High-temperature-resistant functional inhibitor for drilling fluid and production process of high-temperature-resistant functional inhibitor

Abstract

The invention belongs to the technical field of petrochemical engineering, and discloses a high-temperature-resistant functional inhibitor for drilling fluid and a production process of the high-temperature-resistant functional inhibitor. The inhibitor is prepared from the following raw materials in parts by weight: 16 to 20 parts of triethylene tetramine, 5 to 6 parts of dichloroethane, 30 parts of 2, 5-bis (imide-1-methylimidazole) terephthaloyl chloride, 10 to 15 parts of pyridine, 1.5 to 2.5 parts of potassium chloride and 3 to 5 parts of water. The preparation method comprises the following steps: slowly dropwise adding dichloroethane into triethylene tetramine, adding pyridine and 2, 5-bis (imide-1-methylimidazole) terephthaloyl chloride after the reaction is completed, continuing the reaction, finally adding a potassium chloride solution, and uniformly mixing to obtain the high-temperature-resistant functional inhibitor. The shale inhibitor has good shale inhibition performance, can be normally used at the temperature of 200 DEG C or above, and solves the problems that a traditional inhibitor is high in linear expansion rate, poor in inhibition performance and the like.

Description

Technical Field

[0001] The invention relates to the technical field of petrochemical industry, and more particularly to a high temperature resistant functional inhibitor for drilling fluid and a production process thereof. Background Art

[0002] In recent years, as the development of oil and gas has gradually expanded to deep wells and unconventional oil and gas wells, the demand for high-temperature resistant drilling fluids has increased. At present, the temperature resistance of drilling fluid systems is generally lower than 200°C, and during drilling, major safety accidents such as well collapse, drill bit sticking, well leakage, and blowouts are often caused by the failure of drilling fluids, resulting in high drilling costs and reservoir damage, which has a significant impact on deep oil and gas development. Wellbore instability is a serious problem in the process of oil and gas drilling and production. Wellbore instability can lead to a series of problems such as diameter reduction, collapse, drill bit sticking, and wellbore expansion, which brings great harm to drilling projects. During drilling, about 75% of the drilled formations are shale formations, and 90% of wellbore instability occurs in shale formations. Because shale formations are rich in water-absorbing clay minerals and have significant nanopore structures, they are very easy to hydrate, expand, and disperse.

[0003] Under high temperature and high pressure environment, the performance of drilling fluid additives directly affects the safety and efficiency of drilling operations. Therefore, inhibitors in high temperature resistant drilling fluids have become a research hotspot. At present, oil-based drilling fluids are mostly used in shale gas horizontal well drilling in my country. Although oil-based drilling fluids have excellent inhibitory properties, their preparation costs are high and there are environmental issues. It is difficult to deal with well leakage. Once a well leakage problem occurs, it will inevitably cause significant economic losses. Water-based drilling fluids have the advantages of low cost and environmental friendliness. However, in shale gas horizontal well drilling, conventional water-based drilling fluids are difficult to solve the problem of hydration expansion of shale gas shale, and thus it is difficult to meet the engineering and technical needs of shale gas horizontal well exploration.

[0004] Commonly used shale inhibitors in the prior art mainly include polymers, inorganic salts, asphalts and humic acids, but these shale inhibitors all have some shortcomings, such as the difficulty in controlling the rheology of drilling fluids at high temperatures, the inability to penetrate into clay layers due to large molecular size, toxicity issues, and difficulty in achieving environmental protection indicators.

[0005] Therefore, in order to solve the problem of wellbore instability caused by surface hydration of extremely thick mudstone, it is of great practical significance to develop a high-temperature resistant, pollution-free water-based inhibitor that can effectively inhibit shale hydration expansion. Summary of the invention

[0006] In view of the above problems, the present invention provides a high-temperature resistant functional inhibitor for drilling fluid and its production process, which has good shale inhibition and can be used normally under conditions above 200°C, solving the problems of high linear expansion rate and poor inhibition performance of traditional inhibitors.

[0007] One of the purposes of the present invention is to provide a high temperature resistant functional inhibitor for drilling fluid. The raw materials of the inhibitor include, by weight: 16-20 parts of triethylenetetramine; 5-6 parts of ethylene dichloride; 30 parts of 2,5-di(imide-1-methylimidazole)terephthaloyl chloride; 10-15 parts of pyridine; 1.5-2.5 parts of potassium chloride; and 3-5 parts of water.

