阅读说明：本技术 油层调剖方法 (Oil layer profile control method ) 是由 唐可 罗强 原风刚 李凯 白雷 徐崇军 袁恩来 向小玲 李明 陈丽艳 万青山 于 2020-06-24 设计创作，主要内容包括：本发明提供了一种油层调剖方法,包括：步骤S1：向油层中注入第一填充剂以对油层上的裂缝进行封堵,其中,第一填充剂采用无机固化体系；步骤S2：向油层中注入第二填充剂以对油层内的大孔道进行封堵,其中,第二填充剂采用固化凝胶；步骤S3：向油层中注入第三填充剂以对高渗条带进行封堵,其中,第三填充剂包括弱凝胶与颗粒复合调剖剂；步骤S4：向油层中注入第四填充剂以对第一填充剂、第二填充剂和第三填充剂进行固定,其中,第四填充剂采用凝胶调剖剂。本发明的油层调剖方法解决了现有技术中的油层调剖效果不好的问题。(The invention provides an oil layer profile control method, which comprises the following steps: step S1: injecting a first filling agent into the oil layer to plug cracks on the oil layer, wherein the first filling agent adopts an inorganic curing system; step S2: injecting a second filling agent into the oil layer to plug large pores in the oil layer, wherein the second filling agent is solidified gel; step S3: injecting a third filler into the oil layer to plug the high-permeability strip, wherein the third filler comprises weak gel and particle composite profile control agent; step S4: and injecting a fourth filler into the oil layer to fix the first filler, the second filler and the third filler, wherein the fourth filler adopts a gel profile control agent. The oil layer profile control method solves the problem of poor oil layer profile control effect in the prior art.)

1. A method of reservoir profile control, comprising:

step S1: injecting a first filling agent into an oil layer to plug cracks on the oil layer, wherein the first filling agent adopts an inorganic curing system;

step S2: injecting a second filler into the oil layer to block large pore passages in the oil layer, wherein the second filler adopts solidified gel;

step S3: injecting a third filler into the oil layer to plug a high permeability strip, wherein the third filler comprises a weak gel and particle composite profile control agent;

step S4: and injecting a fourth filler into the oil layer to fix the first filler, the second filler and the third filler, wherein the fourth filler is a gel profile control agent.

2. The zonal profile control method of claim 1, wherein the step S1 comprises:

step S11: measuring the thickness of a strong water absorption layer, wherein the strong water absorption layer is a water absorption layer with water absorption rate more than 50%;

step S12: determining the injection amount of the first filler according to the thickness of the strong water absorption layer, wherein the injection amount of the first filler is injected into the strong water absorption layer by 40m per meter³To 60m³。

3. The zonal profile control method of claim 1, wherein in step S1, the first filler comprises: bentonite, oil well cement, calcium oxide, a dispersant and water.

4. A reservoir profile control method according to claim 3, wherein the first filler comprises, in mass percent: the bentonite accounts for 5-8 wt%, the oil well cement accounts for 20-30 wt%, the calcium oxide accounts for 5-8 wt%, and the dispersant accounts for 1-3 wt%.

5. The zonal profile control method according to claim 1, wherein in step S2, the injection amount of the second filler is 50m³To 200m³。

6. The zonal profile control method according to claim 1, wherein in step S2, the second filler includes: acrylamide, modified starch, ammonium persulfate, N-methylene-bisacrylamide, anionic polyacrylamide and water.

7. The method for oil layer profile control according to claim 6, wherein in the second filler, the acrylamide is 5 to 8% by weight, the modified starch is 2 to 4% by weight, the ammonium persulfate is 0.2 to 0.6% by weight, the N, N-methylene-bis-acrylamide is 0.005 to 0.03% by weight, and the anionic polyacrylamide is 0.1 to 0.2% by weight.

8. The zonal profile control method according to claim 1, wherein in step S3, the injection amount of the third filler is 1000m³To 3000m³。

9. The zonal profile control method of claim 1, wherein in step S3, the third filler comprises: anionic polyacrylamide, solid formaldehyde, resorcinol, particulates and water.

