A reservoir protection circulation method for controlling water and gas channeling outside casing

Abstract

The present invention belongs to the field of oil exploration technology, and specifically provides a reservoir protection circulation method for controlling water and gas channeling outside the casing. The first step is to establish temporary plugging of reservoir pores by using reservoir protection gel, the second step is to perforate an engineering hole in the water-producing layer section, the third step is to use an oil pipe to send a packer to the area between the perforated section of the production layer and the engineering hole and seal it to establish a circulation channel, the third step is to pump a plugging agent system into the annular channeling groove outside the casing in the circulation channel, and the fourth step is to wait for the reservoir protection gel to degrade and treat the wellbore, and then perforate the reservoir to resume production, thereby solving the water and gas channeling problem caused by incomplete cement ring outside the casing and the problem of resumption and increase of production wells. The present invention injects the plugging agent system into the formed channel through the circulation channel, which can effectively guide the plugging agent system into the annular water channeling channel, realizes effective plugging of the water and gas channel under various pressure systems of the water-producing layer and the reservoir, and reduces the problem of solid phase blockage of formation pores caused by cement slurry squeezing into the formation.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum exploration, and in particular relates to a reservoir protection circulation method for controlling water and gas channeling outside a casing. Background Art

[0002] Substandard cementing quality in some production wells in Changqing Oilfield resulted in water and gas channeling outside the pipes after the wells were put into production, leading to loss of production. This necessitated treatment of water and gas channeling in the annular space outside the pipes.

[0003] The application number is CN201921254573.1, and the application date is August 5, 2019. It discloses an external pipe sealing device. The device includes a packer, a cement retainer, and a liquid flow conversion structure. It has relatively independent liquid inlet and return channels. The return channel is connected from top to bottom. The upper end of the liquid inlet channel passes through the upper end of the liquid flow conversion structure, and the lower end passes through the lower end side of the liquid flow conversion structure. The outer pipe is provided with a return outlet connected to the return channel. The inner pipe has a lower end sealedly connected to the upper end of the liquid inlet channel, an upper end extending through the packer, and an upper end extending into the outer pipe and located above the return outlet. A sealing member is used to seal the annulus between the inner pipe and the outer pipe. The oil pipe is connected to the upper end of the outer pipe and is internally connected to the inner pipe. The cannula is connected to the lower end of the liquid flow conversion structure and is connected to the return channel. Since the sealing agent passes through the upper stratum first, the upper stratum is subjected to greater pressure, while the lower stratum is subjected to less pressure. Less sealing agent enters the lower stratum, which can better protect the lower stratum.

[0004] Application number CN201410535075.X, filed on October 11, 2014, discloses a method for sealing external channeling in oil wells. The method comprises: locating the water-producing layer of the external channeling by using a boron neutron water search method; injecting ash into the oil well to seal the layer; and performing a patching operation on the inner wall of the oil well at a position above the top of the water-producing layer; injecting a chemical plugging agent into the oil well so that the top of the chemical plugging agent is located at a specified position above the water-producing layer; drilling the chemical plugging agent to the specified position using a drill string; injecting ash into the layer using a drill string to seal the layer; performing a patching operation in the original production layer, and finally completing the well. This document utilizes a chemical plugging agent to seal the channel of the external channeling groove connecting oil and water, thereby preventing formation water in the water layer from entering the wellbore, eliminating the interference of the water layer with the target oil layer, reducing the overall water content of the oil well produced fluid, restoring normal production of the oil well, and improving the efficiency of oil well production. However, this document fails to consider formation porosity and liquid absorption, ideally assuming a zero-porosity, zero-permeability formation. In reality, however, formation absorption and permeability are significantly correlated. This leads to significant limitations in this document. When the formation has high permeability, low formation energy, and high absorption, this approach cannot effectively isolate water-gas channeling. It may even allow the plugging agent to enter the reservoir, blocking it and causing permanent damage. Both external plugging agents are affected by pressure and gas channeling within the water-gas channel, and fail to consider their dissolution and erosion effects on cement. Summary of the Invention

