Clay stabilizer for oil field as well as preparation method and application of clay stabilizer

Abstract

The invention belongs to the technical field of oil exploitation, and particularly relates to a clay stabilizer for an oil field as well as a preparation method and application thereof. The preparation method comprises the following steps: adding 1, 1 '-bis (4-aminophenyl)-[4, 4'-dipyridyl]-1, 1 '-ammonium dichloride, DMF (Dimethyl Formamide), triethylamine and (3-chloropropyl)-trimethyl ammonium chloride into a reactor, and carrying out a first heat preservation reaction; adding chloroalkane into the reactor, and carrying out a second heat preservation reaction; adding diacyl chloride into the reactor, and carrying out a third heat preservation reaction; and carrying out reduced pressure distillation to remove DMF to obtain a clay stabilizer crude product, adding water and ethyl acetate, fully mixing, separating out ethyl acetate, and carrying out reduced pressure distillation to obtain the clay stabilizer. The clay stabilizer has the advantages of high anti-swelling rate and washing resistance, the anti-swelling rate reaches 97% or above, and the washing anti-swelling rate reaches 93.5% or above.

Description

Technical Field

[0001] This invention belongs to the field of petroleum extraction technology, specifically relating to an oilfield clay stabilizer, its preparation method, and its application. Background Technology

[0002] During drilling, well completion, fracturing, and water injection operations in oil fields, when external fluids (such as drilling fluid, fracturing fluid, and injected water) come into contact with clay minerals in the reservoir, a series of reservoir damage problems can occur, seriously affecting the exploration and development results of the oil field. These hazards are mainly manifested in the following aspects.

[0003] Hydration swelling: When water-sensitive clay minerals such as montmorillonite and illite-montmorillonite mixed layers in the reservoir come into contact with water, they will undergo lattice expansion and hydration swelling, which will narrow or even block the formation pores and throats, greatly reducing the permeability of the reservoir.

[0004] Dispersion and migration: When clay minerals such as kaolinite and illite encounter foreign fluids with low mineralization or incompatibility with formation water, their structural bonds are broken, causing them to detach from the pore walls and form tiny clay particles. These particles migrate with the fluid in the pores and cause blockages at the throats, resulting in irreversible reservoir damage.

[0005] Clay stabilizers are widely used to inhibit the decrease in oil and gas reservoir permeability, prevent clay swelling and migration from damaging the reservoir, and achieve high and stable oil and gas production.

[0006] Typically, clay stabilizers not only need to have high anti-swelling effect and low effective concentration, but also need to be compatible with formation water, have a stable and long-lasting effect on inhibiting the swelling of clay in the formation, and be resistant to various fluid erosions.

[0007] CN106147739A discloses a clay stabilizer for fracturing and its preparation method. It is prepared from the following raw materials in parts by weight: 35-50 parts choline chloride, 3-8 parts calcium chloride, 40-50 parts water, 5-10 parts methanol, and 1-5 parts alcohol ether solvent. The fracturing clay stabilizer prepared by this method exhibits excellent anti-swelling properties and good compatibility. However, the clay stabilizer contains a large amount of methanol and alcohol ether, which are easily washed away by water, indicating limited water resistance. Furthermore, the anti-swelling rate is only 50%, which cannot meet practical needs.

[0008] CN109456748B discloses a clay stabilizer for reservoir fracturing and its preparation method. It includes the following steps: (1) using p-aminophenol and epichlorohydrin as raw materials, and under the catalysis of sodium alkoxide, obtaining intermediate product formula I; (2) using intermediate product formula I and ammonia as raw materials, obtaining the clay stabilizer for reservoir fracturing shown in formula II. Formula II contains a highly polar benzene ring, which gives it the advantages of general polyetheramine clay stabilizers while also possessing high polarity. This makes it easier to reverse-flow after being used as a fracturing fluid additive, resulting in better environmental protection and greater advantages in anti-swelling rate evaluation, thus showing greater development potential for oil and gas field exploitation. However, the molecule lacks cations, and the clay surface is negatively charged, causing the clay to be unable to adsorb the stabilizer well, thereby affecting the anti-swelling effect. Summary of the Invention

[0009] This invention addresses the shortcomings of the existing technology by providing an oilfield clay stabilizer, its preparation method, and its application. The clay stabilizer of this invention has the advantages of high anti-swelling rate and water washability, with an anti-swelling rate exceeding 97% and a water washability anti-swelling rate exceeding 93.5%.

