CN111333857A

CN111333857A - Shale inhibitor and water-based drilling fluid

Info

Publication number: CN111333857A
Application number: CN202010286283.6A
Authority: CN
Inventors: 谢刚; 肖玉容; 邓明毅; 白杨; 罗平亚
Original assignee: Southwest Petroleum University
Current assignee: Southwest Petroleum University
Priority date: 2020-04-13
Filing date: 2020-04-13
Publication date: 2020-06-26
Anticipated expiration: 2040-04-13
Also published as: CN111333857B

Abstract

The invention discloses a shale inhibitor and a water-based drilling fluid, and belongs to the technical field of oil and gas field drilling. The shale inhibitor is a hyperbranched polymer which is prepared by taking N, N' - (1, 2-dihydroxyethylene) bisacrylamide and diethylenetriamine as raw materials and taking vinylsulfonic acid as a blocking reagent and has a large number of sulfonic acid groups at the tail end, and can be directly added into water-based drilling fluid. The shale inhibitor and the water-based drilling fluid provided by the invention can effectively inhibit hydration expansion of shale, have good temperature resistance and salt resistance, have good compatibility with other treating agents, and can play a long-acting inhibiting role. The preparation method provided by the invention is simple, the synthetic raw materials are easy to obtain, and the method is suitable for industrial production.

Description

Shale inhibitor and water-based drilling fluid

Technical Field

The invention relates to the technical field of oil field drilling, in particular to a shale inhibitor and a water-based drilling fluid containing the shale inhibitor.

Background

With the increasing development of petroleum and natural gas exploration, the problem of instability of the shale well wall becomes the most common and intractable technical problem related to drilling fluid worldwide. Due to the high clay proportion of the shale stratum, hydration expansion is easy to occur, great negative effects are brought to drilling operation, complex underground accidents such as borehole collapse, hole shrinkage and drill sticking are caused, and the drilling time and cost are increased.

In addition, with the continuous development of the petroleum industry in China, the drilling of deep wells and ultra-deep wells becomes a necessary trend, so that the drilling construction faces a more severe environment, and the requirements on salt-resistant and high-temperature-resistant drilling fluids are increased. The conventional shale inhibitors have respective defects, such as unfavorable environmental protection of asphalts, difficult control of silicate rheological property and the like. The salt resistance and temperature resistance of the drilling fluid treating agent are necessary preconditions for salt resistance and high temperature resistance of the drilling fluid, so that the development of the high temperature resistant and salt resistant shale inhibitor is beneficial to the exploration and development of a better and more comprehensive drilling fluid system of an oil field.

Disclosure of Invention

Aiming at the problems of the existing shale inhibitors, the invention aims to provide the shale inhibitor, the molecular terminal of which contains a large number of sulfonic acid groups, has good high temperature resistance and salt resistance, has good compatibility with other drilling fluid treating agents and can effectively inhibit the hydration expansion of shale; it is another object of the present invention to provide a water-based drilling fluid employing the shale inhibitor of the present invention.

In order to achieve the purpose, the invention provides a shale inhibitor which is prepared by taking diethylenetriamine and N, N' - (1, 2-dihydroxyethylene) bisacrylamide as raw materials and vinyl sulfonic acid as an end capping reagent, and the shale inhibitor comprises the following specific preparation steps:

(1) synthesis of amino-terminated hyperbranched polymer C: taking diethylenetriamine, preparing the diethylenetriamine into a 50% solution by using absolute ethanol, adding triethylamine into the 50% solution to prepare a solution a under the conditions of introducing nitrogen and stirring, wherein the adding amount of the triethylamine is 10% of that of the diethylenetriamine, taking N, N '- (1, 2-dihydroxyethylene) bisacrylamide, preparing the N, N' - (1, 2-dihydroxyethylene) bisacrylamide into a 50% solution B by using absolute ethanol, dropwise adding the solution B into the solution a, ensuring that the dropwise adding temperature is 50 ℃ and the dropwise adding time is 55-60 min, heating to 90-105 ℃ after the dropwise adding is finished, carrying out reflux reaction for 8-12 h, carrying out rotary evaporation at 45 ℃ after the reaction is finished to obtain a crude product A, washing the crude product A with acetone for a plurality of times, carrying out suction filtration to obtain a product B, dissolving the product B with absolute ethanol, and carrying out rotary evaporation at 50 ℃ to obtain an amino-terminated hyperbranched polymer C;

