Edge water prevention and control method

Abstract

The invention discloses an edge water prevention and control method, and relates to the field of oil reservoir development, and the method comprises the following steps: controlling the difference value between the edge pressure of a target oil reservoir and the formation pressure value to be within a preset difference value range; the self-produced super-heavy oil of the target oil reservoir is heated and dispersed, so that the viscosity of the self-produced super-heavy oil is reduced to preset viscosity; injecting the self-produced thick oil with reduced viscosity into an edge water control area so as to enable the self-produced thick oil to be injected into a protective layer to reach a preset thickness; injecting self-produced sewage of the combination station into the protective layer; and injecting a preset volume of air into the protective layer.

Description

Technical Field

[0001] The present specification relates to the field of oil reservoir development, and more specifically, the present application relates to an edge water control method. Background Art

[0002] SAGD (Steam-Assisted Gravity Drainage) is a thermal recovery technology used for oil recovery, mainly used for heavy oil sands and oil shale. SAGD is a surface oil recovery technology, usually used for oil sands and oil shale. This technology is suitable for the development of heavy oil or extra heavy oil with thick oil layers, high oil content in the reservoir, and no interlayers in the oil layers.

[0003] Edge water usually refers to water in underground reservoirs. When conducting oil exploration and production, oil and natural gas are usually located underground, and the water mixed with them is usually called edge water. In the process of oil and gas development, it is necessary to effectively prevent and control edge water to solve the problem of steam chamber expansion to the edge. However, the existing methods have limited edge water control capabilities and are prone to edge water invasion, which in turn affects oil and gas production and production safety. Summary of the invention

[0004] A series of simplified concepts are introduced in the Summary of the Invention section, which will be further described in detail in the Detailed Description of the Invention section. The Summary of the Invention section of this application does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0005] In the first aspect, the present application proposes a method for edge water prevention and control, comprising:

[0006] Control the difference between the edge pressure and the formation pressure of the target reservoir within a preset difference range;

[0007] Heating and dispersing the self-produced super-heavy oil in the target reservoir to reduce the viscosity of the self-produced super-heavy oil to a preset viscosity;

[0008] Inject the self-produced heavy oil after reducing the viscosity into the edge water control area, so that the injection protection layer reaches a preset thickness;

[0009] Inject the self-produced sewage of the joint station into the above-mentioned protective layer;

[0010] A preset volume of air is injected into the protective layer.

[0011] In some embodiments, the target oil reservoir comprises at least a first row of injection wells, a second row of injection wells and a third row of injection wells, and the distances between the first row of injection wells, the second row of injection wells and the third row of injection wells and the edge gradually increase.

[0012] In some embodiments, the difference between the edge pressure and the formation pressure of the target reservoir is controlled to be within a preset difference range, including:

[0013] The steam injection intensity of the second row of injection wells and the third row of injection wells is increased to control the difference between the edge pressure and the formation pressure of the target reservoir within a preset difference range.

[0014] In some embodiments, the heating and dispersion operation of the self-produced super-heavy oil in the target reservoir comprises:

[0015] Heating the self-produced extra-heavy oil of the target reservoir to a preset temperature;

[0016] A viscosity reducing dispersant is added to the self-produced super-heavy oil heated to the preset temperature and a dispersing and stirring operation is performed, wherein the viscosity reducing dispersant is a mixture of an ether compound, a sulfonate and a surfactant.

[0017] In some embodiments, injecting the self-produced heavy oil after reducing viscosity into the marginal water control area comprises:

[0018] The self-produced heavy oil after reducing viscosity is injected into the marginal water control area through the first row of injection wells.

[0019] In some embodiments, injecting the self-produced heavy oil after reducing viscosity into the marginal water control area through the first row of injection wells comprises:

[0020] Based on the intermittent pumping method, the self-produced heavy oil with reduced viscosity is injected into the marginal water control area through the first row of injection wells.

[0021] In some embodiments, the second row of injection wells includes a second row of first injection wells and a second row of second injection wells, and the second row of first injection wells and the second row of second injection wells are arranged alternately;

[0022] The above-mentioned injection of self-produced sewage from the joint station into the above-mentioned protective layer includes:

[0023] The self-produced sewage of the joint station is injected into the above-mentioned protective layer through the above-mentioned second row of first injection wells.

