SAGD (Steam Assisted Gravity Drainage) well pattern development method for deep super heavy oil reservoir

Abstract

A deep super heavy oil reservoir SAGD (steam assisted gravity drainage) well pattern development method belongs to the technical field of oil field oil extraction, and adopts a vertical well and horizontal well combined SAGD which has the advantages of high steam chamber height in the initial stage of flooding conversion, high gravity drainage capacity, high yield rising speed, small influence of heterogeneity and interlayer, high oil drainage efficiency, high oil drainage efficiency and the like. The vertical well and horizontal well combination SAGD vertical well and the horizontal well have the opposite and lateral position relations, the steam injection vertical well is located above the side of the production horizontal well, the swept volume of an inter-well steam cavity is enlarged, the oil drainage area is increased, the reserve control degree is high, and the recovery efficiency is improved. According to the method, in the deep SAGD development process, main control factors, mainly steam injection speed and steam temperature, influencing the heat loss of the shaft are studied and determined. Well temperature monitoring data and a numerical simulation method are utilized to finely describe shaft heat loss of SAGD steam injection. And determining a reasonable well pattern structure, injection-production well spacing, position optimization, perforation position and thickness of the deep extra-heavy oil reservoir SAGD (Steam Assisted Gravity Drainage).

Description

Technical Field

[0001] The invention belongs to the technical field of oil field production, and in particular relates to a SAGD development well pattern method for deep super heavy oil reservoirs. Background Art

[0002] SAGD development technology is a cutting-edge technology for developing super-heavy oil. Its production mechanism is to inject high-dryness steam into the steam injection well. The steam overlaps upward in the formation to form a steam chamber. The steam chamber expands upward and laterally, and heat exchanges with the crude oil in the oil layer. The heated and reduced-viscosity crude oil and steam condensate rely on gravity to be discharged to the horizontal production well below. The steam chamber continues to expand and continuously occupies the volume of crude oil. This technology was invented by Dr. Butler in 1978. At present, it has been promoted and applied in some oil fields at home and abroad. Xinjiang Oilfield and Liaohe Oilfield in China have successfully introduced SAGD technology and successfully implemented it in super-heavy oil reservoirs, achieving good development results, greatly reversing the situation of continuous decrease in annual oil production due to steam throughput. It has high oil production rate and low production cost. Its technical advantages are recognized by people in the oil industry and is considered to be one of the thermal recovery development technologies with the highest recovery rate.

[0003] In the process of oil reservoir exploitation, in order to effectively improve the efficiency of crude oil extraction, it is necessary to carry out reasonable well network structure deployment during crude oil extraction. Different well network structure deployments are also required for different reservoir structures and different extraction methods. At present, SAGD mainly has two well layout methods: vertical well and horizontal well combination, and double horizontal well combination. However, due to the deep burial depth, high formation pressure, small available latent heat of vaporization in the reservoir, and low steam utilization efficiency, deep super-heavy oil reservoirs require a higher steam injection rate than shallow SAGD. Only horizontal well drainage cannot meet the production-injection ratio. Therefore, it is necessary to propose a suitable well network structure that has met the SAGD development requirements of deep super-heavy oil reservoirs.

[0004] Related patent search:

[0005] CN20140645727.5 discloses a method for exploiting a heavy oil reservoir using SAGD. The present invention provides a method for exploiting a heavy oil reservoir using SAGD. The SAGD includes a process of using an injection-production well group to produce oil. The injection-production well group includes at least one pair of adjacent injection wells and production wells. The injection well has a horizontal section of the injection well set in the oil layer of the heavy oil reservoir. The production well has a horizontal section of the production well set in the oil layer. The horizontal section of the injection well is located above the horizontal section of the production well. In the middle and late stages of SAGD, the method further includes: step S1, setting a vertical well at a position where at least part of the steam chamber is not developed above the horizontal section of the injection well; step S2, injecting steam into the vertical well and the injection well, and using the production well to produce oil. In the late stage of SAGD, by setting a vertical well at a position where no steam chamber is developed, and injecting steam into the vertical well, the heat of the steam is used to promote the development of no steam chamber, thereby achieving the effect of uniform development of the steam chamber in the horizontal section. Summary of the invention

[0006] In order to solve the above-mentioned problems, the present invention proposes: a SAGD development well pattern method for deep ultra-heavy oil reservoirs, the well layout is designed as follows: the use of a combination of vertical wells and horizontal wells SAGD has a large initial steam chamber height, strong gravity oil drainage capacity, fast production increase rate, and is less affected by heterogeneity and interlayers. The position relationship between the vertical wells and horizontal wells in the combination of vertical wells and horizontal wells SAGD vertical wells and horizontal wells has two forms: facing and lateral. The steam injection vertical well is located above the side of the production horizontal well, which expands the swept volume of the steam chamber between wells, increases the oil drainage area, has a high degree of reserve control, and improves the recovery rate.

