A preferred method, system and apparatus for floating lengths
By acquiring well site data, filtering and optimizing drill bit position and hook load, calculating wellbore friction coefficient using a rigid rod model, and combining the floating length optimization equation, the optimal floating length is determined. This solves the problems of poor floating length selection accuracy and difficulty in lowering the air section in existing technologies, and achieves a more efficient lowering process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CNPC BOHAI DRILLING ENG
- Filing Date
- 2023-12-13
- Publication Date
- 2026-05-19
AI Technical Summary
The existing technology has poor accuracy in selecting the floating length, which leads to problems such as excessively long floating length affecting the lowering efficiency and difficulty in lowering the air section during floating casing operations.
By acquiring well site data, filtering and optimizing drill bit position and hook load, calculating well friction coefficient using a rigid rod model, and combining the floating length optimization equation to determine the optimal floating length, adding a safety value to closely approximate on-site construction, optimizing hook load prediction, and avoiding difficulties in lowering the air section.
It improves the accuracy of floating length selection, solves the problem of difficulty in lowering the air section, and enhances the hook load and lowering efficiency during the lowering process.
Smart Images
Figure CN120139648B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of drilling, and specifically relates to a method, system and equipment for optimizing the floating length. Background Technology
[0002] In recent years, floating casing technology has been widely applied in the domestic shale gas market and in extended reach horizontal wells in various oilfields. It utilizes floating couplings within the casing string as a "temporary barrier." After the casing is lowered into position, the floating couplings are opened by pressurizing the wellhead, enabling efficient and safe casing lowering. Currently, in floating casing lowering operations, the floating length is mainly predicted by software simulation, selecting the maximum wellhead hook load when the casing reaches the bottom of the well as the means of determining the floating length. However, in practical applications, the selected friction coefficient is often an empirical value, which does not match the field conditions. Using the maximum wellhead hook load when the casing reaches the bottom of the well as the floating length also presents the problem of excessively long floating lengths affecting lowering efficiency, as the floating section of the casing is not heavy enough to require back clamps for re-closing. Furthermore, in some extended reach horizontal wells, using the maximum wellhead hook load when the casing reaches the bottom of the well as the floating length results in difficulties in lowering the air section. Summary of the Invention
[0003] To address the aforementioned problems in the prior art, namely the poor accuracy of the selected floating length and the difficulty in lowering the air section, the first aspect of the present invention provides a method for optimizing the floating length, used to calculate the optimal floating length of the floating coupling during floating casing lowering operations, comprising:
[0004] Step S10: Obtain and filter well site data from the start of well cleaning to the bottom of the well. After filtering, calculate the optimized solution for drill bit position and hook load, and use the calculated data as input data. The well site data includes drill bit position, hook load, rotation speed, pump pressure, displacement, traveling block height, and torque data.
[0005] Step S20: Based on the input data, the wellbore friction coefficient is obtained through a pre-constructed rigid rod model; the wellbore friction coefficient includes the friction coefficient inside the wellbore tube and the friction coefficient outside the wellbore tube.
[0006] Step S30: The friction coefficient inside the well-through pipe and the friction coefficient outside the well-through pipe are added to the safety value to obtain the friction coefficient inside the lower casing and the friction coefficient outside the lower casing.
[0007] Step S40: Combining the friction coefficient inside the lower sleeve and the friction coefficient outside the lower sleeve, the optimal floating length is obtained through a pre-constructed floating length optimization equation.
[0008] In some preferred embodiments, well site data from the start of well cleaning to the bottom of the well is acquired and filtered. After filtering, the optimized solution for the drill bit position and hook load is calculated. The method is as follows:
[0009] Data on drill bit position, hook load, and traveling block height corresponding to non-zero rotation speed, pump pressure, displacement, and torque were filtered out. The collected data were then grouped according to time sequence and traveling block height, with each group corresponding to the process of a casing pipe from connection to the wellhead. Numerical optimization was performed on the drill bit position and hook load of each group after filtering. The optimization formula is as follows:
[0010]
[0011] Where M is the optimized drill bit position; m i H represents the well depth at a certain point in time when the casing is run into the group; H represents the optimized hook load; h i For the corresponding drill bit position m in the group i The hook load at the wellhead; n is the number of data in the group.
[0012] In some preferred embodiments, the rigid bar model is:
[0013]
[0014] Among them, K d For the wellbore curvature, C k Here is the conversion factor, and Δα is the change in well inclination angle. K is the rate of change of azimuth angle. α Let E be the rate of change of well inclination angle, E be the elastic modulus of the tubing string, I be the moment of inertia of the tubing string, K be the wellbore curvature, τ be the wellbore deflection, and F be the wellbore angle variation rate. t2 F represents the axial force at the upper end of the selected infinitesimal element of the tubular column. t1 q represents the axial force at the lower end of the selected infinitesimal element of the tubular column. m K represents the weight per unit length of the casing. f The buoyancy coefficient, r m r represents the density of the drilling fluid. s α represents the casing material density, α represents the well inclination angle, Δs represents the length of the micro-element, μ represents the friction coefficient, N represents the contact pressure between the casing and the wellbore, and ΔK represents the change in wellbore curvature at the upper and lower ends of the micro-element. n This represents the uniformly distributed contact pressure along the principal normal direction, in N. b M represents the uniformly distributed contact pressure in the direction of the binormal. b The torque in the secondary direction is represented by s, and the length of the infinitesimal element is represented by s.
