Gas-liquid multiphase dispersion fluid as well as preparation method and application thereof

Abstract

The invention discloses a gas-liquid multiphase dispersion fluid as well as a preparation method and application thereof, and belongs to the technical field of oil and gas development. The gas-liquid multiphase dispersion fluid is a novel multiphase dispersion system formed by dispersing a water-insoluble liquid (oil) containing a gas phase in water, is prepared from a water-soluble polymer material with a specific structure, a surfactant and the water-insoluble liquid, and is structurally a water-oil-gas multiphase system; the plugging agent has excellent plugging performance, acid resistance, salt resistance and unique viscosity-temperature performance, can be used for plugging high-permeability zone stratums in oil and gas exploitation projects such as temporary plugging acidification, repeated fracturing and profile control water plugging, and provides a new method for oil and gas resource development.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas development, and particularly relates to a gas-liquid multiphase dispersed fluid, a preparation method thereof, and an application thereof. Background Art

[0002] During the process of oil and gas exploitation, acidification technology is an effective measure for plugging removal and oil and gas production increase. Temporary plugging acidification can block high-permeability layers, enable acid fluid to enter low-permeability layers and improve their permeability, thereby obtaining better acidification effects. Currently, the temporary plugging agents used in temporary plugging acidification include foams, polymer or surfactant gels, and particulate materials. These materials show the function of temporary plugging acidification, but there are also some problems: the foam strength is relatively low; the gel-like materials are difficult to flow back, causing greater damage to the formation; the size and shape of the particulate materials do not match well with the pore and fracture structure of the formation, and the temporary plugging effect is not ideal.

[0003] The velvet capsule structure is an airbag-like material containing a certain amount of gas formed by surfactants and water-soluble polymer materials through physicochemical actions in a fluid medium (water). It has the performance characteristics of being able to block formation channels by relying on low-pressure expansion, deforming according to the environment, and increasing the plugging strength with temperature increase. The velvet capsule fluid is an airbag-like water-gas multiphase system that has a plugging effect on formation pores and fractures and can be used as a leak-proof and collapse-proof drilling fluid, workover fluid, kill fluid, repeated fracturing plugging agent, and water shutoff agent.

[0004] For example, Chinese Patent CN116731693A discloses a velvet capsule temporary plugging agent, which includes an alkaline compound and the following components in parts by mass: 100 parts of water, 1.5 - 2.5 parts of capsule layer agent, 0.8 - 1.5 parts of fluff agent, 0.2 - 0.8 parts of nucleating agent, 0.4 - 1 part of film-forming agent, and 0.8 - 1.5 parts of high-temperature stabilizer. The temporary plugging agent of this invention is a velvet capsule temporary plugging agent, which has good high-temperature stability. Due to its unique velvet capsule structure, its pressure-bearing capacity can reach more than 19.8 MPa at 150 °C, and it has excellent plugging performance and can meet the requirements of plugging carbonate rock low-pressure gas layers. However, the velvet capsule fluid has a complex structure, requires the use of a variety of materials including fluff agent, capsule layer agent, capsule film agent, capsule core agent, etc., and there has been no report on a velvet capsule fluid with good stability under acidic conditions.

[0005] Therefore, there is an urgent need to develop a new material for plugging formation channels with excellent plugging performance, acid resistance, and temperature resistance. Summary of the Invention

[0006] To achieve this goal, the present invention proposes a novel multiphase dispersed system in which a non-water-soluble liquid (oil) containing gas phase is dispersed in water.

[0007] Structurally, it is a water-oil-gas multiphase system with excellent acid and salt resistance, strong plugging effect, and structural and performance characteristics different from those of the fluff ball. It can be used in oil and gas exploitation projects for plugging high-permeability zones in formations, including temporary plugging acidification, and has broad application prospects.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] On the one hand, the present invention provides a gas-liquid multiphase dispersion fluid, which comprises the following components by weight percentage:

[0010] Water-soluble polymer: 0.5%-3.0%;

[0011] Surfactant: 0.1%-0.5%;

[0012] Water-insoluble liquid material: 0.1%-4%;

[0013] pH regulator: 0.1%-4%;

[0014] Water: the balance.

