Cob granule powder profile control water plugging agent and its preparation and application

Abstract

The present application relates to a kind of corncob granular powder profile control water plugging agent preparation and its application.The main components of the profile control water plugging agent include corncob granular powder, liquid water glass and surfactant.Under stirring conditions, corncob granular powder is uniformly dispersed in water glass solution containing surfactant, and during stirring and dispersion, the micropores in corncob granules and their surfaces are fully wetted by water glass solution under the action of surfactant, the specific gravity of the granules is changed, and a kind of corncob granular powder profile control water plugging agent can be obtained, which is stably suspended in the solution.The profile control water plugging agent can be prepared by using injection water with appropriate concentration, and combined with different activation processes, to achieve profile control and water plugging in water drive reservoirs and gas channeling control in carbon dioxide drive reservoirs.

Description

Technical Field

[0001] This invention belongs to the field of oil production, specifically relating to a profile control, water shut-off, and channeling agent, its preparation, and its application. Background Technology

[0002] Due to the heterogeneity of the formation, water-injected oil reservoirs contain high-permeability layers. Injected water surges along these layers, causing uneven water absorption profiles. Simultaneously, edge and bottom water intrusion around the well significantly reduces the effectiveness of water injection, increasing the water cut in the well's production fluid and decreasing crude oil production. Chemical profile control and water shut-off operations can seal high-permeability layers, adjust the water injection and production profiles, and improve the swept volume and utilization rate of the injected water, thereby increasing oil recovery. Commonly used profile control and water shut-off agents include: inorganic or organic polymer particles, inorganic salt precipitates, water-soluble polymer gels, organic or inorganic gels, and resins. As can be seen from the article "A Review of Research on the Application of Chemical Water Shutoff and Profile Control Agents in Oilfields" (Shandong Chemical Industry, 2022, 51(03):56-57+60), various profile control and water shutoff agents have their own advantages and disadvantages. Water glass is usually used as an inorganic salt precipitant for profile control and water shutoff. In use, one chemical agent is first injected into the formation, then separated by other agents, and then another chemical agent is injected to react with the former. This method has the problem of sufficient contact in the formation and low utilization rate. For example, the article "A New Technology for Water Shutoff and Profile Control Combining Single-Liquid Method and Two-Liquid Method" (Oilfield Chemistry, 2002(01):33-35) proposes that the core test of the two-liquid method of water glass and calcium chloride only achieves a shutoff rate of about 90% because only a portion of the two liquids react. The article “Research on Gel Cement for Water Blocking and Leakage Plugging” (Drilling and Production Technology, 2018, 41(02):105-107+121) points out that ultrafine cement has technical difficulties in water blocking due to its small affected volume and poor construction safety, and it cannot effectively remain in the sealing layer.

[0003] Carbon dioxide flooding is an effective technology for enhancing oil recovery in low-permeability reservoirs and has been widely used both domestically and internationally. However, due to the complex geological conditions of reservoirs, significant differences in permeability, and the high mobility of carbon dioxide gas, gas channeling is prone to occur. Gas channeling severely impacts the effectiveness of gas injection development. Currently, to effectively block gas channeling pathways, many chemical blocking agents have been developed both domestically and internationally, effectively improving gas intake and production profiles, and increasing the swept volume and oil displacement efficiency of gas injection development. Commonly used blocking agents include foam blocking agents, reactive gel blocking agents, and gel blocking agents. However, foam blocking agents suffer from weak blocking strength and short effective period; gel and gel blocking agents are easily broken down and lose their effectiveness under the impact of subsequent high-pressure gas.

[0004] Therefore, it is necessary to further develop sealing agents that are strong in sealing power and inexpensive. Summary of the Invention

[0005] The purpose of this invention is to provide a low-cost, high-sealing-force corn cob granule powder profile control, water blocking, and channel sealing agent.

[0006] The present invention also provides a method for preparing the above-mentioned corn cob granule powder profile-adjusting, water-blocking and channeling agent.

[0007] The present invention also provides a method for applying the above-mentioned corn cob granule powder profile control, water-blocking and channeling agent.