[0024] In some embodiments, the step of injecting the self-produced sewage of the joint station into the protective layer through the second row of first injection wells comprises:

[0025] Monitor the temperature information of the above target reservoirs

[0026] Based on the temperature information, the injection amount of the self-produced sewage of the joint station is injected into the protective layer by the first injection well of the second row, wherein the injection amount is negatively correlated with the temperature information, and the maximum value of the injection amount is the output of the self-produced sewage of the joint station.

[0027] In some embodiments, injecting a preset volume of air into the protective layer comprises:

[0028] A preset volume of air is injected into the protective layer through the second row of second injection wells.

[0029] In some embodiments, the preset difference is 0.1 MPa to 0.2 MPa; and / or,

[0030] The preset viscosity is 2000mPa.s to 3000mPa.s; and / or,

[0031] The preset thickness is 1m to 2m; and / or,

[0032] The above preset volume is 200 to 250 times the injection volume of the self-produced heavy oil.

[0033] In summary, the edge water control method of the embodiment of the present application includes: controlling the difference between the edge pressure and the formation pressure of the target reservoir within a preset difference range; heating and dispersing the self-produced super-heavy oil of the above target reservoir to reduce the viscosity of the above self-produced super-heavy oil to a preset viscosity; injecting the above self-produced heavy oil after reducing the viscosity into the edge water control area to inject the protective layer to a preset thickness; injecting the self-produced sewage of the joint station into the above protective layer; injecting a preset volume of air into the above protective layer. The edge water control method proposed in the embodiment of the present application combines thickening the asphalt shell with water injection cooling, and adopts a five-step technical approach of controlling and reducing edge pressure, reducing viscosity and dispersing adjustment, supplementing asphalt medium, temperature reduction control reaction and air low-temperature oxidation to form a systematic SAGD edge water control method, strengthen the water retaining function of the asphalt shell, effectively improve the safety during oil and gas development, and improve oil and gas production efficiency. In addition, the method utilizes the super-heavy oil produced by the oil field, the sewage separated by the joint station, and the air as injection media, with low operating costs, and solves the problems of difficulty and insufficient capacity in sewage treatment due to overload operation of the joint station in the oil field. Super-heavy oil, sewage separated by the joint station, and air can be injected in large doses, and the formed thickened heavy oil can be used as a supplement to the natural asphalt shell, which can better isolate the intrusion of edge water.

[0034] The edge water control method proposed in this application, and other advantages, objectives and features of this application will be reflected in part through the following description, and in part will also be understood by technical personnel in this field through research and practice of this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present specification. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0036] Figure 1 A schematic diagram of the process of edge water prevention and control method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0037] The edge water prevention and control method proposed in the embodiment of the present application combines thickening of the asphalt shell with water injection cooling and temperature reduction, and adopts the technical idea of ​​controlling and reducing edge pressure, reducing viscosity and dispersing adjustment, supplementing asphalt medium, temperature reduction control reaction and air low-temperature oxidation in five steps to form a systematic SAGD edge water prevention and control method, strengthen the water-blocking function of the asphalt shell, effectively improve the safety in the oil and gas development process, and improve the efficiency of oil and gas extraction. In addition, this method uses the self-produced super-heavy oil of this oil field, the sewage separated by the joint station, and the air as the injection medium, and the operating cost is low. It solves the problem of difficulty and insufficient capacity of sewage treatment in this oil field due to the overload operation of the joint station. Super-heavy oil, sewage separated by the joint station, and air can be injected in large doses. The thickened thick oil formed as a supplement to the natural asphalt shell can better isolate the invasion of edge water.

