Automatic curvature control method and system for rotary steering system, and computer equipment

Abstract

The present invention provides a method and system for automatic curvature control of a rotary steering system, and a computer device. The automatic curvature control method includes the following steps: determining a predetermined mechanical penetration rate (ROP) based on the previous drilling situation; sending an automatic curvature instruction to the well via the surface, the automatic curvature instruction including the predetermined mechanical penetration rate (ROP), the expected curvature γ, the initial deflection force, and the deflection direction; recording the downhole time T once every predetermined well section length. i 、Well inclination angle INC i and azimuth AZ i The system calculates the build-up curvature for a predetermined well section and compares it with the expected curvature, automatically adjusting the magnitude and direction of the build-up force based on the comparison results. This invention enables downhole instruments to sense their own well depth in real time, solving the core challenge of automatic curvature downhole closed-loop control. This method forms an automatic curvature control method for rotary steerable systems, significantly improving the efficiency of rotary steerable build-up control and the quality of the wellbore trajectory.

Description

Technical Field

[0001] The present invention relates to the technical field of wellbore trajectory control, and in particular to an automatic curvature control method for a rotary steering system, an automatic curvature control system for a rotary steering system, a computer device for implementing the automatic curvature control method, and a computer-readable storage medium storing a computer program. Background Art

[0002] The rotary steerable drilling system is a cutting-edge automated drilling technology that provides a novel approach to achieving superior drilling performance, precise well trajectory control, and exceptional wellbore quality. To reduce drilling time lost due to frequent surface inclination commands and further improve drilling efficiency and wellbore trajectory control, two downhole closed-loop control methods for rotary steerable drilling systems have been developed: automatic verticalization and automatic inclination stabilization. Field applications have yielded significant improvements in both quality and efficiency. These two downhole automated control methods share the same fundamental principles: they compare the inclination and azimuth values ​​measured while drilling by downhole inclination sensors with the desired inclination and azimuth values. If the measured inclination exceeds the preset inclination, the inclination-increasing force is increased; otherwise, the force is reduced. If the measured azimuth exceeds the preset azimuth, the directional force is increased; otherwise, the directional force is reduced. This closed-loop process is executed continuously, ensuring that the inclination and azimuth angles remain within the tolerance range of the preset inclination and azimuth angles. Both of these rotary steering downhole automatic control methods do not need to rely on information such as the downhole spatial position of the inclinometer sensor, and their implementation principles and methods are relatively simple.

[0003] When drilling in the build-up section, the rotary steerable drilling system needs to calculate the build-up curvature based on the inclination and azimuth data uploaded from downhole, combined with surface well depth data. If the curvature differs significantly from the expected curvature, the required downhole steering force command must be manually calculated and transmitted to the downhole rotary steerable system via a signal downlink device to execute the modified steering force command. This process is repeated to achieve a stable build-up curvature. During this process, due to the frequent surface-downhole interaction involved, rotary steerable commands need to be sent from the surface multiple times, which is time-consuming and has low control accuracy. If automatic downhole closed-loop control of the rotary steerable curvature can be achieved, the efficiency of rotary steerable build-up control and the quality of the wellbore trajectory will be greatly improved.

[0004] However, during rotary steerable drilling, the rotary steerable system is located thousands of meters underground. While it currently has the ability to obtain information about its own position, well inclination, azimuth, and other parameters at a rate of 10 seconds or faster, there are currently no mature sensor products and technologies that can autonomously and accurately determine its own well depth or the length of the well section it has traversed. Furthermore, the current downlink communication link between the surface and the downhole rotary steerable system is based on drilling fluid pressure pulses generated by throttling the downhole system. Under normal circumstances, transmitting a single piece of data can take eight minutes or longer, and there is a certain probability of transmission failure. Therefore, the method of transmitting well depth or the length of the well section traversed from the surface to the downhole rotary steerable system every 1-5 minutes is not practical for engineering purposes. For example, a Chinese patent document entitled "A Wellbore Trajectory Control Method and System Thereof," published on June 13, 2012, with publication number CN102493766A, describes a new wellbore trajectory monitoring method. Before drilling, wellbore trajectory design target parameters, model number, trajectory node parameters, starting depth, measurement control point depth, monitoring targets, and deviations are pre-stored in the steering tool memory and the surface monitoring computer. When the surface monitoring drill reaches the measurement control point depth, an easily recognizable operation instruction is sent downhole. The downhole system reads the depth data indicated by the instruction according to a rule. Based on the read depth data, the adopted design model, and trajectory node parameters, the trajectory design data corresponding to the wellbore depth is automatically calculated. The actual wellbore trajectory parameters are measured and uploaded to the downhole measurement parameters. Track monitoring and analysis are performed simultaneously downhole and on the surface. A Chinese patent application titled "A Horizontal Well Landing Control Method Based on Rotary Steerable Drilling," published on June 25, 2014, and with publication number CN103883249A, describes a method for calculating the radius of curvature of a measuring section based on inclination data. The inclination data includes well depth, inclination angle, and azimuth. The inclination data is obtained by using a measurement while drilling instrument to measure along a series of measuring points Mi (i = 1, 2, ..., n). While these techniques can determine the current well depth at a specific monitoring point, they are limited by the measurement instrumentation and measurement environment, making it impossible to obtain well depth data at any location with high frequency.