10. A process for oil layer profile control according to claim 9, wherein in the third filler, the anionic polyacrylamide is contained in an amount of 0.2 to 0.4% by weight, the solid formaldehyde is contained in an amount of 0.2 to 0.3% by weight, the resorcinol is contained in an amount of 0.02 to 0.05% by weight, and the particles are contained in an amount of 0.1 to 0.5% by weight.

11. The zonal profile control method according to claim 1, wherein in step S4, the injection amount of the fourth filler is 150m³To 300m³。

12. The zonal profile control method of claim 1, wherein in step S4, the fourth filler comprises: anionic polyacrylamide, solid formaldehyde, resorcinol and water.

13. A process for oil layer profile control according to claim 12, wherein in the fourth filler, the anionic polyacrylamide is contained in an amount of 0.5 to 0.7% by weight, the solid formaldehyde is contained in an amount of 0.3 to 0.4% by weight, and the resorcinol is contained in an amount of 0.03 to 0.05% by weight.

14. A process of oil zonal profile control according to any of claims 6, 9 or 12, wherein the molecular weight of the anionic polyacrylamide is 2000 to 3500 ten thousand, and the degree of hydrolysis of the anionic polyacrylamide is 20 to 30%.

Technical Field

The invention relates to the technical field of oilfield exploitation, in particular to an oil layer profile control method.

Background

In the development process of water flooding or chemical flooding of an oil field, the problem of serious water channeling or chemical channeling exists basically in oil reservoirs with high permeability and cracks, the cracks, high-permeability large pores formed by long-term scouring and the like are main reasons for causing water channeling or chemical channeling, so that water injection and chemical ineffective circulation are caused, the development effect is seriously influenced, and the recovery ratio of the oil field is influenced.

Profile control is a common means for plugging the dominant channel of an oil layer, profile control agents widely applied on site include polymer jelly, particles, salt precipitation, cement and the like, and the profile control process is usually one or a combination of several profile control agents. However, the existing plugging control technology for the fractured reservoir has the conditions of insufficient fracture plugging strength, short profile control action distance, short profile control validity period and the like, so that the profile control effect is not ideal.

Disclosure of Invention

The invention mainly aims to provide an oil layer profile control method to solve the problem of poor oil layer profile control effect in the prior art.

In order to achieve the above object, according to an aspect of the present invention, there is provided a reservoir profile control method including: step S1: injecting a first filling agent into the oil layer to plug cracks on the oil layer, wherein the first filling agent adopts an inorganic curing system; step S2: injecting a second filling agent into the oil layer to plug large pores in the oil layer, wherein the second filling agent is solidified gel; step S3: injecting a third filler into the oil layer to plug the high-permeability strip, wherein the third filler comprises weak gel and particle composite profile control agent; step S4: and injecting a fourth filler into the oil layer to fix the first filler, the second filler and the third filler, wherein the fourth filler adopts a gel profile control agent.

Further, step S1 includes: step S11: measuring the thickness of a strong water absorption layer, wherein the strong water absorption layer is a water absorption layer with the water absorption rate of more than 50%; step S12: determining the injection amount of the first filler according to the thickness of the strong water absorption layer, wherein the injection amount of the first filler is 40m according to the thickness of the strong water absorption layer per meter³To 60m³。

Further, in step S1, the first filler includes: bentonite, oil well cement, calcium oxide, a dispersant and water.

Further, the first filler comprises the following components in percentage by mass: the bentonite accounts for 5-8 wt%, the oil well cement accounts for 20-30 wt%, the calcium oxide accounts for 5-8 wt%, and the dispersant accounts for 1-3 wt%.

Further, in step S2, the injection amount of the second filler is 50m³To 200m³。

Further, in step S2, the second filler includes: acrylamide, modified starch, ammonium persulfate, N-methylene-bisacrylamide, anionic polyacrylamide and water.