[0015] Among them,

[0016] The water-soluble polymer is one or more of carboxymethyl starch, carboxyethyl starch, hydroxyethyl starch, hydroxypropyl starch, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose and hydroxypropyl cellulose;

[0017] The function of the water-soluble polymer is to improve the stability and viscosity (strength) of the dispersion system.

[0018] The surfactant is one or more of non-ionic surfactants, cationic surfactants, amine salt surfactants and quaternary ammonium salt surfactants;

[0019] The non-ionic surfactant is one or more of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, fatty acid methyl ester ethoxylate and Tween;

[0020] The cationic surfactant is a surfactant containing a pyridine ring, an imidazole ring, a piperazine ring or a quinoline ring.

[0021] The function of the surfactant is to reduce the gas-liquid and liquid-liquid interfacial tensions, which is beneficial to the formation and stability of the gas-liquid multiphase dispersion phase.

[0022] The water-insoluble liquid material is one or more of fatty alcohols, sorbitan esters, ethyl acetate, butyl acetate and cyclohexanone.

[0023] The function of the water-insoluble liquid material is to create conditions for the formation of the multiphase dispersion.

[0024] The pH regulator described above is Na 2 CO 3 or / and HCl.

[0025] The function of the pH regulator described above is to regulate the performance of the gas-liquid multiphase dispersed fluid.

[0026] On the other hand, the present invention provides a method for preparing the gas-liquid multiphase dispersed fluid described above, including the following steps:

[0027] (1) Add the pH regulator to deionized water and stir until completely dissolved to obtain Solution 1;

[0028] (2) Add the water-soluble polymer to Solution 1 and stir until completely dissolved to obtain Solution 2;

[0029] (3) Add the surfactant to Solution 2 and stir until completely dissolved to obtain Solution 3;

[0030] (3) Add the water-insoluble liquid material to Solution 3 and stir for 20 min under the condition of a rotation speed of about 1000 r / min to obtain the gas-liquid multiphase dispersed fluid described above.

[0031] On yet another aspect, the present invention provides the use of the gas-liquid multiphase dispersed fluid described above in the preparation of oilfield plugging agents.

[0032] The gas-liquid multiphase dispersed fluid described in the present invention is a multiphase dispersion system in which a water-insoluble liquid containing a gas phase is dispersed in water, and is prepared using a water-soluble polymer material, a surfactant, and a water-insoluble liquid with a specific structure, and is a water-oil-gas multiphase system in structure. This system has excellent plugging performance, salt and acid resistance performance, and unique viscosity-temperature performance: when 2% NaCl is added to the system or the hydrochloric acid concentration is increased to 1 mol / L, the apparent viscosity change rate is within 10%; at high temperature, the viscosity does not change significantly with the increase in temperature; the pressure-bearing capacity after plugging is greater than 20 MPa, and it can be used to plug high-permeability formation in oil and gas production engineering such as temporary plugging acidification, refracturing, and profile control and water shutoff, providing a new method for developing oil and gas resources. + Compared with the prior art, the performance characteristics of the gas-liquid multiphase dispersed fluid described in the present invention are:

[0033] (1) It has a unique viscosity-temperature characteristic: the multiphase dispersed fluid with a composition of 0.2% alkylphenol polyoxyethylene ether + 1% hydroxyethyl cellulose + 0.1% sorbitan ester does not change significantly with the increase in temperature at high temperature, and has good temperature resistance (

[0034] (1) It has a unique viscosity-temperature characteristic: the multiphase dispersed fluid with a composition of 0.2% alkylphenol polyoxyethylene ether + 1% hydroxyethyl cellulose + 0.1% sorbitan ester does not change significantly with the increase in temperature at high temperature, and has good temperature resistance ( Figure 1 );