[0005] It can be seen from this that the current rotary steerable system is unable to obtain its own well depth data at a high frequency, resulting in the rotary steerable system being unable to use a deflection curvature sent from the ground and then automatically perform downhole closed-loop control according to the specified curvature. Summary of the Invention

[0006] The present invention aims to address at least one of the aforementioned deficiencies in the prior art. For example, one of the objectives of the present invention is to provide a method for obtaining well depth information at a high frequency (e.g., obtaining well section length data every 5 to 30 seconds), thereby enabling automatic downhole closed-loop curvature control of a rotary steerable drilling tool.

[0007] To achieve the above objectives, the present invention provides, on one hand, an automatic curvature control method for a rotary steerable drilling system, the automatic curvature control method comprising the following steps: determining a predetermined mechanical penetration rate (ROP) based on the previous drilling conditions; sending an automatic curvature instruction to the downhole via the surface, the automatic curvature instruction including the predetermined mechanical penetration rate (ROP), the expected curvature γ, the magnitude of the initial steering force, and the direction of the steering force; the downhole portion of the rotary steerable drilling tool operates according to the automatic curvature instruction, and records the downhole time T every interval of a predetermined well section length ΔL. i 、Well inclination angle INC i and azimuth AZ i ; and calculate the deflection curvature of the predetermined well section length, compare it with the expected curvature, and automatically adjust the magnitude and direction of the steering force based on the comparison results.

[0008] In an exemplary embodiment of the automatic curvature control method of a rotary steering system of the present invention, determining a predetermined mechanical drilling rate (ROP) may include: before drilling a current well, collecting the drill bit combination, bit pressure, rotation speed, displacement and mechanical drilling rate of the current platform and / or adjacent platforms during rotary steering drilling in the same geological formation, and establishing a rotary steering drilling parameter data set; based on the rotary steering drilling parameter data set, taking the mechanical drilling rate as the target variable, standardizing and normalizing each parameter in the data set, and using a normal distribution mathematical processing method to obtain an expected value of the mechanical drilling rate; and determining a predetermined mechanical drilling rate (ROP) based on the expected value of the mechanical drilling rate.

[0009] In an exemplary embodiment of the automatic curvature control method for a rotary steerable system of the present invention, 85% to 95% of the expected value of the mechanical drilling rate may be determined as the predetermined mechanical drilling rate ROP.

[0010] In an exemplary embodiment of the automatic curvature control method for a rotary steerable system of the present invention, the predetermined well section length may be determined based on a predetermined rate of penetration (ROP) and a drilling time difference (ΔT) between two consecutive points.

[0011] In an exemplary embodiment of the automatic curvature control method for a rotary steerable system of the present invention, the predetermined well section length may be 0.1 to 1 m.

[0012] In an exemplary embodiment of the automatic curvature control method of a rotary steerable system of the present invention, before the downhole portion of the rotary steerable drilling tool operates according to the automatic curvature instruction, whether it is in a drilling state can be determined based on the downhole rotation speed or downhole bit pressure.

[0013] In an exemplary embodiment of the automatic curvature control method of a rotary steerable system of the present invention, the rules for determining whether the system is in a drilling state are as follows: when a screw drill is not added to the rotary steerable drill assembly, the downhole bit pressure is ≥ 5kN, or the downhole rotation speed is ≥ 50RPM, and the drilling state is determined; when a screw drill is included in the rotary steerable drill assembly, the downhole rotation speed is ≥ the screw drilling speed + 40RPM, and the drilling state is determined.

