Multi-stage pressure control method and system for preventing blowout in fine pressure control drilling

Abstract

The invention relates to a multi-stage pressure control method and system for preventing blowout in fine pressure control well drilling, and belongs to the technical field of intelligent control. Wherein a first-stage pressure parameter, a second-stage pressure parameter and a third-stage pressure parameter are respectively obtained by adopting a pressure parameter recording method; step 2), analyzing each stage of pressure trajectory distribution in each stage of pressure parameters by adopting a pressure trajectory analysis method; 3) controlling and monitoring the pressure of each stage in real time; wherein the pressure of each stage is controlled and monitored in real time by adopting a time pressure analysis method; (4) evaluating the pressure condition of each stage, and judging whether a blowout phenomenon occurs in the drilled well or the oil well or not; the method has the beneficial effect that the blowout phenomenon is reduced or avoided by adjusting the pressure of each stage at the same time until the pressure values of each stage are equal.

Description

Technical Field

[0001] The present invention belongs to the field of intelligent control technology, and in particular relates to a multi-stage pressure control method and system for preventing blowout in fine pressure controlled drilling. Background Art

[0002] Oil wells are drilled into holes by drilling methods. Generally, after the oil layer in the oil well is drilled, casing is lowered to the drilled oil layer, and cement is injected into the annular space between the casing and the well wall to maintain the seal between the well wall and the casing. In this way, the lowered casing can be tightened in the oil well.

[0003] After the casing is tightened, the oil and gas in the oil well are collected through the casing, and there will be oil well pressure in the casing. The oil well pressure refers to the pressure exerted by the liquid or gas inside the oil well on the oil well wall. If the oil well pressure is too high, oil and gas will spray out of the oil well. Oil well pressure is an important concept. It has a vital impact on oil and gas exploration, production and recovery.

[0004] Well control is a crucial technology in the process of oil and gas collection in oil wells. Well control is divided into: primary well control, secondary well control and tertiary well control. The control of oil and gas pressure at each level is well control. Well control at each level is a commonly used classification method in the process of oil and gas collection. Once the well control at each level fails to control the oil well pressure well, oil and gas will spray out of the oil well. Summary of the invention

[0005] The main technical problem solved by the present invention is how to prevent blowouts from occurring in multi-stage oil and gas pressures during drilling. The present invention provides a multi-stage pressure control method and system for preventing blowouts in fine pressure controlled drilling, which reduces or avoids the occurrence of blowouts by simultaneously adjusting the pressures of each stage until the pressure values ​​of each stage are equal.

[0006] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0007] A multi-stage pressure control method for preventing blowout in fine pressure controlled drilling comprises the following steps:

[0008] Step 1): Obtaining pressure parameters at various levels; wherein the first-level pressure parameter, the second-level pressure parameter and the third-level pressure parameter are respectively obtained by using a pressure parameter recording method;

[0009] Step 2): Analyze the pressure trajectory distribution of each level of pressure parameters using the pressure trajectory analysis method;

[0010] Step 3): Real-time control and monitoring of pressure at each level; wherein, the time pressure analysis method is used to control and monitor pressure at each level in real time;

[0011] Step 4): Evaluate the pressure conditions at each level to determine whether a blowout occurs in the drilling or oil well.

[0012] Optionally, in step 1), the acquisition of the first-level pressure parameter, the second-level pressure parameter and the third-level pressure parameter is performed sequentially, and the specific steps are as follows:

[0013] Step S1): first obtain the third-level pressure parameter, and determine whether the third-level pressure parameter exceeds its threshold value; if the third-level pressure parameter does not exceed its threshold value, obtain the second-level pressure parameter; if the third-level pressure parameter exceeds its threshold value, no longer obtain the second-level pressure parameter;

[0014] Step S2): when the second-level pressure parameter is less than or equal to the threshold value of the third-level pressure parameter, the first-level pressure parameter is obtained; when the second-level pressure parameter is greater than the threshold value of the third-level pressure parameter, the first-level pressure parameter is no longer obtained;

[0015] Step S3): Determine the respective parameter values ​​of the first-level pressure parameter, the second-level pressure parameter and the third-level pressure parameter.