dissolving the amino-terminated hyperbranched polymer C with secondary distilled water, adding 2ml of triethylamine, stirring uniformly, preparing a secondary distilled water solution of vinyl sulfonic acid, dropwise adding the vinyl sulfonic acid solution into the solution of the polymer C at the dropwise adding temperature of 50 ℃ for 55-60 min, heating to 90 ℃ after dropwise adding, reacting for 8h, performing rotary evaporation at 60 ℃ after the reaction is finished to obtain a product D, washing the product D for a plurality of times with 10-20 times of anhydrous ether to obtain a product E, dissolving the product E with the secondary distilled water, performing rotary evaporation at 60 ℃ until no liquid drips within 5min, and performing vacuum drying at 60 ℃ for a plurality of hours to obtain HP-SO₃H。

Meanwhile, the invention also provides a water-based drilling fluid which comprises the following specific components: 100 parts of water, 5-10 parts of bentonite, 0.5-1 part of tackifier, 0.5-5 parts of lubricant, 0.5-5 parts of viscosity reducer, 0.25-5 parts of filtrate reducer, 25-30 parts of weighting agent and 1-5 parts of shale inhibitor.

The water-based drilling fluid of the invention is a common component in the existing water-based drilling fluid except the shale inhibitor, and has no special component.

The invention has the following beneficial effects:

1. compared with similar products, the shale inhibitor provided by the invention has obviously improved inhibition performance, the synthesized hyperbranched polymer HP-SO3H can effectively inhibit hydration expansion of shale, and has good compatibility with other drilling fluid treatment agents, and meanwhile, the inhibitor provided by the invention has small dosage and saves cost.

2. The terminal of the shale inhibitor molecule provided by the invention contains a large amount of sulfonic acid groups, so that the shale inhibitor has good high temperature resistance and salt resistance, the raw materials for synthesizing the shale inhibitor molecule are easy to obtain, the synthesis method is simple, the synthesized hyperbranched polymer has stable performance, the method technology is stable and reliable, and the shale inhibitor molecule is suitable for large-scale industrial production.

Drawings

FIG. 1 shows hyperbranched polymers HP-SO₃H infrared spectrogram;

FIG. 2 shows hyperbranched polymers HP-SO₃Molecular weight distribution profile of H;

FIG. 3 shows hyperbranched polymers HP-SO₃H, thermogravimetric tendency chart.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1:

1) synthesis of amino-terminated hyperbranched polymer C

Diluting 2.0633g of diethylenetriamine with absolute ethyl alcohol to prepare a 50% solution, placing the solution in a three-neck flask which is provided with a magnetic stirring device and a thermometer and is filled with nitrogen, and adding triethylamine with the mass of 10% of that of the diethylenetriamine to prepare a solution a; 20.0192g of N, N ' - (1, 2-dihydroxyethylene) bisacrylamide is taken, and N, N ' - (1, 2-dihydroxyethylene) bisacrylamide is prepared into a solution b by absolute ethyl alcohol, wherein the mass ratio of the absolute ethyl alcohol to the N, N ' - (1, 2-dihydroxyethylene) bisacrylamide is 1: 1. Adding the solution b into the solution a in a titration mode at 50 ℃, stirring while titrating, and dripping for 60 min; after titration is finished, heating to 100 ℃, and carrying out reflux reaction for 8 hours; after the reflux reaction is finished, rotary evaporation is carried out at the temperature of 45 ℃ to obtain a crude product A, then the crude product A is washed for a plurality of times in a pear-shaped separating funnel by acetone with the volume of 15, and then the crude product A is filtered by suction to remove the acetone to obtain an initial product B. And finally dissolving the B obtained by suction filtration in absolute ethyl alcohol, and then rotationally evaporating at 50 ℃ to remove the solvent to obtain a product C. The molecular structure is shown below.