[0038] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0039] The target layer for SAGD development can be Guantao oil layer, which is a thick block super-heavy oil reservoir with top and bottom water. The reservoir is buried at a depth of 515-720m. There is no pure mudstone interlayer between the oil layer and the water body. The oil-bearing area is 1.92km2, the thickness of the oil layer is between 23.6 and 126.6m, the average thickness is 77.0m, and the reported geological reserves are 26.26 million tons. In a certain oil field area, the SAGD pilot test was started in 2005, and all of them were transferred to SAGD development in 2009. By the end of May 2023, the cumulative gas injection was 17.4 million tons, the cumulative liquid production was 21.55 million tons, the cumulative oil production was 5.298 million tons, the production-injection ratio was 1.24, the oil-gas ratio was 0.30, the recovery degree was 67.0%, and the oil production rate was 3.2%. In the plane, the steam chamber is fully formed, showing the characteristics of "high in the west and low in the east, high in the north and low in the south". Affected by the shielding of the 600m low physical property section, the steam chamber began to expand horizontally in 2016. At present, the steam chamber has reached the reservoir boundary, 40-50m away from the edge water. Vertically, affected by the shielding of the 600m low physical property section, the overall steam chamber has reached the top. The top boundary of the main steam chamber is at 590-610m (50-80m away from the top boundary of the oil layer), and the recovery rate in the steam chamber has reached 90%. With the lateral expansion of the steam chamber, on July 14, 2018, the temperature test of the new well Du 84-65-51 found that the temperature at 622m (vertical depth 612m) was 167℃, and the resistivity dropped from 243Ω·m to 30Ω·m. After the temperature anomaly appeared, the vertical wells passing through the well area were quickly checked, 15 wells were selected to be converted into monitoring wells, the edge monitoring well network was improved, and the temperature changes were closely tracked to monitor the expansion of the steam chamber. On November 3, 2018, the temperature of Du 84-65-51 Well rose to 214°C. The temperatures of the five observation wells outside the surrounding area did not show abnormal high temperatures. On December 7, 2018, Du 84-65-51 Well was sealed by squeezing ultrafine cement, and 360m of mortar was squeezed. 3 (Calculated based on a treatment radius of 10m), the ash squeezing pressure is stable at 8MPa. After plugging (December 11, 2018), the test temperature dropped from 214°C to 51°C; 2 months later (February 12, 2019), the test temperature rose to 238°C, which was higher than the temperature before plugging. Starting in March 2019 (3 ​​months after plugging), 3 new wells with abnormal temperatures were added to the edge. The temperature of the outermost observation well rose rapidly from 38°C to 173°C within half a year, confirming that the steam cavity is only about 30m away from the edge water, facing the risk of edge water intrusion, which seriously threatens the safety of Guantao's 800,000-ton production.

[0040] Therefore, it is urgent to study a method for edge water prevention and control in the SAGD development of thick-layered massive ultra-heavy oil reservoirs to solve the problem that the steam chamber advances to the edge during expansion, which easily causes edge water invasion and thus seriously threatens Guantao's 800,000 tons of production.

[0041] Patent CN113283092A discloses a method and system for constructing a three-dimensional physical model of edge and top water intrusion; Patent CN112963128A discloses a method for reducing steam chamber overflow and preventing top water from flowing downward during SAGD development; Patent CN112943194A discloses a method for preventing edge water intrusion during SAGD development; "Special Oil and Gas Reservoirs" 2021 Issue 04, Description and Control Measures for the Steam Chamber of SAGD in Ultra-Heavy Oil Reservoirs with Edge and Top Water discloses a method for balancing and controlling the steam chamber.

[0042] The methods for preventing edge and top water mentioned in the above patents and articles involve regulating the steam chamber pressure or shutting down the steam injection wells to control the steam volume. There are problems such as insufficient prevention and control capabilities or difficulty in regulation. They are only suitable in the early stages of SAGD development. At this stage, the steam chamber is only about 30m away from the edge water, and this prevention and control method is still slightly insufficient, affecting the implementation effect and the accuracy of prevention and control.

[0043] See also Figure 1 , which is a schematic diagram of the process of a water edge prevention and control method provided in an embodiment of the present application, which may specifically include:

[0044] S110, controlling the difference between the edge pressure and the formation pressure of the target reservoir to be within a preset difference range;

[0045] Exemplarily, the target oil reservoir is the oil reservoir to be exploited using SAGD technology, the edge pressure is the pressure near the edge water, and the formation pressure is the formation pressure in the area where the target oil reservoir is located. The difference between the edge pressure and the formation pressure is controlled within a preset difference range, which may be within the range of 0.1-0.2 MPa, to create conditions for subsequent injection of asphalt medium into the edge asphalt shell layer.