[0008] Preferably, the raw materials of the inhibitor include, by weight: 18 parts of triethylenetetramine; 6 parts of ethylene dichloride; 30 parts of 2,5-di(imide-1-methylimidazole)terephthaloyl chloride; 15 parts of pyridine; 2 parts of potassium chloride; and 3 parts of water.

[0009] The second object of the present invention is to provide a preparation process of a high temperature resistant functional inhibitor for drilling fluid, comprising the following steps: (1) Weighing raw materials; (2) Add triethylenetetramine to the reaction vessel and slowly raise the temperature to 65-90°C; (3) Slowly drop ethylene dichloride into triethylenetetramine under continuous stirring. After the dropwise addition is complete, continue stirring to react. Stop heating and cool to room temperature to obtain a reaction solution. (4) Under anaerobic conditions, pyridine is added to the reaction solution, and after cooling, 2,5-di(imide-1-methylimidazole)terephthaloyl chloride is added to react, and then the temperature is slowly raised to continue the reaction; (5) After the reaction is completed, cool to room temperature, add potassium chloride solution, mix well, and obtain a high temperature resistant functional inhibitor.

[0010] Preferably, in step (3), the slow dripping time is 30-40 min, and the stirring reaction time is 15 min.

[0011] The beneficial effect of adopting the above technical means is: dichloroethane is slowly added dropwise to triethylenetetramine, and the triethylenetetramine is always kept in excess during the reaction process, so the generated product is a polyamine compound rather than a quaternary ammonium salt compound.

[0012] Preferably, in step (4), the anaerobic condition is to introduce nitrogen for 20-30 minutes.

[0013] Preferably, in step (4), the cooling is to cool the mixture to 0-5°C and then add 2,5-di(imide-1-methylimidazole)terephthaloyl chloride and react for 30-40 minutes.

[0014] Preferably, in step (4), the temperature is raised to 20-40° C. and the reaction is continued for 5-7 hours.

[0015] The beneficial effects of the above technical means are: 2,5-di(imide-1-methylimidazole) terephthaloyl chloride is used to react with excess triethylenetetramine in the reaction solution at low temperature to obtain hydrophilic groups such as quaternary ammonium salts and amide bonds, which make the inhibitor have good water solubility and dispersibility. Its quaternary ammonium salt group can exchange ions with inorganic cations in the intercrystalline layers of bentonite minerals, tighten the crystal layers of bentonite minerals, fix the lattice, and inhibit the expansion and dispersion of bentonite; at the same time, the inhibitor forms ionic interactions and hydrogen bond interactions with bentonite, forming a coating film on the surface of bentonite, which can prevent water molecules from entering the intercrystalline layers of bentonite minerals, thereby reducing the degree of hydration expansion of bentonite minerals. The linear expansion rate is significantly reduced, showing an excellent expansion inhibition effect.

[0016] Preferably, in step (5), the potassium chloride solution is prepared by adding potassium chloride into water and stirring to dissolve it.

[0017] It can be seen from the above technical solution that, compared with the prior art, the beneficial effects achieved by the present invention are: The polyamine molecule has multiple binding sites with clay, namely, amine and hydroxyl groups. The amine groups in the molecule can enter the clay layers or adsorb on the clay surface to form multi-point adsorption, firmly binding the clay. The hydroxyl groups in the molecule can also enhance the effect of the polyamine inhibitor and clay through hydrogen bonds.

[0018] The invention has good resistance to thermal decomposition and high temperature resistance. After high temperature heat treatment, the inhibitor has a small increase in the linear expansion rate of bentonite minerals, and still shows a good expansion inhibition effect, and can be applied to drilling and exploitation of high temperature oil reservoirs.

[0019] The invention controls the equivalent and the adding sequence of each raw material, obtains a polyamine compound by reacting triethylenetetramine with ethylene dichloride, and adds a certain amount of potassium chloride to the system after the reaction, so as to form a novel inhibitor composed of a polyamine compound, a quaternary ammonium salt, an amide bond and other hydrophilic groups and potassium chloride. The potassium chloride inhibitor ionizes potassium ions in water, and the potassium ions can enter between clay sheets. The clay layer forms a compact structure by relying on the lattice fixation of the ions, and the distance between the clay layers is reduced, so as to inhibit the hydration expansion inside the clay. The polyamine inhibitor has a plurality of active amine points and a sufficiently long chain bridged on the clay surface, so as to form a hydrophobic barrier on the clay surface. The two are used in combination with each other, so as to inhibit both the surface hydration of the clay and the penetration hydration of the clay, and the inhibition effect is significantly improved.