Wherein R is₁＝-CHOHCHOH-；R₂＝-CH₂CH₂-。

2) Terminal sulfonic hyperbranched shale inhibitor HP-SO₃Synthesis of H

The product C is dissolved by secondary distilled water with 20 times volume of C, then transferred to a round-bottom flask, 2mL of triethylamine is added, after stirring uniformly, vinylsulfonic acid (diluted to 80% aqueous solution) dissolved in the secondary distilled water is added into a reaction vessel in a titration mode. Wherein the titration temperature is 50 ℃, the dripping time is 60min, the temperature is raised to 90 ℃ after the titration is finished, and the reaction is carried out for 8 h. After the end of the process, the secondary distilled water is removed by rotary evaporation at 60 ℃ to obtain a crude product D, the crude product D is washed for 3 times by using anhydrous ether with the volume 20 times that of the crude product D to obtain a primary product E, and after the end of the process, the E is dissolved by using the secondary distilled water and is subjected to rotary evaporation at 60 ℃ until no liquid drips within 5 min. Taking down, and drying the product at 60 ℃ for 8h in vacuum to obtain a product HP-SO₃H. The molecular structure is shown below.

Wherein R is₁＝-CHOHCHOH-；R₂＝-CH₂CH₂-。

2. Characterization of the Synthesis products

1) Structural characterization of the synthesized product

The amino-terminated hyperbranched polymer C prepared in the examples was subjected to infrared characterization by a conventional experimental method. The infrared spectrum is shown in FIG. 1. As can be seen from FIG. 1, the measured substance is at 3500cm^-1The peak is the stretching vibration peak of-OH, 3350cm^-1is-NH₂-stretching vibration peak of NH 2960cm^-1is-CH₃2750cm-¹is-CH₂Peak of stretching vibration of 1716cm^-1Stretching vibration peak of-C ═ O，1610cm^-1In-plane bending vibration of N-H, 1450cm^-1is-CH₃Out-of-plane bending vibration of 1185cm^-1C-O, 950cm^-1Out-of-plane oscillatory vibration with-OH. Therefore, the tested product can be proved to be the terminal amino compound C of the target product. To verify the correctness of the conclusion, the TOF/LC-MS test was performed on the amino-terminated hyperbranched polymers prepared in the examples at the same time, and the results are shown in fig. 2. As can be seen from FIG. 2, the polymers show stronger ion peaks at positions with m/z of 405.323, 709.743, 1013.546 and 1316.254, respectively, which are generated by the amino-terminated hyperbranched polymers with different degrees of branching. The interval between ion peaks is 301-304, and the ion peaks just contact with the monomer C₁₂H₂₃N₅O₄The molecular weight of the polymer is equivalent, namely, one repeating unit is different between each ion peak, and the difference is consistent with a theoretical calculation value, so that the existence of the amino-terminated hyperbranched polymer C is proved, and the detection result is consistent with the infrared spectrum detection result.

2) Characterization of temperature resistance of synthesized product

Testing of hyperbranched HP-SO by thermogravimetric analysis₃Temperature resistance of H molecule itself, wherein N is 0.1MPa₂The temperature rise rate is 15-20 ℃/min and the temperature rise range is 40-800 ℃ as the blowing gas and the protective gas. And the results are recorded in figure 3. It can be seen that there is hyperbranched HP-SO₃The initial decomposition temperature of H was 299 ℃ and it can therefore be shown that the hyperbranched HP-SO of the invention₃The H molecule has good thermal stability.

3. Performance testing

1) Evaluation of temperature resistance

In order to examine the influence of temperature on the drilling fluid treatment agent, the change of rheological parameters of a drilling fluid system before and after hot rolling along with the change of temperature is measured indoors, the drilling fluid is prepared according to the following formula and steps in an experiment, the temperature resistance of the drilling fluid is tested by hot rolling aging under the conditions of 90 ℃, 100 ℃, 120 ℃ and 150 ℃, and the result is recorded in table 1.

(1) The bentonite prehydration treatment method comprises the following specific steps: measuring 10L of tap water, heating to 65 ℃, adding 500g of bentonite under the condition of low-speed stirring, fully and uniformly stirring (30min), sealing and standing for 24h to obtain the prehydrated bentonite slurry.

