Method and device for determining build-up rate of flexible drilling tool and medium

Abstract

The invention provides a method and device for determining the deflecting rate of a flexible drilling tool and a medium, and relates to the technical field of data processing.The method comprises the steps that axial force and lateral force borne by a unit body in the flexible drilling tool in a deflecting section are determined; determining an anisotropy index of the drill bit and a first hole drift angle of the first wellbore trajectory; and according to the axial force, the lateral force, the anisotropy index, the first hole drift angle and a drilling speed equation, the build-up rate of the flexible drilling tool is determined. Thus, the build-up rate of the flexible drilling tool is determined, the precision, accuracy and efficiency of the build-up rate calculated through short-radius and ultra-short-radius sidetracking are improved, the timeliness of drilling operation is improved, and the technical requirements for remaining oil development and directional drilling engineering in the near-wellbore area of an old oil field wellbore are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of data processing, in particular to a method and device for determining the build-up rate of a flexible drill string and a medium. BACKGROUND

[0002] In the middle and late stages of old oilfield development, a large number of low-yield and low-efficiency wells need to be reused to effectively reduce the engineering operation cost of oil and gas development. Using old well borehole sidetracking to develop remaining oil in the near wellbore area is an effective engineering technical means. In the sidetracking construction process of the remaining oil in the near wellbore area, the use of coiled tubing, articulated drill pipes and other flexible drill strings to realize short radius and ultra-short radius drilling can minimize the drilling operation footage, achieve cost reduction and efficiency improvement, and the calculation of the build-up rate of the flexible drill string used in sidetracking is the key to the design and control of the wellbore trajectory.

[0003] At present, the calculation method of the build-up rate in the prior art is mostly based on a conventional drill pipe. The build-up rate calculated by using the conventional drill pipe has low precision, which affects the drilling operation efficiency and the accuracy of the construction.

[0004] In view of the problems in the prior art, the present application provides a method and device for determining the build-up rate of a flexible drill string and a medium. SUMMARY

[0005] In view of the problems in the prior art, the present application provides a method and device for determining the build-up rate of a flexible drill string and a medium, which comprises the following steps:

[0006] determining the axial force and the lateral force on a unit body in the flexible drill string in a build-up section;

[0007] determining the anisotropy index of the drill bit and the first inclination angle of the first wellbore trajectory;

[0008] determining the build-up rate of the flexible drill string according to the axial force, the lateral force, the anisotropy index, the first inclination angle and a drilling speed equation.

[0009] According to one embodiment of the present application, the unit body comprises a current pipe string and a target pipe string after the current pipe string;

[0010] The lateral force and the axial force are determined by the following steps:

[0011] determining a first attitude angle of the current pipe string and a second attitude angle of the target pipe string;

[0012] determining the lateral force and the axial force based on the first attitude angle, the second attitude angle, the mechanical equilibrium equation corresponding to the unit body in the X-axis direction and the Y-axis direction and the torque balance equation in the X-Y plane.

[0013] According to one embodiment of the present invention, the mechanical equilibrium equation corresponding to the X-axis direction is:

[0014] f in cosα i -f iτ sinα i -(f i+1,n -R i+1 cosα i+1 +(f i+1,τ -R i+1 f)sinα i+1 =0

[0015] Among them, f in The axial force currently acting on the tubing string; α i The first attitude angle; f iτ The lateral force currently acting on the tubing string; f i+1,n The axial force acting on the target tubing; R i+1 The contact force between the current tubing string and the target tubing string; α i+1 The second attitude angle; f i+1,τ The lateral force on the target tubing refers to the force applied to it; f refers to the coefficient of friction.

[0016] The mechanical equilibrium equation corresponding to the Y-axis direction is:

[0017] f in sinα i +f iτ cosα i -(f i+1,n -R i+1 )s i nα i+1 -(f i+1,τ -R i+1 f)cosα i+1 -W i =0

[0018] Among them, W i The gravitational force acting on a unit cell;

[0019] The torque balance equation in the XY plane is:

[0020]

[0021] Among them, L i This refers to the length of the drill pipe between the current drill string and the target drill string; The angle between the unit cell and the horizontal direction.