[0005] The present invention provides a reservoir protection circulation method for controlling water and gas channeling outside the casing. The first purpose is to overcome the problem that the existing technology will cause oil layer pollution during squeezing and sealing, the cement slurry whose flow direction cannot be controlled cannot effectively enter the water and gas channel outside the pipe, and the conventional cement slurry has no effect on water and gas dissolution and erosion; the second purpose is to overcome the problem that the existing technology cannot effectively seal the water and gas channel when the formation permeability is large, the formation energy is low, and the absorption capacity is large, and even causes the plugging agent to enter the reservoir, thereby blocking the reservoir and causing permanent damage.

[0006] To this end, the present invention provides a reservoir protection circulation method for controlling water-gas crosstalk outside casing, comprising the following steps:

[0007] 1) Flushing the production wellbore until it is clean and unobstructed;

[0008] 2) Conduct pressure test on casing outside the production layer to ensure the integrity of the outer casing outside the production layer;

[0009] 3) Inject reservoir protection gel into the perforated section of the production layer through the oil pipe to fill the pores of the production layer with the reservoir protection gel; after the filling is completed, clean the remaining reservoir protection gel in the casing;

[0010] 4) Drill engineering holes on the casing at the water-producing layer or gas-producing layer;

[0011] 5) The packer is delivered to the sealing location through the oil pipe and is seated, forming a circulation channel after the sealing. The sealing location is located between the perforated section of the production layer and the engineering hole;

[0012] 6) Inject the plugging agent system into the circulation channel to fill the annular channel outside the casing;

[0013] 7) Pull out the tubing and packer, wait for the filled plugging agent system to solidify to the set time, drill out the plug, and then perforate the producing layer to resume production.

[0014] Preferably, the production well is a water-gas crossover production well caused by casing cement sheath isolation failure.

[0015] Preferably, when squeezing the reservoir protection gel, the injection pressure is below the breakdown pressure of the production layer.

[0016] Preferably, the squeezed amount of the reservoir protection gel is calculated according to the depth of the perforation section, the static liquid level in the wellbore during production, and the formation pressure.

[0017] Preferably, the reservoir protection gel has a density of

[0018] 1.02-1.04g / cm 3 , the base liquid viscosity is 15-27mPa·s.

[0019] Preferably, when the perforated section of the production layer is located above the engineering hole, the circulation channel is tubing-packer-engineering hole-annular channeling groove-production layer perforated section-casing annulus.

[0020] Preferably, when the perforated section of the production layer is located below the engineering hole, the circulation channel is tubing-packer-perforated section of the production layer-annular channeling groove-engineering hole-casing annulus.

[0021] Preferably, the pumping volume of the plugging agent system requires that the plugging agent system completely fills the annular channeling groove outside the casing, and the static liquid columns inside and outside the circulation channel are balanced.

[0022] Preferably, the water loss of the plugging agent system is less than 30 mL.

[0023] Preferably, the packer is a squeeze packer.

[0024] Beneficial effects of the present invention:

[0025] 1. The reservoir protection circulation method provided by the present invention is a method for controlling water and gas channeling outside the casing. First, the oil layer is protected by gel, and the reservoir protection gel is squeezed into the perforated section of the production layer through the oil pipe so that the reservoir protection gel fills the pores of the production layer; after the filling is completed, the remaining reservoir protection gel in the casing is cleaned; an engineering hole is perforated on the casing at the water-producing layer or the gas-producing layer; a packer is sent to a sealing position through the oil pipe and sealed, and a circulation channel is formed after the sealing, and the sealing position is located between the perforated section of the production layer and the engineering hole; a plugging agent system is injected into the circulation channel so that the plugging agent system fills the annular channeling groove outside the casing; the oil pipe and the packer are pulled out, and the plugging agent system to be filled solidifies for a set time, and the production layer is perforated to resume production after drilling. By injecting the plugging agent system into the formed channel through the circulation channel, the plugging agent system can be effectively guided into the annular water channel, thereby achieving effective blocking of the water and gas channels under various pressure systems of the water-producing layer and reservoir, reducing the problem of solid phase contamination caused by cement slurry squeezing into the formation, and avoiding the problems of water and gas dissolution and erosion during conventional cement slurry injection.

