Device for on-site preparation of emulsified acid and method thereof, emulsified acid prepared by the method and application of the emulsified acid

Abstract

The present application relates to the field of energy exploration and development, in particular to a device and method for on-site preparation of emulsified acid, and the emulsified acid prepared by the method and its application, the device comprising: a pump truck, a jet pump and a buffer tank connected in sequence; wherein the pump truck provides circulating pressure for the jet pump; the jet pump is used for jet shearing mixing of acid liquid and emulsifier under the condition that the circulating pressure is greater than or equal to 0.8 MPa, the obtained mixed liquid enters the buffer tank for secondary mixing, and then is recycled back to the jet pump for repeating the jet shearing mixing to obtain emulsified acid; wherein the number of times of repeating the jet shearing mixing is greater than or equal to 8 times. The device fully utilizes the engineering equipment to realize on-site preparation of emulsified acid; at the same time, the method provided by the present application solves the problem of on-site preparation of emulsified acid, and the emulsified acid prepared by the method has the characteristics of good stability, good corrosion inhibition effect, strong deep penetration ability and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of energy exploration and development, and particularly relates to a device for on-site preparation of emulsified acid, a method for on-site preparation of emulsified acid, emulsified acid prepared by the method and application thereof. BACKGROUND

[0002] Acid fracturing is an important means of yield increase in oil and gas development, which can open fractures in oil and gas reservoirs and communicate larger area of oil and gas to produce oil and gas resources through fracture channels, so as to achieve the purpose of optimal economic development of oilfield. Emulsified acid is an emulsion prepared by mixing acid, oil and emulsifier, which is a main form of acid used in the process of oilfield acidification. Emulsified acid is an oil-in-acid emulsion, which has the characteristics of high viscosity, good retarding performance, small conventional filtration loss, good compatibility with the formation and demulsification. When emulsified acid enters the formation, the oil-in-acid droplets can enter the deep part of the formation due to the oil film between the droplets and the formation rock, so as to increase the action radius of conventional acid fracturing, which is suitable for deep reconstruction of the formation and beneficial to communicate more and farther solution cavity cracks. Meanwhile, emulsified acid has higher viscosity than pure acid, which can effectively reduce the filtration loss of acid, and make the acid be more uniformly distributed in the heterogeneous formation during the treatment of bedrock.

[0003] At present, emulsified acid needs to be mixed at high speed (rotation speed greater than 2000 rpm) in the laboratory to form, for example, CN201811451718 discloses a staged retarding crosslinking emulsified acid and a preparation method thereof, and the stirring speed is 500-3000 rpm, preferably 1000-2000 rpm. However, the on-site equipment and conditions are difficult to meet the requirements, and it is urgent to solve the problem of on-site quick and efficient acid preparation method for the industrialization and application of emulsified acid construction. SUMMARY

[0004] The present application aims to overcome the problems of emulsified acid on-site preparation, such as the need for special equipment, special acid preparation station for fixed-point acid preparation, and the inconvenience of pulling and transporting, safety risks and other problems when sending the prepared acid from the acid preparation station to the construction site. The present application provides a device for on-site preparation of emulsified acid, a method for on-site preparation of emulsified acid, emulsified acid prepared by the method and application thereof. The method solves the problem of on-site preparation of emulsified acid, and the emulsified acid prepared by the method has the characteristics of good stability, good corrosion inhibition effect and strong deep penetration ability.

[0005] To achieve the above object, the first aspect of the present application provides a device for preparing emulsified acid on site, which comprises: a pump truck, a jet pump and a buffer tank connected in sequence; wherein the pump truck provides circulating pressure for the jet pump; the jet pump is used for jet shearing mixing of acid liquid and emulsifier under the condition that the circulating pressure is greater than or equal to 0.8 MPa, and the obtained mixed liquid enters the buffer tank for secondary mixing, and then is recycled back to the jet pump for repeating the jet shearing mixing to obtain emulsified acid.

