionized water, 75.53g of 2-acrylamido-2-methylpropanesulfonic acid, 9.21g of acrylic acid, and 13.23g of sodium styrene sulfonate into a stirring kettle, turn on the cooling water circulation and stir, stir until completely dissolved, add 2g of compound molecular emulsifier, slowly drop 65.67g of 30% NaOH, control the temperature at 15-30°C, add into the stirring kettle, add 2.82g of dodecyl acrylate, pass nitrogen and heat for 30 minutes, dissolve 3.20g of APS with 10g of deionized water, put into the reactor, pass nitrogen and heat to 60°C for reaction for 5 hours to obtain the retarder.

[0046] Embodiment 5:

[0047] Add 442.54g of deionized water, 88.76g of 2-acrylamido-2-methylpropanesulfonic acid and 9.21g of acrylic acid into a stirring kettle, turn on the cooling water circulation and stir, stir until completely dissolved, add 2g of compound molecular emulsifier, slowly drop 51.91g of 30% NaOH, control the temperature at 15-30°C, add into the stirring kettle, add 1.56g of butyl acrylate, pass nitrogen and heat for 30 minutes, dissolve 3.20g of APS with 10g of deionized water, put into the reactor, pass nitrogen and heat to 60°C for reaction for 5 hours to obtain the retarder.

[0048] Table 1 Thickening test results of the retarders obtained in each embodiment

[0049] Retarder serial number Retarder dosage, % Test conditions, ℃*MPa Thickening time, min Example 1 6 240℃*120MPa 346 Example 1 4 240℃*120MPa 257 Example 1 6 220℃*110MPa 412 Example 1 4 220℃*110MPa 292 Example 1 2 220℃*110MPa 154 Example 1 1.6 150℃*75MPa 427 Example 1 1.2 150℃*75MPa 293 Example 1 0.8 150℃*75MPa 160 Example 2 6 220℃*110MPa 313 Example 2 4 220℃*110MPa 206 Example 3 14 220℃*110MPa 344 Example 3 10 220℃*110MPa 218 Example 4 14 220℃*110MPa 192 Example 4 10 220℃*110MPa 156 Example 5 14 220℃*110MPa 176 Example 5 10 220℃*110MPa 134

[0050] Table 2 Cement stone compressive strength test results of the retarders obtained in each embodiment

[0051]

[0052] As shown in Table 1, the retarder prepared by emulsion polymerization of a hydrophilic monomer and a sulfhydryl monomer in a mass ratio of (95-99): (5-1) using a composite molecular emulsifier (containing sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, and alkylphenol polyoxyethylene ether in a mass ratio of 45:45:10) can effectively improve the temperature resistance of the retarder to 240°C. Among them, the retarder obtained in Example 1 has the most obvious retarding effect when the amount added is low; Figure 1 The thickening curve of the retarder prepared in Example 1 at 240°C and 120MPa is shown. The temperature and pressure curves are stable, there is no abnormal gelation phenomenon, and the thickening is at a right angle. As shown in Table 2, the compressive strength of the cement paste of the prepared retarder at 150°C meets the 14MPa required by the oil well cement standard and is more than 50% higher than the standard requirement, which proves that the cement slurry added with the retarder of the present invention has the characteristic of high early strength. The experimental results show that the retarder of the present invention has reached the conditions for on-site application, and the retarder prepared in Example 1 is relatively good.

[0053] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions. Therefore, the content of the present invention is not limited to the examples listed in the embodiments, and any equivalent transformations taken by ordinary technicians of the art to the technical solution of the present invention by reading the specification of the present invention are all covered by the claims of the present invention.

Claims

1. A high temperature resistant oil well cement retarder, characterized in that: Its components and the mass fractions of each component are as follows: 1-3 parts of compound molecular emulsifier, 95-99 parts of hydrophilic monomer, 1-5 parts of hydrophobic monomer, 1-5 parts of initiator, 390-470 parts of deionized water, and 45-85 parts of 30% W / W NaOH solution.

2. The high temperature resistant oil well cement retarder according to claim 1, characterized in that: The compound molecular emulsifier is a compound of sodium dodecylbenzene sulfonate, sodium dodecyl sulfate and alkylphenol polyoxyethylene ether; the mass ratio of sodium dodecylbenzene sulfonate, sodium dodecyl sulfate and alkylphenol polyoxyethylene ether is 40-45:55-40:5-15.

3. The high temperature resistant oil well cement retarder according to claim 2, characterized in that: The mass ratio of sodium dodecylbenzene sulfonate, sodium dodecyl sulfate and alkylphenol polyoxyethylene ether is 45:45:

10.

4. The high temperature resistant oil well cement retarder according to claim 1, characterized in that: The hydrophilic monomers are at least two of 2-acrylamido-2-methylpropanesulfonic acid, itaconic acid, sodium styrene sulfonate, and acrylic acid; and the initiator is VA044 or APS thermal initiator.

5. The high temperature resistant oil well cement retarder according to claim 1, characterized in that: The hydrophobic monomer is a long-chain alkene ester monomer.

6. The high temperature resistant oil well cement retarder according to claim 5, characterized in that: The long-chain alkene ester monomer is butyl acrylate, dodecyl acrylate, and octadecyl acrylate; and the hydrophobic monomer is at least one of butyl acrylate, dodecyl acrylate, and octadecyl acrylate.

7. A method for preparing a high temperature resistant oil well cement retarder according to any one of claims 1 to 6, characterized in that: The following steps are involved: Add hydrophilic monomer to the first portion of deionized water in proportion, stir until completely dissolved, add compound molecular emulsifier, drop 30% W / W NaOH solution, control the temperature at 15-30°C, stir, add hydrophobic monomer, pass nitrogen and heat for 30 minutes to obtain a reaction solution; The initiator is dissolved in the second portion of deionized water, added into the reaction solution, heated to 60° C. by nitrogen, and reacted for 5 hours to obtain the high temperature resistant oil well cement retarder of the present invention.

8. The preparation method according to claim 7, characterized in that: The mass ratio of the first portion of deionized water to the second portion of deionized water is 42-46:

1.

9. Use of a high temperature resistant oil well cement retarder according to any one of claims 1 to 6 in cementing of deep wells and ultra-deep wells.

10. The use according to claim 9, characterized in that: The applicable temperature range in deep well and ultra-deep well cementing is 150-240° C.; under the conditions of 240° C. and 120 MPa, the retarder dosage is 6%.

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