[0022] According to an embodiment of the present invention, the anisotropy index is determined by the following steps:

[0023] Determine the geometric characteristic parameters of the drill bit;

[0024] The anisotropy index is determined based on the geometric feature parameters and the target formula.

[0025] According to one embodiment of the present invention, the geometric feature parameters include: diameter, longitudinal rake angle, friction angle, inner cone depth, and outer structure length;

[0026] The target formula is:

[0027]

[0028] Among them, I b Anisotropy index; D refers to diameter; ω c The longitudinal front angle; θ f The friction angle is indicated by C; the inner cone depth is indicated by G; the external structural height is indicated by K; and the coefficient is indicated by K.

[0029] According to an embodiment of the present invention, the slope ratio is determined by the following steps:

[0030] The second well inclination angle is determined based on the axial force, the lateral force, the anisotropy index, the first well inclination angle, and the drilling rate equation.

[0031] If the second well inclination angle is not less than the target angle, the difference between the second well inclination angle and the first well inclination angle is divided by the preset footage and determined as the build-up rate.

[0032] If the second well inclination angle is less than the target angle, then update the first attitude angle and the second attitude angle.

[0033] According to an embodiment of the present invention, the second well inclination angle is determined by the following steps:

[0034] The axial force, the lateral force, and the anisotropy index are input into the drilling rate equation to obtain the first drilling rate component and the second drilling rate component of the flexible drill bit in the X-axis direction and the Y-axis direction, respectively.

[0035] The second wellbore trajectory is determined based on the first drilling rate component, the second drilling rate component, the footage, and the first well inclination angle;

[0036] The angle between the second wellbore trajectory and the first wellbore trajectory is determined as the second well inclination angle.

[0037] According to one embodiment of the present invention, the second wellbore trajectory is determined by the following steps:

[0038] Multiply the first drilling rate component, the footage, and the cosine of the first well inclination angle to obtain the first change in the first wellbore trajectory in the X-axis direction;

[0039] Multiply the second drilling rate component, the footage, and the sine of the first well inclination angle to obtain the second change in the first wellbore trajectory in the Y-axis direction;

[0040] The second wellbore trajectory is determined based on the first wellbore trajectory, the first change, and the second change.

[0041] According to another aspect of the invention, a storage medium is also provided, comprising a series of instructions for performing the steps of the method as described in any of the preceding claims.

[0042] According to another aspect of the invention, an apparatus for determining the build-up rate of a flexible drill string is also provided, performing the method as described in any of the preceding claims, the apparatus comprising:

[0043] The first determining module is used to determine the axial force and lateral force experienced by the unit body in the directional drilling section of the flexible drilling tool;

[0044] The second determining module is used to determine the anisotropy index of the drill bit and the first inclination angle of the first wellbore trajectory;

[0045] The third determining module is used to determine the build-up rate of the flexible drill string based on the axial force, the lateral force, the anisotropy index, the first well inclination angle, and the drilling rate equation.

[0046] This invention provides a method, apparatus, and medium for determining the build-up rate of a flexible drill bit, which has the following advantages compared with the prior art:

[0047] This invention determines the axial and lateral forces acting on the flexible drilling tool, then determines the anisotropy index of the drill bit and the first inclination angle of the first wellbore trajectory. Subsequently, based on the axial force, lateral force, anisotropy index, first inclination angle, and drilling rate equation, the build-up rate of the flexible drilling tool is determined. This method of determining the build-up rate of the flexible drilling tool improves the accuracy, precision, and efficiency of the build-up rate calculated for short-radius and ultra-short-radius sidetracking, enhances the timeliness of drilling operations, and meets the technical requirements for developing residual oil in the near-wellbore zone of old oilfields and for directional drilling engineering.

[0048] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0049] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0050] Figure 1 A flowchart illustrating a method for determining the build-up rate of a flexible drill string according to an embodiment of the present invention is shown;

[0051] Figure 2 A schematic diagram of a flexible drilling tool according to an embodiment of the present invention is shown;

[0052] Figure 3 A schematic diagram of the forces acting on a flexible drill bit in the build-up section according to an embodiment of the present invention is shown;

[0053] Figure 4 A schematic diagram of a drill bit according to an embodiment of the present invention is shown;

[0054] Figure 5 A block diagram of a device for determining the inclination rate of a flexible drill bit according to an embodiment of the present invention is shown;

[0055] Figure 6 A schematic diagram of a second wellbore trajectory according to an embodiment of the present invention is shown.