[0026] 2. The reservoir protection circulation method provided by the present invention for controlling water and gas crosstalk outside the casing uses an oil pipe to squeeze reservoir protection gel into the perforated section of the production layer, so that a sufficient amount of reservoir protection gel is filled in the pores of the production layer near the casing. Relying on the viscosity and strength of the reservoir protection gel, the unidirectional pressure bearing capacity of the production layer is improved, so that a shielding temporary plugging layer is formed in the production layer near the perforated section of the production layer.

[0027] 3. The reservoir protection circulation method provided by the present invention for controlling water and gas channeling outside the casing can temporarily block the pores of the production layer and automatically degrade after construction or use a gel breaker to help break the gel, thereby releasing the reservoir pores without blocking or damaging the reservoir. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be described in further detail below with reference to the accompanying drawings.

[0029] Figure 1 This is a flow chart of the reservoir protection circulation method for controlling water and gas channeling outside the casing;

[0030] Figure 2 It is a schematic flow diagram of Example 1;

[0031] Figure 3 It is a schematic flow chart of Example 2.

[0032] Explanation of the accompanying symbols: 1. casing; 2. perforation section of the producing layer; 3. producing layer; 4. annular channel; 5. water-producing layer or gas-producing layer; 6. oil pipe; 7. reservoir protection gel; 8. packer; 9. plugging agent system; 10. engineering hole. DETAILED DESCRIPTION

[0033] like Figure 1As shown, a reservoir protection circulation method for controlling water and gas channeling outside the casing includes the following steps:

[0034] 1) Clean the production well casing 1 until it is clean and unobstructed;

[0035] 2) Conduct pressure test on the casing 1 outside the production layer 3 to ensure the integrity of the outer casing 1 around the production layer 3;

[0036] 3) Injecting the reservoir protection gel 7 into the perforated section 2 of the production layer through the oil pipe 6, so that the reservoir protection gel 7 fills the pores of the production layer 3; after the filling is completed, clean the remaining reservoir protection gel 7 in the casing 1;

[0037] 4) drilling an engineering hole 10 on the casing 1 at the water-producing layer or gas-producing layer 5;

[0038] 5) The packer 8 is delivered to the sealing location through the oil pipe 6 and sealed, forming a circulation channel after the sealing. The sealing location is located between the perforated section 2 of the production layer and the engineering hole 10;

[0039] 6) Inject the plugging agent system 9 into the circulation channel so that the plugging agent system 9 fills the annular channeling groove 4 outside the casing 1;

[0040] 7) The oil pipe 6 and the packer 8 are pulled out, and the plugging agent system 9 to be filled solidifies to the set time. After the plug is drilled out, the production layer 3 is perforated to resume production.

[0041] In the existing technology, the formation is set to be non-porous and non-absorbent to the plugging agent, which is contrary to the objective facts. The actual formation has absorption capacity and relative pressure. As a result, when using this method, the plugging agent cannot accurately flow into the annular channel outside the pipe during the squeezing process, and there may be situations where the plugging agent cannot be blocked or the plugging agent is completely squeezed into the formation. At the same time, the existing technology adopts the method of directly squeezing cement or plugging agents into the annular space outside the casing for treatment. However, due to the different pressures of the formation and the water annular channel, the blockage of water and gas in the annular space is different, resulting in the plugging agent squeezing into the oil layer during the sealing or the annular water and gas channel is not completely blocked. After the sealing outside the pipe, the pores of the oil layer may be severely blocked by the plugging agent, resulting in no liquid production, the water and gas channel cannot be effectively blocked, and the production well continues to produce water and gas after resuming production.

