A method for preventing and controlling edge water

Abstract

The application discloses a method for preventing and controlling edge water, and relates to the field of oil reservoir development, which comprises the following steps: controlling the difference between the edge pressure of a target oil reservoir and the formation pressure value within a preset difference range; performing heating and dispersing operations on self-produced super-thick oil of the target oil reservoir, so that the viscosity of the self-produced super-thick oil is reduced to a preset viscosity; injecting the self-produced super-thick oil with reduced viscosity into an edge water control area, so that the injection protection layer reaches a preset thickness; injecting self-produced sewage of a joint station into the protection layer; and injecting a preset volume of air into the protection layer.

Description

TECHNICAL FIELD

[0001] The present specification relates to the field of oil reservoir development, and more particularly, to a method for preventing and controlling edge water. BACKGROUND

[0002] SAGD (Steam-Assisted Gravity Drainage) is a thermal recovery technique for oil production, mainly used for heavy oil sand and oil shale exploitation. SAGD is a surface oil production technology, usually used for oil sand and oil shale exploitation, which is suitable for the development of heavy oil or super heavy oil with large oil layer thickness, high oil content in the reservoir, and no interlayer in the oil layer.

[0003] Edge water generally refers to water in underground reservoirs. When oil exploration and production is carried out, oil and natural gas are usually located underground, and the water mixed with them is usually referred to as edge water. It is necessary to effectively prevent and control edge water during oil and gas development, solve the problem of steam cavity expansion towards the edge, but the existing method has limited edge water control ability, which is easy to cause edge water invasion, and further affect oil and gas production and production safety. SUMMARY

[0004] A series of simplified concepts are introduced in the summary section, which will be further described in detail in the specific embodiment section. The summary section of the present application does not mean to attempt to limit the key features and necessary technical features of the claimed technical solutions, nor to attempt to determine the protection scope of the claimed technical solutions.

[0005] In a first aspect, the present application provides a method for preventing and controlling edge water, comprising:

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

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

[0008] injecting the self-produced heavy oil with reduced viscosity into the edge water control area to make the injection protection layer to a preset thickness;

[0009] injecting joint station self-produced sewage into the above-mentioned protection layer;

[0010] injecting a preset volume of air into the above-mentioned protection layer.

[0011] In some embodiments, the above-mentioned target oil reservoir at least includes a first row of injection wells, a second row of injection wells and a third row of injection wells, and the distance between the above-mentioned first row of injection wells, the above-mentioned second row of injection wells and the above-mentioned third row of injection wells and the edge gradually increases.

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

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

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

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

[0016] Adding a viscosity-reducing dispersant to the self-produced super heavy oil heated to the preset temperature and performing a dispersing stirring operation, wherein the viscosity-reducing dispersant is a mixture of ether compounds, sulfonates, and surfactants.

[0017] In some embodiments, the injection of the self-produced heavy oil with reduced viscosity into the edge water control area includes:

[0018] Injecting the self-produced heavy oil with reduced viscosity into the edge water control area through the first row of injection wells.

[0019] In some embodiments, the injection of the self-produced heavy oil with reduced viscosity into the edge water control area through the first row of injection wells includes:

[0020] Injecting the self-produced heavy oil with reduced viscosity into the edge water control area through the first row of injection wells based on the gap injection method.

[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 at intervals.

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

[0023] Injecting the joint station self-produced sewage into the protective layer through the second row of first injection wells.

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

[0025] Monitoring the temperature information of the target oil reservoir

[0026] Controlling the injection amount of the joint station self-produced sewage into the protective layer based on the temperature information, wherein the injection amount is negatively correlated with the temperature information, and the maximum value of the injection amount is the production of the joint station self-produced sewage.

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

[0028] The injecting the preset volume of air into the protective layer is performed by the second injection well.