[0016] Optionally, in step 1), the pressure parameter recording method is the following formula (1):

[0017] (1);

[0018] in, , and Representing the first, second and third levels respectively. , and represent the first pressure parameter, the second pressure parameter and the third pressure parameter respectively; , and They respectively represent that the first pressure parameter corresponds to the first level to generate the first level pressure parameter, the second pressure parameter corresponds to the second level to generate the second level pressure parameter, and the third pressure parameter corresponds to the third level to generate the third level pressure parameter;

[0019] To determine the respective parameter values ​​of the first level pressure parameter, the second level pressure parameter and the third level pressure parameter;

[0020] For identification operation, used to identify the first level , Second level and third level ;

[0021] To record the first level pressure parameters, the second level pressure parameters and the third level pressure parameters, It is the recording function of pressure parameters at each level; It is the recorded results of pressure parameters at each level.

[0022] Optionally, in step 2), the pressure trajectory analysis method is the following formula (2):

[0023] (2);

[0024] in, is the trajectory distribution of pressure, which can be horizontal or vertical distribution. In order to analyze the trajectory distribution of pressure, is the function for analyzing the trajectory distribution of the analysis pressure;

[0025] is the unit length of the first, second, or third order, from one direction to another; An operation for adjusting the unit length of the first, second or third stage from one direction to another;

[0026] The trajectory distribution of the pressure per unit length of the adjustable first stage, second stage or third stage; This is the trajectory distribution result of pressure.

[0027] Optionally, in step 3), in the process of real-time control and monitoring of pressure at each level, the following steps are adopted:

[0028] Step A): monitoring the pressure of the first stage, the second stage and the third stage respectively;

[0029] Step B): Adjust the pressure of each level simultaneously until the pressure values ​​of each level are equal to reduce the occurrence of blowout.

[0030] Furthermore, in step 3), the time pressure analysis method is the following formula (3):

[0031] (3);

[0032] in, is the pressure value in the first, second or third stage, is the change of pressure value, the pressure value can increase or decrease, A function for monitoring changes in pressure values;

[0033] is the unit time, For the adjustment of unit time, the unit time can be extended or shortened. is the regulation function per unit time;

[0034] It is the change of the pressure value in the first stage, the second stage or the third stage within the adjustable unit time; To record the changes in pressure values ​​in a certain level.

[0035] Optionally, in step 4), after the pressures at each level are equal, it is determined whether a blowout occurs in the drilling well or the oil well.

[0036] A multi-stage pressure control system for preventing blowout in fine pressure controlled drilling, comprising:

[0037] The first-level well control module is used to obtain the first-level pressure parameters, analyze the first-level pressure trajectory distribution, and monitor the first-level pressure;

[0038] The secondary well control module is used to obtain the second-stage pressure parameters, analyze the second-stage pressure trajectory distribution, and monitor the second-stage pressure;

[0039] The third-level well control module is used to obtain third-level pressure parameters, analyze third-level pressure trajectory distribution, and monitor third-level pressure;

[0040] The third-level well control module is connected to the first-level well control module through the second-level well control module. The first-level well control module, the second-level well control module and the third-level well control module determine whether a blowout occurs in the drilling or oil well based on the pressure parameters obtained by each.

[0041] Optionally, a control unit in the oil pressure regulating valve is connected between the first-level well control module and the second-level well control module, and a control unit in the oil pressure regulating valve is connected between the second-level well control module and the third-level well control module. The control unit in the oil pressure regulating valve is used to adjust the pressure in the first, second or third stage.

[0042] Beneficial effects of the present invention:

[0043] 1. The present invention utilizes a control unit in an oil pressure regulating valve connected between the first-level well control module and the second-level well control module, and a control unit in the oil pressure regulating valve connected between the second-level well control module and the third-level well control module. The control unit in the oil pressure regulating valve is used to adjust the pressure in the first stage, the second stage or the third stage, and adjust the pressure of each stage at the same time until the pressure values ​​of each stage are equal, so as to reduce the occurrence of blowout.

