High temperature and high salinity resistant micron-sized precipitation profile control agent and methods of making and using same

Abstract

The present application relates to the technical field of low-permeability reservoir development, and discloses a high-temperature and high-salinity resistant micron precipitated glue profile control agent and a preparation and use method thereof. The high-temperature and high-salinity resistant micron precipitated glue profile control agent comprises a main plug, a spacer fluid and an auxiliary plug. The raw materials of the main plug comprise water glass, sodium hydroxide and potassium chloride. The raw materials of the spacer fluid comprise potassium chloride. The raw materials of the auxiliary plug comprise calcium chloride and potassium chloride. During construction, first, twice the volume of the wellbore of clean water is injected into the wellbore, and then multiple portions of the high-temperature and high-salinity resistant micron precipitated glue profile control agent are injected in circulation until the designed construction scale is reached. The high-temperature and high-salinity resistant micron precipitated glue profile control agent of the present application makes the solution micelles reach the nanometer level through concentration control and charge distribution adjustment, and the gel aggregates are generated after the base fluid is injected into the formation, and are retained in the pore throat through bridging and other ways to block the dominant water flow channel, so that the profile control agent can be injected into the low-permeability reservoir and can block the water flow.

Description

Technical Field

[0001] This invention relates to the field of medium- and low-permeability reservoir development technology, and is a high-temperature resistant, high-salinity micron-sized precipitant profile modifier and its preparation and application methods. Background Technology

[0002] In the later stages of development of low-to-medium permeability reservoirs, the water cut is generally at a medium-to-high level (>60%), necessitating chemical profile control techniques to manage water cut. However, low-to-medium permeability reservoirs have low permeability (20mD to 40mD) and small pore throat diameters (1.89μm to 7.93μm), thus requiring high-performance profile control agents. Currently, conventional chemical profile control agents in the Turpan-Hami oilfield's low-to-medium permeability reservoirs suffer from problems such as "injection failure" with high molecular weight polymer gel profile control agents and "injection failure" with low molecular weight polymer gel profile control agents.

[0003] In view of the fact that existing conventional chemical profile control agents are not suitable for the profile control needs of medium and low permeability reservoirs, there is an urgent need to develop a high-temperature resistant and high-salinity profile control agent for medium and low permeability reservoirs. Summary of the Invention

[0004] This invention provides a high-temperature resistant, high-mineralization micron-sized precipitate profile control agent that overcomes the shortcomings of the prior art and can effectively solve the problem that existing profile control agents cannot meet the development needs of medium- and low-permeability reservoirs.

[0005] One of the technical solutions of the present invention is achieved through the following measures: a high-temperature resistant, high-mineralization micron-sized precipitate profile control agent, comprising a main slug, a separating fluid, and an auxiliary slug, wherein the raw materials of the main slug include water glass, sodium hydroxide, and potassium chloride; the raw material of the separating fluid includes potassium chloride; and the raw materials of the auxiliary slug include calcium chloride and potassium chloride.

[0006] The following are further optimizations and / or improvements to the above-mentioned technical solution: The raw materials of the aforementioned main plug are composed of the following by mass percentage: 0.5% to 10% water glass, 0.05% to 0.5% sodium hydroxide, 0.2% to 0.5% potassium chloride, and the remainder is water.

[0007] The raw materials of the above-mentioned isolation fluid are composed of: potassium chloride 0.2% to 0.5% by mass percentage, with the remainder being water.

[0008] The raw materials of the above-mentioned auxiliary slug are composed of the following by mass percentage: calcium chloride 0.1% to 2%, potassium chloride 0.2% to 0.5%, and the remainder is water.

[0009] The volume ratio of the main plug, isolation plug and auxiliary plug is (200 to 300): 50: (200 to 300).

