Dynamic regulation and control method for SAGD development assisted by artificial liquid level

Abstract

The invention relates to the technical field of SAGD (steam assisted gravity drainage) development dynamic regulation and control methods, in particular to an artificial liquid level assisted SAGD development dynamic regulation and control method which comprises the steps of evaluating the difficulty degree of oil well regulation and control according to the number of oil well steam channeling days, the steam channeling length, the steam channeling position and the dynamic regulation and control history, making an adjustment scheme, performing field implementation according to the adjustment scheme and performing later regulation and control recovery. The method is suitable for all stages of super heavy oil SAGD development, through active water injection to a production well, rapid establishment of an artificial liquid level, plugging of a steam channeling channel and resetting of an underground temperature field, uniform liquid drainage of a horizontal section is achieved, yield recovery of a steam channeling well is accelerated, the problems that a conventional regulation and control recovery period is long, the yield is large, even the yield cannot be recovered and the like are solved, and the production efficiency is improved. The maximum oil production potential of an oil well is exerted, and oil well development benefits are improved.

Description

Technical Field

[0001] The invention relates to the technical field of SAGD development dynamic control methods, in particular to an artificial liquid level-assisted SAGD development dynamic control method. Background Art

[0002] During the development of super-heavy oil SAGD, affected by the heterogeneity of the reservoir and the uneven distribution of temperature and pressure fields in the horizontal section of the well, steam channeling is prone to occur to varying degrees at the front end of the horizontal section and some strong production points during oil well production, resulting in reduced oil production levels. In the process of restoring the normal oil production level of the oil well, the existing control means mainly adjust the injection-production balance to make the oil well production volume less than the steam chamber discharge volume, passively wait for the gas-liquid interface to be re-established after the downhole liquid accumulates, block the steam channeling channel, and then gradually adjust the parameters to restore the normal production level of the oil well. The overall control cycle is long and the impact on production is large. After steam channeling, some well groups are difficult to restore the oil production level due to uneven production of the horizontal section or decreased production, which seriously restricts the oil well from exerting its maximum oil production potential. New control and management ideas are urgently needed to shorten the control and recovery cycle of steam channeling wells, reduce the impact on production, and restore the normal oil production level of the oil well. Summary of the invention

[0003] The present invention provides a method for dynamic regulation of SAGD development assisted by artificial liquid level, which overcomes the shortcomings of the above-mentioned prior art and can solve the problems of long regulation and recovery period of steam crossover well group in SAGD development process, large impact on production, and difficulty in recovering oil production level due to uneven utilization or decreased utilization degree of horizontal sections in some well groups after steam crossover.

[0004] The technical solution of the present invention is achieved by the following measures: A method for dynamic regulation of artificial liquid level-assisted SAGD development, comprising the following steps:

[0005] Step 1, preliminary assessment: according to the number of days, length, location and dynamic control history of the oil well steam channeling, the difficulty of oil well control is assessed, and an adjustment plan is formulated, which includes the determination of construction parameters and the control rhythm when resuming production;

[0006] Step 2, parameter determination: based on the preliminary evaluation in step 1, determine the injection medium, injection method and injection amount;

[0007] Step 3, on-site implementation: according to the injection medium, injection method and injection amount determined in step 2, the medium is injected into the well to quickly establish an artificial liquid level to block the steam channel and reset the temperature field of the horizontal section downhole;

[0008] Step 4, control recovery: Use conventional oil nozzle flushing control methods. The entire control recovery cycle is 8 to 17 days, gradually restoring normal production levels.

[0009] The following are further optimizations and / or improvements to the above technical solutions:

[0010] In the above step 2, the injection medium is deoiled hot sewage at 70°C to 100°C or cold water for well pressure at normal temperature.

[0011] In the above step 2, the injection method is: injection through the production well casing or auxiliary pipe.

[0012] In the above step 2, the injection volume is calculated according to the following formula:

[0013] M 注入 =h 2 *R*L / H*φ*S 0 *ρ

[0014] Where M 注入 —artificial liquid level injection volume, t; h—artificial liquid level height, m; R—steam cavity radius, m; L—steam cavity length, m; φ—porosity, %; S 0 —Oil saturation, %; ρ—injection medium density, Kg / m 3 .