[0056] In the accompanying drawings, the same parts use the same reference numerals. Also, the drawings are not drawn to scale. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0058] The prior art (CN111144053A) mentions a method and system for predicting the build-up rate during drilling based on a genetic algorithm. The steps are: S1, acquiring data on several factors affecting the build-up rate during drilling; S2, based on the data obtained in step S1, analyzing the Pearson correlation coefficient, and further removing data with low correlation coefficients to obtain an initial dataset; S3, normalizing the initial dataset based on step S2 to obtain a normalized dataset; S4, inputting the normalized dataset as the whole into a BP neural network to build a build-up rate prediction network model; wherein, a genetic algorithm is used for network optimization during network construction; S5, using the build-up rate prediction model built in step S4 to predict the build-up rate. The prior art does not determine the build-up rate based on flexible drilling tools, and the steps of the prior art differ from those of this invention.

[0059] The prior art (CN116911073B) mentions a method and system for predicting the ultimate build-up rate of a push-type rotary steerable tool, including: Step 1: Selecting a push-type rotary steerable device that has been used in actual directional well operations; Step 2: Calculating the theoretical ultimate build-up rate of the push-type rotary steerable device using a mechanical mathematical model; Step 3: Calculating the measured maximum build-up rate in the operating well depth range based on measured well inclination data and the guiding force records used by the rotary steerable device in the operating well depth range; Step 4: Calculating a correction coefficient using the theoretical ultimate build-up rate and the measured maximum build-up rate; Step 5: Based on the correction coefficient, changing the parameters in the mechanical mathematical model to predict the ultimate build-up rate of push-type rotary steerable devices with different configurations; wherein, when establishing the mechanical mathematical model, the wellbore curvature where the rotary steerable device is located is set to kc, and the rotary steerable device is mechanically simplified, considering the rotary steerable device as composed of two beams and columns, obtaining the beam-column model of the rotary steerable device; wherein, in the mechanical simplification, the push-type rotary steerable device is simplified to consist of a drill bit, a centralizer, and a guiding device. The prior art does not determine the build-up rate based on flexible drilling tools, and the steps of the prior art are different from those of the present invention.

[0060] In view of the above-mentioned deficiencies of the prior art, the present invention provides a method, device and medium for determining the inclination rate of a flexible drill bit. Figure 1 A flowchart of a method for determining the build-up rate of a flexible drill string according to an embodiment of the present invention is shown, the method comprising:

[0061] S101, Determine the axial and lateral forces acting on the unit body in the build-up section of the flexible drilling tool;

[0062] S102, determine the anisotropy index of the drill bit and the first inclination angle of the first wellbore trajectory;

[0063] S103. Based on the axial force, lateral force, anisotropy index, first well inclination angle, and drilling rate equation, determine the build-up rate of the flexible drilling tool.

[0064] The build-up section is the process located between the casing window and the horizontal section. For flexible drilling tools, the casing window process will advance 0.7-0.8m at a 15-18° inclination, which fixes the azimuth of the entire wellbore. Then, the flexible drilling tool is replaced and the build-up is advanced to a 90° inclination. Horizontal drilling then proceeds. The drill bit is used to improve the build-up performance of the flexible drilling tool.

[0065] For example, the first well inclination angle can be determined using the following formula:

[0066]

[0067] in, The first well inclination angle; (x) t,k ,yt,k (x) refers to the coordinates of the node in the k-th section of the trajectory in the first wellbore trajectory; t,k-1 ,y t,k-1 () refers to the coordinates of the node in the (k-1)th section of the trajectory in the first wellbore trajectory.

[0068] This invention determines the axial and lateral forces acting on the flexible drilling tool, then determines the anisotropy index of the drill bit and the first inclination angle of the first wellbore trajectory. Subsequently, based on the axial force, lateral force, anisotropy index, first inclination angle, and drilling rate equation, the build-up rate of the flexible drilling tool is determined. This method of determining the build-up rate of the flexible drilling tool improves the accuracy, precision, and efficiency of the build-up rate calculated for short-radius and ultra-short-radius sidetracking, enhances the timeliness of drilling operations, and meets the technical requirements for developing residual oil in the near-wellbore zone of old oilfields and for directional drilling engineering.