[0042] The present invention first uses tubing to inject reservoir protection gel into the perforated section 2 of the producing layer, filling the pores of the producing layer near the casing with a sufficient amount of the gel. Leveraging the viscosity and strength of the gel, the unidirectional pressure-bearing capacity of the producing layer is enhanced, forming a temporary barrier layer in the producing layer near the perforated section 2. The gel temporarily blocks the pores of the producing layer 3 and then degrades automatically or after gel breakage after application, releasing the reservoir pores without clogging or damaging the reservoir. Then, tubing 6 is used to deliver a packer 8 between the perforated section 2 of the producing layer and the engineered hole 10 for seating. This sealing creates a circulation channel. Unlike existing methods that directly inject the plugging agent into the annulus and oil layer, the present invention injects a plugging agent system into the formed circulation channel, effectively guiding the plugging agent system into the annular water channel. This allows for effective sealing of the water and gas channel under various pressure regimes within the water-producing layer and reservoir, reducing the problem of solid-phase contamination caused by cement slurry extrusion into the formation and avoiding the water-gas dissolution and erosion issues associated with conventional cement slurry injection.

[0043] Preferably, the production well is a water-gas crossover production well caused by casing cement sheath isolation failure.

[0044] The present invention is aimed at treating production wells after water-gas crossover is caused by failure of casing cement sheath isolation.

[0045] Preferably, when squeezing the reservoir protection gel 7 , the injection pressure is below the breaking pressure of the production layer 3 .

[0046] Preferably, the squeezed amount of the reservoir protection gel 7 is calculated according to the depth of the perforation section, the static liquid level in the wellbore during production, and the formation pressure.

[0047] The calculation method is an existing technology, which ensures that the pressure of the wellbore after squeezing can meet the pressure requirements required for sealing the channel in the later construction.

[0048] Preferably, the reservoir protection gel 7 has a density of 1.02-1.04 g / cm at room temperature after being prepared. 3 , the base liquid viscosity is 15-27mPa·s.

[0049] Reservoir Protection Gel 7 is a weak gel system composed of a relatively low molecular weight polymer and an organic crosslinker, forming a three-dimensional network structure dominated by intermolecular crosslinking. This reservoir protection gel system is in the form of an aqueous solution before crosslinking. After the crosslinking reaction, it forms an unstable network gel structure in the formation, which acts as a temporary plugging and fluid loss reducer during construction. After gelling, it gradually breaks down and degrades under the influence of formation temperature or the action of an internal slow-release breaker, causing minimal damage to the reservoir. After preparation, the density at room temperature is 1.02-1.04 g / cm 3; The base liquid viscosity is 15-27mPa·s; the gelation time at 60℃ is controllable at 5-15h; the applicable temperature after gelation is 40-90℃; the gelation strength is 5000-20000mPa·s; the reservoir protection gel 7 uses the existing gel, and it is selected according to the specific situation when used.

[0050] Preferably, when the production layer perforation section 2 is located above the engineering hole 10 , the circulation channel is the oil pipe 6 - packer 8 - engineering hole 10 - annular channel 4 - production layer perforation section 2 - casing annulus.

[0051] This circulation channel is suitable for effectively blocking the water and gas producing layer when the perforation section 2 of the production layer is located above the engineering hole 10.

[0052] Preferably, when the production layer perforation section 2 is located below the engineering hole 10, the circulation channel is the oil pipe 6 - packer 8 - production layer perforation section 2 - annular channel 4 - engineering hole 10 - casing annulus.

[0053] This circulation channel is suitable for effectively blocking the water and gas producing layer when the perforation section 2 of the production layer is located below the engineering hole 10.

[0054] Preferably, the pumping amount of the plugging agent system 9 requires that the plugging agent system 9 completely fills the annular channeling groove 4 outside the casing 1, and the static liquid columns inside and outside the circulation channel are balanced, ensuring that the annular channeling groove 4 outside the casing is fully filled and effective plugging is achieved.

[0055] Preferably, the water loss of the plugging agent system 9 is less than 30 ml (6.9 MPa / 30 min).

[0056] The plugging agent system of the present invention can adopt the cement system used for well cementing in the oil testing industry, or other plugging agent systems. However, the performance index of the plugging agent is that the water loss of the plugging agent system is less than 30 ml (6.9 MPa / 30 min), ensuring that the plugging agent system effectively blocks the annular channeling groove 4 outside the casing 1.