Further, in the second filler, the weight content of acrylamide is 5-8%, the weight content of modified starch is 2-4%, the weight content of ammonium persulfate is 0.2-0.6%, the weight content of N, N-methylene-bisacrylamide is 0.005-0.03%, and the weight content of anionic polyacrylamide is 0.1-0.2%.

Further, the method can be used for preparing a novel materialIn step S3, the injection amount of the third filler is 1000m³To 3000m³。

Further, in step S3, the third filler includes: anionic polyacrylamide, solid formaldehyde, resorcinol, particulates and water.

Further, in the third filler, the weight content of the anionic polyacrylamide is 0.2 to 0.4%, the weight content of solid formaldehyde is 0.2 to 0.3%, the weight content of resorcinol is 0.02 to 0.05%, and the weight content of the particles is 0.1 to 0.5%.

Further, in step S4, the injection amount of the fourth filler was 150m³To 300m³。

Further, in step S4, the fourth filler includes: anionic polyacrylamide, solid formaldehyde, resorcinol and water.

Further, in the fourth filler, the weight content of the anionic polyacrylamide is 0.5-0.7%, the weight content of solid formaldehyde is 0.3-0.4%, and the weight content of resorcinol is 0.03-0.05%.

Further, the molecular weight of the anionic polyacrylamide is 2000 to 3500 ten thousand, and the degree of hydrolysis of the anionic polyacrylamide is 20 to 30%.

The oil layer profile control method applied to the technical scheme of the invention is used for solving the problem of insufficient fracture plugging strength of the existing oil reservoir, and effectively treats water channeling or agent channeling caused by fractures and hypertonic strips through four plugging systems, wherein the four plugging systems specifically comprise: firstly, injecting a first filling agent into an oil layer to plug cracks on the oil layer, wherein the first filling agent adopts a high-strength inorganic curing system to plug the cracks; step S2: injecting a second filling agent into the oil layer to plug large pores in the oil layer, wherein the second filling agent is stratum cured gel; step S3: injecting a third filler into the oil layer to plug the high-permeability strip, wherein the third filler comprises weak gel and particle composite profile control agent; step S4: the fourth filling agent is injected into the oil layer to fix the first filling agent, the second filling agent and the third filling agent, wherein the fourth filling agent adopts a high-concentration gel profile control agent so as to prevent the fixed filling agent from being diluted by water or washed away and lost in the previous three steps, and the problem of poor profile control effect of the oil layer in the prior art is solved through the arrangement.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail with reference to examples.

The invention provides an oil layer profile control method, which comprises the following steps: step S1: injecting a first filling agent into the oil layer to plug cracks on the oil layer, wherein the first filling agent adopts an inorganic curing system; step S2: injecting a second filling agent into the oil layer to plug large pores in the oil layer, wherein the second filling agent is solidified gel; step S3: injecting a third filler into the oil layer to plug the high-permeability strip, wherein the third filler comprises weak gel and particle composite profile control agent; step S4: and injecting a fourth filler into the oil layer to fix the first filler, the second filler and the third filler, wherein the fourth filler adopts a gel profile control agent.

The oil layer profile control method is used for solving the problem that the existing oil reservoir has insufficient fracture plugging strength, and effectively treats water channeling or agent channeling caused by fractures and hypertonic strips through four plugging systems, wherein the four plugging systems comprise: firstly, injecting a first filling agent into an oil layer to plug cracks on the oil layer, wherein the first filling agent adopts a high-strength inorganic curing system to plug the cracks; step S2: injecting a second filling agent into the oil layer to plug large pores in the oil layer, wherein the second filling agent is stratum cured gel; step S3: injecting a third filler into the oil layer to plug the high-permeability strip, wherein the third filler comprises weak gel and particle composite profile control agent; step S4: the fourth filling agent is injected into the oil layer to fix the first filling agent, the second filling agent and the third filling agent, wherein the fourth filling agent adopts a high-concentration gel profile control agent so as to prevent the fixed filling agent from being diluted by water or washed away and lost in the previous three steps, and the problem of poor profile control effect of the oil layer in the prior art is solved through the arrangement.