[0069] like Figure 2 and Figure 3 As shown, the unit cell includes the current tubing and the target tubing following the current tubing;

[0070] The lateral and axial forces are determined using the following steps:

[0071] Determine the first attitude angle of the current tubing and the second attitude angle of the target tubing;

[0072] Based on the first attitude angle, the second attitude angle, the mechanical equilibrium equations corresponding to the unit in the X-axis direction and the Y-axis direction, and the torque equilibrium equation in the XY plane, the lateral force and axial force are determined.

[0073] For example, the current tubing string and the target tubing string are rigid bodies with no material deformation. The current tubing string and the target tubing string can be connected by drill pipe, and the drill pipe can be connected to the current tubing string and the target tubing string by hinge joints. The hinge joints are in contact with the wellbore. The deformation between the two hinge joints is negligible, and the hinge joints are in point contact with the wellbore. The length of the drill pipe is greater than the sum of the length of the horizontal section and the length of the curved section of the wellbore.

[0074] The formula for the first attitude angle is:

[0075]

[0076] Where, α i The attitude angle of the i-th section of the tubing; (x p,i ,y p,i (x) refers to the coordinates of the endpoint of the i-th section of the tubing; p,i-1 ,y p,i-1 () refers to the coordinates of the endpoint of the (i-1)th section of the pipe.

[0077] Thus, the first attitude angle can be calculated based on Equation 2.

[0078] Next, by solving the system of equations, the coordinates (x, y) of the endpoint of the (i+1)th section of the tubular column are obtained. p,i+1 ,y p,i+1 ):

[0079]

[0080] Among them, L p Refers to the length of the tubing.

[0081] In Equation 3, L p The following relationship must be satisfied:

[0082] L t,k ≤L p ≤L t,k-1 Formula 4

[0083] In Equation 4, L t,k for:

[0084]

[0085] Among them, L t,k This refers to the distance from the endpoint of the i-th section of the pipe to the node of the k-th section of the trajectory.

[0086] In Equation 4, L t,k-1 for:

[0087]

[0088] Among them, L t,k-1 This refers to the distance from the endpoint of the i-th section of the pipe to the node of the (k-1)-th section of the trajectory.

[0089] After obtaining the coordinates of the midpoint of the (i+1)th section of the tubing, the second attitude angle can be calculated based on the following formula:

[0090]

[0091] Where, α i+1 Refers to the second attitude angle.

[0092] Depend on Figure 2 and Figure 3 It can be seen that the unit is subjected to an axial force f in Lateral force f iτ , contact force R i The factors are gravity W and frictional resistance, with frictional resistance being negligible.

[0093] The force matrix of the unit cell is as follows:

[0094]

[0095] The contact matrix is ​​as follows:

[0096]

[0097] The gravity matrix is:

[0098]

[0099] based on Figure 3 The mechanical equilibrium equations and torque equilibrium equations in the XY plane corresponding to the unit body in the X-axis and Y-axis directions can be determined. Then, the first attitude angle and the second attitude angle are substituted into the mechanical equilibrium equations and torque equilibrium equations corresponding to the X-axis and Y-axis directions to obtain the lateral force and axial force on the current pipe and the target pipe in the unit body, respectively.

[0100] This determined the axial and lateral forces of the unit body in the inclined section, providing a basis for determining the inclination rate.

[0101] In one possible embodiment, the mechanical equilibrium equation corresponding to the X-axis direction is:

[0102] f in cosα i -f iτ sinα i -(f i+1,n -R i+1 cosα i+1 +(f i+1,τ -R i+1 f)sinα i+1 =0

[0103] Among them, f in The axial force currently acting on the tubing string; α i Refers to the first attitude angle; (f τ The lateral force currently acting on the tubing string; f i+1,n The axial force acting on the target tubing; R i+1 The contact force between the current tubing string and the target tubing string; α i+1 The second attitude angle; f i+1,τ The lateral force on the target tubing refers to the force applied to it; f refers to the coefficient of friction.