[0015] In the above step 3, after the injection of the medium into the well is completed, the production well is shut in for 1 day to quickly reset the temperature field of the horizontal section downhole.

[0016] In the above step 4, the specific regulation and recovery is: maintain a regulation rhythm of fast first and slow later, use conventional oil nozzle flushing regulation means, first use 1 to 2 days to recover to 50% of the normal production level, then use 2 to 5 days to recover to 80% of the normal production level, and finally use 5 to 10 days to recover to the normal production level.

[0017] The method of the present invention is applicable to all stages of super-heavy oil SAGD development. By actively injecting water into the production well, an artificial liquid level is quickly established, the steam channeling channel is blocked, and the downhole temperature field is reset to uniformly drain the horizontal section, thereby accelerating the recovery of the production of the steam channeling well. The method solves the problems of long recovery cycle of conventional regulation, great impact on production, and even inability to recover production, thereby giving full play to the maximum oil production potential of the oil well and improving the efficiency of oil well development. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Attached Figure 1 A control principle diagram of the method for developing dynamic control of artificial liquid level-assisted SAGD according to the present invention.

[0019] Attached Figure 2 It is a calculation model for the amount of artificial liquid surface fluid replenishment (injection volume).

[0020] Attached Figure 3 This is the artificial liquid level replenishment volume-liquid level height chart. DETAILED DESCRIPTION

[0021] The present invention is not limited by the following embodiments, and the specific implementation method can be determined according to the technical solution of the present invention and the actual situation. Normal temperature in the present invention generally refers to a temperature of 20°C to 25°C, generally defined as 25°C.

[0022] The present invention will be further described below in conjunction with embodiments:

[0023] Example 1: The method for dynamic regulation of artificial liquid level-assisted SAGD development comprises the following steps:

[0024] Step 1, preliminary assessment: according to the number of days, length, location and dynamic control history of the oil well steam channeling, the difficulty of oil well control is assessed, and an adjustment plan is formulated, which includes the determination of construction parameters and the control rhythm when resuming production;

[0025] Step 2, parameter determination: based on the preliminary evaluation in step 1, determine the injection medium, injection method and injection amount;

[0026] Step 3, on-site implementation: according to the injection medium, injection method and injection volume determined in step 2, the medium is injected into the well to quickly establish an artificial liquid level, so as to block the steam channel and reset the temperature field of the horizontal section downhole (if necessary, the production well can be shut down for 1 day), so as to lay a good foundation for uniform drainage of the oil well and recovery of the utilization degree of the horizontal section in the later stage;

[0027] Step 4, control recovery: Use conventional oil nozzle flushing control methods. The entire control recovery cycle is 8 to 17 days, gradually restoring normal production levels.

[0028] Depend on Figure 1 It can be seen that in the process of using the method of dynamic regulation of artificial liquid level-assisted SAGD development described in the present invention, from single-point steam crosstalk to artificial liquid level blocking the steam crosstalk channel, to the re-balancing of the downhole temperature field, the mobilization becomes uniform, and finally the oil wells are evenly discharged, the output returns to normal and the production is stable.

[0029] The method described in the present invention breaks through the original control ideas and innovatively proposes a method for dynamic control of SAGD development assisted by artificial liquid level, which changes the passive control of liquid storage level to active and rapid establishment of artificial liquid level, blocks the steam channeling channel, and resets the downhole temperature field to make the oil wells discharge liquid evenly, accelerates the recovery of production of steam channeling well groups, greatly shortens the recovery time of problem wells, and reduces the impact on oil production.

[0030] Embodiment 2: As an optimization of the above embodiment, in step 2, the injection medium is deoiled hot sewage at 70°C to 100°C or cold water for well pressure at normal temperature.

[0031] Embodiment 3: As an optimization of the above embodiment, in step 2, the injection method is: injection through the production well casing or auxiliary pipe.

[0032] Embodiment 4: As an optimization of the above embodiment, in step 2, the injection amount is calculated according to the following formula:

[0033] M 注入 =h 2 *R*L / H*φ*S 0 *ρ

[0034] Where M 注入 —artificial liquid level injection volume (i.e. injection volume), t; h—artificial liquid level height, m; R—vapor cavity radius, m; L—vapor cavity length, m; φ—porosity, %; S 0 —Oil saturation, %; ρ—injection medium density, Kg / m 3 .