[0057] Preferably, the packer 8 is a squeeze packer.

[0058] The squeeze-in type packer is easy to expand and contract, that is, easy to seal and unseal, and is easy to operate. After squeezing the temporary plugging agent system, the drill can be quickly lifted. The sealing position can be determined according to the actual situation on site, reducing the risk of the pipe string being fixed. After the squeezing is completed, the packer can be pulled out without the need for drilling accessories, effectively shortening the drilling and plugging operation. It has good sealing performance and can effectively seal the annulus between the squeezed oil pipe and the casing to prevent the plugging agent from leaking into the groove.

[0059] Example 1:

[0060] like Figure 2As shown in Figure 1, the pay zone of Well A is buried at a depth of 1500m and 5m thick. The perforated section of the pay zone is 1500-1502m. After it was put into production, the well had high water content and no production. The cementing quality test found that the cementing quality 50m below the pay zone was unqualified. The unqualified cementing quality section included a 20m water layer at the bottom. There was no cement isolation in the 50m between the lower water layer and the pay zone, forming a water channel. The water produced by the water layer followed the water channel without cement isolation in the annulus outside the pipe to the perforated section of the pay zone and entered the wellbore, resulting in high water content and no production in the pay zone (see Figure 1). Figure 2 (Image of water breakthrough in the middle annular space). A reservoir protection circulation method was used to control water and gas breakthrough outside the casing.

[0061] The reservoir protection circulation method for controlling water and gas channeling outside the casing is as follows:

[0062] 1) Wash the wellbore to 1550m to ensure it is clean and unobstructed;

[0063] 2) Conduct pressure test on casing outside the pay zone (0-1549m, 1504-bottomhole) to verify casing integrity;

[0064] 3) Use the smooth oil pipe to go down to 1500m and squeeze 30m into the production layer through the perforation section 2 of the production layer 3 Reservoir protection gel (see Figure 2 (Image of protective gel injection); then the remaining reservoir protective gel in the wellbore is cleaned out;

[0065] 4) Perforate the well at 1549-1550 m where the cementing quality is poor, with a perforation length of 1 m;

[0066] 5) Use tubing to insert a squeeze packer between the perforated section 2 of the pay zone and the engineering hole 10 (1502-1519 m) and set the packer. After setting the packer, a circulation channel is formed: tubing 6 - packer 8 - engineering hole 10 - annular channel - pay zone perforated section 2 - casing annulus;

[0067] 6) Test the flow pressure of the circulation channel and pump 3m of cement slurry system into the circulation channel. 3 , replace 4m of clean water 3 (See Figure 2 Reservoir protection method to control water and gas breakthrough outside casing (Figure);

[0068] 7) Remove the tubing and squeeze packer, wait for the filled cement slurry system to solidify to the set time, drill the plug, and then perforate the producing layer 3 to resume production.

[0069] The squeeze sealing method was used to seal two production wells outside the pipe. After resumption of production, the average daily oil production of the production wells was 0.23 tons, and the daily liquid production was only 1m 3Cause analysis: Experimental research on reservoir contamination by cement slurry revealed that 3-50μm particles and solidified filtrate from the cement slurry hydrate component filled the rock pores. The research revealed that the natural invasion radius of the reservoir by cement slurry exceeded 1m, which exceeded the 0.6-0.85m depth of conventional perforation. The sweep radius of the cement slurry squeezed into the formation exceeded 5m, significantly leading to pore blockage near the wellbore. Squeeze caused the cement slurry to directly block the reservoir pores, resulting in poor oil and liquid flow.

[0070] After adopting the circulation method to control the external leakage of pipes, the average daily oil production of production wells is 0.88 tons and the daily liquid production is 2.73m3. 3 The circulation method increased oil production, reduced formation pollution, and ensured that the cement slurry effectively blocked the water and gas channel outside the pipe, but it did not solve the problem of cement slurry contamination of the production layer.