[0006] Preferably, the number of times of repeating the jet shearing mixing is greater than or equal to 8.

[0007] Preferably, the shearing rate V of the jet shearing mixing satisfies: V = 4Q / (60 x π x D 2 ), wherein V is the shearing flow rate, m / s; Q is the volume flow rate, m 3 / min; π is the circular constant, 3.14; and D is the diameter of the jet nozzle, m.

[0008] Preferably, the shearing rate V of the jet shearing mixing is greater than or equal to 5.7 m / s.

[0009] The second aspect of the present application provides a method for preparing emulsified acid on site, which is carried out in the device provided in the first aspect, and wherein the method comprises:

[0010] (1) under the condition that the circulating pressure is greater than or equal to 0.8 MPa, jet shearing mixing of acid liquid and emulsifier is carried out in the jet pump, and the obtained mixed liquid is subjected to secondary mixing in the buffer tank;

[0011] (2) the material obtained by the secondary mixing is repeated in the above step (1) for more than 8 times to obtain emulsified acid.

[0012] Preferably, the mass ratio of the acid liquid to the emulsifier is 100:35-90, preferably 100:43-80.

[0013] The third aspect of the present application provides emulsified acid prepared by the method provided in the second aspect.

[0014] The fourth aspect of the present application provides application of the emulsified acid provided in the third aspect in oil and gas field exploitation and reservoir retardation deep reconstruction, preferably in carbonate rock and sandstone reservoirs.

[0015] By the technical scheme, the device provided by the application uses a pump truck to provide a power source for a jet pump, under specific parameters and cycle times, so that the acid liquid and the emulsifier are jet sheared and mixed under specific circulating pressure, and then combined with secondary mixing of the buffer tank, especially by optimizing the related parameters of the jet shearing and mixing, the on-site emulsified acid configuration is realized by fully utilizing the engineering available equipment, the purchase of special emulsified acid equipment or the fixed-point acid liquid preparation in the special acid preparation station is avoided, the problem of inconvenient transportation from the acid liquid station to the construction site during construction is solved, the transportation cost is saved, and the safety and environmental protection risks in the transportation process are reduced.

[0016] Meanwhile, the emulsified acid prepared by the method has high stability, good corrosion inhibition effect and strong deep penetration capacity, and can be applied to oil and gas field exploitation and deep reservoir modification, especially for carbonate and sandstone reservoirs, and has a wide application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a structural schematic view of a device for on-site emulsified acid configuration provided by the application.

[0018] BRIEF DESCRIPTION OF DRAWINGS

[0019] I, pump truck II, jet pump III, buffer tank 1, jet nozzle 2, liquid inlet 3, mixing pipe diameter 4, liquid outlet DETAILED DESCRIPTION

[0020] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and any values should be interpreted as approximately the value so stated. For ranges comprising a single numerical value, that numerical value is equivalent to approximately that value. For numerical values of a range, the endpoints are provided as approximations as the range is understood to include values sufficiently close thereto.

[0021] The first aspect of the application provides a device for on-site emulsified acid configuration, the device comprising: a pump truck, a jet pump and a buffer tank connected in sequence; wherein the pump truck provides a circulating pressure for the jet pump; the jet pump is used for jet shearing and mixing of an acid liquid and an emulsifier under the condition that the circulating pressure is greater than or equal to 0.8 MPa, the mixed liquid obtained is introduced into the buffer tank for secondary mixing, and then is recycled back to the jet pump to repeat the jet shearing and mixing to obtain emulsified acid.

[0022] The number of times of repeating the jet shearing and mixing is greater than or equal to 8.

[0023] The inventor of the present application has found that: using a field pump truck as a power source, a specific circulating pressure is provided for a jet pump, a high-speed water jet formed by the jet pump is used for shear mixing, and a related circulating shear process and parameters are optimized, so that the acid liquid and the emulsifier are mixed on site to form emulsified acid, and the emulsified acid has the characteristics of high stability, good corrosion inhibition effect, and strong deep penetration capacity.