[0035] The artificial level of fluid replacement is derived from Figure 2 ,

[0036] Figure 2 In the figure, the volume of the artificial liquid surface replenishment is a triangular prism, and its cross-sectional area is an inverted triangle:

[0037] S 汽腔 =R*H

[0038] S 液面 =h 2 / H 2 *S 汽腔 →V 液面 =h 2 *R*L / H

[0039] V 液面 =S 液面 *L

[0040] Injection volume:

[0041] V 注入 =V 液面 *φ*S 0

[0042] M 注入 =V 注入 *ρ→M 注入 =V 液面 *φ*S 0 *ρ

[0043] =h 2 *R*L / H*φ*S 0 *ρ

[0044] In the above formula,

[0045] R—steam cavity radius, m; S 汽腔 —Cavity cross-sectional area, m 2 ;

[0046] H—oil layer thickness, m; S 液面 —Artificial liquid surface cross-sectional area, m 2 ;

[0047] L—steam cavity length, m; V 液面 —artificial liquid surface volume, m 3 ;

[0048] h—artificial liquid level height, m; V 注入 —Injection volume of artificial liquid level, m 3 ;

[0049] M 注入 — artificial liquid level injection volume, t; φ—porosity, %;

[0050] S 0 —Oil saturation, %; ρ—injection medium density, Kg / m 3 .

[0051] Example 5: As an optimization of the above example, in step 4, the regulation and recovery are specifically as follows: maintain a regulation rhythm of first fast and then slow, use conventional nozzle flushing regulation means, first use 1 to 2 days to recover to 50% of the normal production level, then use 2 to 5 days to recover to 80% of the normal production level, and finally use 5 to 10 days to recover to the normal production level.

[0052] According to the method of the present invention, Figure 3 The amount of fluid replenishment can be quickly determined based on the number of steam breakthrough points in the well group and the difficulty of regulation (determining the height of the artificial liquid level).

[0053] Implementation Cases:

[0054] Taking the dynamic regulation of the FHW1311 well group in the Chongqing 1 well area as an example, the normal liquid production level of the well group is 100t / d, and the oil production level is 22t / d. In December 2021, steam channeling occurred at two points at the front end of the well, and the temperature at the rear end of the horizontal section decreased accordingly. The liquid storage level was then controlled and steam channeling was controlled. Until June 2022, the well group had not restored its normal production level. During this period, it underwent multiple rounds of conventional regulation such as controlling liquid production, stopping steam and controlling temperature, optimizing steam injection methods, and optimizing liquid production methods. The highest liquid production level recovered to 80t / d, and the oil production level recovered to 17t / d. The front end of the horizontal section of the well was prone to channeling, uneven mobilization, and unstable production of the well group.

[0055] In July 2022, the method of artificial liquid level assisted dynamic control of SAGD development described in the present invention was adopted to carry out an artificial liquid level assisted dynamic control test of SAGD. Two trucks of deoiled hot sewage totaling 40 cubic meters were injected into the casing of the production well, and the well was shut down for half a day to store liquid. At the same time, the temperature distribution of the horizontal section was balanced to make the oil well evenly drained, and then the well was opened for production, and the liquid was gradually raised. After 17 days of water injection, the production level of the well group returned to normal, with a liquid production of 102t / d and an oil production of 22t / d. The utilization level of the horizontal section recovered by 20% to 90%, and the temperature distribution downhole was more uniform, which greatly shortened the control cycle and reduced the impact on production. Compared with conventional control, the liquid production level recovered by 20t / d, the oil production level recovered by 5t / d, the oil-gas ratio increased by 0.05, and stable production has been maintained to date. The problem of the difficulty in recovering the production of the steam channeling well due to uneven utilization was solved, the maximum oil production potential of the oil well was brought into play, and the benefits of heavy oil development were improved.

[0056] By adopting the method of artificial liquid level assisted dynamic control of SAGD development described in the present invention, after the on-site artificial liquid level assisted dynamic control of SAGD, the control cycle of the steam channeling well group adjustment recovery stage and the affected oil volume are only 1 / 5-1 / 10 of the conventional control, the horizontal section utilization degree and the well group recovery utilization degree are improved, the single well group recovers oil production, the oil increase level is more than 3.0t / d, and the oil-gas ratio is increased by more than 0.04. The problems of long recovery cycle of conventional control, large impact on production and even inability to recover production are solved, the maximum oil production potential of the oil well is brought into play, and the development efficiency of the oil well is improved.