[0046] S120, heating and dispersing the self-produced super-heavy oil of the target oil reservoir to reduce the viscosity of the self-produced super-heavy oil to a preset viscosity;

[0047] For example, the extra heavy oil produced by the oil field, which is an oil product with a colloidal asphaltene content between 40-55%, can be heated on site and stirred by adding a certain amount of viscosity-reducing dispersant to reduce the viscosity of the extra heavy oil to a preset viscosity, thereby achieving low-viscosity pumping. The preset viscosity can be 2000-3000mPa.s.

[0048] S130, injecting the self-produced heavy oil after reducing the viscosity into the edge water control area, so that the injection protection layer reaches a preset thickness;

[0049] For example, the self-produced heavy oil with reduced viscosity is injected into the marginal water control area to form a protective layer and ensure that it reaches a preset thickness. The formation of this protective layer may help control and stabilize oil reservoir production S140, inject the self-produced sewage of the joint station into the above protective layer;

[0050] Exemplarily, the self-produced sewage of the joint station is injected into the protective layer, and the sewage injection amount is controlled to accelerate the cooling as quickly as possible (below 200° C.) without causing the steam cavity to shrink.

[0051] S150, injecting a preset volume of air into the protective layer.

[0052] For example, the preset volume is calculated based on the amount of injected super-heavy oil, and air is injected to thicken the super-heavy oil underground, which is then added to the surface of the natural asphalt shell to form a dense protective layer.

[0053] In summary, the edge water prevention and control method proposed in the embodiment of the present application combines thickening of the asphalt shell with water injection cooling and temperature reduction, and adopts the technical idea of ​​controlling and reducing edge pressure, reducing viscosity and dispersing adjustment, supplementing asphalt medium, temperature reduction control reaction and air low-temperature oxidation in five steps to form a systematic SAGD edge water prevention and control method, strengthen the water retaining function of the asphalt shell, effectively improve the safety in the oil and gas development process, and improve the efficiency of oil and gas extraction. In addition, this method uses the self-produced super-heavy oil of this oil field, the sewage separated by the joint station, and the air as the injection medium, and the operating cost is low. It solves the problem of difficulty and insufficient capacity of sewage treatment in this oil field due to the overload operation of the joint station. Super-heavy oil, sewage separated by the joint station, and air can be injected in large doses. The thickened thick oil formed as a supplement to the natural asphalt shell can better isolate the invasion of edge water.

[0054] In some embodiments, the target oil reservoir comprises at least a first row of injection wells, a second row of injection wells and a third row of injection wells, and the distances between the first row of injection wells, the second row of injection wells and the third row of injection wells and the edge gradually increase.

[0055] Exemplarily, the target reservoir includes at least three rows of injection wells, which are respectively referred to as "first row of injection wells", "second row of injection wells" and "third row of injection wells". These wells are used to inject steam or other media to assist in the recovery of super-heavy oil. There is a gradually increasing distance between the injection wells in different rows and the edge of the reservoir. The first row of injection wells is closest to the edge of the reservoir, while the third row of injection wells is farthest from the edge. By arranging the wells in gradually increasing distances, the injection wells can be more evenly distributed to cover the entire reservoir, ensuring that the oil in the reservoir is more evenly thermally treated and recovered. This arrangement may help improve recovery efficiency, reduce energy waste, and minimize problems that may occur during the recovery process. The arrangement of gradually increasing distances may be intended to more effectively manage the recovery process of the reservoir.

[0056] In some embodiments, the difference between the edge pressure and the formation pressure of the target reservoir is controlled to be within a preset difference range, including:

[0057] The steam injection intensity of the second row of injection wells and the third row of injection wells is increased to control the difference between the edge pressure and the formation pressure of the target reservoir within a preset difference range.

[0058] Exemplarily, the steam injection intensity of the second and third rows of injection wells close to the edge water is increased, wherein the steam injection intensity of the second row of steam injection wells is increased by 3-6, and the steam injection intensity of the third row of steam injection wells is increased by 3.5-6.5. And adopt an "increase and observe" approach, and track the formation pressure values ​​of the area with increased steam injection intensity (the second and third rows of steam injection wells) and the area close to the edge water (the first row of steam injection wells) in real time through pressure monitoring data. When the difference between the two reaches 0.1-0.2MPa, stop increasing the steam injection intensity and keep the steam injection intensity unchanged.