[0020] The combined use of the three greatly reduces the amount of potassium chloride used, avoiding environmental pollution caused by excessive potassium chloride concentration. It also has good compatibility with other additives, is easy to regulate, and is convenient to use. The preparation method is simple, the raw material cost is low, and it is convenient for large-scale production. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0022] A preparation process of a high temperature resistant functional inhibitor for drilling fluid, comprising the following steps: (1) Weigh 16 parts of triethylenetetramine, 5 parts of ethylene dichloride, 30 parts of 2,5-di(imide-1-methylimidazole)terephthaloyl chloride, 10 parts of pyridine, 1.5 parts of potassium chloride, and 3 parts of water; (2) Add triethylenetetramine to the reaction vessel and slowly raise the temperature to 65-90°C; (3) Under continuous stirring conditions, slowly add dichloroethane to triethylenetetramine for 40 minutes. After the addition is complete, continue to stir and react for 15 minutes. Stop heating and cool to room temperature to obtain a reaction solution. (4) nitrogen was introduced for 30 min, pyridine was added to the reaction solution, 2,5-di(imide-1-methylimidazole)terephthaloyl chloride was added after cooling to 0-5°C, the reaction was continued for 30 min, and then the temperature was slowly raised to 30°C and the reaction was continued for 6 h; (5) After the reaction is completed, the mixture is cooled to room temperature, potassium chloride is added to water and stirred to dissolve, and the mixture is added to the reaction mixture and mixed evenly to obtain a high temperature resistant functional inhibitor. Example 2

[0023] A preparation process of a high temperature resistant functional inhibitor for drilling fluid, which differs from Example 1 in that: (1) Weigh 17 parts of triethylenetetramine, 5 parts of ethylene dichloride, 30 parts of 2,5-di(imino-1-methylimidazole)terephthaloyl chloride, 12 parts of pyridine, 2.5 parts of potassium chloride, and 3 parts of water. Example 3

[0024] A preparation process of a high temperature resistant functional inhibitor for drilling fluid, which differs from Example 1 in that: (1) Weigh 20 parts of triethylenetetramine, 6 parts of ethylene dichloride, 30 parts of 2,5-di(imino-1-methylimidazole)terephthaloyl chloride, 14 parts of pyridine, 1.5 parts of potassium chloride, and 3 parts of water. Example 4

[0025] A preparation process of a high temperature resistant functional inhibitor for drilling fluid, which differs from Example 1 in that: (1) Weigh 18 parts of triethylenetetramine, 6 parts of ethylene dichloride, 30 parts of 2,5-di(imino-1-methylimidazole)terephthaloyl chloride, 15 parts of pyridine, 2 parts of potassium chloride, and 3 parts of water.

[0026] Comparative Example 1 A preparation process for a drilling fluid inhibitor, which differs from Example 1 in that: (1) Weigh 16 parts of triethylenetetramine, 5 parts of ethylene dichloride, 1.5 parts of potassium chloride, and 3 parts of water; (2) Add triethylenetetramine to the reaction vessel and slowly raise the temperature to 65-90°C; (3) Under continuous stirring conditions, slowly add dichloroethane to triethylenetetramine for 40 minutes. After the addition is complete, continue to stir and react for 15 minutes. Stop heating and cool to room temperature to obtain a reaction solution. (4) Add potassium chloride into water and stir to dissolve, then add the potassium chloride into the reaction mixture and mix well to obtain inhibitor I.

[0027] Comparative Example 2 A preparation process for a drilling fluid inhibitor, which differs from Example 1 in that: (1) Weigh 16 parts of triethylenetetramine, 30 parts of 2,5-di(imino-1-methylimidazole)terephthaloyl chloride, 10 parts of pyridine, 1.5 parts of potassium chloride, and 3 parts of water; (2) Add triethylenetetramine to the reaction vessel, introduce nitrogen for 30 minutes, add pyridine to the reaction solution, cool to 0-5°C, add 2,5-di(imide-1-methylimidazole)terephthaloyl chloride, react for 30 minutes, then slowly raise the temperature to 30°C and continue the reaction for 6 hours; (3) After the reaction is completed, the mixture is cooled to room temperature, potassium chloride is added to water and stirred to dissolve, and the mixture is added to the reaction mixture and mixed evenly to obtain inhibitor II.