[0010] The above-mentioned high-temperature resistant and high-mineralization micron-sized precipitate profile control agent was prepared according to the following method: The main slug, the isolation fluid, and the auxiliary slug were prepared separately. The preparation steps of the main slug plug include: Add the required amount of water to the mixing container; under normal temperature and stirring conditions, add the required amount of water glass and potassium chloride to the mixing container, stir for 15 to 25 minutes, then add sodium hydroxide; after mixing evenly, the main plug is obtained. The preparation steps of the isolation fluid include: Under normal temperature and stirring conditions, the required amount of potassium chloride is added to water and mixed evenly to obtain the isolation solution; The preparation steps of the auxiliary slug include: Under normal temperature and stirring conditions, the required amounts of potassium chloride and calcium chloride are added to water and mixed evenly to obtain the auxiliary slug.

[0011] The second technical solution of the present invention is achieved through the following measures: a method for preparing a high-temperature resistant, high-mineralization micron-sized precipitate profile modifier, comprising the following steps: The main slug, the isolation fluid, and the auxiliary slug were prepared separately. The preparation steps of the main slug plug include: Add the required amount of water to the mixing container; under normal temperature and stirring conditions, add the required amount of water glass and potassium chloride to the mixing container, stir for 15 to 25 minutes, then add sodium hydroxide; after mixing evenly, the main plug is obtained. The preparation steps of the isolation fluid include: Under normal temperature and stirring conditions, the required amount of potassium chloride is added to water and mixed evenly to obtain the isolation solution; The preparation steps of the auxiliary slug include: Under normal temperature and stirring conditions, the required amounts of potassium chloride and calcium chloride are added to water and mixed evenly to obtain the auxiliary slug.

[0012] The third technical solution of the present invention is achieved through the following measures: a method for using a high-temperature resistant, high-mineralization micron-sized precipitant profile modifier, comprising the following steps: During on-site construction, firstly, twice the volume of clean water is injected into the wellbore, and then multiple portions of high-temperature resistant, high-mineralization micron-sized precipitant profile control agent are circulated and injected until the designed construction scale is reached; each portion of high-temperature resistant, high-mineralization micron-sized precipitant profile control agent is injected in sequence according to the order of main plug, isolation plug, and auxiliary plug.

[0013] The total amount of each of the above-mentioned high-temperature resistant, high-mineralization micron-sized precipitate profile modifiers is 400 to 650 cubic meters.

[0014] The high-temperature and high-mineralization micron-sized precipitated profile control agent of the present invention, through concentration control and charge distribution adjustment, enables the solution molecular micelles to reach the nanoscale. After the base fluid is injected into the formation, it generates gel aggregates, which are retained in the pore throat by bridging and other methods, blocking the dominant water flow channels, thus realizing that the profile control agent can be injected into and blocked in medium and low permeability reservoirs. Attached Figure Description

[0015] Appendix Figure 1 This is a particle size distribution diagram of the main block, isolation block, and auxiliary block of the high-temperature resistant, high-mineralization micron-sized precipitated profile modifier of the present invention at the initial reaction stage. Detailed Implementation

[0016] This invention is not limited to the following embodiments, and specific implementation methods can be determined according to the technical solutions and actual conditions of this invention. Unless otherwise specified, all chemical reagents and chemicals mentioned in this invention are well-known and commonly used chemical reagents and chemicals in the prior art; unless otherwise specified, all percentages in this invention are mass percentages; unless otherwise specified, all solutions in this invention are aqueous solutions with water as the solvent, for example, hydrochloric acid solution is an aqueous solution of hydrochloric acid; room temperature in this invention generally refers to a temperature between 15°C and 25°C, generally defined as 25°C.

[0017] The present invention will be further described below with reference to embodiments: Example 1: The high-temperature resistant, high-mineralization micron-sized precipitate profile control agent includes a main slug, a separator, and an auxiliary slug. The main slug is made from water glass, sodium hydroxide, and potassium chloride; the separator is made from potassium chloride; and the auxiliary slug is made from calcium chloride and potassium chloride.

[0018] Example 2: As an optimization of the above example, the raw materials of the main plug are composed of the following by mass percentage: water glass 0.5% to 10%, sodium hydroxide 0.05% to 0.5%, potassium chloride 0.2% to 0.5%, and the remainder is water.