[0057] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A method for dynamic control of artificial liquid level-assisted SAGD development, characterized in that The following steps are involved: Step 1, preliminary assessment: according to the number of days, length, location and dynamic control history of the oil well steam channeling, the difficulty of oil well control is assessed, and an adjustment plan is formulated, which includes the determination of construction parameters and the control rhythm when resuming production; Step 2, parameter determination: based on the preliminary evaluation in step 1, determine the injection medium, injection method and injection amount; Step 3, on-site implementation: according to the injection medium, injection method and injection amount determined in step 2, the medium is injected into the well to quickly establish an artificial liquid level to block the steam channel and reset the temperature field of the horizontal section downhole; Step 4, control recovery: Use conventional oil nozzle flushing control methods. The entire control recovery cycle is 8 to 17 days, gradually restoring normal production levels.

2. The method for dynamic control of artificial liquid level-assisted SAGD development according to claim 1, characterized in that In step 2, the injection medium is deoiled hot sewage at 70°C to 100°C or cold water for well pressure at normal temperature.

3. The method for dynamic control of artificial liquid level-assisted SAGD development according to claim 1 or 2, characterized in that In step 2, injection method: injection through the production well casing or auxiliary pipe.

4. The method for dynamic control of artificial liquid level-assisted SAGD development according to claim 1 or 2, characterized in that In step 2, the injection volume is calculated according to the following formula: M 注入 =h 2 *R*L / H*φ*S0*ρ Where M 注入 —Injection volume of artificial liquid level, t; h—height of artificial liquid level, m; R—radius of steam cavity, m; L—length of steam cavity, m; φ—porosity, %; S0—oil saturation, %; ρ—density of injected medium, Kg / m 3 .

5. The method for dynamic control of artificial liquid level-assisted SAGD development according to claim 3, characterized in that In step 2, the injection volume is calculated according to the following formula: M 注入 =h 2 *R*L / H*φ*S0*ρ Where M 注入 —Injection volume of artificial liquid level, t; h—height of artificial liquid level, m; R—radius of steam cavity, m; L—length of steam cavity, m; φ—porosity, %; S0—oil saturation, %; ρ—density of injected medium, Kg / m 3 .

6. The method for dynamic control of artificial liquid level-assisted SAGD development according to claim 1, 2 or 5, characterized in that In step 4, the specific regulation and recovery is: maintain a regulation rhythm of fast first and slow later, use conventional oil nozzle flushing regulation means, first use 1 to 2 days to recover to 50% of the normal production level, then use 2 to 5 days to recover to 80% of the normal production level, and finally use 5 to 10 days to recover to the normal production level.

7. The method for dynamic control of artificial liquid level-assisted SAGD development according to claim 3, characterized in that In step 4, the specific regulation and recovery is: maintain a regulation rhythm of fast first and slow later, use conventional oil nozzle flushing regulation means, first use 1 to 2 days to recover to 50% of the normal production level, then use 2 to 5 days to recover to 80% of the normal production level, and finally use 5 to 10 days to recover to the normal production level.

8. The method for dynamic control of artificial liquid level-assisted SAGD development according to claim 4, characterized in that In step 4, the specific regulation and recovery is: maintain a regulation rhythm of fast first and slow later, use conventional oil nozzle flushing regulation means, first use 1 to 2 days to recover to 50% of the normal production level, then use 2 to 5 days to recover to 80% of the normal production level, and finally use 5 to 10 days to recover to the normal production level.

9. The method for dynamic control of artificial liquid level-assisted SAGD development according to claim 1, 2, 5, 7 or 8, characterized in that In step 3, after the injection of the medium into the well is completed, the production well is shut in for 1 day to quickly reset the temperature field of the horizontal section downhole.

10. The method for dynamic control of artificial liquid level-assisted SAGD development according to claim 6, characterized in that In step 3, after the injection of the medium into the well is completed, the production well is shut in for 1 day to quickly reset the temperature field of the horizontal section downhole.

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