[0044] 2. The present invention adopts the pressure trajectory analysis method to analyze the pressure trajectory distribution of each level in the pressure parameters of each level, and adopts the time pressure analysis method to control and monitor the pressure of each level in real time, evaluate the pressure conditions of each level, and determine whether a blowout phenomenon occurs in the drilling or oil well. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0046] Figure 1 It is a schematic diagram of the system structure of the present invention;

[0047] Figure 2 A schematic diagram of the flow direction of fluid in an oil well or a drilling well of the present invention;

[0048] Figure 3 It is a schematic diagram of the internal structure layout of an oil well or drilling well of the present invention;

[0049] Figure 4 It is a schematic diagram of the workflow of the present invention. DETAILED DESCRIPTION

[0050] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0051] Example 1

[0052] like Figure 1 As shown, this embodiment provides a multi-stage pressure control system for preventing blowout in fine pressure controlled drilling, comprising:

[0053] The first-level well control module is used to obtain the first-level pressure parameters, analyze the first-level pressure trajectory distribution, and monitor the first-level pressure;

[0054] The secondary well control module is used to obtain the second-stage pressure parameters, analyze the second-stage pressure trajectory distribution, and monitor the second-stage pressure;

[0055] The third-level well control module is used to obtain third-level pressure parameters, analyze third-level pressure trajectory distribution, and monitor third-level pressure;

[0056] The third-level well control module is connected to the first-level well control module through the second-level well control module. The first-level well control module, the second-level well control module and the third-level well control module determine whether a blowout occurs in the drilling or oil well based on the pressure parameters obtained by each of them. That is, the first-level well control module, the second-level well control module and the third-level well control module determine whether a blowout occurs in the drilling or oil well based on the pressure parameters obtained by each of them.

[0057] A control unit in the oil pressure regulating valve (not shown in the figure) is connected between the first-level well control module and the second-level well control module, and a control unit in the oil pressure regulating valve (not shown in the figure) is connected between the second-level well control module and the third-level well control module. The control unit in the oil pressure regulating valve is used to adjust the pressure in the first, second or third stage.

[0058] The control unit in the oil pressure regulating valve is controlled according to the pressure parameters obtained by the first-level well control module, the second-level well control module and the third-level well control module respectively. The first-level well control module, the second-level well control module, the third-level well control module and the control unit in the oil pressure regulating valve can be connected to the control platform outside the oil well (not shown in the figure) for wireless communication, and the control unit in the oil pressure regulating valve is used to adjust the pressure in the first, second or third stage.

[0059] Example 2

[0060] Based on Example 1, Figure 1 As shown, each secondary well control module manages two tertiary well control modules, and one primary well control module manages three secondary well control modules, which reflects the hierarchical management mode of the well control modules.

[0061] Example 3

[0062] Based on Example 1, Figure 4 As shown, this embodiment provides a multi-stage pressure control method for preventing blowout in fine pressure controlled drilling, comprising the following steps:

[0063] Step 1): Obtaining pressure parameters at various levels; wherein the first-level pressure parameter, the second-level pressure parameter and the third-level pressure parameter are respectively obtained by using a pressure parameter recording method;

[0064] Step 2): Analyze the pressure trajectory distribution of each level of pressure parameters using the pressure trajectory analysis method;

[0065] Step 3): Real-time control and monitoring of pressure at each level; wherein, the time pressure analysis method is used to control and monitor pressure at each level in real time;

[0066] Step 4): Evaluate the pressure conditions at each level to determine whether a blowout occurs in the drilling or oil well.

[0067] Specifically, Figure 3 As shown, in step 1), the acquisition of the first-level pressure parameter (i.e., the pressure parameter of the L1 segment), the second-level pressure parameter (i.e., the pressure parameter of the L2 segment), and the third-level pressure parameter (i.e., the pressure parameter of the L3 segment) is performed in sequence, and the specific steps are as follows:

[0068] Step S1): first obtain the third-level pressure parameter, and determine whether the third-level pressure parameter exceeds its threshold value (determined according to the pressure conditions of the oil well or drilling well); if the third-level pressure parameter does not exceed its threshold value, obtain the second-level pressure parameter; if the third-level pressure parameter exceeds its threshold value, no longer obtain the second-level pressure parameter;

[0069] Step S2): when the second-level pressure parameter is less than or equal to the threshold value of the third-level pressure parameter, the first-level pressure parameter is obtained; when the second-level pressure parameter is greater than the threshold value of the third-level pressure parameter, the first-level pressure parameter is no longer obtained;

[0070] Through steps S1) to S2), it can be known that when the third-level pressure parameter of the third-level L3 segment exceeds its threshold value, a blowout will occur in the third-level L3 segment, and the second-level L2 segment will no longer obtain the second-level pressure parameter. Similarly, when the second-level pressure parameter of the second-level L2 segment is greater than the threshold value of the third-level pressure parameter of the third-level L3 segment, the first-level L1 segment will no longer obtain the first-level pressure parameter.