[0008] In a first aspect, the present invention provides a corn cob granule powder profile control and water-blocking agent, comprising corn cob granule powder, liquid water glass, and a cationic surfactant, wherein the amount of corn cob granule powder is X%, the amount of liquid water glass is Y%, and the amount of surfactant is Z%, and X, Y, and Z conform to the following relationship:

[0009] (1) The specific gravity of corn cob powder × X% + the specific gravity of water glass × Y% + the specific gravity of surfactant × Z% = the specific gravity of water to be added;

[0010] (2) X% + Y% + Z% = 100%, and the value of Z is in the range of 0.1-5%, preferably 0.5-2%. The values ​​of X and Y are calculated based on the relationship.

[0011] The corn cob granules are produced by crushing corn cobs and then screening them to obtain powders of different mesh sizes. Commercially available corn cob granules have a specific gravity of 0.3-0.35 g / mL and a specific surface area greater than 6000 cm². 2 Based on its mesh count, it can be divided into 60 mesh, 80 mesh, 100 mesh, 120 mesh, 140 mesh, and 160 mesh, with corresponding specific gravities of 0.3 g / mL, 0.31 g / mL, 0.32 g / mL, 0.33 g / mL, 0.34 g / mL, and 0.35 g / mL, respectively.

[0012] The liquid water glass is a soluble silicate produced by melting a mixture of quartz sand and alkali in a certain proportion at high temperature. Its molecular formula is Na₂O·nSiO₂. The molar ratio of quartz sand to alkali in the water glass, i.e., the molar ratio of SiO₂ to Na₂O, determines the modulus n of the water glass. The modulus reflects both the composition of the water glass and affects the physical and chemical properties of sodium silicate. Therefore, sodium silicate with different moduli has different uses. According to the national standard for liquid water glass (GB / T4209-2008), the specific gravity of liquid water glass produced is divided into 1.336-1.362 g / mL, 1.368-1.394 g / mL, 1.436-1.465 g / mL, and 1.526-1.559 g / mL, with corresponding moduli of 3.41-3.60, 3.10-3.40, 2.60-2.90, and 2.20-2.50, respectively. The preferred water glass modulus of this invention is 3.10-3.40, corresponding to a specific gravity of 1.368-1.394 g / mL.

[0013] The cationic surfactant is selected from quaternary ammonium salt type and imidazoline type cationic surfactants. Quaternary ammonium salt type cationic surfactants are preferred, and dodecyltrimethylammonium chloride (1231), hexadecyltrimethylammonium chloride (1631), and octadecyltrimethylammonium chloride (1831) are more preferred.

[0014] In this invention, the corn cob granules have a microporous structure, with most micropores around 1 nm in size. Furthermore, the organic corn cob granules are somewhat hydrophobic, making it difficult for a denser liquid water glass solution to penetrate the micropores and adhere to their surface. Therefore, to ensure that water glass fully fills the microporous structure of the corn cob granules and adheres to their surface, thereby improving the particle density, a surfactant is needed to wet and disperse the corn cob. Cationic surfactants can be adsorbed into the micropores or onto the particle surface through Coulomb forces. Corn cob particles wetted with cationic surfactants exhibit a significantly increased ion exchange capacity, thereby enhancing their adsorption capacity for liquid water glass.

[0015] Secondly, the present invention provides a method for preparing the aforementioned corn cob granule powder profile-modifying, water-blocking, and channeling agent. The method includes: dissolving a cationic surfactant in liquid water glass, stirring and mixing until homogeneous, then adding corn cob granule powder to the mixed solution and mixing until homogeneous;

[0016] Where the amount of corn cob powder is X%, the amount of liquid water glass is Y%, and the amount of surfactant is Z%, then X, Y, and Z satisfy the following relationship:

[0017] (1) The specific gravity of corn cob powder × X% + the specific gravity of water glass × Y% + the specific gravity of cationic surfactant × Z% = the specific gravity of the water to be added;

[0018] (2) X% + Y% + Z% = 100%, and the value of Z is in the range of 0.1-5%, preferably 0.5-2%. The values ​​of X and Y are calculated according to the formula.