Step S1 includes: step S11: measuring the thickness of a strong water absorption layer, wherein the strong water absorption layer is a water absorption layer with the water absorption rate of more than 50%; step S12: determining the injection amount of the first filler according to the thickness of the strong water absorption layer, wherein the injection amount of the first filler is 40m according to the thickness of the strong water absorption layer per meter³To 60m³。

In this embodiment, since the depth of the water injection well is deep, typically up to several kilometers, the water injection well penetrates different formations, wherein in order to ensure and evaluate the injection amount of the first filler, it is preferable to measure the thickness of the strong water absorption layer having a water absorption rate of more than 50%, and then inject 50m per meter according to the thickness of the strong water absorption layer³Injected from a water injection well to plug a fracture in the reservoir.

In step S1, the first filler includes: bentonite, oil well cement, calcium oxide, a dispersant and water.

The first filler comprises the following components in percentage by mass: 5 to 8 percent of bentonite, 20 to 30 percent of oil well cement, 5 to 8 percent of calcium oxide, 1 to 3 percent of dispersant and the balance of water.

Among them, it is preferable that the bentonite content is 6.5% by weight, the oil well cement content is 25% by weight, the calcium oxide content is 6.5% by weight, the dispersant content is 2% by weight, and the water content is 60% by weight.

In step S2, the injection amount of the second filler is 50m³To 200m³。

Preferably, the injection amount of the second filler is 125m³。

In step S2, the second filler includes: acrylamide, modified starch, ammonium persulfate, N-methylene-bisacrylamide, anionic polyacrylamide and water.

In the second filling agent, the weight content of acrylamide is 5-8%, the weight content of modified starch is 2-4%, the weight content of ammonium persulfate is 0.2-0.6%, the weight content of N, N-methylene-bisacrylamide is 0.005-0.03%, and the weight content of anionic polyacrylamide is 0.1-0.2%.

Preferably, the weight content of acrylamide is 6.5%, the weight content of modified starch is 3%, the weight content of ammonium persulfate is 0.4%, the weight content of N, N-methylene-bisacrylamide is 0.0125% to 0.03%, the weight content of anionic polyacrylamide is 0.15%, and the balance is water.

In step S3, the injection amount of the third filler is 1000m³To 3000m³。

Preferably, the injection amount of the third filler is 2000m³。

In step S3, the third filler includes: anionic polyacrylamide, solid formaldehyde, resorcinol, particulates and water.

In the third filler, the weight content of anionic polyacrylamide is 0.2-0.4%, the weight content of solid formaldehyde is 0.2-0.3%, the weight content of resorcinol is 0.02-0.05%, the weight content of particles is 0.1-0.5%, and the balance is water.

Preferably, the anionic polyacrylamide is present in an amount of 0.3% by weight, the solid formaldehyde is present in an amount of 0.25% by weight, the resorcinol is present in an amount of 0.035% by weight, the granulate is present in an amount of 0.3% by weight, and the remainder is water.

In step S4, the injection amount of the fourth filler is 150m³To 300m³。

Preferably, the injection amount of the fourth filler is 200m³。

In step S4, the fourth filler includes: anionic polyacrylamide, solid formaldehyde, resorcinol and water.

In the fourth filler, the weight content of anionic polyacrylamide is 0.5-0.7%, the weight content of solid formaldehyde is 0.3-0.4%, the weight content of resorcinol is 0.03-0.05%, and the balance is water.

Preferably, the anionic polyacrylamide is present in an amount of 0.6% by weight, the solid formaldehyde is present in an amount of 0.35% by weight, the resorcinol is present in an amount of 0.04% by weight, and the balance is water.

The molecular weight of the anionic polyacrylamide is 2000-3500 ten thousand, and the hydrolysis degree of the anionic polyacrylamide is 20-30%.