[0071] Step S3): Determine the respective parameter values ​​of the first-level pressure parameter, the second-level pressure parameter and the third-level pressure parameter.

[0072] In step 1), the pressure parameter recording method is as follows:

[0073] (1);

[0074] in, , and They represent the first level, i.e., L1 segment, the second level, i.e., L2 segment, and the third level, i.e., L3 segment, respectively. , and represent the first pressure parameter, the second pressure parameter and the third pressure parameter respectively; , and They respectively represent that the first pressure parameter corresponds to the first level to generate the first level pressure parameter, the second pressure parameter corresponds to the second level to generate the second level pressure parameter, and the third pressure parameter corresponds to the third level to generate the third level pressure parameter;

[0075] To determine the respective parameter values ​​of the first level pressure parameter, the second level pressure parameter and the third level pressure parameter;

[0076] For identification operation, used to identify the first level , Second level and third level ;

[0077] To record the first level pressure parameters, the second level pressure parameters and the third level pressure parameters, It is the recording function of pressure parameters at each level; It is the recorded results of pressure parameters at each level.

[0078] like Figure 2 and Figure 3 As shown, in step 2), the pressure trajectory analysis method is the following formula (2):

[0079] (2);

[0080] in, is the trajectory distribution of pressure. The trajectory distribution of pressure is horizontal distribution or vertical distribution, that is, the trajectory distribution of pressure is along Figure 2 The arrow direction is the longitudinal distribution, and the pressure trajectory is distributed along the vertical direction. Figure 2 The arrow direction distribution is horizontal distribution, To analyze the trajectory distribution of pressure, it can be known that the trajectory distribution of pressure is horizontal distribution or vertical distribution. is the function for analyzing the trajectory distribution of the analysis pressure;

[0081] for Figure 3 The unit length of the first level, i.e., L1 segment, the second level, i.e., L2 segment, or the third level, i.e., L3 segment, is the unit length from one direction to another direction. Figure 2 The direction of the arrow; The operation of adjusting the unit length of the first, second or third stage from one direction to another direction, i.e. the length of the L1 segment, the L2 segment or the L3 segment is adjustable;

[0082] The trajectory distribution of the pressure per unit length of the adjustable first stage, second stage or third stage; This is the trajectory distribution result of pressure.

[0083] Formula (2) monitors the trajectory distribution of the pressure of the first stage, the second stage or the third stage by adjusting the unit length of the first stage, the second stage or the third stage.

[0084] Combination Figure 2 and Figure 3 It can be seen that Figure 2 This reflects that the flow direction of the fluid in the oil well is from right to left. Figure 3 It reflects that the first stage, namely the L1 section, the second stage, namely the L2 section, and the third stage, namely the L3 section, in the oil well are arranged from left to right. Therefore, the flow direction of the fluid in the oil well is from the third stage, namely the L3 section, to the first stage, namely the L1 section.

[0085] In step 3), in the process of real-time control and monitoring of pressure at each level, the following steps are adopted:

[0086] Step A): monitoring the pressure of the first stage, the second stage and the third stage respectively;

[0087] Step B): Adjust the pressure of each level at the same time until the pressure values ​​of each level are equal to reduce the occurrence of blowout. Because, after the pressure of each level is equal, the occurrence of blowout in the entire drilling or oil well can be reduced.

[0088] based on Figure 3 It should be noted here that an oil pressure regulating valve is provided between the first stage and the second stage, and an oil pressure regulating valve is provided between the second stage and the third stage, and a control unit in the oil pressure regulating valve is connected between the first-level well control module and the second-level well control module, and a control unit in the oil pressure regulating valve is connected between the second-level well control module and the third-level well control module. The control unit in the oil pressure regulating valve is controlled according to the pressure parameters obtained by the first-level well control module, the second-level well control module and the third-level well control module respectively, and the control unit in the oil pressure regulating valve is used to adjust the pressure in the first stage, the second stage or the third stage. The control unit in the oil pressure regulating valve controls the opening and closing of the oil pressure regulating valve to adjust the pressure at each stage, and the use of the oil pressure regulating valve can adjust the pressure at each stage.