[0059] In some embodiments, the heating and dispersion operation of the self-produced super-heavy oil in the target reservoir comprises:

[0060] Heating the self-produced extra-heavy oil of the target reservoir to a preset temperature;

[0061] A viscosity reducing dispersant is added to the self-produced super-heavy oil heated to the preset temperature and a dispersing and stirring operation is performed, wherein the viscosity reducing dispersant is a mixture of an ether compound, a sulfonate and a surfactant.

[0062] For example, the oilfield produces super-heavy oil, i.e., the content of colloid asphaltene components is between 40-55%, and the density of crude oil at 20°C is between 1.00-1.03 g / cm 3 , heated to 50-55°C by an on-site electric heating device, and a certain amount of viscosity-reducing dispersant is added for stirring. The composition of the viscosity-reducing dispersant is generally 0.3-0.5% ether compound + 0.2-0.5% sulfonate + 0.3-0.5% surfactant (such as: 0.3-0.5% alkylphenol polyoxyethylene ether + 0.2-0.5% sodium dodecylbenzene sulfonate + 0.3-0.5% betaine), which reduces the viscosity of the super-heavy oil to 2000-3000mPa.s and realizes low-viscosity pumping.

[0063] In some embodiments, injecting the self-produced heavy oil after reducing viscosity into the marginal water control area comprises:

[0064] The self-produced heavy oil after reducing viscosity is injected into the marginal water control area through the first row of injection wells.

[0065] For example, in the first row of injection wells near the edge water, the super-heavy oil produced in the oil field that meets the above conditions and has been heated and stirred is injected, and the continuous injection state can be maintained to ensure the injection volume, and to ensure that the final injection volume of the area reaches the asphalt shell thickening to the preset thickness in the edge water control area.

[0066] In some embodiments, injecting the self-produced heavy oil after reducing viscosity into the marginal water control area through the first row of injection wells comprises:

[0067] Based on the intermittent pumping method, the self-produced heavy oil with reduced viscosity is injected into the marginal water control area through the first row of injection wells.

[0068] For example, in the first row of injection wells near the edge water, the self-produced extra-heavy oil of the oil field that meets the above conditions and has been heated and stirred is injected, and intermittent pumping is adopted according to the injection pressure change, that is, the injection displacement is controlled at 0.3-0.5m 3 / min, the injection pressure is guaranteed to be within the rated pressure range allowed by the surface pump, generally 18-20MPa. When the injection pressure exceeds the rated pressure, the well is shut down and injection is stopped after displacing the hot sewage that exceeds the wellbore volume, and the injection is resumed when the pressure drops below 10MPa; if the injection pressure remains at a low level below the rated pressure, the continuous injection state can be maintained. The final injection volume is guaranteed to reach the asphalt shell thickening of 1-2m in the edge water control area.

[0069] In some embodiments, the second row of injection wells includes a second row of first injection wells and a second row of second injection wells, and the second row of first injection wells and the second row of second injection wells are arranged alternately;

[0070] The above-mentioned injection of self-produced sewage from the joint station into the above-mentioned protective layer includes:

[0071] The self-produced sewage of the joint station is injected into the above-mentioned protective layer through the above-mentioned second row of first injection wells.

[0072] Exemplarily, the second row of injection wells includes a plurality of injection wells, and the plurality of injection wells can be numbered consecutively along the circumference of the center of the reservoir, and the odd-numbered injection wells are defined as the first injection wells in the second row, and the even-numbered injection wells are defined as the second injection wells in the second row. Among the second row of injection wells close to the edge water, the odd-numbered wells are selected to inject the self-produced sewage of the joint station.

[0073] In some embodiments, the step of injecting the self-produced sewage of the joint station into the protective layer through the second row of first injection wells comprises:

[0074] Monitor the temperature information of the above target reservoirs

[0075] Based on the temperature information, the injection amount of the self-produced sewage of the joint station is injected into the protective layer by the first injection well of the second row, wherein the injection amount is negatively correlated with the temperature information, and the maximum value of the injection amount is the output of the self-produced sewage of the joint station.