[0104] The mechanical equilibrium equations corresponding to the Y-axis direction are:

[0105] f in sinα i +f iτ cosα i -(f i+1,n -R i+1 sinα i+1 -(f i+1,τ -R i+1 f)cosα i+1 -W i =0

[0106] Among them, W i The gravitational force acting on a unit cell;

[0107] The torque balance equation in the XY plane is:

[0108]

[0109] Among them, L i This refers to the length of the drill pipe between the current drill string and the target drill string; The angle between the unit cell and the horizontal direction.

[0110] For example, based on the mechanical equilibrium equations corresponding to the unit in the X-axis and Y-axis directions, and the torque equilibrium equation in the XY plane, the axial force currently acting on the tubing can be derived as follows:

[0111] f in =f i+1,τ sin(α i -α i+1 )+f i+1,n cos(α i -α i+1 )-R i+1 [fsin(α i -α i+1 )+cos(α i -α i+1 )]+W i sinα i Formula 8

[0112] We can also deduce that the lateral force currently acting on the tubing is:

[0113] f iτ =f i+1,τ cos(α i -α i+1 )-f i+1,n sin(α i -α i+1 )-R i+1 [fcos(α i -α i+1 )+sin(α i -α i+1 )]+W i cosα i Formula 9

[0114] The contact force between the current tubing and the target tubing can also be derived as follows:

[0115]

[0116] Substituting the first attitude angle, the second attitude angle, gravity, friction coefficient, axial force and lateral force of the target string, drill pipe length, and the angle between the unit and the horizontal direction into Equations 8, 9, and 10, we obtain the axial force, lateral force, and contact force of the current string.

[0117] This determined the axial force, lateral force, and contact force of the current tubing in the skew section, providing a basis for determining the skew rate.

[0118] In one possible embodiment, the anisotropy index is determined through the following steps:

[0119] Determine the geometric characteristic parameters of the drill bit;

[0120] The anisotropy index is determined based on the geometric characteristic parameters and the target formula.

[0121] For example, the drill bit can be a PDC drill bit. The type and structure of the drill bit are crucial factors affecting the effectiveness of flexible drilling tools in controlling well deviation. Studying the matching mechanism between the two is significant for optimizing drill bits and controlling wellbore trajectory. Therefore, this invention will determine the anisotropy index of the drill bit based on its structural parameters (i.e., geometric characteristic parameters) and target formula to study its influence on different flexible drilling tools, thereby identifying the matching mechanism between the drill bit and the flexible drilling tool.

[0122] In this way, based on the geometric characteristic parameters of the drill bit, the anisotropy index of the drill bit can be determined to match the relationship between the drill bit and the flexible drilling tool, providing a basis for the calculation of the build-up rate.

[0123] In one possible embodiment, the geometric feature parameters may include: diameter, longitudinal rake angle, friction angle, inner cone depth, and outer structure length.

[0124] The target formula can be:

[0125]

[0126] Among them, I b Anisotropy index; D refers to diameter; ω c The longitudinal front angle; θ f The friction angle is indicated by C; the inner cone depth is indicated by G; the external structural height is indicated by K; and the coefficient is indicated by K.

[0127] For example, K can be 1 / 8, or other values. Figure 4 As shown, the anisotropy index of the drill bit is related not only to the geometric characteristics of the drill bit, but also to formation parameters (formation strength, formation hardness) and the lateral forces of the drill bit. Figure 4As can be seen, the geometric characteristic parameters mainly include the cutting structure and the hydraulic structure. Among them, the cutting structure includes the crown shape, the distribution of cutting teeth, and diameter protection (active diameter protection, passive diameter protection), etc. Detailed parameters are shown in Table 1.

[0128] Table 1 Geometric characteristic parameters of the drill bit

[0129]

[0130]

[0131] In this way, based on the geometric characteristic parameters of the drill bit, the anisotropy index of the drill bit can be determined to match the relationship between the drill bit and the flexible drilling tool, providing a basis for the calculation of the build-up rate, which is beneficial to improving the build-up performance of ultra-short radius drill bits.