[0089] In step 3), the time pressure analysis method is the following formula (3):

[0090] (3);

[0091] in, is the pressure value in the first, second or third stage, is the change of pressure value, the pressure value can increase or decrease, A function for monitoring changes in pressure values;

[0092] is the unit time, For the adjustment of unit time, the unit time can be extended or shortened. is the regulation function per unit time;

[0093] It is the change of the pressure value in the first stage, the second stage or the third stage within the adjustable unit time; To record the changes in pressure values ​​in the first, second or third stage.

[0094] In step 4), after the pressures at each level are equal, it is determined whether a blowout occurs in the drilling well or oil well. Because the equal pressures at each level can determine whether a blowout occurs in the entire drilling well or oil well.

[0095] Example 4

[0096] Based on Example 3, Figure 2 and Figure 3 As shown, since the flow direction of the fluid in the oil well is from right to left, that is, the flow direction of the fluid in the oil well is from the third stage, namely, the L3 section, to the first stage, namely, the L1 section.

[0097] In step S1)-step S3), when the third-level pressure parameter of the third-level L3 segment exceeds its threshold value, a blowout will occur in the third-level L3 segment, and the fluid will flow from the third-level L3 segment to the first-level L1 segment, and the first-level L1 segment and the second-level L2 segment will no longer obtain pressure parameters. Similarly, when the second-level pressure parameter of the second-level L2 segment is greater than the threshold value of the third-level pressure parameter of the third-level L3 segment, the fluid will flow from the third-level L2 segment to the first-level L1 segment, and the first-level L1 segment will no longer obtain pressure parameters.

[0098] Example 5

[0099] Based on Example 3, Figure 2 and Figure 3 As shown, the pressure trajectory distribution is horizontal distribution or vertical distribution, that is, the pressure trajectory distribution along Figure 2 The arrow direction is the longitudinal distribution, and the pressure trajectory is distributed along the vertical direction. Figure 2 The arrow direction distribution is the horizontal distribution.

[0100] In formula (2), along Figure 2 The unit length of the first, second or third stage is adjusted in the direction of the arrow, and then the pressure trajectory distribution of the first, second or third stage is analyzed.

[0101] In general, the fluid flow direction within the first, second, and third stages is from the third stage to the first stage, and it is rare to see a direction perpendicular to the fluid flow direction (i.e., perpendicular to the direction of the fluid flow). Figure 2 direction of the arrow).

[0102] Example 6

[0103] Based on Example 3, in formula (3), the change of the pressure value of the first stage, the second stage or the third stage, that is, the increase or decrease of the pressure value, is monitored within an adjustable unit time.

[0104] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope of the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A multi-stage pressure control method for preventing blowout in fine pressure controlled drilling, characterized in that: The steps include: Step 1): Obtaining pressure parameters at various levels; wherein the first-level pressure parameter, the second-level pressure parameter and the third-level pressure parameter are respectively obtained by using a pressure parameter recording method; Step 2): using a pressure trajectory analysis method to analyze the pressure trajectory distribution of each level of pressure parameters; Step 3): Real-time control and monitoring of pressure at each level; wherein, the time pressure analysis method is used to control and monitor pressure at each level in real time; Step 4): Evaluate the pressure conditions at each level to determine whether a blowout occurs in the drilling or oil well.

2. A multi-stage pressure control method for preventing blowout in fine pressure controlled drilling according to claim 1, characterized in that: In the step 1), the acquisition of the first-level pressure parameter, the second-level pressure parameter and the third-level pressure parameter is performed sequentially, and the specific steps are as follows: Step S1): first obtain the third-level pressure parameter, and determine whether the third-level pressure parameter exceeds its threshold value; if the third-level pressure parameter does not exceed its threshold value, obtain the second-level pressure parameter; if the third-level pressure parameter exceeds its threshold value, no longer obtain the second-level pressure parameter; Step S2): when the second-level pressure parameter is less than or equal to the threshold value of the third-level pressure parameter, the first-level pressure parameter is obtained; when the second-level pressure parameter is greater than the threshold value of the third-level pressure parameter, the first-level pressure parameter is no longer obtained; Step S3): Determine the respective parameter values ​​of the first-level pressure parameter, the second-level pressure parameter and the third-level pressure parameter.