[0019] In order to ensure that the corn cob granule powder profile control and water-blocking agent can be evenly mixed with the injected water, the principle followed in preparing the corn cob granule powder profile control and water-blocking agent is that the specific gravity of the prepared corn cob granule powder profile control and water-blocking agent is equal to the specific gravity of the injected water, so that a stable suspension can be formed after preparation.

[0020] Specifically, the preparation steps are as follows:

[0021] First, calculate the dosage of each component based on its composition and the specific gravity of the water to be added. Then, dissolve the surfactant in liquid water glass, stir and mix thoroughly, add the corn cob granules to the mixed solution, and stir and disperse for 4-8 hours to ensure that the corn cob granules are evenly dispersed in the water glass solution. This ensures that the micropores in the corn cob granules are fully wetted by the water glass solution, changing the specific gravity of the granules. Under the action of the surfactant, the granules can be stably dispersed in the solution, resulting in a paste-like corn cob granule powder profile control, water blocking, and channel sealing agent.

[0022] Thirdly, the present invention provides a method for applying the aforementioned corn cob granular powder profile control, water shut-off, and channeling agent, including: it can be applied to profile control and water shut-off operations in water-drive reservoirs, and can also be used for the treatment of gas channeling in carbon dioxide flooding.

[0023] The specific application methods are as follows:

[0024] (1) Used for profile control and water shut-off in water-drive reservoirs

[0025] A two-liquid method is used, in which the prepared corn cob granular powder profile control, water plugging, and channeling agent is mixed with injection water in a certain proportion to form an injection system. Depending on the designed dosage and activation system, the system is alternately injected into the formation through segmented plugs from the injection well, followed by the injection of a certain amount of displacement fluid. The activation system includes, but is not limited to, acidic gases, acidic liquids, calcium chloride solutions, etc., which are used to activate the gel by acidity.

[0026] Using a single-liquid method, the prepared corn cob granule powder profile control, water plugging, and channeling agent is mixed with injection water and potential acid (an activator that can release acidic substances under certain temperature conditions) or slow-release acid (an activator that can slowly release acidic substances) in a certain proportion to form an injection system. According to the designed dosage, it is directly injected into the formation from the water injection well or oil well. Then, a certain amount of displacement fluid is injected to allow it to enter the target formation. The slow release of potential acid and slow-release acid accumulates acidic gel.

[0027] (2) Used for preventing carbon dioxide gas channeling

[0028] The prepared corn cob granular powder profile control, water plugging, and channeling agent was mixed with injection water in a certain proportion to form an injection system. Based on the designed dosage, it was directly injected into the formation from the gas injection well. Then, a certain amount of displacement fluid was injected to allow it to enter the target formation. Subsequently, carbon dioxide gas was injected to activate the gelation process using the acidity of carbon dioxide.

[0029] my country is a major corn producer. Burning tens of millions of tons of corn cobs annually is both a waste of resources and environmental pollution. The corn cob granule powder of this invention is produced by crushing and processing corn cobs, followed by screening to create powders of different mesh sizes. The raw materials are widely available and inexpensive. This powder is rich in cellulose, hemicellulose, lignin, etc. Commercially available corn cob granule powder has a large specific surface area and strong adsorption capacity, making it suitable as an adsorption carrier for reactants. It also features uniform structure, suitable hardness, good toughness, and strong water absorption. This invention uses inexpensive corn cob powder and water glass as the main components. On the one hand, this provides high sealing strength as a granular plugging agent; on the other hand, the combination of particles and gel greatly enhances the gel's breaking strength. In addition to leveraging the advantages of both materials, this method also reduces construction costs, increases the amount of profile control, water plugging, and channeling agent used, expands the swept volume, and avoids fluid bypass during subsequent water-driven or gas-driven processes. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the core flow test process.