[0024] In some embodiments of the application, a structural diagram of the device for on-site preparation of emulsified acid is shown in Figure 1 As can be seen from Figure 1 , the device comprises: a pump truck I, a jet pump II and a buffer tank III connected in sequence; wherein the pump truck I provides a circulating pressure for the jet pump II; the jet pump II is used for jet shear mixing of the acid liquid and the emulsifier under the condition that the circulating pressure is greater than or equal to 0.8 MPa, and the mixed liquid obtained is subjected to secondary mixing in the buffer tank III, and then is recycled back to the jet pump II for repeated jet shear mixing to obtain emulsified acid; wherein the number of times of repeated jet shear mixing is greater than or equal to 8.

[0025] In the present application, the type of the pump truck has a wide selection range, as long as the pump truck can provide a circulating pressure greater than or equal to 0.8 MPa.

[0026] In some embodiments of the present application, preferably, as shown in Figure 1 , the jet pump II is provided with a jet nozzle 1, a liquid inlet 2, a mixing pipe diameter 3 and a liquid outlet 4. In the present application, the jet nozzle 1 is used to locally contract to form a high-pressure high-speed water jet, and a vacuum negative pressure area is formed around the jet, so that the auxiliary materials are sucked in through the liquid inlet 2, the high-speed water jet and the sucked auxiliary materials are subjected to jet shear mixing in the mixing pipe diameter 3, and the first shear emulsification effect is achieved, and after shear emulsification, the liquid outlet 4 enters the buffer tank, and the buffer tank can be pumped to be pressurized for secondary high-speed shear emulsification.

[0027] In some embodiments of the present application, preferably, as shown in Figure 1 , the pump truck I is connected to the jet nozzle 1, so that the jet pump is under the specific condition that the circulating pressure is greater than or equal to 0.8 MPa.

[0028] In some embodiments of the present application, preferably, as shown in Figure 1 , the liquid outlet 4 is connected to the inlet of the buffer tank III, and the outlet of the buffer tank III is connected to the liquid inlet 2.

[0029] In the present application, under no special circumstances, the buffer tank is used to fully mix the acid liquid and the emulsifier in the mixed liquid to form a uniform solution.

[0030] In some embodiments of the present invention, preferably, the shear rate V of the jet shear mixing satisfies: V = 4Q / (60 × π × D) 2 Where V is the shear velocity (m / s) and Q is the volumetric flow rate (m³ / s). 3 / min; π is pi, 3.14; D is the diameter of the jet nozzle, m.

[0031] In this invention, a rotation speed of 5.7 to 11.4 m / s is used as a preliminary condition for determining the formation of emulsified acid shear in the laboratory, and is used to guide the equipment and process for seeking high-shear mixing conditions in on-site solution preparation.

[0032] In some embodiments of the present invention, preferably, the shear rate V of the jet shear mixing is ≥ 5.7 m / s.

[0033] In some embodiments of the present invention, the circulating pressure is preferably 0.8–1.6 MPa, for example, 0.8 MPa, 0.9 MPa, 1 MPa, 1.2 MPa, 1.4 MPa, and 1.6 MPa, or any value within any range of any two values, preferably 1–1.6 MPa. In this invention, only under sufficient circulating pressure can the jet nozzle velocity meet the shear mixing requirements. The higher the circulating pressure, the higher the jet velocity, and the better the shear mixing and vacuum suction effects. However, considering the impact of operating pressure on on-site safety and economic costs…

[0034] In some embodiments of the present invention, preferably, the jet shear mixing is repeated 8 to 15 times, more preferably 8 to 12 times. In the present invention, the more times the jet shear mixing is repeated, the better the shear mixing effect and the more stable the prepared emulsified acid. However, considering the timeliness and economy of on-site construction, it is not feasible to spend a lot of time on the solution preparation process. Therefore, it is required that the effect of preparing qualified emulsified acid be achieved after 8 to 12 shear cycles.