[0007] Furthermore, based on the vertical square well pattern and 70m well spacing used in the process of super-heavy oil steam stimulation and production, the injection-production well spacing was converted into four types: 25m, 35m, 50m, and 70m. Effective thermal connectivity was formed within a well spacing of 50m. However, as the injection-production well spacing increased, the thermal connectivity time between the injection-production wells would increase, and it would be difficult to form effective thermal connectivity with a well spacing of 70m. Moreover, as the injection-production well spacing increased, the oil-gas ratio and the ultimate recovery factor gradually decreased.

[0008] Furthermore, at present, it is more appropriate to use a vertical well and horizontal well with an injection-production well spacing of 35m. However, due to the deep burial depth, high formation pressure, small available latent heat of vaporization in the reservoir, and low steam utilization efficiency of deep super-heavy oil reservoirs, the required steam injection rate is greater than that of shallow SAGD. Only horizontal well drainage cannot meet the production-injection ratio. Under the premise of ensuring dryness, the steam injection rate of a single well is 120-140t / d. In order to maintain the injection-production balance, the drainage of a single well group must reach 280t / d. After switching to SAGD, the initial drainage is only about 150t / d, which cannot meet the requirements. Therefore, the initial steam injection method of "strong point and weak surface" is adopted, the steam injection well points are appropriately reduced, and the steam injection rate of a single well is increased. Therefore, auxiliary drainage is added at the heel and toe positions of the horizontal well, and the steam injection wells adopt rotation steam injection.

[0009] Furthermore, SAGD tracking studies of vertical and horizontal well combinations show that the steam chamber is formed and expanded in accordance with the law of "multiple points of steam, threading the needle, and connecting the lines into a body". The configuration relationship of the injection and production wells and the location of the steam injection vertical well directly affect the development of the steam chamber.

[0010] Furthermore, the specific steps for optimizing the design of vertical steam injection wells are as follows: vertical well and horizontal well combination layout, a horizontal production well needs to be equipped with several vertical steam injection wells, and the relative positions of the vertical wells are selected according to the following principles:

[0011] (1) Each horizontal production well must have at least three corresponding vertical steam injection wells, located near the heel, middle and toe of the horizontal section;

[0012] (2) The positions of two adjacent rows of steam injection wells should be staggered, forming an "isosceles" triangle distribution;

[0013] (3) Even if only two vertical steam injection wells are needed in the row after staggering, an additional vertical steam injection well should be deployed at the toe of the horizontal well;

[0014] (4) If the selected vertical steam injection wells cannot form an "isosceles" triangle distribution due to the well conditions of the vertical wells, the first condition that needs to be met is whether there is a steam injection well near the toe of the horizontal well;

[0015] (5) Fully consider the well conditions and the rotation steam injection implemented in the SAGD stage.

[0016] Further, the process of designing the perforation locations is as follows:

[0017] SAGD production practice shows that when the bottom boundary of the perforated well section is lower than the vertical depth of the horizontal section or is the same depth as the horizontal section, the steam will directly flow to the production well after steam injection, seriously affecting the development effect. Therefore, the perforation position of the steam injection well is set to be higher than the vertical depth of the horizontal well section.

[0018] Further, the process of designing the perforation thickness is as follows:

[0019] The results of numerical simulation research show that the higher the perforation thickness, the higher the permeability and the higher the steam injection rate. When the perforation thickness is 8 to 10 m, the oil-gas ratio and recovery degree in the SAGD stage are higher. This thickness is conducive to reducing the injection pressure of the steam injection well, improving the bottom hole dryness and reducing the risk of steam channeling.

[0020] Furthermore, the process of designing the horizontal section trajectory of the horizontal production well is as follows:

[0021] Operational practice has proved that the more horizontal the horizontal section is drilled, the more conducive it is to production control. In order to prevent the steam in the upper steam chamber from entering the horizontal production well, a certain liquid level is maintained above the production well, which should be kept within the range of 3.0 to 5.0 m. The steam-liquid interface is determined by the highest point of the horizontal screen section, in order to reduce the risk of steam cross-talk, reduce the difficulty of regulation, increase the SAGD recovery rate, and reduce the up and down displacement of the newly drilled horizontal production well on the horizontal section trajectory.