[0132] In one possible embodiment, the slope rate is determined by the following steps:

[0133] The second well inclination angle is determined based on the axial force, lateral force, anisotropy index, first well inclination angle, and drilling rate equation.

[0134] If the inclination angle of the second well is not less than the target angle, the difference between the inclination angle of the second well and the inclination angle of the first well is divided by the preset footage and determined as the build-up rate.

[0135] If the second well inclination angle is less than the target angle, then update the first attitude angle and the second attitude angle.

[0136] For example, the target angle can be 90 degrees and the advance can be 0.05m.

[0137] The formula for the slope is as follows:

[0138]

[0139] In Equation 12, BUR refers to the slope. ΔL refers to the difference between the inclination angle of the second well and the inclination angle of the first well; ΔL refers to the footage advanced.

[0140] If the second well inclination angle does not meet the termination condition (not less than the target angle), the current result is stored as intermediate data for further analysis. Then, the first and second attitude angles are updated to iteratively calculate the second well inclination angle. Otherwise, the calculation process ends and the build-up rate is output.

[0141] In this way, when the second well inclination angle meets the termination condition, the build-up rate is output, which improves the continuity and reliability of the build-up rate.

[0142] In one possible embodiment, the second well inclination angle is determined by the following steps:

[0143] By inputting axial force, lateral force, and anisotropy index into the drilling rate equation, the first and second drilling rate components corresponding to the flexible drilling tool in the X-axis and Y-axis directions are obtained, respectively.

[0144] The second wellbore trajectory is determined based on the first drilling rate component, the second drilling rate component, the footage, and the first well inclination angle;

[0145] The angle between the second wellbore trajectory and the first wellbore trajectory is defined as the second wellbore inclination angle.

[0146] The drilling rate equation is as follows:

[0147]

[0148] Among them, R b The first drilling speed component; R l Refers to the second drilling speed component; D n Standard (normal) drilling efficiency; I r This refers to the anisotropy coefficient of the formation, which is set to 1 here.

[0149] In Equation 13, the R matrix is ​​as follows:

[0150]

[0151] In Equation 13, the S matrix is ​​as follows:

[0152]

[0153] Then, based on the first drilling speed component, the second drilling speed component, the footage, and the first wellbore inclination angle of the first wellbore trajectory, the second wellbore trajectory is determined; the angle between the second wellbore trajectory and the first wellbore trajectory is determined as the second wellbore inclination angle. This improves the accuracy of the second wellbore inclination angle.

[0154] In one possible embodiment, the second wellbore trajectory is determined through the following steps:

[0155] Multiply the first drilling speed component, the footage, and the cosine value of the first well inclination angle to obtain the first change in the first wellbore trajectory in the X-axis direction;

[0156] Multiply the second drilling speed component, the footage, and the sine value of the first well inclination angle to obtain the second change in the first wellbore trajectory in the Y-axis direction;

[0157] The second wellbore trajectory is determined based on the first wellbore trajectory, the first change, and the second change.

[0158] The formulas for the first and second changes are as follows:

[0159]

[0160] In Equation 16, Δx i The first change; Δy i Refers to the second change.

[0161] Then, based on the first wellbore trajectory, the first change, and the second change, the second wellbore trajectory can be determined. This improves the accuracy of the second wellbore trajectory.

[0162] The method for determining the build-up rate of a flexible drill string provided by this invention can also be used in conjunction with a computer-readable storage medium. The storage medium stores a computer program, which is executed to run the method for determining the build-up rate of a flexible drill string. The computer program can execute computer instructions, which include computer program code. The computer program code can be in the form of source code, object code, executable file, or some intermediate form.

[0163] Computer-readable storage media can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0164] It should be noted that the contents of computer-readable storage media may be appropriately added to or subtracted from the contents according to the requirements of legislation and patent practice in a jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable storage media may not include electrical carrier signals and telecommunication signals.

[0165] According to another aspect of the present invention, an apparatus for determining the build-up rate of a flexible drill string is also provided, which performs a method for determining the build-up rate of a flexible drill string. Figure 5 A block diagram of a device for determining the build-up rate of a flexible drill string according to an embodiment of the present invention is shown. The device includes:

[0166] The first determining module 510 is used to determine the axial force and lateral force experienced by the unit body in the directional drilling section of the flexible drilling tool;

[0167] The second determining module 520 is used to determine the anisotropy index of the drill bit and the first inclination angle of the first wellbore trajectory;

[0168] The third determining module 530 is used to determine the build-up rate of the flexible drilling tool based on the axial force, lateral force, anisotropy index, first well inclination angle, and drilling rate equation.