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

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

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

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

[0033] In summary, the edge water prevention and control method of the embodiments of the present application comprises: controlling the difference between the edge pressure and the formation pressure value of the target reservoir within a preset difference value range; heating and dispersing the produced super heavy oil of the target reservoir to reduce the viscosity of the produced super heavy oil to a preset viscosity; injecting the produced super heavy oil with reduced viscosity into the edge water control area to make the protective layer to a preset thickness; injecting the produced sewage of the joint station into the protective layer; and injecting a preset volume of air into the protective layer. The edge water prevention and control method proposed in the embodiments of the present application combines thickening asphalt shell with water injection cooling and temperature reduction, and adopts the technical ideas of five-step method of controlling and reducing edge pressure, viscosity reduction and dispersion adjustment, asphalt medium supplement injection, temperature reduction control reaction and air low-temperature oxidation, to form a systematic SAGD edge water prevention and control method, which strengthens the water blocking function of the asphalt shell, effectively improves the safety during oil and gas development, and improves the oil and gas production efficiency. Moreover, the method uses the produced super heavy oil, the sewage separated from the joint station and air as injection medium, which has low operation cost, solves the problem of difficult sewage treatment and insufficient capacity due to overload operation of the joint station, and can inject the super heavy oil, the sewage separated from the joint station and air in large doses. The thickened heavy oil formed as a supplement of natural asphalt shell can better isolate the edge water invasion.

[0034] The edge water prevention and control method proposed in the present application, other advantages, objects and features of the present application will be embodied in part through the following description, and will be understood by those skilled in the art through research and practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0035] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit this specification. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0036] Figure 1 This is a schematic flowchart of a waterway control method provided in an embodiment of this application. Detailed Implementation

[0037] The edge water control method proposed in this application combines thickening the asphalt shell with water injection for cooling. It employs a five-step approach: controlling and reducing edge pressure, adjusting viscosity and dispersion, replenishing asphalt medium, controlling reaction through temperature drop, and low-temperature air oxidation. This forms a systematic SAGD edge water control method, strengthening the water-blocking function of the asphalt shell, effectively improving safety during oil and gas development, and increasing oil and gas extraction efficiency. Furthermore, this method utilizes the oilfield's own produced extra-heavy oil, wastewater separated from the combined station, and air as the injection medium, resulting in lower operating costs. It solves the problem of difficult and insufficient wastewater treatment capacity due to the combined station's overload operation in this oilfield. Large doses of extra-heavy oil, wastewater separated from the combined station, and air can be injected, forming a thickened oil that supplements the natural asphalt shell, thus better isolating edge water intrusion.

[0038] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus. The technical solutions of the embodiments of this application will now be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them.

[0039] SAGD development target layer can be Guantao oil layer, which belongs to thick blocky super heavy oil edge top and bottom water reservoir. The reservoir burial depth is 515-720 m, there is no pure mudstone barrier between oil layer and water body, oil-bearing area is 1.92 km2, oil layer thickness is between 23.6-126.6 m, average thickness is 77.0 m, and reported geological reserves are 26.26 million tons. In a certain oilfield area, SAGD pilot test started in 2005, and all converted to SAGD development in 2009. By the end of May 2023, cumulative steam injection was 17.4 million tons, cumulative liquid production was 21.55 million tons, cumulative oil production was 5.298 million tons, injection-production ratio was 1.24, oil-steam ratio was 0.30, recovery degree was 67.0%, and oil production rate was 3.2%. On the plane, the steam cavity 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 600 m low property section, the steam cavity began to expand horizontally in 2016, and the steam cavity has reached the reservoir boundary, which is 40-50 m away from the edge water. Vertically, affected by the 600 m low property section, the overall steam cavity has reached the top, and the main steam cavity top boundary is 590-610 m (50-80 m away from the top boundary of the oil layer), and the recovery degree in the steam cavity has reached 90%. With the horizontal expansion of the steam cavity, on July 14, 2018, well Du 84-65-51 was tested, and the temperature at 622 m (vertical depth 612 m) was 167℃, and the resistivity decreased from 243Ω·m to 30Ω·m. After the temperature anomaly occurred, the wells in the well area were quickly investigated, 15 wells were selected as monitoring wells, the edge monitoring well pattern was improved, the temperature change was closely tracked, and the steam cavity expansion was monitored. On November 3, 2018, the temperature of well Du 84-65-51 rose to 214℃. The temperature of the 5 observation wells outside the periphery did not show high temperature anomaly. On December 7, 2018, the well Du 84-65-51 was plugged with ultra-fine cement, and the cement slurry was 360 m (calculated according to the treatment radius of 10 m), and the cementing pressure was stabilized at 8 MPa. After plugging (December 11, 2018), the test temperature decreased from 214℃ to 51℃; 2 months later (February 12, 2019), the test temperature rose to 238℃, which was higher than the temperature before plugging. In March 2019 (3 months after plugging), 3 temperature anomaly wells were added on the edge. The temperature of the outermost observation well increased rapidly from 38℃ to 173℃ within half a year, which confirmed that the steam cavity was only about 30 m away from the edge water, facing the risk of edge water invasion, which seriously threatened the safety of Guantao 800,000 tons of production. 3

[0040] Therefore, it is urgent to study an edge water prevention and control method in the SAGD development process of thick blocky super heavy oil reservoirs, to solve the problem that the steam cavity expands to the edge during the expansion process, which is easy to cause edge water invasion, and further leads to the problem that Guantao 800,000 tons of production is seriously threatened.