[0035] (2) Good salt tolerance: When 2% NaCl is added to the multiphase dispersion fluid with the composition of 0.2% alkylphenol polyoxyethylene ether + 1% hydroxyethyl cellulose + 0.2% sorbitan ester, the apparent viscosity reduction rate of the system is less than 5% (Table 1);

[0036] (3) Excellent acid tolerance: Under the condition that other components remain unchanged, when HCl is added to the system with the composition of 0.2% alkyl quaternary ammonium salt + 1% hydroxyethyl cellulose + 0.2% sorbitan ester at pH 10, the system performance changes little. When the addition amount of HCl reaches the H⁺ concentration of 1 mol / L in the system, the apparent viscosity change rate can be within 10% (Table 2);

[0037] (4) Strong plugging ability: The pressure-bearing capacity is greater than 23 MPa ( Figure 2 ), and it can be used in oil and gas exploitation projects such as temporary plugging acidification, refracturing, and profile control and water plugging to plug high-permeability zones in formations. Description of the Drawings

[0038] Figure 1 Variation relationship of the viscosity of the liquid multiphase dispersion fluid (0.2% alkylphenol polyoxyethylene ether + 1% hydroxyethyl cellulose + 0.1% sorbitan ester) with temperature;

[0039] Figure 2 Variation relationship of the viscosity of the gas-liquid multiphase dispersion fluid with temperature;

[0040] Figure 3 Plugging effect of the gas-liquid multiphase dispersion fluid (core with φ25mm×40mm, slit width 1mm, confining pressure 30 MPa, injection rate 1 mL / min, simulated formation water is 8% KCl) Detailed Implementation Modes

[0041] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0042] Example 1: A preparation method of a gas-liquid multiphase dispersion fluid

[0043] It includes the following steps:

[0044] (1) Add 1.5 g of sodium carbonate to 1000 g of water and stir until completely dissolved to obtain Solution 1;

[0045] (2) Add 10 g of cellulose ether to Solution 1 and stir until completely dissolved to obtain Solution 2;

[0046] (3) Add 2 g of alkylphenol polyoxyethylene ether to Solution 2 and stir until completely dissolved to obtain Solution 3;

[0047] (4) Add 2 g of sorbitan ester to Solution 3 and stir for 20 min under the condition of about 3000 r / min to obtain the gas-liquid multiphase dispersion fluid.

[0048] The relationship between the viscosity measured by a MARS Ⅲ rotational rheometer at 170 s -1 and the temperature is shown in Figure 1 , and the apparent viscosity, plastic viscosity and dynamic shear force of the polydisperse system before and after adding 2% NaCl were measured by a ZNN-D6 six-speed rotational viscometer, as shown in Table 1.

[0049] Table 1 Salt tolerance performance of the gas-liquid multiphase dispersion fluid prepared with alkylphenol polyoxyethylene ether and cellulose ether

[0050] NaCl (%) Apparent viscosity (mPa·s) Plastic viscosity (mPa·s) Yield point (Pa) 0 44 19 25.55 2％ 43 21 22.48

[0051] Conclusion: The rheological properties of this gas-liquid multiphase dispersion fluid do not change significantly at different NaCl concentrations, and it has good salt tolerance.

[0052] Example 2: A preparation method of a gas-liquid multiphase dispersion fluid

[0053] It includes the following steps:

[0054] (1) Add 1.5 g of sodium carbonate to 1000 g of water and stir until completely dissolved to obtain Solution 1;

[0055] (2) Add 10 g of cellulose ether to Solution 1 and stir until completely dissolved to obtain Solution 2;

[0056] (3) Add 2 g of alkyl quaternary ammonium salt to Solution 2 and stir until completely dissolved to obtain Solution 3;

[0057] (4) Add 2 g of sorbitan ester to Solution 3 and stir for 20 min under the condition of about 3000 r / min to obtain the gas-liquid multiphase dispersion fluid.