[0014] In an exemplary embodiment of the automatic curvature control method for a rotary steerable system of the present invention, the downhole deflection curvature may be changed by changing a predetermined mechanical rate of penetration (ROP).

[0015] Another aspect of the present invention provides an automatic curvature control system for a rotary steering system, the automatic curvature control system comprising a predetermined mechanical drilling speed determination module, an automatic curvature instruction generation module, a downhole parameter acquisition module, and a deflection curvature calculation module, wherein the predetermined mechanical drilling speed determination module is used to determine a predetermined mechanical drilling speed ROP based on the previous drilling conditions; the automatic curvature instruction generation module is connected to the predetermined mechanical drilling speed determination module and is used to send an automatic curvature instruction to the downhole via the ground, the automatic curvature instruction including the predetermined mechanical drilling speed ROP, the expected curvature γ, the initial guide force magnitude, and the guide force direction; the downhole parameter acquisition module is connected to the automatic curvature instruction generation module and is used to record the downhole time T once every predetermined well section length ΔL. i 、Well inclination angle INC i and azimuth AZ i The deflection curvature calculation module is connected to the downhole parameter acquisition module and is used to calculate the deflection curvature of a predetermined well section length.

[0016] On the other hand, the present invention provides a computer device, which includes: a processor and a memory, which stores a computer program. When the computer program is executed by the processor, the automatic curvature control method of the rotary steering system as described above is implemented.

[0017] In another aspect, the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the automatic curvature control method of the rotary steering system as described above.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] (1) The present invention indirectly determines the well depth data by presetting the mechanical drilling speed on the ground, thereby solving the problem that the current rotary steerable drilling tool cannot accurately sense its own current well depth;

[0020] (2) The present invention realizes the real-time perception of the downhole instrument on its own well depth information (or the length of the drilled section), solves the core problem of automatic curvature downhole closed-loop control, and forms an automatic curvature control method for the rotary steering system, which greatly improves the efficiency of rotary steering inclination control and the quality of the wellbore trajectory. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other objects and / or features of the present invention will become more apparent from the following description in conjunction with the accompanying drawings, in which:

[0022] Figure 1 A control method flow chart showing an exemplary embodiment of the automatic curvature control method of the steering system of the present invention is shown.

[0023] Figure 2 A schematic diagram showing a comparison of effects between a conventional curvature control method and an automatic curvature control method, illustrating an exemplary embodiment of the automatic curvature control method for a steering system of the present invention.

[0024] Figure 3 A schematic diagram of the control system structure of an exemplary embodiment of the automatic curvature control system of the steering system of the present invention is shown.

[0025] Figure 4 A schematic diagram of the computer device structure of an exemplary embodiment of the automatic curvature control system of the steering system of the present invention is shown.

[0026] Description of reference numerals;

[0027] 100 - Automatic curvature control system of rotary steering system, 101 - Predetermined mechanical drilling speed determination module, 102 - Automatic curvature instruction generation module, 103 - Downhole parameter acquisition module, 104 - Deflection curvature calculation module, 200 - Computer equipment, 201 - Memory, 202 - Processor. DETAILED DESCRIPTION

[0028] Hereinafter, the automatic curvature control method and system of the rotary steering system and the computer device of the present invention will be described in detail with reference to exemplary embodiments.

[0029] It should be noted that, for ordinary technicians in this field, some of the terms "pressure" in this article are equivalent to pressure.

[0030] Currently, the key issue preventing rotary steerable systems from achieving automatic curvature closed-loop downhole control is the inability to obtain high-frequency well depth information, making it impossible to determine the curvature radius for inclination. Therefore, the key to automatic curvature closed-loop downhole control is to enable downhole instruments to sense their own well depth or the length of the drilled section in real time.

[0031] In order to solve the above technical problems, the core idea of ​​the present invention to realize automatic curvature downhole closed-loop control is as follows: first, a fixed ROP value in the automatic curvature mode is set in the rotary steering system, and in the automatic curvature mode, the starting point A0 and the subsequent drilling point A2-A i The relevant parameters are recorded as shown in Table 1 below. If we drill at a mechanical penetration rate that is consistent with the fixed ROP value downhole, the corresponding curvature value can be calculated downhole by the change in well inclination and azimuth between two points and the well section passed through. Then, by comparing it with the set curvature value, the rotary steering is used to automatically change the deflecting force and direction downhole based on the difference in the comparison results to achieve the purpose of drilling with the expected curvature.