[0022] The beneficial effects of the present invention are:

[0023] The present invention provides a method for determining the main controlling factors affecting the heat loss of the wellbore during the deep SAGD development process, which are mainly the steam injection rate and the steam temperature. The wellbore heat loss of SAGD steam injection is precisely described using well temperature monitoring data and numerical simulation methods. The reasonable well pattern structure, injection-production well spacing, location optimization, perforation location and thickness of deep extra-heavy oil reservoir SAGD are determined. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Attached Figure 1 It is a curve diagram of the influence of different oil pipe radii on wellhead pressure calculated by numerical simulation in an embodiment of the present invention;

[0025] Attached Figure 2 It is a curve diagram of the influence of different oil pipe roughness on wellhead pressure calculated by numerical simulation in an embodiment of the present invention;

[0026] Attached Figure 3 It is a curve diagram showing the influence of steam injection rate on steam dryness in a wellbore according to numerical simulation calculation in an embodiment of the present invention;

[0027] Attached Figure 4 It is a curve diagram of the influence of steam temperature on steam dryness in a wellbore calculated by numerical simulation in an embodiment of the present invention;

[0028] Attached Figure 5 It is a curve diagram of the influence of reservoir pressure on wellbore steam dryness calculated by numerical simulation in an embodiment of the present invention;

[0029] Attached Figure 6 It is a curve diagram of the influence of the wellhead steam pressure on the steam dryness of the wellbore calculated by numerical simulation in an embodiment of the present invention;

[0030] Attached Figure 7 It is a trend diagram of the effect of different factors of the steam dryness at the bottom of the well on the numerical simulation calculation in the implementation example of the present invention;

[0031] Attached Figure 8 is a schematic diagram of a deep SAGD well pattern in an embodiment of the present invention;

[0032] Attached Fig. 9 It is a schematic diagram of the formation and expansion of the SAGD steam chamber in an embodiment of the present invention;

[0033] Attached Fig.10 This is a comparison diagram of the effects of different perforation positions for simulating deep SAGD in an embodiment of the present invention;

[0034] Attached Fig.11 It is a schematic diagram of the injection and production positions of horizontal wells with different vertical depths for simulating deep SAGD in an embodiment of the present invention (vertical to the horizontal well direction);

[0035] Attached Fig.12 It is a comparison diagram of the effects of different perforation thicknesses of deep SAGD in an embodiment of the present invention. DETAILED DESCRIPTION

[0036] A SAGD development well pattern method for deep ultra-heavy oil reservoirs.

[0037] The purpose of the present invention is to meet the production-injection ratio of SAGD development of deep oil reservoirs through a reasonable well pattern, quickly establish an underground temperature field, ensure the maximum utilization (development) of such deep extra-heavy oil reservoirs, and tap the maximum value of petroleum, a non-renewable resource.

[0038] 1. During the SAGD development process, the SAGD steam heat utilization rate is low due to the deep burial of the reservoir and the large heat loss of the wellbore. Use the actual well temperature monitoring data and numerical simulation technology to accurately describe the steam phase change law along the wellbore and the factors affecting heat loss, including steam injection rate sensitivity, steam temperature sensitivity, reservoir pressure sensitivity, and steam injection pressure sensitivity, and clarify the impact level of different factors on the heat loss of the steam injection wellbore;

[0039] 2. Determine the main controlling factors affecting wellbore heat loss;

[0040] 3. Well pattern structure of SAGD in deep extra-heavy oil reservoirs;

[0041] 4. Optimal injection and production well spacing, location, perforation location and thickness for SAGD in deep extra-heavy oil reservoirs.

[0042] A deep super heavy oil reservoir SAGD development well pattern structure is designed to solve the problem that the steam utilization efficiency of deep oil reservoir SAGD is low, the required steam injection rate is greater than that of shallow SAGD, and only horizontal well drainage cannot meet the production-injection ratio. The well pattern is designed to meet the development requirements of deep super heavy oil reservoir SAGD and gradually expand the depth limit of SAGD implementation. The technical solutions adopted by the method include:

[0043] 1. During the SAGD development process, due to the deep burial depth of the oil reservoir and the large heat loss in the wellbore, the SAGD steam heat utilization rate is low.