Preferably, the molecular weight of the anionic polyacrylamide is 3000 ten thousand, and the hydrolysis degree of the anionic polyacrylamide is 25%.

The deep profile control method of the high-permeability fractured reservoir is further described with reference to specific examples.

Example 1

A high-permeability fractured reservoir deep profile control method comprises the following steps:

the method comprises the following steps: injecting 100m from water injection well into strong water absorption layer with 2m thickness in oil layer³Plugging the crack by a high-strength inorganic curing system;

step two: the stratum solidified gel is 100m in total³Injecting an oil layer to plug a large pore passage in the deep part of the stratum;

step three: implant 1500m³The weak gel and the swelling particle composite profile control agent blocks the hypertonic strips;

step four: implant 150m³The high concentration gel profile control agent of (1) is used for sealing.

Wherein, the high-strength inorganic curing system in the first step comprises the following components in percentage by weight: 5% of bentonite, 25% of oil well cement, 6% of calcium oxide, 1% of a dispersant and the balance of water. In the second step, the stratum solidified gel comprises the following components in percentage by weight: 6% of acrylamide, 2% of modified starch and 0.4% of ammonium persulfate; 0.01 percent of N, N-methylene bisacrylamide, 0.15 percent of anionic polyacrylamide and the balance of water; the weak gel and particle composite profile control agent in the third step comprises the following components in percentage by weight: 0.3 percent of anionic polyacrylamide, 0.2 percent of solid formaldehyde, 0.03 percent of resorcinol, 0.5 percent of bulk swelling particles and the balance of water. The high-concentration gel profile control agent in the fourth step comprises the following components in percentage by weight: 0.6% of anionic polyacrylamide, 0.4% of solid formaldehyde, 0.035% of resorcinol and the balance of water. Wherein, the molecular weight of the anionic polyacrylamide in the second, third and fourth steps is 2500 ten thousand, and the degree of hydrolysis is 27.2%.

Example 2

A high-permeability fractured reservoir deep profile control method comprises the following steps:

the method comprises the following steps: injecting 80m from the water injection well into the strong water absorption layer with the thickness of 2m in the oil layer³Plugging the crack by a high-strength inorganic curing system;

step two: the stratum solidified gel is 50m in total³Injecting an oil layer to plug a large pore passage in the deep part of the stratum;

step three: injection 3000m³The weak gel and the rubber particle composite profile control agent are used for plugging the high permeability strip;

step four: implant 200m³The high concentration gel profile control agent of (1) is used for sealing.

Wherein, the high-strength inorganic curing system in the first step comprises the following components in percentage by weight: 5% of bentonite, 20% of oil well cement, 5% of calcium oxide, 1% of dispersant and the balance of water. In the second step, the stratum solidified gel comprises the following components in percentage by weight: 8% of acrylamide, 2% of modified starch and 0.6% of ammonium persulfate; 0.01 percent of N, N-methylene bisacrylamide, 0.1 percent of anionic polyacrylamide and the balance of water; the weak gel and the particle profile control agent in the third step comprise the following components in percentage by weight: 0.3% anionic polyacrylamide, 0.2% solid formaldehyde, 0.03% resorcinol, 0.5% rubber particles, the balance water. The high-concentration gel profile control agent in the fourth step comprises the following components in percentage by weight: 0.6% of anionic polyacrylamide, 0.4% of solid formaldehyde, 0.035% of resorcinol and the balance of water. Wherein, the molecular weight of the anionic polyacrylamide in the second, third and fourth steps is 2500 ten thousand, and the degree of hydrolysis is 27.2%.

Example 3

A high-permeability fractured reservoir deep profile control method comprises the following steps:

the method comprises the following steps: injecting 60m from water injection well into strong water absorption layer with thickness of 1m in oil layer³Plugging the crack by a high-strength inorganic curing system;

step two: the stratum solidified gel is 200m in total³Injecting an oil layer to plug a large pore passage in the deep part of the stratum;

step three: implant 1000m³The weak gel and the swelling particle composite profile control agent blocks the hypertonic strips;

step four: injection of 300m³The high concentration gel profile control agent of (1) is used for sealing.