[0032] Table 1 Related parameters of each test point

[0033] Downhole time, h Mechanical drilling speed, m / h Drilled well section, m Well deviation, ° Azimuth, ° <![CDATA[Current point A1]]> <![CDATA[T0]]> ROP 0 <![CDATA[INC0]]> <![CDATA[AZ0]]> <![CDATA[Point A2]]> <![CDATA[T1]]> ROP <![CDATA[T1*ROP]]> <![CDATA[INC1]]> <![CDATA[AZ1]]> <![CDATA[Point A3]]> <![CDATA[T2]]> ROP <![CDATA[T2*ROP]]> <![CDATA[INC2]]> <![CDATA[AZ2]]> ……… ……… ……… ……… ……… ……… <![CDATA[Point A i > <![CDATA[T i ]]> ROP <![CDATA[T i *ROP]]> <![CDATA[INC i ]]> <![CDATA[AZ i ]]>

[0034] In order to achieve the above objectives, the present invention provides an automatic curvature control method for a rotary steering system.

[0035] In an exemplary embodiment of the automatic curvature control method of a rotary steerable system of the present invention, the automatic curvature downhole closed-loop control method comprises the following steps:

[0036] Step S1: Determine a predetermined rate of penetration (ROP) based on the previous drilling conditions.

[0037] Step S2: Sending an automatic curvature instruction to the downhole (ie, the downhole portion of the rotary steerable drilling tool) through the ground, wherein the automatic curvature instruction includes a predetermined mechanical penetration rate ROP, an expected curvature γ, an initial steering force magnitude, and a steering force direction.

[0038] Step S3: The downhole part of the rotary steering drilling tool works according to the automatic curvature instruction and records the downhole time T every time the predetermined well section length ΔL (that is, the well depth data) is spaced. i 、Well inclination angle INC i and azimuth AZ i .

[0039] Step S4: Calculate the deflection curvature of the predetermined well section length and compare it with the expected curvature. According to the comparison result, control the downhole part of the rotary steerable drilling tool to automatically adjust the magnitude and direction of the deflection force.

[0040] In this embodiment, determining the predetermined rate of penetration (ROP) may include the following sub-steps:

[0041] Sub-step S11: Before drilling the current well, collect the drill string assembly, weight on bit, rotation speed, displacement and mechanical penetration rate of the current platform and / or adjacent platforms during rotary steerable drilling in the same geological layer to establish a rotary steerable drilling parameter data set.

[0042] Sub-step S12: Based on the rotary steerable drilling parameter data set, with the mechanical penetration rate as the target variable, each parameter in the data set is standardized and normalized, and then a normal distribution mathematical processing method is used to obtain an expected value of the mechanical penetration rate.

[0043] Sub-step S13: determining a predetermined rate of penetration (ROP) based on the expected value of the rate of penetration (ROP). For example, 85% to 95% of the expected value of the rate of penetration (ROP) may be determined as the predetermined rate of penetration (ROP).

[0044] In an embodiment, the predetermined well section length may be determined based on a predetermined mechanical penetration rate (ROP) and a drilling time difference (ΔT) between two consecutive points. For example, the predetermined well section length may be 0.1-1 m.

[0045] In an embodiment, before the downhole portion of the rotary steerable drilling tool operates according to the automatic curvature instruction, it can be determined whether it is in a drilling state based on the downhole rotation speed or the downhole bit pressure.

[0046] For example, the rules for determining whether a well is in the drilling state are as follows: when a rotary steerable drill bit is not included in the rotary steerable drill bit assembly, the downhole bit pressure is ≥ 5kN, or the downhole rotation speed is ≥ 50RPM, and the well is determined to be in the drilling state; when a rotary steerable drill bit is included in the rotary steerable drill bit assembly, the downhole rotation speed is ≥ the screw drilling speed + 40RPM, and the well is determined to be in the drilling state.

[0047] In this embodiment, the downhole deflection curvature can be changed by changing the predetermined mechanical penetration rate ROP.

[0048] Another aspect of the present invention provides an automatic curvature control system for a rotary steering system.