[0041] ​Patent CN113283092A discloses a method and system for constructing a three-dimensional physical model of edge and top water invasion; patent CN112963128A discloses a method for reducing steam cavity overflow to prevent edge water invasion during SAGD development; patent CN112943194A discloses a method for preventing edge water invasion during SAGD development; "Special Oil and Gas Reservoirs", April 2021, describes and controls the countermeasures of SAGD steam cavity in super heavy oil reservoirs with edge and top water, and discloses a steam cavity balancing control method.

[0042] The edge and top water prevention methods mentioned in the above patents and articles involve controlling steam cavity pressure or stopping steam injection wells to control steam volume, which has problems such as insufficient prevention and control ability or difficult regulation, and is only suitable for the early stage of SAGD development. At present, the steam cavity is only about 30m away from the edge water, and it is slightly insufficient to still adopt this prevention and control method, which affects the implementation effect and prevention and control accuracy.

[0043] Please refer to Figure 1 A flowchart of an edge water prevention and control method provided for the embodiments of the present application can specifically include:

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

[0045] Illustratively, the target reservoir is an oil reservoir prepared for exploitation using SAGD technology, the edge pressure is the pressure near the edge water, the formation pressure is the formation pressure of the region where the target reservoir is located, and the difference between the edge pressure and the formation pressure value is controlled within a preset difference range. The preset difference range can be within the range of 0.1-0.2MPa, which creates conditions for subsequent injection of bitumen medium into the edge bitumen shell.

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

[0047] Illustratively, the self-produced super heavy oil of the oilfield is heated by a field heating device, and a certain amount of viscosity reducing dispersant is added and stirred to reduce the viscosity of the super heavy oil to a preset viscosity, achieving low viscosity pumping. The preset viscosity can be 2000-3000mPa.s.

[0048] S130, injecting the self-produced heavy oil with reduced viscosity into the edge water control area to form a protective layer to a preset thickness;

[0049] Illustratively, the self-produced heavy oil with reduced viscosity is injected into the edge water control area to form a protective layer and ensure that it reaches a preset thickness. The formation of this protective layer can help control and stabilize the oil reservoir

[0050] S140, injecting self-produced sewage of the joint station into the protective layer;

[0051] For example, self-produced sewage of the joint station is injected into the protective layer, and the injection amount of the sewage is controlled to accelerate cooling (below 200°C) as soon as possible under the premise that the steam cavity does not shrink.

[0052] S150, injecting a preset volume of air into the protective layer.

[0053] For example, the preset volume is calculated according to the injection amount of super heavy oil, and the air is injected to increase the viscosity of the super heavy oil underground and subsidize on the surface of the natural asphalt shell to form a dense protective layer.

[0054] In summary, the edge water prevention and control method proposed in the embodiments of the present application combines thickening asphalt shell with water injection cooling and adopts the technical idea of the five-step method of controlling edge pressure reduction, viscosity reduction dispersion adjustment, asphalt medium supplement, temperature reduction control reaction and air low-temperature oxidation to form a systematic SAGD edge water prevention and control method, which strengthens the water blocking function of the asphalt shell, effectively improves the safety during oil and gas development, and improves the oil and gas production efficiency. Moreover, the method uses self-produced super heavy oil, sewage separated from the joint station and air as injection medium, has low operation cost, solves the problem of difficult sewage treatment and insufficient capacity due to overload operation of the joint station, can inject super heavy oil, sewage separated from the joint station and air in large doses, and the thickened oil formed as a supplement to the natural asphalt shell can better isolate the edge water intrusion.

[0055] In some embodiments, the target reservoir includes at least a first row of injection wells, a second row of injection wells, and a third row of injection wells, and the distance between the first row of injection wells, the second row of injection wells, and the third row of injection wells and the edge of the reservoir gradually increases.

[0056] For example, the target reservoir includes at least three rows of injection wells, which are 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 of 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 injection wells in a gradually increasing distance, the injection wells can be more evenly distributed to cover the entire reservoir, ensuring that the oil in the reservoir is more evenly subjected to heat treatment and recovery. This arrangement may help improve recovery efficiency, reduce energy waste, and minimize problems that may arise during recovery. The gradually increasing distance arrangement may be to more effectively manage the exploitation process of the reservoir.