[0035] A second aspect of the present invention provides a method for on-site preparation of emulsified acids, the method being carried out in the apparatus provided in the first aspect, wherein the method includes:

[0036] (1) Under the condition of circulating pressure ≥0.8MPa, the acid and emulsifier are jet-shear mixed in a jet pump, and the resulting mixture is mixed again in a buffer tank.

[0037] (2) Repeat step (1) above more than 8 times to obtain emulsified acid.

[0038] In some embodiments of the present invention, preferably, in step (1), the mass ratio of the acid to the emulsifier is 100:35 to 90, for example, 100:35, 100:43, 100:50, 100:60, 100:70, 100:80, 100:90, and any value within any range of any two values, preferably 100:43 to 80. In the present invention, using the above mass ratio is beneficial to obtaining the optimal shear mixing rate. If it is not within the above mass ratio range, on the one hand, it is not easy to mix and form a stable emulsified acid, and on the other hand, it also has a significant impact on the acid slowing and dissolving effects; overall, a low emulsifier ratio results in poor corrosion slowing effect, and a low acid ratio results in poor dissolving effect.

[0039] In some embodiments of the present invention, preferably, the acid solution is selected from hydrochloric acid with a concentration of 20 to 50 wt%, including but not limited to industrial hydrochloric acid with a concentration of 35 wt%.

[0040] In this invention, the types of emulsifiers are selected from a wide range. Preferably, the emulsifier is selected from at least one of hexadecyl primary amine acetate, dimethyl dodecyl tertiary amine acetate, dodecyl primary amine acetate, tetradecyl acetate, cocoaamine acetate, hydrogenated tallow amine, methyl dihydrotallow amine, and industrial-grade white oil.

[0041] In some embodiments of the present invention, the circulating pressure is preferably 0.8 to 1.6 MPa, for example, 0.8 MPa, 0.9 MPa, 1 MPa, 1.2 MPa, 1.4 MPa and 1.6 MPa, and any value within the range of any two values, preferably 1 to 1.6 MPa.

[0042] In some embodiments of the present invention, preferably, in step (1), the shear rate V of the jet shear mixing satisfies: V = 4Q / (60×π×D) 2 Where V is the shear velocity (m / s) and Q is the volumetric flow rate (m³ / s). 3 / min; π is pi, 3.14; D is the diameter of the jet nozzle, m.

[0043] In some embodiments of the present invention, preferably, in step (1), the shear rate V of the jet shear mixing is ≥5.7 m / s.

[0044] In some embodiments of the present invention, preferably, in step (1), the conditions for the secondary mixing include: a temperature of 15 to 40°C, preferably 20 to 30°C; and a time of 0.1 to 5 hours, preferably 0.1 to 2 hours.

[0045] In some embodiments of the present invention, preferably, step (1) is repeated 8 to 15 times, more preferably 8 to 12 times. In the present invention, the more times the jet shear mixing is repeated, the better the shear mixing effect and the more stable the prepared emulsified acid. However, considering the timeliness and economy of on-site construction, it is not feasible to spend a lot of time on the solution preparation process. Therefore, it is required that the effect of preparing qualified emulsified acid be achieved after 8 to 12 shear cycles.

[0046] The third aspect of the present invention provides an emulsified acid prepared by the method provided in the second aspect.

[0047] In some embodiments of the present invention, preferably, the emulsified acid has the following properties: (20±5℃) density of 1~1.1g / cm³. 3 (20±5℃) Viscosity ≥30mPa·s; Volume of clear liquid precipitated ≤1mL in 2h; Volume of clear liquid precipitated ≤1.5mL in 4h; Volume of clear liquid precipitated ≤3mL in 8h; Volume of clear liquid precipitated ≤10mL in 24h.