[0031] 1, 2, 3—Intermediate container; 4, 5—Three-way valve; 6—Constant speed pump; 7—Beaker or burette; 8—Balance; 9—Back pressure valve; 10, 11—Digital pressure gauge; 12—Confining pressure gauge; 13—Core holder; 14—Confining pressure pump; 15—Constant temperature chamber. Detailed Implementation

[0032] Methods for evaluating plugging performance:

[0033] The plugging rate and recovery rate of profile control agents were evaluated according to the core flow test in the industry standard SY / T 5590-2004, "Evaluation Method for Performance of Profile Control Agents". First, the core was vacuum-saturated with formation water, such as... Figure 1 As shown, insert the core holder. Use a rubber bulb to drain any water that might affect metering from the pipeline and holder plug. Connect the flow path and maintain a constant temperature for 20 minutes at the simulated formation temperature. Then, use simulated oil at a flow rate below 1 cm. 3 The core sample is displaced at a flow rate of [flow rate in min], and the discharged fluid is collected. The saturated oil volume is calculated based on the total volume of discharged fluid and the core porosity. Water is injected at a simulated flow rate to displace 10 times the pore volume. The water injection efficiency and residual oil volume are calculated based on the total discharged oil volume and the total oil volume. A profile control and water shut-off system is injected, and the profile control and water shut-off operation is completed according to the process parameters. The permeability change before and after the profile control and water shut-off operation is measured, and the shut-off rate is calculated. Subsequently, water is injected again to drive 10 times the pore volume. The profile control and water shut-off oil displacement efficiency, i.e., improved oil recovery, is calculated based on the residual oil volume after water drive and the total discharged oil volume after profile control and water shut-off.

[0034] In the embodiments, the specifications and specific gravity of corn cob powder are shown in Table 1, and the specifications and specific gravity of liquid water glass are shown in Table 2.

[0035] Table 1: Specifications and Specific Gravity of Corn Cob Powder

[0036]

[0037] Table 2: Specifications and Specific Gravity of Liquid Water Glass

[0038]

[0039] Example 1

[0040] Preparation of profile control, water sealing and channeling agent:

[0041] When the specific gravity of the injected water is 1 g / mL, calculate the dosage of each component. Dissolve surfactant 1231 (0.5% of the total mass fraction) in liquid water glass (66.4% of the total mass fraction, modulus 3.41-3.60, specific gravity 1.336-1.362) at room temperature with stirring. Then, add corn cob granules (33.1% of the total mass fraction, 60 mesh, specific gravity 0.3) in batches to the mixed solution while stirring. After stirring and dispersing for 8 hours, the corn cob granule profile-adjusting, water-blocking, and channel-sealing agent can be obtained.

[0042] Application method:

[0043] For preventing gas channeling in carbon dioxide gas drive, the prepared corn cob granular powder profile control and water blocking agent was mixed with injected water in a 1:1 ratio to form an injection system. 1 PV (PV refers to the core pore volume) of this system was injected into the core. Subsequent injection of carbon dioxide gas was used to evaluate its blocking rate at 95%, which increased the recovery rate by 8% compared to water drive. Specific data are shown in Table 3.

[0044] Example 2

[0045] Preparation of profile control, water sealing and channeling agent:

[0046] When the specific gravity of the injected water is 1 g / mL, calculate the dosage of each component. Dissolve surfactant 1631 (0.5% of the total mass fraction) in liquid water glass (64.4% of the total mass fraction, modulus 3.10-3.40, specific gravity 1.368-1.394) at room temperature with stirring. Then, add corn cob granules (35.1% of the total mass fraction, 60 mesh, specific gravity 0.3) in batches to the mixed solution while stirring. After stirring and dispersing for 6 hours, the corn cob granule profile control, water blocking and channel sealing agent can be obtained.

[0047] Application method:

[0048] The two-liquid method was used for profile control and water shut-off in water-drive reservoirs. The prepared corn cob granular powder profile control, water shut-off, and channeling agent was mixed with injection water at a 1:1 ratio to form an injection system, with a dosage of 0.5 PV. A 5% calcium chloride solution was also used, with 0.5 PV of each agent injected alternately into the core in two slugs. The shut-off rate was evaluated at 92%, increasing the oil recovery rate by 6% compared to water drive. Specific data are shown in Table 3.