[0057] In some embodiments, the difference between the edge pressure of the target reservoir and the formation pressure value is within a preset difference range, including:

[0058] Increasing the steam injection intensity of the second row of injection wells and the third row of injection wells to control the difference between the edge pressure and the formation pressure value of the target reservoir within a preset difference range.

[0059] For example, the steam injection intensity of the second row of injection wells and the third row of injection wells near the edge water is increased, the steam injection intensity of the second row of injection wells is increased by 3-6, the steam injection intensity of the third row of injection wells is increased by 3.5-6.5, and the method of "increasing and observing" is adopted. Through pressure monitoring data, the formation pressure value of the area where the steam injection intensity is increased (the second and third rows of injection wells) and the area near the edge water (the first row of injection wells) is tracked in real time, and when the difference between the two reaches 0.1-0.2 MPa, the steam injection intensity is stopped and kept unchanged.

[0060] In some embodiments, the heating and dispersing operation of the self-produced super heavy oil of the target reservoir includes:

[0061] Heating the self-produced super heavy oil of the target reservoir to a preset temperature;

[0062] Adding a viscosity-reducing dispersant to the self-produced super heavy oil heated to the preset temperature and performing a dispersing stirring operation, wherein the viscosity-reducing dispersant is a mixture of ether compounds, sulfonates, and surfactants.

[0063] For example, the self-produced super heavy oil of the oilfield, i.e., the content of gum and asphaltene components is between 40-55%, the crude oil density at 20°C is between 1.00-1.03 g / cm 3 , is heated to 50-55°C by a field electric heating device, and a certain amount of viscosity-reducing dispersant is stirred, and the composition of the viscosity-reducing dispersant is generally 0.3-0.5% ether compounds + 0.2-0.5% sulfonates + 0.3-0.5% surfactants (such as 0.3-0.5% alkyl phenol polyoxyethylene ether + 0.2-0.5% sodium dodecyl benzene sulfonate + 0.3-0.5% betaine), to reduce the viscosity of the super heavy oil to 2000-3000 mPa.s, and realize low-viscosity pump injection.

[0064] In some embodiments, the self-produced heavy oil with reduced viscosity is injected into the edge water control area, including:

[0065] The self-produced heavy oil with reduced viscosity is injected into the edge water control area through the first row of injection wells.

[0066] For example, in the first row of injection wells near the edge water, the self-produced super heavy oil of the oilfield that meets the above conditions and is heated and stirred can be continuously injected to ensure the injection amount and ensure that the final injection amount of this area reaches the thickness of the asphalt shell in the edge water control area to a preset thickness.

[0067] In some embodiments, the injecting the self-produced heavy oil with reduced viscosity into the edge water control area through the first row of injection wells comprises:

[0068] The injecting the self-produced heavy oil with reduced viscosity into the edge water control area through the first row of injection wells based on the gap injection mode.

[0069] For example, in the first row of injection wells close to the edge water, the self-produced super heavy oil of the oilfield that meets the above conditions and is heated and stirred is injected, and the intermittent injection mode is adopted according to the change of the injection pressure, that is, the injection displacement is controlled at 0.3-0.5 m 3 / min, and the injection pressure is ensured to be within the rated pressure range allowed by the ground pump, generally 18-20 MPa. When the injection pressure exceeds the rated pressure, the well is shut down after the hot sewage that exceeds the volume of the wellbore is replaced, and the injection is resumed when the pressure drops below 10 MPa; if the injection pressure remains below the rated pressure, the continuous injection state can be maintained. The final injection amount is ensured to reach 1-2 m of the thickening of the asphalt shell in the edge water control area.

[0070] In some embodiments, the second row of injection wells comprises 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.

[0071] The injecting the self-produced sewage of the joint station into the protective layer comprises:

[0072] The injecting the self-produced sewage of the joint station into the protective layer through the second row of first injection wells.

[0073] For example, the second row of injection wells comprises a plurality of injection wells, which can be continuously numbered along the circumference of the reservoir center, and the odd-numbered injection wells are defined as the second row of first injection wells, and the even-numbered injection wells are defined as the second row of second injection wells. In the second row of injection wells close to the edge water, the odd-numbered injection wells are selected to inject the self-produced sewage of the joint station.