[0169] In summary, this invention provides a method, apparatus, and medium for determining the inclination rate of a flexible drill bit, which has the following advantages compared with the prior art:

[0170] This invention determines the axial and lateral forces acting on the flexible drilling tool, then determines the anisotropy index of the drill bit and the first inclination angle of the first wellbore trajectory. Subsequently, based on the axial force, lateral force, anisotropy index, first inclination angle, and drilling rate equation, the build-up rate of the flexible drilling tool is determined. This method of determining the build-up rate of the flexible drilling tool improves the accuracy, precision, and efficiency of the build-up rate calculated for short-radius and ultra-short-radius sidetracking, enhances the timeliness of drilling operations, and meets the technical requirements for developing residual oil in the near-wellbore zone of old oilfields and for directional drilling engineering.

[0171] Example 1: Setting the parameters of the flexible drilling tool, as shown in Tables 2 and 3:

[0172] Table 2 Parameters of Flexible Drill Strings

[0173]

[0174] Table 3 Parameters of Flexible Drill Strings

[0175]

[0176] The range of drill pressure was set from 1t to 6t to reflect the possible variations in drill pressure during actual operation. The anisotropy index of the drill bit was increased from 0.5 to 1.7 to analyze the asymmetric rock breaking performance of different drill bit structures. Other parameters, such as the torsion angle between the tubing strings, the window angle, the friction coefficient, and different values ​​of the tubing string length, simulated different drilling conditions and downhole environments.

[0177] By integrating these parameters, drilling trajectories under different conditions can be simulated, which is crucial for predicting situations that may be encountered in actual drilling operations. The selection and setting of these parameters provide strong support for predicting the build-up and extension capabilities of ultra-short radius horizontal wells, and also ensure the reliability and practicality of wellbore trajectory output.

[0178] like Figure 6 As shown, the second wellbore trajectory was calculated using this method. It can be observed that the wellbore completed the build-up at a vertical depth of approximately 3m from the window opening point, achieving ultra-short radius build-up. On-site measurements of Well Y show that the section from 3006.00m to 3010.40m is the build-up section, with the inclination angle increasing from 2.8° to 87.1°, and a build-up footage of 4.4m. The numerically calculated build-up radius is 2.71m, which differs from the on-site measured value of Well Y by less than 9%, proving the accuracy of the method.

[0179] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should be extended to equivalent substitutions of these features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0180] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0181] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0182] Certain terms are used throughout this application to refer to specific system components. As those skilled in the art will recognize, the same components may often be referred to by different names, and therefore this application is not intended to distinguish those components that differ only in name and not in function. In this application, the terms “comprise,” “include,” and “have” are used in an open-ended manner and should therefore be interpreted as meaning “including, but not limited to…”. Furthermore, the terms “substantially,” “materially,” or “approximately” as used herein refer to industry-accepted tolerances for the corresponding terms. The term “coupling,” as may be used herein, includes direct coupling and indirect coupling via additional components, elements, circuits, or modules, wherein, for indirect coupling, the intermediate component, element, circuit, or module does not alter the information of the signal but may adjust its current level, voltage level, and / or power level. Inferred coupling (e.g., one element is inferredly coupled to another element) includes direct and indirect coupling between two elements in the same manner as “coupling.”

[0183] The phrase "an embodiment" or "an embodiment" used in this specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, the phrase "an embodiment" or "an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0184] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

[0185] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A method for determining the build-up rate of a flexible drill bit, characterized in that, The method includes: Determine the axial and lateral forces acting on a unit in the build-up section of the flexible drilling tool; Determine the anisotropy index of the drill bit and the first inclination angle of the first wellbore trajectory; The build-up rate of the flexible drill string is determined based on the axial force, the lateral force, the anisotropy index, the first well inclination angle, and the drilling rate equation.