Wherein, the high-strength inorganic curing system in the first step comprises the following components in percentage by weight: 8% of bentonite, 30% of oil well cement, 5% of calcium oxide, 3% of a dispersant and the balance of water. In the second step, the stratum solidified gel comprises the following components in percentage by weight: 6% of acrylamide, 2% of modified starch and 0.6% of ammonium persulfate; 0.01 percent of N, N-methylene bisacrylamide, 0.15 percent of anionic polyacrylamide and the balance of water; the weak gel and swelling particle composite profile control agent in the third step comprises the following components in percentage by weight: 0.25% of anionic polyacrylamide, 0.2% of solid formaldehyde, 0.025% of resorcinol, 0.3% of volume-expanded particles and the balance of water. The high-concentration gel profile control agent in the fourth step comprises the following components in percentage by weight: 0.5% of anionic polyacrylamide, 0.3% of solid formaldehyde, 0.03% of resorcinol and the balance of water. Wherein, the molecular weight of the anionic polyacrylamide in the second, third and fourth steps is 2500 ten thousand, and the degree of hydrolysis is 27.2%.

Comparative example 1

The only difference from example 1 is that no high strength inorganic curing system slug was provided.

Comparative example 2

The only difference from example 1 is that neither a weak gel and a volume-expanded granular profile control agent slug, nor a high concentration gel profile control agent slug, was injected.

Comparative example 3

The only difference from example 1 is that step one is carried out in terms of 80m of strong water absorption layer per meter³Injecting a high-strength inorganic curing system, wherein the injection amount of the second step of formation curing gel is 300m³And step three, the injection amount of the weak gel and the swelling particle composite profile control agent is 4000m³。

Comparative example 4

The only difference from example 1 is that the high strength inorganic curing system comprises, in weight percent: 10% of bentonite, 35% of oil well cement, 10% of calcium oxide, 5% of a dispersant and the balance of water; the stratum solidified gel comprises the following components in percentage by weight: 10% of acrylamide, 5% of modified starch and 0.8% of ammonium persulfate; 0.01 percent of N, N-methylene bisacrylamide, 0.15 percent of anionic polyacrylamide and the balance of water; the weak gel and swelling particle composite profile control agent comprises the following components in percentage by weight: 0.15% of anionic polyacrylamide, 0.1% of solid formaldehyde, 0.02% of resorcinol, 0.3% of bulk swelling particles and the balance of water.

Before and after the examples 1 to 3 and the comparative examples 1 to 3 were carried out, the concentration and the water content of the polymer in the oil well production fluid and the daily oil production of the well group were counted, and the oil-increasing effective period of each example was counted to obtain the following table 1.

As can be seen from Table 1, after the field implementation, the injection pressure of the water injection well in the embodiment 1 is increased by 2MPa, the average daily oil increment of a single well group is 5.6t, and the water content is reduced by 6 percentage points; the injection pressure of the water injection well in the embodiment 2 is increased by 1.8MPa, the average daily oil increase of a single well group is 3.6t, and the water content is reduced by 5.4 percentage points; the injection pressure of the water injection well in the embodiment 3 is increased by 1.3MPa, the average daily oil increase of a single well group is 3.0t, and the water content is reduced by 5.1 percentage points; meanwhile, the oil increasing effective period of the three components is between 90 and 125 days. Comparative example 1 has no high-strength inorganic curing system slug, cannot effectively block large cracks of the stratum, and has no obvious water control and oil increasing effects after profile control; comparative example 2 only injects high strength inorganic curing system and stratum curing gel, does not inject the weak gel of the subsequent large dose and swells the particle slug, the plugging range is smaller, although the water control oil increasing effect is obvious after the profile control, but the effective period is only 45 days; comparative example 3 the injection amount of the high-strength inorganic curing system slug, the stratum curing gel slug and the weak gel and particle composite profile control agent slug exceeds that of example 1, so that the injection pressure is excessively increased, and a low permeable layer in a near-wellbore area causes pollution to a certain extent, thereby affecting the profile control effect. Therefore, through the field test of the high-permeability fractured reservoir deep profile control method, the inorganic curing system realizes effective plugging of the fracture, and the problem that systems such as gel, particles and the like are blown out of the fracture is prevented; and the subsequent stratum solidifies the gel, the weak gel and the particle slug to realize the plugging of the secondary dominant channel, thereby expanding the subsequent fluid swept volume and prolonging the oil-increasing effective period.