[0010] One objective of this invention is to disclose a method for preparing a clay stabilizer for oilfields, the specific steps of which are as follows: (1) Add 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-diammonium chloride, DMF, triethylamine, and (3-chloropropyl)-trimethylammonium chloride to the reactor and carry out the first heat preservation reaction; (2) Chloroalkane was added to the above reactor to carry out the second heat preservation reaction; (3) Add diacyl chloride to the above reactor and carry out the third heat preservation reaction; (4) DMF was removed by vacuum distillation to obtain crude clay stabilizer. Water and ethyl acetate were added and mixed thoroughly. The ethyl acetate was separated and then distilled under vacuum to obtain clay stabilizer.

[0011] Based on 1 mole of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-diammonium chloride, the amounts of (3-chloropropyl)-trimethylammonium chloride, chloroalkane, and diacyl chloride are 0.8-1.2 moles, 0.8-1.2 moles, and 0.8-1.2 moles, respectively.

[0012] More preferably, based on 1 mole of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-diammonium chloride, the amounts of (3-chloropropyl)-trimethylammonium chloride, chloroalkane, and diacyl chloride are 0.9-1.2 moles, 0.9-1.2 moles, and 0.9-1.2 moles, respectively.

[0013] The structural formula of the chloroalkane is: , where R is C8-C6. 18 Straight-chain alkanes.

[0014] The diacyl chloride is one of malonyl chloride, succinic chloride, glutaryl chloride, and adipyl chloride.

[0015] Preferably, in step (1), the weight ratio of DMF, triethylamine and 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-diammonium chloride is 20-40:3-5:1.

[0016] Preferably, the temperatures of the first, second, and third heat preservation reactions are 50-70℃, 60-80℃, and 40-60℃, respectively, and the times are 30 minutes or more, 60 minutes or more, and 30 minutes or more, respectively.

[0017] The reaction equation for the clay stabilizer of the present invention is as follows: Another objective of this invention discloses a clay stabilizer for oilfield use, the molecular structural formula of which is as follows: , Where R is C8-C 18 The straight-chain alkanes, where n is a natural number from 1 to 4, and m is a natural number greater than 2.

[0018] The third objective of this invention is to disclose the application of the above-mentioned clay stabilizer in oilfield drilling, well completion, fracturing, and water injection operations.

[0019] The clay stabilizer of this invention is a multi-quaternary ammonium small molecule polymer. The quaternary ammonium cations can adsorb and neutralize the negative charge on the clay surface, reduce the repulsion between crystal layers, and play an anti-swelling role; the molecular chains can be adsorbed on multiple clay particles simultaneously, or adsorbed at multiple sites on a single clay particle. The "multi-point anchoring" effect greatly limits the expansion of the interlayer spacing of clay and the dispersion of the lamellar crystals themselves; the long-chain alkyl groups can effectively prevent water molecules from wetting the clay particles, inhibiting the hydration swelling of clay by avoiding contact between water molecules and clay; the hydrophobic groups introduced by the acyl chloride further prevent water and clay from contacting each other, enhancing the erosion resistance.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) The clay stabilizer of the present invention has the advantage of high anti-swelling rate, with the highest anti-swelling rate reaching 98.8%; (2) The clay stabilizer of the present invention has the advantage of being water-resistant, and the water-washing anti-swelling rate reaches up to 95.2%. Detailed Implementation

[0021] The present invention will be further described below with reference to specific embodiments: Example 1 (1) Add 10 mmol of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-diammonium chloride, 82 g of DMF, 12.3 g of triethylamine, and 8 mmol of (3-chloropropyl)-trimethylammonium chloride to the reactor and react at 50 °C for 30 min. (2) Add 8 mmol of chlorooctane to the above reactor and react at 60°C for 60 min; (3) Add 8 mmol of malonyl chloride to the above reactor and react at 40°C for 30 min; (4) DMF was removed by vacuum distillation to obtain crude clay stabilizer. Water and ethyl acetate were added and mixed thoroughly. The ethyl acetate was separated and then distilled under vacuum to obtain clay stabilizer.