[0049] In an exemplary embodiment of the automatic curvature control system of the rotary steering system of the present invention, the automatic curvature control system includes a predetermined mechanical drilling speed determination module, an automatic curvature instruction generation module, a downhole parameter acquisition module and a deflection curvature calculation module.

[0050] The module for determining the predetermined mechanical drilling rate (ROP) is used to determine the predetermined mechanical drilling rate (ROP) based on the previous drilling conditions.

[0051] The automatic curvature instruction generation module is connected to the predetermined mechanical penetration rate determination module and is used to send an automatic curvature instruction to the well through the ground. The automatic curvature instruction includes the predetermined mechanical penetration rate ROP, the expected curvature γ, the initial guide force magnitude and the guide force direction.

[0052] The downhole parameter acquisition module is connected to the automatic curvature instruction generation module to record the downhole time T every time the predetermined well section length ΔL is set. i 、Well inclination angle INC i and azimuth AZ i .

[0053] The deflection curvature calculation module is connected to the downhole parameter acquisition module and is used to calculate the deflection curvature of a predetermined well section length.

[0054] According to the present invention, the automatic curvature control method of the rotary steering system can be programmed as a computer program and the corresponding program code or instructions can be stored in a computer-readable storage medium. When the program code or instructions are executed by the processor, the processor executes the above-mentioned automatic curvature control method of the rotary steering system. The above-mentioned processor and memory can be included in a computer device.

[0055] According to yet another exemplary embodiment of the present invention, a computer-readable storage medium storing a computer program is further provided. The computer-readable storage medium stores a computer program that, when executed by a processor, causes the processor to perform the method for automatic curvature control of a rotary steerable system according to the present invention. The computer-readable recording medium is any data storage device that can store data read by a computer system. Examples of computer-readable recording media include read-only memory, random access memory, read-only optical discs, magnetic tapes, floppy disks, optical data storage devices, and carrier waves (such as data storage via the Internet via a wired or wireless transmission path).

[0056] According to yet another exemplary embodiment of the present invention, a computer device is provided. The computer device includes a processor and a memory. The memory is configured to store a computer program. The computer program is executed by the processor, causing the processor to implement the method for automatic curvature control of a rotary steerable system according to the present invention.

[0057] In order to better understand the above exemplary embodiments of the present invention, they are further described below with reference to the accompanying drawings and specific examples.

[0058] Example 1

[0059] For drilling a certain horizontal well section, the automatic curvature control mode is written into the downhole memory of the rotary steering system. In this mode, the ground mechanical penetration rate (ROP), the expected drilling curvature (γ), and the initial deflection force and deflection direction manually given by the ground need to be transmitted from the ground. When entering the automatic curvature control mode, the downhole rotary steering part first determines whether it is in the drilling state based on the downhole rotation speed. When it is in the drilling state, it starts to record the three parameters of the first point time T0, well inclination INC0, and azimuth AZ0. Then, at a certain interval T i 、Well Deviation INC i 、Azimuth A-Zi parameter.

[0060] like Figure 1 As shown, the subsequent specific implementation process is as follows.

[0061] Step 1: Before drilling this well, collect data on the drill string assembly, weight on bit, rotation speed, displacement, and mechanical penetration rate (ROP) from rotary steerable drilling in the same geological formation on this platform and neighboring platforms in the region to establish a rotary steerable drilling parameter dataset.

[0062] Step 2: Based on the established data set, with ROP as the target variable, the drilling parameters of the data set are standardized and normalized, and the normal distribution mathematical processing method is used to obtain the expected value of ROP under the predetermined drilling parameters of this well.

[0063] Step 3: Set the ROP (Rotor of Penetration) in automatic curvature drilling mode at 85% to 95% of the desired ROP. This ROP setting offers three key benefits: first, ensuring that the ROP will be achieved during actual rotary steerable drilling; second, providing some margin for adjusting the build-up curvature; and third, minimizing the sacrificed ROP during automatic curvature drilling. During actual drilling, the ROP in automatic curvature mode can be further adjusted based on the well's ROP to achieve even higher wellbore trajectory control efficiency.

[0064] Step 4: Agree on the communication instructions between the ground and the rotary steering downhole central control, and define the automatic curvature instruction sequence, including the instruction identification field, the preset mechanical drilling speed (ROP) field, the expected curvature γ field (including the well inclination change rate (BR) and the azimuth change rate (WR), and the initial steering force magnitude and steering force direction fields.