3. The multi-stage pressure control method for preventing blowout in fine pressure controlled drilling according to claim 1, characterized in that: In the step 1), the pressure parameter recording method is the following formula (1): (1)； in, , and Representing the first, second and third levels respectively. , and represent the first pressure parameter, the second pressure parameter and the third pressure parameter respectively; , and They respectively represent that the first pressure parameter corresponds to the first level to generate the first level pressure parameter, the second pressure parameter corresponds to the second level to generate the second level pressure parameter, and the third pressure parameter corresponds to the third level to generate the third level pressure parameter; To determine the respective parameter values ​​of the first level pressure parameter, the second level pressure parameter and the third level pressure parameter; For identification operation, used to identify the first level , Second level and third level ; To record the first level pressure parameters, the second level pressure parameters and the third level pressure parameters, It is the recording function of pressure parameters at each level; It is the recorded results of pressure parameters at each level.

4. The multi-stage pressure control method for preventing blowout in fine pressure controlled drilling according to claim 1, characterized in that: In the step 2), the pressure trajectory analysis method is the following formula (2): (2)； in, is the trajectory distribution of pressure, which can be horizontal or vertical distribution. In order to analyze the trajectory distribution of pressure, is the function for analyzing the trajectory distribution of the analysis pressure; is the unit length of the first, second, or third order, from one direction to another; An operation for adjusting the unit length of the first, second or third stage from one direction to another; The trajectory distribution of the pressure per unit length of the adjustable first stage, second stage or third stage; This is the trajectory distribution result of pressure.

5. The multi-stage pressure control method for preventing blowout in fine pressure controlled drilling according to claim 1, characterized in that: In step 3), in the process of real-time control and monitoring of the pressures at each level, the following steps are adopted: Step A): monitoring the pressure of the first stage, the second stage and the third stage respectively; Step B): Adjust the pressure of each level simultaneously until the pressure values ​​of each level are equal to reduce the occurrence of blowout.

6. A multi-stage pressure control method for preventing blowout in fine pressure controlled drilling according to claim 5, characterized in that: In the step 3), the time pressure analysis method is the following formula (3): (3)； in, is the pressure value in the first, second or third stage, is the change of pressure value, the pressure value can increase or decrease, A function for monitoring changes in pressure values; is the unit time, For the adjustment of unit time, the unit time can be extended or shortened. is the regulation function per unit time; It is the change of the pressure value in the first stage, the second stage or the third stage within the adjustable unit time; To record the changes in pressure values ​​in a certain level.

7. The multi-stage pressure control method for preventing blowout in fine pressure controlled drilling according to claim 1, characterized in that: In the step 4), after the pressures at each level are equal, it is determined whether a blowout occurs in the drilling well or the oil well.

8. A multi-stage pressure control system for preventing blowouts in precision pressure-controlled drilling, used to execute a multi-stage pressure control method for preventing blowouts in precision pressure-controlled drilling as claimed in any one of claims 1 to 7, characterized in that: include: The first-level well control module is used to obtain the first-level pressure parameters, analyze the first-level pressure trajectory distribution, and monitor the first-level pressure; The secondary well control module is used to obtain the second-stage pressure parameters, analyze the second-stage pressure trajectory distribution, and monitor the second-stage pressure; The third-level well control module is used to obtain third-level pressure parameters, analyze third-level pressure trajectory distribution, and monitor third-level pressure; The third-level well control module is connected to the first-level well control module through the second-level well control module. The first-level well control module, the second-level well control module and the third-level well control module determine whether a blowout occurs in the drilling or oil well based on the pressure parameters obtained by each.

9. A multi-stage pressure control system for preventing blowout in precision pressure controlled drilling according to claim 8, characterized in that: A control unit in the oil pressure regulating valve is connected between the first-level well control module and the second-level well control module, and a control unit in the oil pressure regulating valve is connected between the second-level well control module and the third-level well control module. The control unit in the oil pressure regulating valve is used to adjust the pressure in the first, second or third stage.

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