[0048] In this invention, unless otherwise specified, the density parameter is measured using a hydrometer; the viscosity parameter is tested by shaking the emulsified acid and measuring its reading at 100 rpm using a six-speed rotary viscometer, and multiplying the reading by 3 as the viscosity parameter measurement result; the volume parameter of the precipitated clear liquid is tested by shaking the emulsified acid and pouring 100 mL of emulsified acid into a 100 mL stoppered graduated cylinder, allowing it to stand at room temperature for 2 h, 4 h, 8 h, and 24 h, and then reading the volume of the precipitated clear liquid.

[0049] The fourth aspect of this invention provides an application of the emulsified acid provided in the third aspect in oil and gas field development and reservoir slow-reduction deep stimulation, preferably in carbonate and sandstone reservoirs.

[0050] In this invention, acidification is one of the main measures to increase oil and gas production. Acid is a key material in acid production enhancement measures. It is widely used in carbonate and sandstone reservoirs and is also frequently used in other fields. The emulsified acid provided by this invention has broad application prospects due to its safety and environmental protection, good slowing effect, and strong penetration ability.

[0051] According to a particularly preferred embodiment of the present invention, a method for on-site preparation of emulsified acids, wherein the method comprises:

[0052] (1) Under the condition of circulating pressure ≥0.8MPa, the acid and emulsifier are jet-shear mixed in a jet pump, and the resulting mixture is mixed again in a buffer tank.

[0053] (2) Repeat step (1) above more than 8 times with the material obtained by the secondary mixing to obtain emulsified acid;

[0054] The mass ratio of the acid to the emulsifier is 100:35 to 90.

[0055] Wherein, the shear rate V of the jet shear mixing satisfies: V=4Q / (60×π×D) 2 Where V is the shear velocity (m / s) and Q is the volumetric flow rate (m³ / s). 3 / min; π is pi, 3.14; D is the diameter of the jet nozzle, m; the shear rate of the jet shear mixing V≥5.7m / s;

[0056] The emulsified acid satisfies the following condition: (20±5℃) density of 1~1.1g / cm³. 3 (20±5℃) Viscosity ≥30mPa·s; Volume of clear liquid precipitated ≤1mL in 2h; Volume of clear liquid precipitated ≤1.5mL in 4h; Volume of clear liquid precipitated ≤3mL in 8h; Volume of clear liquid precipitated ≤10mL in 24h.

[0057] The present invention will be described in detail below through embodiments.

[0058] The density parameter (at 20±5℃) was measured using a hydrometer.

[0059] (20±5℃) Viscosity parameter test: After shaking the emulsified acid well, use a six-speed rotational viscometer to measure its reading at 100 rpm. The reading × 3 is taken as the result of the viscosity parameter measurement.

[0060] Test of the volume parameters of the precipitated clear liquid: After shaking the emulsified acid well, pour 100 mL of emulsified acid into a 100 mL stoppered graduated cylinder, let it stand at room temperature for 2 h, 4 h, 8 h, and 24 h, and read the volume of the precipitated clear liquid.

[0061] Example 1

[0062] On-site equipment for emulsified acid preparation, such as Figure 1 As shown, by Figure 1 It is known that the device includes: a pump truck I, a jet pump II and a buffer tank III connected in sequence, wherein the jet pump II includes a jet nozzle 1, a liquid inlet 2, a mixing pipe 3 and a liquid outlet 4.

[0063] A method for on-site preparation of emulsified acid, performed in the aforementioned apparatus, comprising:

[0064] (1) Under a circulating pressure of 1 MPa, acid solution (hydrochloric acid solution with a concentration of 35 wt%) and emulsifier (industrial white oil) are jet-shear mixed in a jet pump at a mass ratio of 100:45, and the resulting mixture is then mixed a second time in a buffer tank.

[0065] The shear rate V of the jet shear mixing is 41.5 m / s, the volumetric flow rate Q is 500 L / min, and the nozzle diameter D is 16 mm. Calculation process:

[0066] (2) Repeat step (1) 8 times with the material obtained by the above two mixing to obtain emulsified acid S1; wherein, the physical properties of emulsified acid S1 are listed in Table 1.