[0074] In some embodiments, the injecting the self-produced sewage of the joint station into the protective layer through the second row of first injection wells comprises:

[0075] Monitoring temperature information of the target reservoir

[0076] Controlling the injection amount of the self-produced sewage of the joint station into the protective layer through the second row of first injection wells based on the temperature information, wherein the injection amount is negatively correlated with the temperature information, and the maximum value of the injection amount is the production of the self-produced sewage of the joint station.

[0077] For example, the injection amount of sewage is controlled to accelerate the cooling as soon as possible (below 200 DEG C) without causing the cavity to shrink, the maximum injection amount is the amount of sewage produced by the oilfield per day, the injection is monitored while the injection is in progress, the total injection amount is adjusted according to the monitored formation temperature, when the monitored temperature is below 200 DEG C, the injection amount of sewage is reduced to 60-80% of the original injection amount, when the monitored temperature is 150 DEG C, the injection amount of sewage is reduced to 30-60% of the original injection amount, and when the monitored temperature is 100 DEG C, the original injection amount is maintained at 30% for intermittent injection.

[0078] In some embodiments, the injecting a preset volume of air into the protective layer comprises:

[0079] The injecting a preset volume of air into the protective layer is performed by the second injection well in the second row.

[0080] For example, in the second injection well near the edge water, even-numbered wells are selected for the second injection of air, and the injection amount is controlled at 800-1200 Nm 3 / h, the injection pressure is controlled at 5-10 MPa, the injection amount is calculated according to the injection of super heavy oil, according to the process of low-temperature oxidation reaction, generally according to the volume ratio of super heavy oil to air of 1:200-1:250, until the super heavy oil undergoes low-temperature oxidation reaction to increase viscosity and is supplemented on the surface of the natural asphalt shell to form a dense protective layer.

[0081] In some embodiments, the preset difference is 0.1 MPa to 0.2 MPa; and / or,

[0082] The preset viscosity is 2000 mPa.s to 3000 mPa.s; and / or,

[0083] The preset thickness is 1 m to 2 m; and / or,

[0084] The preset volume is 200 times to 250 times the injection of the produced heavy oil.

[0085] In some embodiments, the method is used for the edge water prevention and control in the northwest SAGD of Guantao, and the following implementation steps are designed and constructed:

[0086] S210, control the edge pressure: the steam injection intensity of the second row of steam injection wells is increased by 4.5, the steam injection intensity of the third row of steam injection wells is increased by 5, and the method of "increasing while observing" is adopted, through the pressure monitoring data, it is found that after 58 days of increasing the steam injection intensity, the formation pressure difference between the second and third rows of steam injection wells and the first row of steam injection wells reaches 0.2 MPa, which meets the design requirements, and the steam injection intensity is kept unchanged.

[0087] S220, Viscosity Reduction and Dispersion Adjustment: This adjusts the viscosity and dispersion of the extra-heavy oil produced in this oilfield, i.e., the content of asphaltenes and resins is between 40-55%, and the density of the crude oil at 20℃ is between 1.00-1.03 g / cm³. 3 The oil is heated to 50-55℃ using an on-site electric heating device, and a certain amount of viscosity-reducing dispersant is added and stirred. The viscosity-reducing dispersant consists of 0.3% alkylphenol polyoxyethylene ether + 0.35% sodium dodecylbenzene sulfonate + 0.4% betaine, which reduces the viscosity of the extra-heavy oil from 20.3 × 10⁻⁶ at room temperature. 4 The viscosity was reduced to 2500 mPa·s, achieving stable pumping at low viscosity.

[0088] S230, Asphalt Refill Medium: In the first row of injection wells near the edge water, inject locally produced extra-heavy oil that meets the above conditions and has been heated and stirred, i.e., the injection rate is controlled at 0.4 m³ / h. 3 The injection rate is 6-8 MPa / min, which can maintain continuous injection. The injection volume is 5800 cubic meters, ensuring that the final injection volume in this area will increase the asphalt shell thickness by 1-2 meters in the edge water control area.

[0089] S240, Temperature Drop Control Response: In the second row of steam injection wells near the edge water, select odd-numbered wells to inject the self-produced wastewater from the combined station, controlling the wastewater injection volume at 200-300m³. 3 / d, while injecting, the formation temperature was monitored. After 130 days of injection, the monitored temperature reached 180℃, and the wastewater injection volume was reduced to 150-200m³. 3 / d, after 230 days of injection, the monitored temperature reached 150℃, and the sewage injection volume was reduced to 75-150m³. 3 / d, after 380 days of injection, if the monitored temperature drops to 100℃, maintain 75m 3 / d intermittent injection.