(2) Stirring the pre-hydrated bentonite slurry prepared in the step (1) for 10-15 min, sequentially adding 50g of coating tackifier FA-367, 50g of viscosity reducer XY-27, 25g of filtrate reducer CMC, 50g of lubricant RH-220 and 2.5-3.0 kg of barite at the rotating speed of 2500r/min, and adjusting the density of the drilling fluid to 1.35g/cm³. Adding one substance, stirring for 10-20 min until the substances are uniformly dispersed in the system, and then adding the other substance.

(3) And (3) taking 2 parts of the drilling fluid base slurry prepared in the step (2) in the same amount, respectively adding 0 percent and 1 percent of the shale inhibitor prepared in the embodiment, performing hot rolling ageing at 90 ℃, and testing the temperature resistance of the shale inhibitor, which is similar to the temperature resistance of the shale inhibitor prepared in the step (2) at 100 ℃, 120 ℃ and 150 ℃.

TABLE 1 drilling fluid System Performance as a function of temperature for different inhibitor loadings

Note: the hot rolling time was 16h and the test conditions were 50 ℃.

As can be seen from table 1, when 1% of the shale inhibitor synthesized in the example is added, the viscosity and the shear force of the drilling fluid are increased under the same temperature condition; after hot rolling under different conditions. The viscosity and the shear force of the drilling fluid and the water loss amount are slightly changed, but the drilling fluid is normally influenced by high temperature, so that the water-based drilling fluid prepared from the drilling fluid shale inhibitor prepared in the embodiment has good temperature resistance, and the temperature resistance is closely related to the structure of the hyperbranched polymer molecules synthesized in the embodiment.

2) Evaluation of salt resistance

Using NaCl and CaCl indoors₂Salt resistance experiments are carried out according to the mass ratio of 1:1, 0%, 5% and 10% of composite salt is added into a system with the density respectively, and the performance of the system (consistent with the system used in the temperature resistance experiments, the adding amount of the inhibitor is 1%) before and after hot rolling is tested.

TABLE 2 results of the salt resistance test

Note: the hot rolling temperature is 150 ℃, the time is 16h, and the test temperature is 50 ℃.

From the results shown in table 2, it can be seen that with the increase of the salt concentration, the viscosity and the shear force of the system are slightly changed, the water loss under pressure at normal temperature is kept unchanged, the demulsification voltage value is reduced to some extent, but the amplitude is smaller, and when the concentration of the composite salt is 10%, the demulsification voltage value of the system is still higher than 1000V, and good emulsification stability is shown, so that the drilling fluid system has good salt pollution resistance.

3) Inhibition performance test

According to a shale physical and chemical performance test method of a petroleum and natural gas industry standard SY/T5613-2016 drilling fluid test of the people's republic of China, a shale dispersion experiment is carried out, and the inhibition performance of the inhibitor is evaluated.

(1) Roll recovery

Rock debris rolling recovery experiments were performed with varying amounts of the shale inhibitors prepared in the examples to evaluate their inhibition performance. In general, the higher the rolling recovery, the better the inhibition performance; the lower the rolling recovery rate, the worse the suppression performance. The results are reported in table 3.

TABLE 3 Rolling recovery at different inhibitor addition

Type of solution	Sample mass/g	Recovered mass/g	Percent recovery%
				Deionized water
	50	1.28	2.56
				1% shale inhibitor prepared in the examples	50	25.9	51.8
2% shale inhibitor prepared in example	50	30.8	61.6
				3% shale inhibitor prepared in example	50	42.8	85.6
4% shale inhibitor prepared in example	50	45.9	91.8
				5% shale inhibitor prepared in example	50	47.2	94.4

Note: the hot rolling temperature was 150 ℃.

From the results shown in table 3, it can be seen that the rolling recovery rate of rock debris is obviously increased after the shale inhibitor prepared in the example is added, and when the addition amount of the shale inhibitor reaches 5%, the rolling recovery rate of shale reaches 94.4%, which indicates that the shale inhibitor prepared in the example has good heterogeneous effect on the dispersed slurrying of the shale.