[0065] Step 5: Write the automatic curvature command sequence into the programmable memory of the rotary steerable central control sub, and simultaneously add the automatic curvature command transmission sequence to the rotary steerable surface command transmission system. That is, after the surface command transmission system issues the automatic curvature command, the central control sub in the downhole rotary steerable system receives and interprets the command, reads the preset automatic curvature control code, and enters the automatic curvature operating mode.

[0066] Step 6: When the rotary steering automatic curvature command is issued to start the rotary steering automatic curvature control mode:

[0067] (1) Ground part

[0068] The ground drill feed system adopts a constant speed mode, and the drill feed speed is adjusted to be consistent with the preset mechanical drilling speed ROP. It is checked every 2 to 30 minutes. If any difference is found, it will be corrected in time.

[0069] (2) Downhole part (i.e., the downhole part of the rotary steerable drilling tool)

[0070] ① The rotary steerable central control measurement sub first monitors the downhole WOB and downhole speed parameters to determine whether the rotary steerable drilling system is in the drilling state. The drilling state determination rule is: downhole WOB ≥ 5kN or downhole speed ≥ 50RPM (when no screw drill is added to the rotary steerable drilling tool assembly) or downhole speed ≥ screw drill speed + 40RPM (when a screw drill is added to the rotary steerable drilling tool assembly). At this time, the various parameters monitored by the downhole part of the rotary steerable drilling tool are included in the downhole curvature calculation. Otherwise, it is determined to be in the non-drilling state and the relevant parameters are not included in the downhole curvature calculation.

[0071] ② The interval △L of downhole data depth is specified to be between 0.1 and 1m, and the time points T i The well inclination, azimuth, guiding force size and guiding force azimuth data are calculated according to the curvature formula. The curvature value of each interval well section is γ i (including well deviation change rate BR i and azimuth change rate WR i ).

[0072] ③ The actual deflection curvature value γ i (including well deviation change rate BR i and azimuth change rate WR i ) and the preset expected curvature γ (including the well deviation change rate BR i and azimuth change rate WR i ) for comparison, calculate and update the required guiding force size and direction, and use the calculation results to control the actuator of the downhole central control short section to implement the corresponding action.

[0073] ④ The above process constitutes a downhole closed loop, which continuously adjusts the drilling curvature of the wellbore trajectory to achieve consistency with the preset wellbore curvature.

[0074] The curvature adjustment method in automatic curvature drilling mode is:

[0075] ① When the downhole curvature needs to be changed, if the change is small and the increase or decrease in the mechanical penetration rate (ROP) is within the 10% tolerance range, there is no need to re-issue the command. It can be achieved by changing the surface ROP and modifying the parameter settings of the surface software. (For example, if the previous build rate is 5° / 30m and it is now increased to 5.5° / 30m, the surface ROP is reduced to 1 / 1.1 of the previous ROP). This method can save the time of issuing commands from the surface transmission device and significantly improve the efficiency of wellbore trajectory control.

[0076] ② When the downhole curvature that needs to be changed changes greatly (the mechanical drilling speed adjustment cannot meet the needs, or it has a significant impact on the comprehensive drilling speed), it is necessary to resend the command through the ground transmission device.

[0077] Step 7: The ground calculates and monitors the actual downhole curvature using the well inclination and azimuth data uploaded in real time from downhole, combined with the depth data provided by the ground well depth system. If any discrepancy with the expected value is found, manual intervention is performed in a timely manner to avoid wellbore curvature deviation caused by abnormal operation of the downhole rotary steering system.

[0078] Step 8: The rotary steering automatic curvature drilling process is completed, other instructions are issued, and the rotary steering automatic curvature mode is exited.

[0079] The present invention provides a method for obtaining data on the length of a well section traversed at time intervals of 5 to 30 seconds, thereby combining the difference in well inclination and azimuth data at two time points to calculate the curvature of the well section. The method can automatically adjust and correct the magnitude and direction of the guiding force of a downhole rotary steering system based on the comparison of the actual downhole build-up curvature with the desired curvature. The above process is automatically performed downhole, thereby realizing the automatic curvature control function of the rotary steering system.

[0080] Compared with conventional curvature control methods, the automatic curvature control method of the present invention has significant advantages such as smoother wellbore trajectory control and higher wellbore trajectory control efficiency.