[0049] Example 3

[0050] Preparation of profile control, water sealing and channeling agent:

[0051] When the specific gravity of the injected water is 1 g / mL, calculate the dosage of each component. Dissolve surfactant 1231 (0.5% of the total mass fraction) in liquid water glass (56.1% of the total mass fraction, modulus 2.20-2.50, specific gravity 1.526-1.559) at room temperature with stirring. Then, add corn cob granules (43.4% of the total mass fraction, 60 mesh, specific gravity 0.3) in batches to the mixed solution while stirring. After stirring and dispersing for 4 hours, the corn cob granule profile control, water blocking and channel sealing agent can be obtained.

[0052] Application method:

[0053] The single-liquid method was used for profile control and water shut-off in water-drive reservoirs. The prepared corn cob granular powder profile control, water shut-off, and channeling agent was mixed with injection water at a 1:1 ratio to form an injection system, and then 2% slow-release acid was added to this system. One PV of this system was injected into the core, and its shut-off rate was evaluated as 97%, increasing the recovery rate by 10% compared to water drive. Specific data are shown in Table 3.

[0054] Example 4

[0055] Preparation of profile control, water sealing and channeling agent:

[0056] When the specific gravity of the injected water is 1 g / mL, calculate the dosage of each component. Dissolve surfactant 1231 (0.5% of the total mass fraction) in liquid water glass (64.7% of the total mass fraction, modulus 3.41-3.60, specific gravity 1.336-1.362) at room temperature with stirring. Then, add corn cob granules (34.8% of the total mass fraction, 160 mesh, specific gravity 0.35) in batches to the mixed solution while stirring. After stirring and dispersing for 8 hours, the corn cob granule profile control, water blocking and channel sealing agent can be obtained.

[0057] Application method:

[0058] For preventing gas channeling in carbon dioxide gas drive, the prepared corn cob granular powder profile control and water blocking agent was mixed with injected water at a ratio of 1:1.5 to form an injection system. 1 PV of this system was injected into the core, and subsequent injection of carbon dioxide gas evaluated its blocking rate at 92%, which increased the recovery rate by 6% compared to water drive. Specific data are shown in Table 3.

[0059] Example 5

[0060] Preparation of profile control, water sealing and channeling agent:

[0061] When the specific gravity of the injected water is 1 g / mL, calculate the dosage of each component. Dissolve surfactant 1831 (0.5% of the total mass fraction) in liquid water glass (62.7% of the total mass fraction, modulus 3.10-3.40, specific gravity 1.368-1.394) at room temperature with stirring. Then, add corn cob granules (36.8% of the total mass fraction, 160 mesh, specific gravity 0.35) in batches to the mixed solution while stirring. After stirring and dispersing for 8 hours, the corn cob granule profile control, water blocking and channel sealing agent can be obtained.

[0062] Application method:

[0063] The two-liquid method was used for profile control and water shut-off in water-drive reservoirs. The prepared corn cob granular powder profile control, water shut-off, and channeling agent was mixed with injection water at a ratio of 1.5:1 (0.5 PV), and a 5% calcium chloride solution was added at a volume of 0.5 PV. Both were injected alternately into the core in two slugs. The shut-off rate was evaluated at 95%, increasing the oil recovery rate by 8% compared to water drive. Specific data are shown in Table 3.

[0064] Example 6

[0065] Preparation of profile control, water sealing and channeling agent:

[0066] When the specific gravity of the injected water is 1 g / mL, calculate the dosage of each component. Dissolve surfactant 1231 (0.5% of the total mass fraction) in liquid water glass (58.8% of the total mass fraction, modulus 2.60-2.90, specific gravity 1.436-1.465) at room temperature with stirring. Then, add corn cob granules (40.7% of the total mass fraction, 160 mesh, specific gravity 0.35) in batches to the mixed solution while stirring. After stirring and dispersing for 8 hours, the corn cob granule profile control, water blocking and channel sealing agent can be obtained.

[0067] Application method:

[0068] The single-liquid method was used for profile control and water shut-off in water-drive reservoirs. The prepared corn cob granular powder profile control, water shut-off, and channeling agent was mixed with injection water at a ratio of 1:1.5 to form an injection system. Then, 2% potential acid was added to this system. One PV of this system was injected into the core, and its shut-off rate was evaluated as 99%, increasing the recovery rate by 12% compared to water drive. Specific data are shown in Table 3.