[0067] Example 2

[0068] The apparatus according to Example 1;

[0069] The method is the same as in Example 1, except that...

[0070] In step (1), the weight ratio of acid to emulsifier is replaced with 100:30.

[0071] Under the same conditions, emulsified acid S2 was obtained. The measured physical properties of emulsified acid S2 are listed in Table 1.

[0072] Example 3

[0073] The apparatus according to Example 1;

[0074] The method is the same as in Example 1, except that...

[0075] In step (1), the shear rate V of the jet shear mixing is replaced with 5 m / s.

[0076] Under the same conditions, emulsified acid S3 was obtained. The measured physical properties of emulsified acid S3 are listed in Table 1.

[0077] Among them, emulsified acid S3 quickly separates into layers and cannot be measured.

[0078] Example 4

[0079] The apparatus according to Example 1;

[0080] The method is the same as in Example 1, except that...

[0081] In step (2), the material obtained from the above two-stage mixing is repeated 10 times as described in step (1).

[0082] Under the same conditions, emulsified acid S4 was obtained. The measured physical properties of emulsified acid S4 are listed in Table 1.

[0083] Compared to Example 1, Example 4 has an increased number of cycles, resulting in better emulsification. However, the preparation time is increased, with each cycle of 1 ml of mixture taking at least 2 minutes longer, leading to a longer production period and increased costs.

[0084] Comparative Example 1

[0085] The apparatus according to Embodiment 1, except that it does not have buffer tank III;

[0086] The method is the same as in Example 1, except that it is performed in the aforementioned apparatus, i.e.

[0087] (1) Under a circulating pressure of 1 MPa, acid solution (hydrochloric acid solution with a concentration of 35% by weight) and emulsifier (white oil) are jet-shear mixed in a jet pump at a mass ratio of 100:45 to obtain a mixture.

[0088] The shear rate V of the jet shear mixing is 41.46 m / s, the volumetric flow rate Q is 500 L / min, and the pipe diameter D is 16 mm.

[0089] (2) Repeating step (1) above 8 times with the above mixture will not yield emulsified acid DS1; due to the difficulty in fully matching the suction and discharge speeds of the pump, it is easy to cause pump blockage, leakage, and spillage.

[0090] Comparative Example 2

[0091] The apparatus according to Example 1;

[0092] The method is the same as in Example 1, except that...

[0093] In step (1), the circulating pressure is replaced with 0.5 MPa.

[0094] Under the same conditions, emulsified acid DS2 was obtained. The measured physical properties of emulsified acid DS2 are listed in Table 1.

[0095] Comparative Example 3

[0096] The apparatus according to Example 1;

[0097] The method is the same as in Example 1, except that...

[0098] In step (2), the material obtained from the above two-stage mixing is repeated 5 times as described in step (1).

[0099] Under the same conditions, emulsified acid DS3 was obtained. The measured physical properties of emulsified acid DS3 are listed in Table 1.

[0100] Table 1

[0101]

[0102] As can be seen from the results in Table 1, Example 1, which uses the emulsified acid preparation process of the present invention, has significantly better effects in terms of liquid stability, base liquid viscosity, and safe operation feasibility.

[0103] Meanwhile, compared to Examples 2 and 3, the emulsified acid prepared in Example 1 also satisfies the following conditions: (20±5℃) density of 1 to 1.1 g / cm³. 3 (20±5℃) Viscosity ≥30mPa·s; Volume of clear liquid precipitated ≤1mL in 2h; Volume of clear liquid precipitated ≤1.5mL in 4h; Volume of clear liquid precipitated ≤3mL in 8h; Volume of clear liquid precipitated ≤10mL in 24h.

[0104] Test case

[0105] Application of the emulsified acid S1 prepared in Example 1 in carbonate and sandstone reservoirs.