[0028] Test 1 Linear expansion rate test of inhibitor A linear expansion experiment was performed on the high temperature resistant functional inhibitors prepared in Examples 1-4 of the present invention: 5 g of bentonite was weighed, poured into a sleeve, compacted at a pressure of 10 MPa for 5 min, a layer of filter paper was placed on the compacted bentonite, the sleeve was embedded in an expansion instrument, purified water, the high temperature resistant functional inhibitors prepared in Examples 1-4, and the inhibitors prepared in Comparative Examples 1-2 were added respectively, the expansion amount of the bentonite after 1 h and 16 h was recorded, the linear expansion rate was calculated, and the inhibitor performance of the inhibitor was evaluated. Generally speaking, the higher the linear expansion rate, the worse the inhibitor performance, and vice versa. The test results are shown in Table 1.

[0029] Table 1

[0030] As can be seen from the above table, when bentonite is treated with purified water, the linear expansion rate of bentonite is as high as 43.60%. When the high temperature resistant functional inhibitors prepared by Examples 1-4 of the present invention are used, the linear expansion rate of bentonite is reduced to a minimum of 7.06%, which effectively reduces the linear expansion rate of bentonite, and the inhibitory performance is significantly stronger than that of the comparative inhibitor.

[0031] Test 2 Inhibitors for Rock Cuttings Rolling Recovery Inhibition Test: A rock chip recovery experiment was conducted on the inhibitors of Examples 1-4 of the present invention and Comparative Examples 1-2. Generally speaking, the higher the rock chip recovery rate, the better the inhibitory performance, and vice versa. Sandstone was used as a rock sample, and the test results are shown in Table 2.

[0032] Table 2

[0033] According to the above data, the high temperature resistant functional inhibitor obtained by the present invention has good shale stabilization performance and temperature resistance. When the addition amount is 1wt.%, the shale rolling recovery rate is above 95%, and the temperature resistance reaches 200°C.

[0034] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high temperature resistant functional inhibitor for drilling fluid, characterized in that: The raw materials of the inhibitor include, by weight: 16-20 parts of triethylenetetramine; 5-6 parts of ethylene dichloride; 2,5-di(imide-1-methylimidazole)terephthaloyl chloride 30 parts; Pyridine 10-15 parts; 1.5-2.5 parts of potassium chloride; 3-5 parts water.

2. A high temperature resistant functional inhibitor for drilling fluid, characterized in that: The raw materials of the inhibitor include, by weight: 18 parts of triethylenetetramine; 6 parts of ethylene dichloride; 2,5-di(imide-1-methylimidazole)terephthaloyl chloride 30 parts; Pyridine 15 parts; 2 parts potassium chloride; 3 parts water.

3. A process for preparing a high temperature resistant functional inhibitor for drilling fluid, characterized in that: The following steps are involved: (1) Weighing raw materials of the high temperature resistant functional inhibitor according to any one of claims 1 to 2; (2) Add triethylenetetramine to the reaction vessel and slowly raise the temperature to 65-90°C; (3) Slowly drop ethylene dichloride into triethylenetetramine under continuous stirring. After the dropwise addition is complete, continue stirring to react. Stop heating and cool to room temperature to obtain a reaction solution. (4) Under anaerobic conditions, pyridine is added to the reaction solution, and after cooling, 2,5-di(imide-1-methylimidazole)terephthaloyl chloride is added to react, and then the temperature is slowly raised to continue the reaction; (5) After the reaction is completed, cool to room temperature, add potassium chloride solution, mix well, and obtain a high temperature resistant functional inhibitor.

4. The preparation process of a high temperature resistant functional inhibitor for drilling fluid according to claim 3, characterized in that: In step (3), the slow addition time is 30-40 min, and the stirring reaction time is 15 min.

5. The preparation process of a high temperature resistant functional inhibitor for drilling fluid according to claim 3, characterized in that: In step (4), the anaerobic condition is to introduce nitrogen for 20-30 minutes.

6. The preparation process of a high temperature resistant functional inhibitor for drilling fluid according to claim 3, characterized in that: In step (4), the cooling is to cool the mixture to 0-5°C and then add 2,5-di(imide-1-methylimidazole)terephthaloyl chloride and react for 30-40 minutes.

7. The process for preparing a high temperature resistant functional inhibitor for drilling fluid according to claim 3, characterized in that: In step (4), the temperature is raised to 20-40° C. and the reaction is continued for 5-7 hours.

8. The process for preparing a high temperature resistant functional inhibitor for drilling fluid according to claim 3, characterized in that: In step (5), the potassium chloride solution is prepared by adding potassium chloride into water and stirring to dissolve.

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