[0081] like Figure 2 As shown, the conventional curvature control method (i.e., the solid line) first transmits a control instruction containing the steering force and the direction of the steering force according to the designed wellbore curvature during wellbore curvature control. During the drilling process, the wellbore curvature is calculated every 1 to 5 meters based on the well inclination and azimuth values ​​uploaded from the wellbore and compared with the designed wellbore curvature. Based on the difference between the two, the steering force and the direction of the steering force are adjusted and the instruction is transmitted to the downhole rotary steering system through the transmission system. This process needs to be repeated every 10 to 20 m of drilling. This reciprocating execution process will consume several hours of control instruction transmission time. At the same time, there are obvious ups and downs in the wellbore trajectory curvature control. The automatic curvature control method of the present invention (i.e., the dotted line) only needs to issue an automatic curvature control instruction at the beginning when performing wellbore curvature control. During the drilling process, the downhole instrument automatically adjusts the steering force and steering direction every 0.1 to 1 meter based on the deviation between the actual drilling curvature and the designed curvature. The ground only needs to monitor the wellbore curvature control situation. Under normal circumstances, there is no need to transmit ground instructions to the downhole instrument through the downlink system during the entire process, thereby greatly improving the efficiency and quality of wellbore curvature control.

[0082] Example 2

[0083] like Figure 3 As shown, the automatic curvature control system 100 of the rotary steering system includes a predetermined mechanical penetration rate determination module 101, an automatic curvature instruction generation module 102, a downhole parameter acquisition module 103 and a deflection curvature calculation module 104.

[0084] The predetermined mechanical penetration rate determination module 101 is used to determine the predetermined mechanical penetration rate ROP according to the previous drilling conditions.

[0085] The automatic curvature instruction generating module 102 is connected to the predetermined mechanical penetration rate determining module 101 and is used to send the automatic curvature instruction to the well through the surface. The automatic curvature instruction includes the predetermined mechanical penetration rate ROP, the expected curvature γ, the initial guide force magnitude and the guide force direction.

[0086] The downhole parameter acquisition module 103 is connected to the automatic curvature instruction generation module 102 and is used to record the downhole time T every time the predetermined well section length ΔL is set. i 、Well inclination angle INC i and azimuth AZ i .

[0087] The build-up curvature calculation module 104 is connected to the downhole parameter acquisition module 103 and is used to calculate the build-up curvature of a predetermined well section length.

[0088] Example 3

[0089] like Figure 4 As shown, a computer device 200 includes a memory 201 and a processor 202. The memory 201 is used to store a computer program. The computer program is executed by the processor so that the processor executes the computer program of the automatic curvature control method of the rotary steering system according to the present invention.

[0090] In summary, the beneficial effects of the present invention include at least one of the following:

[0091] (1) The present invention indirectly determines the well depth data by presetting the mechanical drilling speed on the ground, thereby solving the problem that the current rotary steerable drilling tool cannot accurately sense its own current well depth;

[0092] (2) The present invention realizes the real-time perception of the downhole instrument on its own well depth information (or the length of the drilled section), solves the core problem of automatic curvature downhole closed-loop control, and forms an automatic curvature control method for the rotary steering system, which greatly improves the efficiency of rotary steering inclination control and the quality of the wellbore trajectory.

[0093] Although the present invention has been described above with reference to the accompanying drawings and exemplary embodiments, it will be apparent to those skilled in the art that various modifications may be made to the above embodiments without departing from the spirit and scope of the claims.

Claims

1. A method for automatic curvature control of a rotary steering system, characterized in that: The automatic curvature control method comprises the following steps: Determine the expected mechanical drilling speed based on the previous drilling conditions ROP ; Determining a predetermined mechanical drilling speed ROP The steps include: before drilling the current well, collecting the drill bit assembly, bit pressure, rotation speed, displacement and mechanical penetration rate of the current platform and / or the adjacent platform during rotary steerable drilling in the same geological layer, and establishing a rotary steerable drilling parameter data set; based on the rotary steerable drilling parameter data set, taking the mechanical penetration rate as the target variable, standardizing and normalizing each parameter in the data set, and using a normal distribution mathematical processing method to obtain an expected value of the mechanical penetration rate; and determining a predetermined mechanical penetration rate based on the expected value of the mechanical penetration rate. ROP ; Determine the expected value of the mechanical drilling speed 85%~95% as the predetermined mechanical drilling speed ROP ; Sending automatic curvature instructions to the well through the ground, the automatic curvature instructions include a predetermined mechanical drilling speed ROP , expected curvature γ , the magnitude and direction of the initial guiding force; The downhole part of the rotary steerable drilling tool works according to the automatic curvature instruction and moves at intervals of predetermined well length. ΔL Record only one underground time T i , well inclination angle INC i and azimuth AZ i ; Based on the predetermined ROP between two consecutive points ROP and drilling time difference ΔT , determine the predetermined well section length; the predetermined well section length is 0.1~1m; and Calculate the build-up curvature of a predetermined well section and compare it with the expected curvature. Automatically adjust the magnitude and direction of the guiding force based on the comparison results. When the downhole curvature needs to be changed, if the change is not large, the mechanical drilling speed ROP If the increase or decrease is within the 10% tolerance range, there is no need to re-issue the command, just change the ground ROP , and change the parameter settings of the ground software; when the downhole curvature that needs to be changed changes greatly, the automatic curvature instruction is resent through the ground transmission device.