[0019] Example 3: As an optimization of the above example, the raw materials of the isolation liquid are composed of: potassium chloride 0.2% to 0.5% by mass percentage, with the remainder being water.

[0020] Example 4: As an optimization of the above example, the raw materials of the auxiliary slug are composed of: calcium chloride 0.1% to 2%, potassium chloride 0.2% to 0.5%, and the remainder is water by mass percentage.

[0021] Example 5: As an optimization of the above example, the volume ratio of the main slug, the isolation slug, and the auxiliary slug is (200 to 300): 50: (200 to 300).

[0022] Example 6: As an optimization of the above examples, a high-temperature resistant, high-mineralization micron-sized precipitate profile modifier was prepared according to the following method: The main slug, the isolation fluid, and the auxiliary slug were prepared separately. The preparation steps of the main slug plug include: Add the required amount of water to the mixing container; under normal temperature and stirring conditions, add the required amount of water glass and potassium chloride to the mixing container, stir for 15 to 25 minutes, then add sodium hydroxide; after mixing evenly, the main plug is obtained. The preparation steps of the isolation fluid include: Under normal temperature and stirring conditions, the required amount of potassium chloride is added to water and mixed evenly to obtain the isolation solution; The preparation steps of the auxiliary slug include: Under normal temperature and stirring conditions, the required amounts of potassium chloride and calcium chloride are added to water and mixed evenly to obtain the auxiliary slug.

[0023] Example 7: The method of using this high-temperature resistant, high-mineralization micron-sized precipitant profile control agent includes the following steps: During on-site construction, firstly, twice the volume of clean water is injected into the wellbore, and then multiple portions of high-temperature resistant, high-mineralization micron-sized precipitant profile control agent are circulated and injected until the designed construction scale is reached; each portion of high-temperature resistant, high-mineralization micron-sized precipitant profile control agent is injected in sequence according to the order of main plug, isolation plug, and auxiliary plug.

[0024] Example 8: As an optimization of the above examples, the total amount of each part of the high-temperature resistant and high-mineralization micron-sized precipitated gel profile modifier is 400 to 650 cubic meters.

[0025] This invention provides a high-temperature resistant, high-mineralization micron-sized precipitated profile control agent, along with its preparation and application methods. This high-temperature resistant, high-mineralization micron-sized precipitated profile control agent, through concentration control and charge distribution adjustment, achieves nanoscale (30nm to 50nm) molecular micelles in the solution, representing only 10% of the molecular size of conventional profile control agents such as HPAM (hydrolyzed polyacrylamide) and 5% of that of conventional inorganic silicon materials. Based on the "bridging theory," the inorganic silicon particles in the micron-sized precipitated profile control agent base solution reach nanoscale radii, making it easier to inject into low-permeability reservoir pore throats with radii of 0.9μm to 3.9μm, thus achieving injection success. During the deep formation migration process, the nano-micelles in the base solution interact with formation water (Ca)... 2+ Mg 2+ The reaction produces gel aggregates with radii ranging from 1 μm to 93 μm, which are retained in the pore throat through bridging and other mechanisms, blocking the dominant water flow channels and achieving salt tolerance and effective plugging. This high-temperature and high-mineralization resistant micron-sized precipitate is easy to inject into low-to-medium permeability reservoirs, has good deep plugging performance, and is resistant to high temperatures and high mineralization.

[0026] Example 9: This high-temperature resistant, high-mineralization micron-sized precipitate profile control agent includes a main plug, a separator fluid, and an auxiliary plug.

[0027] The main plug's raw materials, by mass percentage, consist of: water glass: 5%, sodium hydroxide: 0.2%, potassium chloride: 0.5%, with the remainder being water. The required amount of water is added to a mixing container; under room temperature and stirring conditions, water glass and potassium chloride are added to the mixing container, and after stirring for 15 to 25 minutes, sodium hydroxide is added; the mixture is stirred until homogeneous to obtain the main plug. The raw materials of the isolation solution are composed of: potassium chloride 0.5% by mass percentage, with the remainder being water. Under normal temperature and stirring conditions, potassium chloride is added to water and stirred for 20 minutes to obtain the isolation solution.