[0058] The relationship between the viscosity measured by a MARS Ⅲ rotational rheometer at 170 s -1 and the temperature is shown in Figure 2 , and the apparent viscosity, plastic viscosity and dynamic shear force of the polydisperse system before and after adding 2% NaCl were measured by a ZNN-D6 six-speed rotational viscometer, as shown in Table 3. The influence of pH value on the performance of the gas-liquid multiphase dispersion fluid is small (Table 2), indicating that the gas-liquid multiphase dispersion fluid has excellent temperature, salt and acid tolerance properties.

[0059] Table 2 Influence of pH value on the performance of the gas-liquid multiphase dispersion fluid prepared with alkyl quaternary ammonium salt and cellulose ether

[0060] pH value Apparent viscosity (mPa·s) Plastic viscosity (mPa·s) Yield point (Pa) Yield point / plastic viscosity ratio 10 59.5 30.0 30.1 1.00 3 59.5 30.0 30.2 1.01 2 58.0 30.0 28.6 0.95 1 56.0 28.0 28.6 1.02 0 54.0 26.0 28.6 1.10

[0061] Table 3 Salt tolerance performance of gas-liquid multiphase dispersion fluid prepared with alkyl quaternary ammonium salt and cellulose ether

[0062] NaCl (%) Apparent viscosity (mPa·s) Plastic viscosity (mPa·s) Yield point (Pa) Yield point / plastic viscosity ratio 0 59.5 30 30.1 1.00 2％ 55 29 26.6 0.92

[0063] Conclusion: The rheological properties of this gas-liquid multiphase dispersion fluid change insignificantly under different pH conditions, and the rheological properties change slightly under different NaCl concentrations in acidic conditions, indicating good acid and salt tolerance properties.

[0064] Example 3: A preparation method of a gas-liquid multiphase dispersion fluid

[0065] It includes the following steps:

[0066] (1) Add 1.5 g of sodium carbonate to 1000 g of water and stir until completely dissolved to obtain Solution 1;

[0067] (2) Add 5 g of cellulose ether and 5 g of etherified starch to Solution 1 and stir until completely dissolved to obtain Solution 2;

[0068] (3) Add 0.5 g of alkylphenol polyoxyethylene ether and 1.5 g of alkyl quaternary ammonium salt to Solution 2 and stir until completely dissolved to obtain Solution 3;

[0069] (4) Add 2 g of sorbitan ester to Solution 3 and stir for 20 min under the condition of about 3000 r / min to obtain the gas-liquid multiphase dispersion fluid.

[0070] The apparent viscosity (AV), plastic viscosity (PV) and yield point (YP) of the polydisperse system before and after adding 2% NaCl were measured using a ZNN-D6 type six-speed rotational viscometer, as shown in Table 4, and the influence of pH value on the properties of the gas-liquid multiphase dispersion fluid is shown in Table 5.

[0071] Table 4 Salt tolerance performance of gas-liquid multiphase dispersion fluid prepared with alkylphenol polyoxyethylene ether, alkyl quaternary ammonium salt, cellulose ether and etherified starch

[0072] NaCl (%) Apparent viscosity (mPa·s) Plastic viscosity (mPa·s) Yield point (Pa) Yield point / plastic viscosity ratio 0 46 23 23.51 1.02 2％ 45 22 23.51 1.07

[0073] Table 5 Acid tolerance performance of gas-liquid multiphase dispersion fluid prepared with alkylphenol polyoxyethylene ether, alkyl quaternary ammonium salt, cellulose ether and etherified starch

[0074] pH value Apparent viscosity (mPa·s) Plastic viscosity (mPa·s) Yield point (Pa) Yield point / plastic viscosity ratio 10 46 23 23.51 1.02 3 40 16 24.53 1.53 2 45 19 28.62 1.51 1 40 17 23.51 1.38 0 44 18 26.57 1.48