[0069] Example 7

[0070] Preparation of profile control, water sealing and channeling agent:

[0071] When the specific gravity of the injected water is 1 g / mL, calculate the dosage of each component. Dissolve surfactant 1231 (0.5% of the total mass fraction) in liquid water glass (65.8% of the total mass fraction, modulus 3.41-3.60, specific gravity 1.336-1.362) at room temperature with stirring. Then, add corn cob granules (33.7% of the total mass fraction, 100 mesh, specific gravity 0.32) in batches to the mixed solution while stirring. After stirring and dispersing for 6 hours, the corn cob granule profile control, water blocking and channel sealing agent can be obtained.

[0072] Application method:

[0073] The single-liquid method was used for profile control and water shut-off in water-drive reservoirs. The prepared corn cob granular powder profile control, water shut-off, and channeling agent was mixed with injection water at a ratio of 1.5:1 to form an injection system. Then, 2% potential acid was added to this system. One PV of this system was injected into the core, and its shut-off rate was evaluated as 97%, increasing the recovery rate by 10% compared to water drive. Specific data are shown in Table 3.

[0074] Example 8

[0075] Preparation of profile control, water sealing and channeling agent:

[0076] When the specific gravity of the injected water is 1 g / mL, calculate the dosage of each component. Dissolve surfactant 1631 (1% of the total mass fraction) in liquid water glass (63.4% of the total mass fraction, modulus 3.10-3.40, specific gravity 1.368-1.394) at room temperature with stirring. Then, add corn cob granules (35.6% of the total mass fraction, 100 mesh, specific gravity 0.32) in batches to the mixed solution while stirring. After stirring and dispersing for 6 hours, the corn cob granule profile control, water blocking and channel sealing agent can be obtained.

[0077] Application method:

[0078] The two-liquid method was used for profile control and water shut-off in water-drive reservoirs. The prepared corn cob granular powder profile control, water shut-off, and channeling agent was mixed with injection water at a 1:1 ratio to form an injection system, with a dosage of 0.5 PV. A 1% hydrochloric acid solution was also used at a dosage of 0.5 PV. Both were injected alternately into the core in two slugs. The shut-off rate was evaluated at 92%, increasing the oil recovery rate by 6% compared to water drive. Specific data are shown in Table 3.

[0079] Example 9

[0080] Preparation of profile control, water sealing and channeling agent:

[0081] When the specific gravity of the injected water is 1 g / mL, calculate the dosage of each component. Dissolve surfactant 1231 (1% of the total mass fraction) in liquid water glass (59.5% of the total mass fraction, modulus 2.60-2.90, specific gravity 1.436-1.465) at room temperature with stirring. Then, add corn cob granules (39.5% of the total mass fraction, 100 mesh, specific gravity 0.32) in batches to the mixed solution while stirring. After stirring and dispersing for 6 hours, the corn cob granule profile control, water blocking and channel sealing agent can be obtained.

[0082] Application method:

[0083] For preventing gas channeling in carbon dioxide gas drive, the prepared corn cob granular powder profile control and water blocking agent was mixed with injected water in a 1:1 ratio to form an injection system. 1 PV of this system was injected into the core, and subsequent injection of carbon dioxide gas evaluated its blocking rate at 97%. Compared with water drive, it improved the recovery rate by 10%. Specific data are shown in Table 3.

[0084] Example 10

[0085] Preparation of profile control, water sealing and channeling agent:

[0086] When the specific gravity of the injected water is 1 g / mL, calculate the dosage of each component. Dissolve surfactant 1231 (1.5% of the total mass fraction) in liquid water glass (62.8% of the total mass fraction, modulus 3.10-3.40, specific gravity 1.368-1.394) at room temperature with stirring. Then, add corn cob granules (35.7% of the total mass fraction, 120 mesh, specific gravity 0.33) in batches to the mixed solution while stirring. After stirring and dispersing for 4 hours, the corn cob granule profile control, water blocking and channel sealing agent can be obtained.