[0044] The actual well temperature monitoring data and numerical simulation technology are used to accurately describe the change of steam phase along the wellbore. Figure 1 and attached Figure 2 It shows that the greater the roughness of the tubing and the smaller the radius, the higher the pressure loss per unit length. Under the same bottom hole pressure conditions, the higher the required wellhead steam injection pressure.

[0045] 2. The main controlling factors affecting the heat loss of the wellbore are determined. The degree of heat loss of the wellbore under different steam injection speed, steam temperature, reservoir pressure, and steam injection pressure parameters is compared to clarify the influence of different factors on the heat loss of the steam injection wellbore.

[0046] Attached Figure 3 It shows that the greater the steam injection rate, the smaller the heat loss along the wellbore and the higher the bottom hole dryness;

[0047] Attached Figure 4 It shows that the higher the superheat, the more heat the wellhead carries, and the greater the bottom hole dryness at the same depth;

[0048] Attached Figure 5 It shows that the increase of reservoir pressure has a greater impact on deep reservoirs, and the bottom hole dryness at the same depth decreases linearly with the increase of reservoir pressure;

[0049] Attached Figure 6 It shows that with the increase of steam injection pressure, the bottom hole steam quality decreases linearly. On the basis of ensuring sufficient bottom hole quality, the steam injection pressure should be reduced as much as possible.

[0050] The main controlling factors affecting the heat loss of the wellbore are as follows: Figure 7 As shown in the figure, the order of influence of wellbore steam heat loss is steam injection rate, steam temperature, reservoir pressure, and steam injection pressure.

[0051] 3. Well layout design: Compared with the double horizontal well SAGD well layout, the vertical well and horizontal well combination SAGD has the advantages of large steam chamber height in the initial stage of drive, strong gravity oil drainage capacity, fast production increase rate, less impact of heterogeneity and interlayer, and a relatively complete control method. The vertical well and horizontal well combination SAGD vertical well and horizontal well position relationship has two forms: facing and lateral. The steam injection vertical well is located above the production horizontal well (laterally), which can effectively expand the swept volume of the steam chamber between wells, increase the oil drainage area, have a high degree of reserve control, and effectively improve the recovery rate.

[0052] Design well layout as attached Figure 8 As shown: The combination of vertical wells and horizontal wells in SAGD has a large steam chamber height in the initial stage of drive, strong gravity oil drainage capacity, fast production increase rate, and is less affected by heterogeneity and interlayers. The position relationship between the vertical well and the horizontal well in the combination of vertical wells and horizontal wells in SAGD has two forms: facing and lateral. The steam injection vertical well is located above the side of the production horizontal well, which expands the swept volume of the steam chamber between the wells, increases the oil drainage area, has a high degree of reserve control, and improves the recovery rate;

[0053] Based on the vertical square well pattern and 70m well spacing used in the process of super-heavy oil steam stimulation and extraction, the injection-production well spacing is converted into four types: 25m, 35m, 50m, and 70m. Effective thermal connectivity is formed within a well spacing of 50m. However, as the injection-production well spacing increases, the thermal connectivity time between the injection-production wells will increase, and it is difficult to form effective thermal connectivity with a well spacing of 70m. In addition, as the injection-production well spacing increases, the oil-gas ratio and the ultimate recovery rate gradually decrease.

[0054] At present, it is more appropriate to use a vertical well and horizontal well with an injection-production distance of 35m. However, due to the deep burial depth, high formation pressure, small available latent heat of vaporization in the reservoir, and low steam utilization efficiency of deep super-heavy oil reservoirs, the required steam injection rate is greater than that of shallow SAGD. Only horizontal well drainage cannot meet the production-injection ratio. Under the premise of ensuring dryness, the steam injection rate of a single well is 120-140t / d. In order to maintain the injection-production balance, the drainage of a single well group must reach 280t / d. After switching to SAGD, the initial drainage is only about 150t / d, which cannot meet the requirements. Therefore, the initial steam injection method of "strong point and weak surface" is adopted, and the steam injection well points are appropriately reduced to increase the steam injection rate of a single well. Therefore, auxiliary drainage is added at the heel and toe positions of the horizontal well, and the steam injection wells use rotation steam injection to ensure the balanced expansion of the steam cavity (see Appendix Fig. 9 ).