[0028] The auxiliary slug is composed of the following raw materials by mass percentage: calcium chloride: 2%; potassium chloride: 0.2%; the remainder is water. Under ambient temperature and stirring conditions, potassium chloride and calcium chloride are added to water, and then stirred for 20 minutes to obtain the auxiliary slug.

[0029] Construction process and results: The profile control agent was applied in batches of 400 to 500 cubic meters. The volume ratio of the main slug, the separator fluid, and the auxiliary slug was 200:50:200. The main slug, the separator fluid, and the auxiliary slug were injected into the wellbore in batches, with a total injection volume of 2500 cubic meters. During the application process, the pressure inside the wellbore was gradually increased from 15 MPa to 22.3 MPa.

[0030] The reservoir temperature in this well is 50℃, and the formation water salinity is 16×10⁻⁶. 4 mg / L, the water control and oil increase effect was observed during the profile adjustment construction, and the corresponding three oil wells increased oil production by a total of 2,600 tons after construction.

[0031] Example 10: High-temperature and high-mineralization micron-sized precipitate profile control agent, including main plug, isolation fluid and auxiliary plug.

[0032] The main plug's raw materials, by mass percentage, consist of: water glass: 3%, sodium hydroxide: 0.3%, potassium chloride: 0.2%, and the remainder being water. The required amount of water is added to a mixing container; under room temperature and stirring conditions, water glass and potassium chloride are added to the mixing container, and after stirring for 15 to 25 minutes, sodium hydroxide is added; the mixture is stirred until homogeneous to obtain the main plug. The raw materials of the isolation solution are composed of: potassium chloride 0.2% by mass percentage, with the remainder being water. Under normal temperature and stirring conditions, potassium chloride is added to water and stirred for 20 minutes to obtain the isolation solution.

[0033] The auxiliary slug was composed of the following raw materials by mass percentage: calcium chloride: 1.0%; potassium chloride: 0.2%; the remainder being water. Under ambient temperature and stirring conditions, potassium chloride and calcium chloride were added to water and stirred for 20 minutes to obtain the auxiliary slug.

[0034] Construction process and results: The profile control agent was applied in batches of 500 to 650 cubic meters. The volume ratio of the main slug, separator fluid, and auxiliary slug was 300:50:300. The agent was injected into the wellbore in batches, with a total injection volume of 2500 cubic meters. During the application, the wellbore pressure was gradually increased from 9.2 MPa to 22.4 MPa.

[0035] The reservoir temperature in this well is 85℃, and the formation water salinity is 4.5×10⁻⁶. 4 mg / L, after profile control, the corresponding oil wells saw a cumulative increase of 2,919 tons of oil production and a 10% decrease in water cut.

[0036] Example 11: This high-temperature resistant, high-mineralization micron-sized precipitate profile control agent includes a main plug, a separator fluid, and an auxiliary plug.

[0037] The raw materials for the main plug are composed of the following by mass percentage: water glass: 1.5%, sodium hydroxide: 0.1%, potassium chloride: 0.4%, and the remainder is water. The required amount of water is added to a mixing container; under normal temperature and stirring conditions, water glass and potassium chloride are added to the mixing container, and after stirring for 15 to 25 minutes, sodium hydroxide is added; the mixture is stirred until homogeneous to obtain the main plug. The raw materials of the isolation fluid, by mass percentage, are: potassium chloride: 0.4%, with the remainder being water. Under room temperature and stirring conditions, potassium chloride is added to water and stirred for 20 minutes to obtain the isolation fluid.

[0038] The auxiliary slug was composed of the following raw materials by mass percentage: calcium chloride: 0.25%; potassium chloride: 0.4%; the remainder being water. Under ambient temperature and stirring conditions, potassium chloride and calcium chloride were added to water and stirred for 20 minutes to obtain the auxiliary slug.

[0039] Prepare the main plug, isolation fluid, and auxiliary plug separately, and inject them on site at a volume ratio of 250:50:200.