(2) Linear expansion rate

Various amounts of the shale inhibitors prepared in the examples were added to conduct a linear expansion experiment to evaluate the inhibition performance. In general, the higher the linear expansion ratio, the worse the inhibition performance; the lower the linear expansion ratio, the better the inhibition performance. The results of the experiment are reported in table 4.

TABLE 4 results of the rock sample linear expansion experiment at different inhibitor addition

The results shown in table 4 show that the shale inhibitor prepared in the example has a greatly reduced linear expansion rate of a rock sample, which is far lower than the linear expansion rate in deionized water, and when the amount of the inhibitor is increased, the linear expansion rate is further reduced, which indicates that the shale inhibitor prepared in the example has good inhibition performance on hydration expansion of shale, and a good inhibition effect can be achieved by adding a small amount of the shale inhibitor.

In conclusion, the preparation method has stable and reliable technology, wide sources of raw materials needed by the synthetic product and suitability for industrial production; the hyperbranched polymer has good temperature resistance, salt resistance and inhibition performance, and can completely meet the drilling requirements of various complex well conditions.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. The shale inhibitor is characterized by being prepared from diethylenetriamine and N, N' - (1, 2-dihydroxyethylene) bisacrylamide serving as raw materials and vinyl sulfonic acid serving as a blocking reagent, and specifically prepared by the following steps:

(1) synthesis of amino-terminated hyperbranched polymer C: 2.0633g of diethylenetriamine is taken and prepared into a 50 percent solution by absolute ethyl alcohol, adding 2mL of triethylamine under the condition of introducing nitrogen and stirring to prepare a solution a, taking 20.0192g N, N '- (1, 2-dihydroxyethylene) diacrylamide according to the molar ratio of diethylenetriamine to N, N' - (1, 2-dihydroxyethylene) diacrylamide of 1:5, preparing the solution b into a 50% solution b by using absolute ethyl alcohol, dropwise adding the solution b into the solution a under the condition of continuous stirring, heating to 90-105 ℃, carrying out reflux reaction for 8-12 h, after the reaction is finished, performing rotary evaporation at 45 ℃ to obtain a crude product A, washing the crude product A with acetone for several times, performing suction filtration to obtain a product B, dissolving the product B with absolute ethyl alcohol, and performing rotary evaporation at 50 ℃ to obtain an amino-terminated hyperbranched polymer C;

(2) terminal sulfonic hyperbranched shale inhibitor HP-SO₃H synthesis: dissolving 2.5000g of the amino-terminated hyperbranched polymer C in secondary distilled water with the volume of 20 times that of C, adding triethylamine, uniformly stirring, preparing 10.0g of vinylsulfonic acid into a 50% aqueous solution by using the secondary distilled water, dropwise adding the vinylsulfonic acid aqueous solution into the solution of the polymer C under the conditions of continuous stirring and 50 ℃, after dropwise adding, heating to 90 ℃, reacting for 8 hours, rotationally evaporating at 60 ℃ after the reaction is finished to obtain a product D, washing the product D for 3-4 times by using anhydrous ether to obtain a product E, dissolving the product E in the secondary distilled water, rotationally evaporating at 60 ℃ until no liquid is dropped in 5min, and then vacuum drying the product at 60 ℃ for 8 hours to obtain HP-SO₃H。

2. The shale inhibitor according to claim 1, wherein in the step (1) and the step (2), the dropping temperature is 50 ℃ and the dropping time is 55-60 min.

3. The shale inhibitor according to claim 1, wherein in the step (2), triethylamine is added in an amount of 10% of diethylenetriamine.

4. The shale inhibitor according to claim 1, wherein the volume of the anhydrous ether in the step (2) is 10-20 times of the volume of the product D.

5. The water-based drilling fluid is characterized by comprising the following components in parts by weight: 100 parts by weight of water, 5-10 parts by weight of bentonite, 0.5-1 part by weight of a tackifier, 0.5-5 parts by weight of a lubricant, 0.5-5 parts by weight of a viscosity reducer, 0.25-5 parts by weight of a fluid loss additive, 25-30 parts by weight of a weighting agent, and 1-5 parts by weight of the shale inhibitor as defined in claims 1-4.