[0090] S250, Low-Temperature Air Oxidation: In the second row of steam injection wells near the edge water, select even-numbered wells for air injection, controlling the injection rate at 800-1200 Nm³. 3 / h, injection pressure controlled at 5-10MPa, injection volume 140×10 4 Bidder. Before the measures were implemented, four wells in the northwest of Guantao SAGD showed abnormal temperatures, indicating that the area was only about 30m away from the edge water. After the measures were implemented, monitoring through core sampling showed that the asphalt shell in the area thickened by 1.6m. At the same time, the temperature of the four wells with abnormal temperatures decreased, and the validity period of subsequent continuous monitoring has been more than one year.

[0091] In summary, the edge water prevention and control method provided in the embodiments of the present application uses self-produced super heavy oil of the oilfield, sewage separated from the joint station and air as injection medium, and has low operation cost. The method solves the problem of difficult sewage treatment and insufficient capacity of the joint station due to overload operation of the joint station. The method can inject super heavy oil, sewage separated from the joint station and air in a large dose, and the thickened oil formed can be used as a supplement of natural asphalt shell, so that the edge water invasion can be better isolated. The method provides an effective solution for the edge water prevention and control problem in the SAGD development process.

[0092] The above, the above embodiments are only used to illustrate the technical solutions of the present application, but not limit them; although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate 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 by, The method comprises the following steps: controlling the difference between the edge pressure and the formation pressure of the target oil reservoir within a preset difference range; heating and dispersing the self-produced super-thick oil of the target oil reservoir to reduce the viscosity of the self-produced super-thick oil to a preset viscosity; injecting the self-produced thick oil with reduced viscosity into the edge water control area to make the injection protection layer reach a preset thickness; injecting the self-produced sewage of the joint station into the protection layer; injecting a preset volume of air into the protection layer; The target oil reservoir at least includes a first row of injection wells, a second row of injection wells and a third row of injection wells, and the distance between the first row of injection wells, the second row of injection wells and the third row of injection wells and the edge gradually increases; The method for controlling the difference between the edge pressure and the formation pressure of the target oil reservoir within a preset difference range comprises: Increasing the steam injection intensity of the second row of injection wells and the third row of injection wells to control the difference between the edge pressure and the formation pressure of the target oil reservoir within a preset difference range; The method for injecting the self-produced thick oil with reduced viscosity into the edge water control area comprises: Injecting the self-produced thick oil with reduced viscosity into the edge water control area through the first row of injection wells.

2. The method of edge water prevention and control according to claim 1, wherein, The method for heating and dispersing the self-produced super-thick oil of the target oil reservoir comprises: Heating the self-produced super-thick oil of the target oil reservoir to a preset temperature; Adding a viscosity-reducing dispersant to the self-produced super-thick oil heated to the preset temperature and performing dispersion stirring operation, wherein the viscosity-reducing dispersant is a mixture of ether compounds, sulfonates and surfactants.

3. The method of edge water prevention and control according to claim 1, wherein, The method for injecting the self-produced thick oil with reduced viscosity into the edge water control area through the first row of injection wells comprises: Injecting the self-produced thick oil with reduced viscosity into the edge water control area through the first row of injection wells based on the gap injection mode.

4. The method of edge water prevention and control according to claim 1, wherein, 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 method for injecting the self-produced sewage of the joint station into the protection layer comprises: Injecting the self-produced sewage of the joint station into the protection layer through the second row of first injection wells.

5. The method of edge water prevention and control according to claim 4, wherein, The method for injecting the self-produced sewage of the joint station into the protection layer through the second row of first injection wells comprises: Monitoring the temperature information of the target oil reservoir; Controlling the injection amount of the self-produced sewage of the joint station into the protection layer through the second row of first injection wells based on the temperature information, wherein the injection amount is negatively correlated with the temperature information, and the maximum value of the injection amount is the yield of the self-produced sewage of the joint station.

6. The edge water prevention and control method according to claim 4, wherein The method for injecting a preset volume of air into the protection layer comprises: Injecting a preset volume of air into the protection layer through the second row of second injection wells.

7. The method of controlling or preventing edge water according to any one of claims 1 to 6, wherein, The preset difference is 0.1 MPa to 0.2 MPa; and / or, The preset viscosity is 2000 mPa.s to 3000 mPa.s; and / or, The preset thickness is 1 m to 2 m; and / or, The preset volume is 200 times to 250 times of the injection of the self-produced thick oil.

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