The properties of the formulations of the slug profile control agents of example 1 and comparative example 4 were counted to obtain the following table 2.

As can be seen from Table 2, the curing time of the high-strength inorganic curing system prepared according to the formulation of example 1 was 8 hours, the curing strength was 2MPa, the curing time of the formation curing gel was 8 hours, the curing strength was 1.1MPa, the gelling time of the weak gel and the particle profile control agent was 6 hours, and the gelling strength was 42 mPas. Compared with the prior art, the curing time of the high-strength inorganic curing system is too short (3h), so that the risk of site construction is increased; the curing time of the stratum curing gel is too short (2h), and meanwhile, the curing strength is reduced due to excessive crosslinking, so that the on-site plugging requirement cannot be met; the weak gel and particle composite profile control agent cannot form gel smoothly due to low component concentration. It follows that outside the set concentration range of the formulation components may result in profile control formulation properties that do not meet the application requirements.

From the above description, it can be seen that the above-described embodiments of the present invention achieve the following technical effects:

(1) the inorganic curing system has extremely high plugging strength after being cured in the stratum, can effectively plug large cracks of an oil layer, and prevents a follow-up profile control agent from directly channeling to an oil well along a crack channel.

(2) The stratum solidified gel has the characteristics of low initial viscosity and high strength after solidification, can block large deep channels of the stratum, effectively improves the blocking radius, and ensures that subsequent fluid continuously flows around the deep part of the stratum to enlarge the swept volume. Meanwhile, as the gel is carried by adopting the anionic polyacrylamide solution, the filtration loss of the solidified gel in the stratum can be effectively reduced, the dilution resistance is improved, and the plugging effect in a large pore canal is ensured.

(3) On the basis of plugging large cracks and large channels in the first step and the second step, injecting a weak gel and particle composite profile control system, wherein the weak gel and particle composite profile control system mainly enters a high-permeability strip, particles mainly form a support in the channel under the action of accumulation, and the weak gel wraps the channel to form a gel-particle three-dimensional network plugging system, so that the plugging strength and the flushing resistance are higher.

(4) The high-concentration gel plugs the channel port to prevent the early-stage profile control system from being flushed away by subsequent fluid.

The method has good control effect on water channeling, gathering channeling, gel channeling and the like of the high-permeability fractured reservoir, has wide application prospect in the application of water flooding, polymer flooding, composite flooding, deep profile control flooding technologies and the like of the strong heterogeneous reservoir, solves the problems of insufficient fracture plugging strength, short profile control action distance, short profile control validity period and the like in the prior art, and effectively treats the water channeling or agent channeling caused by fractures and high-permeability strips.

The establishment of the oil layer profile control method provides technical support for the migration and adsorption analysis of the weak phenolic gel in the rock core, and is favorable for the research of the profile control and flooding mechanism of the weak gel. Meanwhile, the flow channeling direction and the flow channeling degree in the profile control process can be judged by detecting the content of the phenolic gel in the oil well output liquid, so that a basis is provided for adjusting the profile control formula, and the plugging effect is improved. Thereby enlarging the swept volume of a subsequent displacement system and achieving the purposes of controlling water and increasing oil.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and the terms have no special meanings unless otherwise stated, and therefore, the scope of the present invention should not be construed as being limited.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.