[0040] Construction process and results: The profile control agent was applied in batches of 400 to 550 cubic meters. The volume ratio of the main slug, separator fluid, and auxiliary slug was 250:50:200. The agent was injected into the wellbore in batches, with a total injection volume of 2100 cubic meters. During the application, the wellbore pressure was gradually increased from 7.8 MPa to 24.2 MPa.

[0041] The reservoir temperature in this well is 95℃, and the formation water salinity is 5.5×10⁻⁶. 4 Following the mg / L profile control operation, the corresponding oil wells saw a cumulative increase in oil production of 186 tons and a decrease in water cut of 12%.

[0042] Comparative Example 1: The difference from Example 9 is that polyacrylamide is used instead of water glass in the formulation to prepare the main plug. The amount of polyacrylamide added in the main plug of this comparative example is 0.2%.

[0043] Results: After injecting only 50 cubic meters of the main plug prepared with polyacrylamide, the construction pressure rose from 15 MPa to 29.8 MPa, reaching the construction pressure limit, and construction could not continue.

[0044] Comparative Example 2: The difference from Example 9 is that calcium chloride is not added to the auxiliary slug reagent.

[0045] Comparative Example 3: The difference from Example 9 is that 2.5% calcium chloride was added to the auxiliary slug reagent.

[0046] Comparative results of Examples 2 and 3: Without calcium chloride in the auxiliary slug, the total injection volume of the three types of slugs reached 1500 cubic meters, and the construction pressure remained stable at 15 MPa, indicating that no sealing effect was achieved. With 2.5% calcium chloride in the auxiliary slug, after a total injection volume of 1000 cubic meters of the three types of slugs, the construction pressure did not increase significantly compared to that with 2% calcium chloride. The initial construction pressure was around 15 MPa, gradually increasing to 22.5 MPa after construction, which was the same as the effect in Example 1.

[0047] Comparative Example 4: The difference from Example 9 is that no isolation fluid is added; during construction, only the main plug and the auxiliary plug are injected.

[0048] Comparative Example 5: The difference from Example 9 is that the amount of isolation liquid added is 35 cubic meters.

[0049] Comparative results of Examples 4 and 5: The main and auxiliary slugs directly combined in the wellbore, forming micron-sized precipitate aggregates, making injection impossible. This indicates that the amount of separator fluid must be sufficient; otherwise, the main and auxiliary slugs can easily accumulate in the wellbore, affecting the construction results.

[0050] The high-temperature, high-mineralization micron-sized precipitated profile control agent of this invention is easy to prepare, has excellent performance, and is suitable for temperatures ranging from 20°C to 100°C. Under temperature conditions from 20°C to 100°C, the solution micelles maintain a stable suspension state, exhibiting good injection performance and easy deep migration. The main slug of this high-temperature, high-mineralization micron-sized precipitated profile control agent has a low viscosity, only 7.5 mPa·s at a water glass concentration of 1.2%, and a particle size of 30 nm to 50 nm. The median particle size of the main slug, isolation slug, and auxiliary slug at the initial reaction reaches 23.4 μm (see...). Figure 1As three or more particles bridge each other (particles bond together end-to-end), they eventually form gel aggregates with a maximum particle size of 187.5 μm, effectively blocking dominant water flow channels. At a water glass concentration of 1.2%, this high-temperature resistant, high-mineralization micron-sized precipitant profile control agent achieves the same sealing effect at different depths in core samples, with a sealing rate >85%, reaching a maximum of 93.6%, meeting the requirements for deep profile control operations in low-to-medium permeability reservoirs.

[0051] In summary, the high-temperature resistant, high-mineralization micron-sized precipitated profile control agent of this invention, through concentration control and charge distribution adjustment, enables the solution molecular micelles to reach the nanoscale, and the inorganic silicon particles in the precipitated base liquid to reach the nanoscale radius, making it easier to inject into the pore throats of low-permeability reservoirs. During the deep migration of the nano micelles in the base liquid, they react with formation water to form gel aggregates, which are retained in the pore throats through bridging and other methods, blocking the dominant water flow channels, thus achieving both successful injection and effective blocking of profile control agents in medium- and low-permeability reservoirs.