[0022] Example 2 (1) Add 10 mmol of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-diammonium chloride, 98 g of DMF, 18.4 g of triethylamine, and 12 mmol of (3-chloropropyl)-trimethylammonium chloride to the reactor and react at 60 °C for 40 min; (2) Add 9 mmol of chlorodecane to the above reactor and react at 70°C for 90 min; (3) Add 8.5 mmol malonyl chloride to the above reactor and react at 40°C for 60 min; (4) DMF was removed by vacuum distillation to obtain crude clay stabilizer. Water and ethyl acetate were added and mixed thoroughly. The ethyl acetate was separated and then distilled under vacuum to obtain clay stabilizer.

[0023] Example 3 (1) Add 10 mmol of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-diammonium chloride, 123 g of DMF, 20.6 g of triethylamine, and 9 mmol of (3-chloropropyl)-trimethylammonium chloride to the reactor and react at 60 °C for 35 min; (2) Add 12 mmol of chlorooctadecane to the above reactor and react at 80°C for 80 min; (3) Add 9 mmol of succinyl chloride to the above reactor and react at 45°C for 40 min; (4) DMF was removed by vacuum distillation to obtain crude clay stabilizer. Water and ethyl acetate were added and mixed thoroughly. The ethyl acetate was separated and then distilled under vacuum to obtain clay stabilizer.

[0024] Example 4 (1) Add 10 mmol of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-diammonium chloride, 145 g of DMF, 14.3 g of triethylamine, and 9.5 mmol of (3-chloropropyl)-trimethylammonium chloride to the reactor and react at 70 °C for 45 min; (2) Add 11 mmol of chlorododecane to the above reactor and react at 80°C for 70 min; (3) Add 12 mmol adipic acid chloride to the above reactor and react at 60°C for 45 min; (4) DMF was removed by vacuum distillation to obtain crude clay stabilizer. Water and ethyl acetate were added and mixed thoroughly. The ethyl acetate was separated and then distilled under vacuum to obtain clay stabilizer.

[0025] Example 5 (1) Add 10 mmol of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-diammonium chloride, 150 g of DMF, 17.6 g of triethylamine, and 11 mmol of (3-chloropropyl)-trimethylammonium chloride to the reactor and react at 65 °C for 50 min; (2) Add 10.5 mmol of hexadecyl chloride to the above reactor and react at 70°C for 75 min; (3) Add 11 mmol of glutaryl chloride to the above reactor and react at 55°C for 50 min. (4) DMF was removed by vacuum distillation to obtain crude clay stabilizer. Water and ethyl acetate were added and mixed thoroughly. The ethyl acetate was separated and then distilled under vacuum to obtain clay stabilizer.

[0026] Example 6 (1) Add 10 mmol of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-diammonium chloride, 164 g of DMF, 16.8 g of triethylamine, and 10.5 mmol of (3-chloropropyl)-trimethylammonium chloride to the reactor and react at 65 °C for 60 min; (2) Add 9.5 mmol of tetradecyl chloride to the above reactor and react at 72°C for 65 min; (3) Add 10 mmol malonyl chloride to the above reactor and react at 50°C for 35 min; (4) DMF was removed by vacuum distillation to obtain crude clay stabilizer. Water and ethyl acetate were added and mixed thoroughly. The ethyl acetate was separated and then distilled under vacuum to obtain clay stabilizer.

[0027] Example 7 (1) Add 10 mmol of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-diammonium chloride, 155 g of DMF, 19 g of triethylamine, and 10 mmol of (3-chloropropyl)-trimethylammonium chloride to the reactor and react at 65 °C for 40 min. (2) Add 10 mmol of hexadecane to the above reactor and react at 73°C for 80 min; (3) Add 10.5 mmol malonyl chloride to the above reactor and react at 45°C for 60 min. (4) DMF was removed by vacuum distillation to obtain crude clay stabilizer. Water and ethyl acetate were added and mixed thoroughly. The ethyl acetate was separated and then distilled under vacuum to obtain clay stabilizer.

[0028] Example 8 Evaluation of the anti-swelling ability of clay stabilizers The anti-swelling rate of the clay stabilizer of this invention (Examples 1-7) was tested by centrifugation according to SY / T 5971-2016 "Performance Evaluation Method of Clay Stabilizer for Fracturing, Acidizing and Water Injection in Oil and Gas Fields". A comparative experiment was conducted using clay stabilizer No. 3 from Tianjin Binpu Technology Development Co., Ltd. The test results are shown in Table 1.