[0075] It can be seen from Table 4 and Table 5 that salt and pH value have little influence on the properties of the dispersion fluid, indicating that this gas-liquid multiphase dispersion fluid has excellent temperature, salt and acid tolerance properties. The plugging performance of the gas-liquid multiphase dispersion fluid for the formation is shown in Figure 3, the prepared gas-liquid multiphase dispersion fluid has strong plugging ability and can be used in oil and gas exploitation projects for plugging high-permeability zones in formations, such as temporary plugging acidification, refracturing, and profile control and water plugging.

[0076] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art can still modify or equivalently replace the specific implementation manners of the present invention, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention are within the scope of protection of the claims of the present invention.

Claims

1. A gas-liquid multiphase dispersed fluid, characterized in that: it comprises the following components by weight percentage: Water-soluble polymer: 0.5%-3.0%; Surfactant: 0.1%-0.5%; Water-insoluble liquid material: 0.1%-4%; pH regulator: 0.1%-4%; Water: the balance.

2. The gas-liquid multiphase dispersed fluid according to claim 1, characterized in that: the water-soluble polymer is one or more of carboxymethyl starch, carboxyethyl starch, hydroxyethyl starch, hydroxypropyl starch, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose and hydroxypropyl cellulose.

3. The gas-liquid multiphase dispersed fluid according to claim 1, characterized in that: the surfactant is one or more of non-ionic surfactants, cationic surfactants, amine salt-type surfactants and quaternary ammonium salt-type surfactants.

4. The gas-liquid multiphase dispersed fluid according to claim 3, characterized in that: the non-ionic surfactant is one or more of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, fatty acid methyl ester ethoxylate and Tween.

5. The gas-liquid multiphase dispersed fluid according to claim 3, characterized in that: the cationic surfactant is a surfactant containing a pyridine ring, an imidazole ring, a piperazine ring or a quinoline ring.

6. The gas-liquid multiphase dispersed fluid according to claim 1, characterized in that: the water-insoluble liquid material is one or more of fatty alcohols, sorbitan esters, ethyl acetate, butyl acetate and cyclohexanone.

7. The gas-liquid multiphase dispersed fluid according to claim 1, characterized in that: The pH regulator described above is Na 2 CO 3 or / and HCl.

8. The gas-liquid multiphase dispersed fluid according to any one of claims 2-6, characterized in that: the water-soluble polymer is cellulose ether; the surfactant is alkylphenol polyoxyethylene ether; the water-insoluble liquid material is sorbitan ester.

9. The gas-liquid multiphase dispersed fluid according to any one of claims 2-6, characterized in that: the water-soluble polymer is cellulose ether; the surfactant is alkyl quaternary ammonium salt; the water-insoluble liquid material is sorbitan ester.

10. The gas-liquid multiphase dispersed fluid according to any one of claims 2-6, characterized in that: the water-soluble polymer is cellulose ether and etherified starch; the surfactant is alkylphenol polyoxyethylene ether and alkyl quaternary ammonium salt; the water-insoluble liquid material is sorbitan ester.

11. The preparation method of the gas-liquid multiphase dispersed fluid according to any one of claims 1-10, characterized in that: it comprises the following steps: (1) Add the pH regulator to deionized water and stir until completely dissolved to obtain Solution 1; (2) Add the water-soluble polymer to Solution 1 and stir until completely dissolved to obtain Solution 2; (3) Add the surfactant to Solution 2 and stir until completely dissolved to obtain Solution 3; (3) Add the water-insoluble liquid material to Solution 3 and stir for 20 min under the condition of a rotation speed of about 1000 r / min to obtain the gas-liquid multiphase dispersed fluid.

12. Use of the gas-liquid multiphase dispersed fluid according to any one of claims 1-10 in the preparation of an oilfield plugging agent.

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