[0052] The above technical features constitute various embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A high-temperature resistant, high-mineralization micron-sized precipitate profile modifier, characterized in that... It includes a main slug, a separator fluid, and an auxiliary slug. The main slug is made from water glass, sodium hydroxide, and potassium chloride; the separator fluid is made from potassium chloride; and the auxiliary slug is made from calcium chloride and potassium chloride.

2. The high-temperature resistant, high-mineralization micron-sized precipitate profile modifier according to claim 1, characterized in that... The raw materials of the main plug are composed of the following by mass percentage: 0.5% to 10% water glass, 0.05% to 0.5% sodium hydroxide, 0.2% to 0.5% potassium chloride, and the remainder is water.

3. The high-temperature resistant, high-mineralization micron-sized precipitant profile modifier according to claim 1 or 2, characterized in that... The raw materials of the isolation fluid are composed of: 0.2% to 0.5% potassium chloride, with the remainder being water, by mass percentage.

4. The high-temperature resistant, high-mineralization micron-sized precipitant profile modifier according to any one of claims 1 to 3, characterized in that... The auxiliary slug is composed of the following raw materials by mass percentage: calcium chloride 0.1% to 2%, potassium chloride 0.2% to 0.5%, and the remainder is water.

5. The high-temperature resistant, high-mineralization micron-sized precipitant profile modifier according to any one of claims 1 to 4, characterized in that... The volume ratio of the main slug, the isolation slug, and the auxiliary slug is 200 to 300: 50: 200 to 300.

6. The high-temperature resistant, high-mineralization micron-sized precipitant profile modifier according to any one of claims 1 to 5, characterized in that... It is prepared by the following method: The main slug, the isolation fluid, and the auxiliary slug were prepared separately. The preparation steps of the main slug plug include: Add the required amount of water to the mixing container; under normal temperature and stirring conditions, add the required amount of water glass and potassium chloride to the mixing container, stir for 15 to 25 minutes, then add sodium hydroxide; after mixing evenly, the main plug is obtained. The preparation steps of the isolation fluid include: Under normal temperature and stirring conditions, the required amount of potassium chloride is added to water and mixed evenly to obtain the isolation solution; The preparation steps of the auxiliary slug include: Under normal temperature and stirring conditions, the required amounts of potassium chloride and calcium chloride are added to water and mixed evenly to obtain the auxiliary slug.

7. A method for preparing a high-temperature resistant, high-mineralization micron-sized precipitate profile modifier according to any one of claims 1 to 5, characterized in that... Includes the following steps: The main slug, the isolation fluid, and the auxiliary slug were prepared separately. The preparation steps of the main slug plug include: Add the required amount of water to the mixing container; under normal temperature and stirring conditions, add the required amount of water glass and potassium chloride to the mixing container, stir for 15 to 25 minutes, then add sodium hydroxide; after mixing evenly, the main plug is obtained. The preparation steps of the isolation fluid include: Under normal temperature and stirring conditions, the required amount of potassium chloride is added to water and mixed evenly to obtain the isolation solution; The preparation steps of the auxiliary slug include: Under normal temperature and stirring conditions, the required amounts of potassium chloride and calcium chloride are added to water and mixed evenly to obtain the auxiliary slug.

8. A method of using a high-temperature resistant, high-mineralization micron-sized precipitant profile modifier according to claims 1 to 6, characterized in that... Includes the following steps: During on-site construction, firstly, twice the volume of clean water is injected into the wellbore, and then multiple portions of high-temperature resistant, high-mineralization micron-sized precipitant profile control agent are circulated and injected until the designed construction scale is reached; each portion of high-temperature resistant, high-mineralization micron-sized precipitant profile control agent is injected in sequence according to the order of main plug, isolation plug, and auxiliary plug.

9. The method of using the high-temperature resistant, high-mineralization micron-sized precipitant profile control agent according to claim 8, characterized in that... Each portion of the high-temperature resistant, high-mineralization micron-sized precipitate profile modifier contains 400 to 650 cubic meters.

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