[0029] As can be seen from Table 1, the anti-swelling rate of the clay stabilizer of the present invention (Examples 1-7) is greater than 97%, with the highest reaching 98.8%; while the anti-swelling rate of the comparative example is 85.2%. Therefore, the clay stabilizer of the present invention has the advantage of high anti-swelling rate.

[0030] Example 9: Evaluation of the water wash resistance of clay stabilizers The water wash resistance of the clay stabilizers of this invention (Examples 1-7) was tested by centrifugation according to SY / T 5971-2016 "Performance Evaluation Method of Clay Stabilizers for Fracturing, Acidizing and Water Injection in Oil and Gas Fields". A comparative experiment was conducted using clay stabilizer No. 3 from Tianjin Binpu Technology Development Co., Ltd. The test results are shown in Table 1.

[0031] Table 1. Test results of anti-swelling rate and water washability Anti-expansion rate, % Water washing anti-swelling rate, % Example 1 97.2 93.6 Example 2 98 94.5 Example 3 98.2 94.5 Example 4 98.5 94.7 Example 5 98.6 95 Example 6 98.8 95.2 Example 7 98.5 95 Comparative Example 85.2 80 As can be seen from Table 1, the anti-swelling rate of the clay stabilizer of the present invention (Examples 1-7) after water washing is greater than 93.5%, with the highest reaching 95.2%; while the anti-swelling rate of the comparative example after water washing is 80%. Therefore, the clay stabilizer of the present invention has the advantage of strong water washing resistance.

[0032] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing a clay stabilizer for oil fields, characterized by, The preparation method comprises the following steps: (1) adding 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-dichloride, DMF, triethylamine and (3-chloropropyl)-trimethylammonium chloride into a reactor to perform a first holding reaction; (2) adding chloroalkane into the reactor to perform a second holding reaction; (3) adding diacyl chloride into the reactor to perform a third holding reaction; (4) distilling the DMF under reduced pressure to obtain a crude clay stabilizer, adding water and ethyl acetate, mixing thoroughly, separating the ethyl acetate, and distilling the ethyl acetate under reduced pressure to obtain the clay stabilizer; Based on 1 mole of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-dichloride, the amounts of (3-chloropropyl)-trimethylammonium chloride, chloroalkane and diacyl chloride are 0.8-1.2 moles, 0.8-1.2 moles and 0.8-1.2 moles respectively.

2. The preparation method according to claim 1, characterized in that, Based on 1 mole of 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-dichloride, the amounts of (3-chloropropyl)-trimethylammonium chloride, chloroalkane and diacyl chloride are 0.9-1.2 moles, 0.9-1.2 moles and 0.9-1.2 moles respectively.

3. The preparation method according to claim 1, characterized in that, The chloroalkane has the structural formula: , R is a C8-C 18 linear alkane.

4. The preparation method according to claim 1, characterized in that, The diacyl chloride is one of malonyl chloride, succinyl chloride, glutaryl chloride and adipyl chloride.

5. The method of claim 1, wherein the step of forming the first and second layers is performed by a process selected from the group consisting of: sputtering, evaporation, and chemical vapor deposition. The weight ratio of DMF, triethylamine and 1,1'-bis(4-aminophenyl)-[4,4'-bipyridine]-1,1'-dichloride is 20-40:3-5:

1.

6. The method of claim 1, wherein the step of forming the first and second layers is performed by a process selected from the group consisting of: sputtering, evaporation, and chemical vapor deposition. The temperatures of the first holding reaction, the second holding reaction and the third holding reaction are 50-70℃, 60-80℃ and 40-60℃ respectively, and the time of each reaction is 30 minutes or more, 60 minutes or more and 30 minutes or more respectively.

7. The clay stabilizer prepared by the preparation method according to any one of claims 1-6.

8. The clay stabilizer of claim 7, wherein, The molecular structure of the clay stabilizer is as follows: ， wherein R is a linear alkane of C8-C 18 n is a natural number of 1-4, and m is a natural number greater than 2.

9. The clay stabilizer according to claim 7 or 8 is applied in oil field drilling, well completion, fracturing and water injection operations.

Images