[0071] After adopting the method of Example 1, the average daily oil production of the production wells increased by 1.81 tons and the daily liquid production was 6.38m 3 This method significantly reduces the contamination of the reservoir. At the same time, according to laboratory test data, the density of the reservoir protection gel at room temperature after preparation is 1.02-1.04g / cm 3 The base fluid viscosity is 15-27mPa·s; the gelling time at 60℃ is controllable within 5-15h; the applicable temperature after gelling is 40-90℃; the gelling strength is 5000-20000mPa·s, which can effectively form a shielding protection layer for the production layer outside the casing. Through experiments, it was found that after the reservoir protection gel enters the formation, it can effectively fill the pores near the wellbore and be retained in the pores by viscosity, with a pore filling rate of up to 86%.

[0072] Example 2:

[0073] like Figure 3 As shown in the figure, the production layer of well b is buried at a depth of 1000m and 5m thick. The perforation section of the production layer is 1000-1002m. After it was put into production, the production well had high water content and no production. Through cementing quality testing, it was found that the cementing quality 200m above the production layer was unqualified. There was no cement water channel outside the upper water layer extending into the wellbore, resulting in high water content in the production well (see Figure 3 Annular water breakthrough diagram). Reservoir protection circulation method is used to control water and gas breakthrough outside the casing.

[0074] The reservoir protection circulation method for controlling water and gas channeling outside the casing is as follows:

[0075] 1) Wash the wellbore to 1010m to ensure it is clean and unobstructed;

[0076] 2) Conduct pressure test on casing outside the pay zone (0-999m, 1003-bottomhole) to verify casing integrity;

[0077] 3) Use the smooth oil pipe to go down to 1000m and squeeze 30m into the production layer through the perforation section 2 of the production layer 3 Reservoir protection gel (see Figure 3 Protective gel injection diagram); then clean out the remaining reservoir protective gel in the wellbore;

[0078] 4) Perforate the 950-951m well where the cementing quality is poor, with a perforation length of 1m;

[0079] 5) Use tubing to insert a squeeze packer between the perforated section 2 of the producing layer and the engineering hole 10 (950-1000m) and set the packer. After the packer is set, a circulation channel is formed from tubing 6 to packer 8 to perforated section 2 of the producing layer to annular channeling groove to engineering hole 10 to casing annulus.

[0080] 6) Test the flow pressure of the circulation channel and pump 3m of cement slurry system into the circulation channel. 3 , replacing 2.2m of clean water 3 (See Figure 3 (Figure 2) Reservoir protection method for controlling water and gas leakage outside casing;

[0081] 7) Remove the tubing and squeeze packer, wait for the filled cement slurry system to solidify to the set time, drill the plug, and then perforate the producing layer 3 to resume production.

[0082] After adopting the circulation method to control the external leakage of pipes, the average daily oil production of production wells is 0 tons and the daily liquid production is 13.4m 3 The interpretation of cementing quality testing after plugging the pipe channel indicated a lack of cement bonding at both the primary and secondary interfaces. Analysis of the cause: Most cement slurry hydrate components, particles 3-50 μm in size, and solidifiable filtrate, were affected by the hydrostatic pressure and, when using the circulation method to control pipe channeling, lost their presence to the producing formation. The cement slurry and filtrate filled the rock pores, and the sweep radius of the cement slurry entering the formation exceeded 3 m, significantly blocking pores near the wellbore. This resulted in water discharge from the upper water layer along the pipe channeling path.

[0083] After adopting the method of Example 2, the average daily oil production of the production wells increased by 2.54 tons and the daily liquid production was 6.68m 3 This method significantly reduces the contamination of the reservoir. At the same time, according to laboratory test data, the density of the reservoir protection gel at room temperature after preparation is 1.02-1.04g / cm 3 The base fluid viscosity is 15-27 mPa·s; the gelation time at 60°C is controllable, ranging from 5-15 hours; the applicable temperature after gelation is 40-90°C; and the gelation strength is 5,000-20,000 mPa·s, effectively forming a shielding layer for the production zone outside the casing. Tests have shown that the reservoir protection gel effectively fills the pores near the wellbore after entering the formation and is retained in the pores through viscosity. The pore filling rate can reach 90%, effectively increasing the wellbore's static fluid column pressure bearing capacity by 10 MPa in practical applications, effectively forming a shielding layer.