[0076] Exemplarily, the amount of sewage injected is controlled to accelerate the cooling as quickly as possible (below 200°C) without causing the steam cavity to shrink. The maximum injection amount is the amount of sewage generated in the oil field every day. The formation temperature is monitored during injection, and the total injection amount is appropriately adjusted based on the monitored formation temperature. When the monitored temperature reaches below 200°C, the sewage injection amount is reduced to 60-80% of the original injection amount. When the monitored temperature reaches 150°C, the sewage injection amount is reduced to 30-60% of the original injection amount. When the monitored temperature reaches 100°C, 30% of the original injection amount is maintained and intermittent injection is performed.

[0077] In some embodiments, injecting a preset volume of air into the protective layer comprises:

[0078] A preset volume of air is injected into the protective layer through the second row of second injection wells.

[0079] For example, in the second row of injection wells near the edge water, an even number of wells is selected, i.e., the second row of second injection wells is injected with air, and the injection displacement is controlled at 800-1200 Nm 3 / h, the injection pressure is controlled at 5-10MPa, the injection volume is calculated based on the amount of super-heavy oil injected, and according to the low-temperature oxidation reaction process, it is generally injected at a volume ratio of super-heavy oil to air of 1:200-1:250, until the super-heavy oil undergoes low-temperature oxidation reaction underground to increase viscosity and is attached to the surface of the natural asphalt shell to form a dense protective layer.

[0080] In some embodiments, the preset difference is 0.1 MPa to 0.2 MPa; and / or,

[0081] The preset viscosity is 2000mPa.s to 3000mPa.s; and / or,

[0082] The preset thickness is 1m to 2m; and / or,

[0083] The above preset volume is 200 to 250 times the injection volume of the self-produced heavy oil.

[0084] In some implementation areas, the water control in the northwest of Guantao SAGD adopts the method proposed by this applicant, and the construction is designed according to the following implementation steps:

[0085] S210. Control and reduce the edge pressure: the steam injection intensity of the second row of steam injection wells was increased by 4.5, and the steam injection intensity of the third row of steam injection wells was increased by 5. The method of "increasing and observing" was adopted. Through pressure monitoring data, it was found that after 58 days of increasing the steam injection intensity, the difference between the formation pressure of the second and third rows of steam injection wells and the formation pressure of the first row of steam injection wells reached 0.2MPa, which met the design requirements of the scheme and kept the steam injection intensity unchanged.

[0086] S220, viscosity reduction and dispersion adjustment: The super-heavy oil produced by the oil field, that is, the content of colloid asphaltene components is between 40-55%, and the density of crude oil at 20℃ is between 1.00-1.03g / cm 3 , heated to 50-55℃ by on-site electric heating device, and added a certain amount of viscosity reducing dispersant for stirring. The viscosity reducing dispersant is composed of 0.3% alkylphenol polyoxyethylene ether + 0.35% sodium dodecylbenzene sulfonate + 0.4% betaine, which makes the viscosity of super heavy oil at room temperature from 20.3×10 4 mPa.s is reduced to 2500mPa.s, achieving low viscosity and stable pumping.

[0087] S230, asphalt medium injection: In the first row of injection wells near the edge water, inject the self-produced extra-heavy oil of the oil field that meets the above conditions and has been heated and stirred, that is, the injection displacement is controlled at 0.4m 3 / min, the injection pressure is 6-8MPa, and the continuous injection state can be maintained. The injection volume is 5800 cubic meters, ensuring that the final injection volume in this area reaches the asphalt shell thickening of the edge water control area by 1-2m.

[0088] S240, temperature drop control reaction: In the second steam injection well close to the edge water, select odd-numbered wells to inject the self-produced sewage of the joint station, and the sewage injection volume is controlled at 200-300m 3 / d, monitor the formation temperature while injecting, and when the injection time reaches 130 days, the monitored temperature reaches 180℃, and the wastewater injection volume is reduced to 150-200m 3 / d. When the temperature reaches 150℃ on the 230th day of injection, the sewage injection volume is reduced to 75-150m 3 / d, when the injection temperature drops to 100℃ on day 380, the temperature is kept at 75m 3 / dIntermittent injection.

[0089] S250, air low temperature oxidation: In the second row of steam injection wells near the edge water, select even-numbered wells to inject air, and control the injection displacement to 800-1200Nm 3 / h, the injection pressure is controlled at 5-10MPa, and the injection volume is 140×10 4 Before the measures were taken, four wells in the northwest of Guantao SAGD had abnormal temperatures, indicating that the area was only about 30m away from the edge water; after the measures were taken, the asphalt shell in the area thickened by 1.6m through core well monitoring, and the temperature of the four wells with abnormal temperatures decreased. After subsequent continuous monitoring, the effective period has lasted for more than one year.