[0087] Application method:

[0088] For profile control and water shut-off in water-drive reservoirs, the prepared corn cob granular powder profile control and water shut-off agent was mixed with injected water at a 1:1 ratio to form an injection system, with a dosage of 1 PV. This system was injected into the core, and then carbon dioxide gas was injected to activate it into a gel. The shut-off rate was evaluated as 97%, which increased the recovery rate by 10% compared to water drive. Specific data are shown in Table 3.

[0089] Comparative Example 1

[0090] A two-liquid method using water glass and calcium chloride was employed for profile control and water shut-off in water-drive reservoirs. Water glass and injection water were mixed in a 1:1 ratio to form Component One, with a dosage of 0.5 PV, and a 5% calcium chloride solution was added at a dosage of 0.5 PV. Both were injected alternately into the core in two slugs. The plugging rate was evaluated at 90%, resulting in a 4% increase in oil recovery compared to waterdrive.

[0091] Comparative Example 2

[0092] Cement particles were used for profile control and water shut-off in water-drive reservoirs. The cement particles and injected water were mixed in a 1:1 ratio to form component one, with a dosage of 1 PV. The mixture was injected into the core, and the shut-off rate was evaluated as 90%. Compared with water drive, the recovery rate was increased by 4%.

[0093] A comparison of the embodiments and comparative examples of this application shows that: using corn cob granular powder profile control, water plugging, and channeling agent allows for various construction methods to meet different on-site construction needs; secondly, the combination of particles and gel enhances the gel breaking strength, improving its plugging rate and recovery rate; and thirdly, it reduces material costs, increases the amount of profile control, water plugging, and channeling agent used per well, and expands its effective radius.

[0094] Table 3: Comparison of performance evaluation data between the examples and comparative examples

[0095]

Claims

1. A corn cob granule powder profile control, water-blocking, and channel-sealing agent, comprising corn cob granule powder, liquid water glass, and a cationic surfactant, wherein, The amount of corn cob granules is X%, the amount of liquid water glass is Y%, and the amount of surfactant is Z%. X, Y, and Z conform to the following relationship: (1) the specific gravity of corn cob granules × X% + the specific gravity of water glass × Y% + the specific gravity of surfactant × Z% = the specific gravity of the water to be mixed; (2) X% + Y% + Z% = 100%, and the value of Z is in the range of 0.1-5%. The values ​​of X and Y are calculated according to the relationship. The specific gravity of the corn cob granules is 0.3-0.35 g / mL, and the specific surface area is greater than 6000 cm². 2 / g, wherein the cationic surfactant is selected from quaternary ammonium salt type and imidazoline type cationic surfactants.

2. The profile control, water-blocking, and channel-sealing agent according to claim 1, wherein, The Z-value ranges from 0.5% to 2%.

3. The profile control, water plugging, and channel sealing agent according to claim 1, wherein, The specific gravity of the liquid water glass is 1.336-1.362 g / mL, 1.368-1.394 g / mL, 1.436-1.465 g / mL, and 1.526-1.559 g / mL.

4. The profile control, water-blocking, and channel-sealing agent according to claim 1, wherein, The specific gravity of the liquid water glass is 1.368-1.394 g / mL.

5. The profile control, water-blocking, and channel-sealing agent according to claim 1, wherein, The cationic surfactant is selected from dodecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, and octadecyltrimethylammonium chloride.

6. The preparation method of the corn cob granule powder profile control, water-blocking and channeling agent according to claim 1, comprising: The cationic surfactant was dissolved in liquid water glass and stirred until homogeneous. Then, corn cob powder was added to the mixture and stirred until homogeneous.

7. The preparation method according to claim 6, wherein, After adding the corn cob powder to the mixed solution, stir and disperse for 4-8 hours.

8. The method of applying the corn cob granule powder profile control, water-blocking, and channel-separating agent according to any one of claims 1 to 5, comprising: It is applied to profile control and water shut-off operations in water-drive reservoirs.

9. The method of applying the corn cob granule powder profile control, water-blocking, and channel-separating agent according to any one of claims 1 to 5, comprising: Used for the treatment of oil and gas channeling caused by carbon dioxide.

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