[0084] In the description of the present invention, it should be understood that if there are terms such as "upper", "inside", and "lower" indicating an orientation or positional relationship, these are based on the orientation or positional relationship shown in the accompanying drawings, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention.

[0085] The above examples are merely illustrative of the present invention and do not limit the scope of protection of the present invention. Any design that is identical or similar to the present invention falls within the scope of protection of the present invention.

Claims

1. A reservoir protection circulation method for controlling water and gas channeling outside casing, characterized by: The steps include: 1) Flushing the production wellbore until it is clean and unobstructed; 2) Conducting pressure testing on the casing (1) outside the production layer (3) to ensure the integrity of the production layer (3) and the outer casing (1); 3) injecting reservoir protection gel (7) into the perforation section (2) of the production layer through the oil pipe (6) so that the reservoir protection gel (7) fills the pores of the production layer (3); after the filling is completed, the remaining reservoir protection gel (7) in the casing (1) is cleaned; after the reservoir protection gel (7) is configured, the density is 1.02-1.04 g / cm3 at room temperature, the base fluid viscosity is 15-27 mPa•s, and the gelling time at 60°C is controllable at 5-15 hours; the applicable temperature after gelling is 40-90°C; and the gelling strength is 5000-20000 mPa•s; 4) drilling an engineering hole (10) on the casing (1) at the water-producing layer or gas-producing layer (5); 5) The packer (8) is delivered to the sealing location through the oil pipe (6) and sealed, and a circulation channel is formed after the sealing, wherein the sealing location is located between the perforated section (2) of the production layer and the engineering hole (10); 6) injecting a plugging agent system (9) into the circulation channel so that the plugging agent system (9) fills the annular channeling groove (4) outside the casing (1); 7) The oil pipe (6) and the packer (8) are lifted out, and the plugging agent system (9) to be filled solidifies to a set time. After drilling the plug, the production layer (3) is perforated to resume production.

2. The reservoir protection circulation method for controlling water and gas channeling outside casing according to claim 1, characterized in that: The production well is a water-gas crossover production well caused by casing cement sheath isolation failure.

3. The reservoir protection circulation method for controlling water and gas channeling outside casing according to claim 1, characterized in that: When squeezing the reservoir protection gel (7), the squeezing injection pressure is below the ground breaking pressure of the production layer (3).

4. The reservoir protection circulation method for controlling water and gas channeling outside casing according to claim 1, characterized in that: The injection volume of the reservoir protection gel (7) is calculated according to the depth of the perforation section, the static liquid level in the wellbore during production, and the formation pressure.

5. The reservoir protection circulation method for controlling water and gas channeling outside casing according to claim 1, characterized in that: When the production layer perforation section (2) is located above the engineering hole (10), the circulation channel is the oil pipe (6) - packer (8) - engineering hole (10) - annular channel (4) - production layer perforation section (2) - oil casing annulus.

6. The reservoir protection circulation method for controlling water and gas cross-contamination outside casing according to claim 1, characterized in that: When the production layer perforation section (2) is located below the engineering hole (10), the circulation channel is the oil pipe (6) - packer (8) - production layer perforation section (2) - annular channel (4) - engineering hole (10) - oil casing annulus.

7. The reservoir protection circulation method for controlling water and gas channeling outside casing according to claim 1, characterized in that: The pumping amount of the plugging agent system (9) requires that the plugging agent system (9) completely fills the annular channeling groove (4) outside the casing (1), and the static liquid columns inside and outside the circulation channel are balanced.

8. The reservoir protection circulation method for controlling water and gas cross-contamination outside casing according to claim 7, characterized in that: The water loss of the plugging agent system (9) is less than 30 ml / 30 min.

9. The reservoir protection circulation method for controlling water and gas cross-contamination outside casing according to claim 1, characterized in that: The packer (8) is a squeeze-type packer.

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