[0090] In summary, the edge water prevention and control method proposed in the embodiment of the present application uses the super-heavy oil produced by the oil field, the sewage separated by the joint station, and the air as the injection medium, and the operating cost is low. It solves the problem of difficulty in sewage treatment and insufficient capacity due to the overload operation of the joint station in the oil field. Super-heavy oil, sewage separated by the joint station, and air can be injected in large doses, and the thickened thick oil formed can be used as a supplement to the natural asphalt shell to better isolate the intrusion of edge water. It provides an effective solution to the problem of edge water prevention and control in the SAGD development process.

[0091] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some of the technical features therein by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preventing and controlling edge water, characterized in that: include: Control the difference between the edge pressure and the formation pressure of the target reservoir within a preset difference range; Heating and dispersing the self-produced super-heavy oil in the target oil reservoir to reduce the viscosity of the self-produced super-heavy oil to a preset viscosity; Injecting the self-produced heavy oil after reducing viscosity into the edge water control area to inject the protective layer to a preset thickness; Injecting sewage produced by the joint station into the protective layer; A preset volume of air is injected into the protective layer.

2. The edge water control method according to claim 1, characterized in that: The target oil reservoir comprises at least a first row of injection wells, a second row of injection wells and a third row of injection wells, and the distances between the first row of injection wells, the second row of injection wells and the third row of injection wells and the edge gradually increase.

3. The edge water control method according to claim 2, characterized in that: The control of the difference between the edge pressure and the formation pressure of the target reservoir within a preset difference range includes: The steam injection intensity of the second row of injection wells and the third row of injection wells is increased to control the difference between the edge pressure and the formation pressure of the target reservoir within a preset difference range.

4. The edge water control method according to claim 1, characterized in that: The heating and dispersion operation of the self-produced super-heavy oil in the target oil reservoir comprises: Heating the self-produced extra-heavy oil in the target oil reservoir to a preset temperature; A viscosity reducing dispersant is added to the self-produced super heavy oil heated to the preset temperature and a dispersing and stirring operation is performed, wherein the viscosity reducing dispersant is a mixture of an ether compound, a sulfonate and a surfactant.

5. The edge water control method according to claim 2, characterized in that: The step of injecting the self-produced heavy oil after reducing viscosity into the marginal water control area comprises: The self-produced heavy oil with reduced viscosity is injected into the marginal water control area through the first row of injection wells.

6. The edge water control method according to claim 5, characterized in that: The step of injecting the self-produced heavy oil with reduced viscosity into the marginal water control area through the first row of injection wells comprises: Based on the intermittent pumping method, the self-produced heavy oil with reduced viscosity is injected into the marginal water control area through the first row of injection wells.

7. The edge water control method according to claim 2, characterized in that: The second row of injection wells includes a second row of first injection wells and a second row of second injection wells, and the second row of first injection wells and the second row of second injection wells are arranged at intervals; The step of injecting the self-produced sewage from the joint station into the protective layer comprises: The self-produced sewage of the joint station is injected into the protective layer through the second row of first injection wells.

8. The edge water control method according to claim 7, characterized in that: The step of injecting the self-produced sewage of the joint station into the protective layer through the second row of first injection wells comprises: Monitor the temperature information of the target reservoir Based on the temperature information, the injection amount of the self-produced sewage of the joint station is controlled by the second row of first injection wells into the protective layer, wherein the injection amount is negatively correlated with the temperature information, and the maximum value of the injection amount is the output of the self-produced sewage of the joint station.

9. The edge water control method according to claim 7, characterized in that: The step of injecting a preset volume of air into the protective layer comprises: A preset volume of air is injected into the protective layer through the second row of second injection wells.

10. The method for controlling edge water according to any one of claims 1 to 9, characterized in that: The preset difference is 0.1 MPa to 0.2 MPa; and / or, The preset viscosity is 2000mPa.s to 3000mPa.s; and / or, The preset thickness is 1m to 2m; and / or, The preset volume is 200 to 250 times the volume of the injected volume of the self-produced heavy oil.

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