[0055] 4. The specific steps for optimizing the design of vertical steam injection wells are as follows:

[0056] The SAGD tracking study of vertical wells and horizontal wells shows that the steam chamber follows the rule of "multiple points of steam, threading and connecting, and connecting into a body" to form and expand. The configuration relationship of the injection and production wells and the location of the vertical steam injection well directly affect the development of the steam chamber.

[0057] In the vertical well and horizontal well combination layout method, a horizontal production well needs to be equipped with several steam injection vertical wells. The relative positions of the vertical wells are selected according to the following principles:

[0058] (1) Each horizontal production well must have at least three corresponding vertical steam injection wells, located near the heel, middle and toe of the horizontal section;

[0059] (2) The positions of two adjacent rows of steam injection wells should be staggered, forming an "isosceles" triangle distribution;

[0060] (3) Even if only two vertical steam injection wells are needed in the row after staggering, an additional vertical steam injection well should be deployed at the toe of the horizontal well;

[0061] (4) If the selected vertical steam injection wells cannot form an "isosceles" triangle distribution due to the well conditions of the vertical wells, the first condition that needs to be met is whether there is a steam injection well near the toe of the horizontal well;

[0062] (5) Fully consider the well conditions and the possible rotation steam injection during the SAGD stage.

[0063] 5. The process of designing the perforation location is as follows:

[0064] The actual SAGD production shows that when the bottom of the perforated well section is lower than the vertical depth of the horizontal section or is the same depth as the horizontal section, the steam will directly flow to the production well after steam injection, seriously affecting the development effect. Therefore, the perforation position of the steam injection well is set to be higher than the vertical depth of the horizontal well section.

[0065] Comparing the three positions of 5m, 10m and 15m vertical depth from the bottom boundary of the perforation in the steam injection well, the simulation results show that with the increase of vertical distance, the production time, recovery rate and oil-gas ratio decrease accordingly; when the vertical distance is 5m, the recovery rate of the SAGD stage is the highest, reaching 47.7% (see Appendix Fig.10 ). 3 to 5 meters is generally used in foreign countries; for deep reservoirs, it is recommended that the perforation section should not be too high. Under possible conditions, it is appropriate to be 3 to 5 meters higher than the horizontal well (see Appendix Fig.11 ). At the same time, considering the large difference in vertical depth between adjacent wells, it is recommended that perforating of steam injection wells should follow the principle of high depth rather than low depth.

[0066] 6. Perforation thickness design. The perforation thickness of the Xing VI steam injection well is 5 to 8 m. Compared with the 38-32 block, the permeability is low and the steam injection rate is high, so the perforation thickness can be appropriately increased. The results of numerical simulation show that when the perforation thickness is 8 to 10 m, the oil-gas ratio and recovery degree in the SAGD stage are higher (see Appendix Fig.12 ), and this thickness is beneficial to reducing the injection pressure of the steam injection well, improving the bottom hole dryness, and reducing the risk of steam channeling. Therefore, the recommended injection thickness is 8 to 10 m.

[0067] 7. Design requirements for horizontal section trajectory of horizontal production wells. Operational practice has proved that the more horizontal the horizontal section is drilled, the more conducive it is to production control. In order to prevent the steam in the upper steam chamber from entering the horizontal production well, a certain height of liquid level must be maintained above the production well, which should generally be maintained at 3.0 to 5.0 m; and the steam-liquid interface is determined by the highest point of the horizontal screen section. In order to reduce the risk of steam channeling, reduce the difficulty of regulation, and improve the SAGD recovery rate, it is recommended to reduce the up and down displacement of the horizontal section trajectory when drilling a new horizontal production well.

[0068] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A SAGD development well pattern method for deep ultra-heavy oil reservoirs, characterized in that: The well layout is designed as follows: SAGD is a combination of vertical wells and horizontal wells, which has the characteristics of large steam chamber height in the initial stage of drive, strong gravity oil drainage capacity, fast production increase rate, and less influence of heterogeneity and interlayer. The position relationship between vertical wells and horizontal wells in the combination of vertical wells and horizontal wells SAGD has two forms: facing and lateral. The steam injection vertical well is located above the side of the production horizontal well, which expands the swept volume of the steam chamber between wells, increases the oil drainage area, improves the degree of reserve control, and improves the recovery rate.