2. The method as described in claim 1, characterized in that, The unit includes the current tubing and the target tubing following the current tubing; The lateral force and the axial force are determined by the following steps: Determine the first attitude angle of the current tubing and the second attitude angle of the target tubing; Based on the first attitude angle, the second attitude angle, the mechanical equilibrium equations corresponding to the unit body in the X-axis direction and the Y-axis direction, and the torque equilibrium equation in the XY plane, the lateral force and the axial force are determined.

3. The method as described in claim 2, characterized in that, The mechanical equilibrium equation corresponding to the X-axis direction is: f in cosα i -f iτ sinα i -(f i+1,n -R i+1 )cosα i+1 +(f i+1,τ -R i+1 f)sinα i+1 =0 Among them, f in The axial force currently acting on the tubing string; α i The first attitude angle; f iτ The lateral force currently acting on the tubing string; f i+1,n The axial force acting on the target tubing; R i+1 The contact force between the current tubing string and the target tubing string; α i+1 The second attitude angle; f i+1,τ The lateral force on the target tubing refers to the force applied to it; f refers to the coefficient of friction. The mechanical equilibrium equation corresponding to the Y-axis direction is: f in sinα i +f iτ cosα i -(f i+1,n -R i+1 )sinα i+1 -(f i+1,τ -R i+1 f)cosα i+1 - W i ＝0 Among them, W i The gravitational force acting on a unit cell; The torque balance equation in the XY plane is: Among them, L i This refers to the length of the drill pipe between the current drill string and the target drill string; The angle between the unit cell and the horizontal direction.

4. The method as described in claim 2 or 3, characterized in that, The anisotropy index is determined by the following steps: Determine the geometric characteristic parameters of the drill bit; The anisotropy index is determined based on the geometric feature parameters and the target formula.

5. The method as described in claim 4, characterized in that, The geometric feature parameters include: diameter, longitudinal rake angle, friction angle, inner cone depth, and outer structure length; The target formula is: Among them, I b Anisotropy index; D refers to diameter; ω c The longitudinal front angle; θ f The friction angle is indicated by C; the inner cone depth is indicated by G; the external structural height is indicated by K; and the coefficient is indicated by K.

6. The method according to any one of claims 2-5, characterized in that, The slope rate is determined by the following steps: The second well inclination angle is determined based on the axial force, the lateral force, the anisotropy index, the first well inclination angle, and the drilling rate equation. If the second well inclination angle is not less than the target angle, the difference between the second well inclination angle and the first well inclination angle is divided by the preset footage and determined as the build-up rate. If the second well inclination angle is less than the target angle, then update the first attitude angle and the second attitude angle.

7. The method as described in claim 6, characterized in that, The second well inclination angle is determined by the following steps: The axial force, the lateral force, and the anisotropy index are input into the drilling rate equation to obtain the first drilling rate component and the second drilling rate component of the flexible drill bit in the X-axis direction and the Y-axis direction, respectively. The second wellbore trajectory is determined based on the first drilling rate component, the second drilling rate component, the footage, and the first well inclination angle; The angle between the second wellbore trajectory and the first wellbore trajectory is determined as the second well inclination angle.

8. The method as described in claim 7, characterized in that, The second wellbore trajectory is determined by the following steps: Multiply the first drilling rate component, the footage, and the cosine of the first well inclination angle to obtain the first change in the first wellbore trajectory in the X-axis direction; Multiply the second drilling rate component, the footage, and the sine of the first well inclination angle to obtain the second change in the first wellbore trajectory in the Y-axis direction; The second wellbore trajectory is determined based on the first wellbore trajectory, the first change, and the second change.

9. A storage medium, characterized in that, It includes a series of instructions for performing the method steps as described in any one of claims 1-8.

10. A device for determining the inclination rate of a flexible drill bit, characterized in that, The apparatus for performing the method as described in any one of claims 1-8 comprises: The first determining module is used to determine the axial force and lateral force experienced by the unit body in the directional drilling section of the flexible drilling tool; The second determining module is used to determine the anisotropy index of the drill bit and the first inclination angle of the first wellbore trajectory; The third determining module is used to determine the build-up rate of the flexible drill string based on the axial force, the lateral force, the anisotropy index, the first well inclination angle, and the drilling rate equation.

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