[0106] In the early stages, low displacement (1-2m) was adopted. 3 Inject low-viscosity acid solution ( / min) to remove blockage and increase discharge rate (3-5m³ / min). 3 Inject strong, slow-moving acid solution ( / min) to increase the acid's contact distance and repair flow channels. Construction discharge rate: 5m³ / min. 3 At a flow rate of 1000 m / min, the pump pressure is only 54.2 MPa, and the resistance reduction rate is about 70% compared with clean water.

[0107] After acidification, the pump stop pressure dropped from 18.7 MPa to 14.7 MPa, a significant decrease, indicating the formation of an effective long-distance acidification channel.

[0108] Following acid fracturing, water injection in the well has been consistently smooth, with SHB5-3 currently injecting 16,184 m³ of water. 3 This constitutes a single injection and two extraction process; the increased injection effect is significant, with a cumulative injection of 29,684 m³ to date. 3 , adding 6600.4t of oil.

[0109] 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 on-site preparation of emulsified acid, characterized in that, The method is carried out in an on-site setup for emulsified acid, the setup comprising a pump truck, a jet pump, and a buffer tank connected in sequence; wherein, the pump truck provides circulating pressure to the jet pump; the jet pump is equipped with a jet nozzle, a liquid inlet, a mixing pipe, and a liquid outlet, the diameter of the jet nozzle being 8~32mm, and the pump truck is connected to the jet nozzle, the liquid outlet is connected to the inlet of the buffer tank, and the outlet of the buffer tank is connected to the liquid inlet; The method includes: (1) Under the condition of circulating pressure ≥0.8MPa, the acid and emulsifier are jet-shear mixed in a jet pump, and the resulting mixture is mixed again in a buffer tank; (2) Repeat step (1) above more than 8 times with the material obtained by the secondary mixing to obtain emulsified acid; The mass ratio of the acid to the emulsifier is 100:35~90; the shear rate V of the jet shear mixing satisfies: V=4Q / (60×π×D) 2 Where V is the shear velocity (m / s) and Q is the volumetric flow rate (m³ / s). 3 / min; π is pi, 3.14; D is the diameter of the jet nozzle, m; the shear rate V of the jet shear mixing is ≥5.7m / s.

2. The method according to claim 1, wherein, In step (1), the mass ratio of the acid to the emulsifier is 100:43~80; And / or, the acid solution is selected from hydrochloric acid with a concentration of 20-50 wt%; And / or, the emulsifier is selected from at least one of hexadecyl primary amine acetate, dimethyl dodecyl tertiary amine acetate, dodecyl primary amine acetate, tetradecyl acetate, cocoalkylamine acetate, hydrogenated tallow amine, methyl dihydrotallow amine, and industrial grade white oil.

3. The method according to claim 1, wherein, The shear rate V of the jet shear mixing is 5.7-11.4 m / s.

4. The method according to claim 1, wherein, In step (1), the conditions for the secondary mixing include: a temperature of 15~40℃ and a time of 0.1~5h.

5. The method according to claim 4, wherein, In step (1), the conditions for the secondary mixing include: a temperature of 20~30℃ and a time of 0.1~2h.

6. The method according to claim 1, wherein, In step (1), the pressure of the cycle is 0.8~1.6MPa.

7. The method according to claim 6, wherein, In step (1), the pressure of the cycle is 1~1.6MPa.

8. The method according to claim 1, wherein, In step (2), the material repeats step (1) 8 to 15 times.

9. The method according to claim 8, wherein, In step (2), the material repeats step (1) 8 to 12 times.

10. The method according to any one of claims 1 to 9, wherein, The emulsified acid has the following properties: a density of 1~1.1 g / cm³ at 20±5℃. 3 Viscosity at 20±5℃ ≥30mPa·s; Volume of clear liquid precipitated ≤1mL after 2h; Volume of clear liquid precipitated ≤1.5mL after 4h; Volume of clear liquid precipitated ≤3mL after 8h; Volume of clear liquid precipitated ≤10mL after 24h.

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