2. The SAGD development well pattern method for deep ultra-heavy oil reservoirs according to claim 1, characterized in that: Based on the vertical square well pattern and 70m well spacing used in the process of super-heavy oil steam stimulation and production, the injection-production well spacing is converted into four types: 25m, 35m, 50m, and 70m. Effective thermal connectivity is formed within a well spacing of 50m. However, as the injection-production well spacing increases, the thermal connectivity time between the injection-production wells will increase, and it is difficult to form effective thermal connectivity with a well spacing of 70m. Moreover, as the injection-production well spacing increases, the oil-gas ratio and the ultimate recovery factor gradually decrease.

3. The SAGD development well pattern method for deep ultra-heavy oil reservoirs according to claim 1, characterized in that: At present, the well spacing between vertical wells and horizontal wells for injection and production is 35m. However, due to the deep burial depth, high formation pressure, small available latent heat of vaporization in the reservoir, and low steam utilization efficiency, the required steam injection rate is greater than that of shallow SAGD in deep super-heavy oil reservoirs. Only horizontal well drainage cannot meet the production-injection ratio. Under the premise of ensuring dryness, the steam injection rate of a single well is 120-140t / d. In order to maintain the balance of injection and production, the drainage of a single well group must reach 280t / d. After switching to SAGD, the initial drainage is only about 150t / d, which cannot meet the requirements. In the early stage, the "strong point and weak surface" steam injection method is adopted to reduce the number of steam injection wells, increase the steam injection rate of a single well, increase auxiliary drainage at the heel and toe positions of the horizontal wells, and adopt rotation steam injection for the steam injection wells.

4. The SAGD development well pattern method for deep super heavy oil reservoirs according to claim 1, characterized in that: The SAGD tracking study of vertical wells and horizontal wells shows that the steam chamber is formed and expanded according to the law of "multiple points of steam, threading and connecting into a body". The configuration relationship of the injection and production wells and the location of the steam injection vertical well directly affect the development of the steam chamber.

5. The SAGD development well pattern method for deep ultra-heavy oil reservoirs according to claim 4, characterized in that: The specific steps for optimizing the design of vertical steam injection wells are as follows: vertical wells and horizontal wells are combined in the well layout. A horizontal production well needs to be equipped with several vertical steam injection wells. The relative positions of the vertical wells are selected according to the following principles: (1) Each horizontal production well must have at least three corresponding vertical steam injection wells, located at the heel, middle and toe of the horizontal section; (2) The positions of two adjacent rows of steam injection wells should be staggered, forming an "isosceles" triangle distribution; (3) Even if only two vertical steam injection wells are needed in the row after staggering, an additional vertical steam injection well should be deployed at the toe of the horizontal well; (4) If the selected vertical steam injection wells cannot form an "isosceles" triangle distribution due to the well conditions of the vertical wells, the first condition that needs to be met is whether there is a steam injection well in the toe area of ​​the horizontal well; (5) Fully consider the well conditions and the rotation steam injection implemented in the SAGD stage.

6. The SAGD development well pattern method for deep ultra-heavy oil reservoirs according to claim 1, characterized in that: The process of designing the perforation locations is as follows: The actual SAGD production shows that when the bottom boundary of the perforated well section is lower than the vertical depth of the horizontal section or is the same depth as the horizontal section, the steam will directly flow to the production well after steam injection, seriously affecting the development effect. The perforation position of the steam injection well is set to be higher than the vertical depth of the horizontal well section.

7. The SAGD development well pattern method for deep ultra-heavy oil reservoirs according to claim 1, characterized in that: The process for designing the perforation thickness is as follows: The results of numerical simulation research show that the higher the perforation thickness, the higher the permeability and the higher the steam injection rate. When the perforation thickness is 8 to 10 m, the oil-gas ratio and recovery degree in the SAGD stage are higher. This thickness is conducive to reducing the injection pressure of the steam injection well, improving the bottom hole dryness and reducing the risk of steam channeling.

8. The SAGD development well pattern method for deep ultra-heavy oil reservoirs according to claim 1, characterized in that: The process of designing the trajectory of the horizontal section of a horizontal production well is as follows: Operational practice has proved that the more horizontal the horizontal section is drilled, the more conducive it is to production control. In order to prevent the steam in the upper steam chamber from entering the horizontal production well, a liquid level of 3.0 to 5.0 m is maintained above the production well, and the steam-liquid interface is determined by the highest point of the horizontal screen section. This is to reduce the risk of steam cross-talk, reduce the difficulty of regulation, increase the SAGD recovery rate, and reduce the up and down displacement of the newly drilled horizontal production well on the horizontal section trajectory.

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