2. The automatic curvature control method of a rotary steering system according to claim 1, characterized in that: Before the downhole portion of the rotary steerable drilling tool operates according to the automatic curvature instruction, it is determined whether it is in a drilling state based on the downhole rotation speed or the downhole bit pressure.

3. The automatic curvature control method of a rotary steering system according to claim 1, characterized in that: The drilling status is determined as follows: when the rotary steerable drill bit assembly does not include a screw drill bit, the downhole bit pressure is ≥ 5kN, or the downhole rotation speed is ≥ 50RPM, which indicates the drilling status; when the rotary steerable drill bit assembly includes a screw drill bit, the downhole rotation speed is ≥ the screw drilling speed + 40RPM, which indicates the drilling status.

4. The automatic curvature control method of a rotary steering system according to claim 1, characterized in that: By changing the predetermined mechanical drilling speed ROP way to change the downhole deflection curvature.

5. An automatic curvature control system for a rotary steering system, characterized in that: The automatic curvature control system includes a predetermined mechanical drilling speed determination module, an automatic curvature instruction generation module, a downhole parameter acquisition module and a deflection curvature calculation module, wherein: The module for determining the expected mechanical drilling speed is used to determine the expected mechanical drilling speed based on the previous drilling conditions. ROP ; Determine target ROP ROP The steps include: before drilling the current well, collecting the drill bit assembly, bit pressure, rotation speed, displacement and mechanical penetration rate of the current platform and / or the adjacent platform during rotary steerable drilling in the same geological layer, and establishing a rotary steerable drilling parameter data set; based on the rotary steerable drilling parameter data set, taking the mechanical penetration rate as the target variable, standardizing and normalizing each parameter in the data set, and using a normal distribution mathematical processing method to obtain an expected value of the mechanical penetration rate; and determining a predetermined mechanical penetration rate based on the expected value of the mechanical penetration rate. ROP ; Determine the expected value of the mechanical drilling speed 85%~95% as the predetermined mechanical drilling speed ROP ; The automatic curvature instruction generation module is connected to the predetermined mechanical drilling speed determination module, and is used to send the automatic curvature instruction to the well through the ground. The automatic curvature instruction includes the predetermined mechanical drilling speed. ROP , expected curvature γ , the magnitude and direction of the initial guiding force; The downhole parameter acquisition module is connected to the automatic curvature instruction generation module for each interval of the predetermined well section length. ΔL Record only one underground time T i , well inclination angle INC i and azimuth AZ i ; Based on the predetermined ROP between two consecutive points ROP and drilling time difference ΔT , determine the predetermined well section length; the predetermined well section length is 0.1~1m; The deflection curvature calculation module is connected to the downhole parameter acquisition module and is used to calculate the deflection curvature of a predetermined well section length; When the downhole curvature needs to be changed, if the change is not large, the mechanical drilling speed ROP If the increase or decrease is within the 10% tolerance range, there is no need to re-issue the command, just change the ground ROP , and change the parameter settings of the ground software; when the downhole curvature that needs to be changed changes greatly, the automatic curvature instruction is resent through the ground transmission device.

6. A computer device, characterized in that: The computer device comprises: processor; and A memory storing a computer program, which, when executed by a processor, implements the automatic curvature control method of a rotary steering system as described in any one of claims 1 to 4.

7. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the automatic curvature control method of the rotary steering system as described in any one of claims 1 to 4 is implemented.

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