[0015] In some preferred embodiments, the preferred equation for the floating length is:
[0016]
[0017] Among them, F xThe sum of the hook loads from the start of the descent to the bottom of the well is given, z is the bottom depth, x is the optimal floating length, y is the floating length when the floating coupling is placed at the critical resistance angle, the function f is the friction calculation model, i.e., the rigid bar model, n is the correction value, η is the optimization solution, and x is the optimal floating length when η is maximized.
[0018] In some preferred embodiments, the internal friction coefficient and the external friction coefficient of the well-connecting pipe are respectively added to a safety value, and the method is as follows:
[0019] The friction coefficient inside and outside the wellbore pipe are added to a safety value to obtain the friction coefficient inside and outside of the lower casing; the safety value is calculated as follows:
[0020] σ=max(|μ min -μ|,|μ-μ max |)×150%
[0021] Where σ is the safety value, and μ is the safety value. min μ, μ max 1.5 times the absolute difference among the three; μ is the external friction coefficient of the wellbore pipe calculated by the rigid rod model using the optimized solution of drill bit position and hook load; μ min The minimum external friction coefficient of the wellbore pipe calculated using only unoptimized data; μ max The maximum external friction coefficient of the wellbore is calculated using only unoptimized data.
[0022] In some preferred embodiments, step S40 is followed by step S50.
[0023] Based on the optimal floating length, the hook load at the wellhead when the entire casing string reaches the optimal floating length is calculated using the rigid rod model. If the hook load is equal to 0, the non-top drive drilling rig adopts the method of connecting the floating coupling in advance to avoid difficulties in lowering the air section. The top drive drilling rig adopts the method of top drive downward pressure to increase the axial downward pressure of the casing string in order to achieve the expected optimal floating length. The method of connecting the floating coupling in advance means connecting the floating coupling when the hook load at the wellhead is a set kN.
[0024] A second aspect of the invention provides a floating length optimization system for calculating the optimal floating length of a floating coupling during floating casing operations. The system comprises:
[0025] The data filtering module is configured to acquire and filter well site data from the start of well cleaning to the bottom of the well, and then calculate the optimized solution for drill bit position and hook load. The calculated data is used as input data. The well site data includes drill bit position, hook load, rotation speed, pump pressure, displacement, traveling block height, and torque data.
[0026] The friction coefficient calculation module is configured to obtain the wellbore friction coefficient based on the input data and through a pre-constructed rigid bar model; the wellbore friction coefficient includes the friction coefficient inside the wellbore tube and the friction coefficient outside the wellbore tube.
[0027] The coefficient weighting module is configured to add the friction coefficient inside the well pipe and the friction coefficient outside the well pipe to the safety value respectively to obtain the friction coefficient inside the lower casing and the friction coefficient outside the lower casing.
[0028] The floating length acquisition module is configured to combine the internal friction coefficient of the lower sleeve and the external friction coefficient of the lower sleeve to obtain the optimal floating length through a pre-constructed floating length optimization equation.
[0029] A third aspect of the present invention provides a device for optimizing the floating length, comprising:
[0030] At least one processor; and a memory communicatively connected to at least one of the processors; wherein the memory stores instructions executable by the processor to implement the preferred method for floating length described above.
[0031] In a fourth aspect, the present invention provides a computer-readable storage medium storing computer instructions for execution by the computer to implement the above-described preferred method for floating length.
[0032] The beneficial effects of this invention are:
[0033] This invention improves the accuracy of selecting the floating length and solves the problem of difficulty in lowering the air section.
[0034] 1) The method of this invention filters well site data, and the filtered data has a smaller variance with the curves calculated by the tubing mechanical equations, making it easier to couple;
[0035] 2) The friction coefficient of the lower casing with an added safety value can better reflect the on-site construction conditions, providing clear guidance for predicting the hook load of the lower casing;
[0036] 3) The present invention uses the optimal floating length calculated based on the floating length optimization equation, which can place the floating coupling below the critical resistance angle without significantly reducing the hook load at the bottom of the well, thereby increasing the hook load during the lowering process;
[0037] 4) This invention checks whether the minimum value of the ungrouted air section is greater than zero. If a negative value is found, in actual construction, the pipe column is lowered by increasing the axial downward pressure by connecting floating couplings in advance or by top driving downward pressure, which solves the problem of the difficulty in lowering the air section. Attached Figure Description
[0038] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:
[0039] Figure 1 This is a flowchart illustrating a preferred method for floating length according to an embodiment of the present invention;
[0040] Figure 2 This is a schematic diagram of the framework of a floating length optimization system according to an embodiment of the present invention;
[0041] Figure 3 This is a simplified flowchart illustrating a preferred method for floating length according to an embodiment of the present invention;
[0042] Figure 4 This is a schematic diagram of the stress analysis of the sleeve according to an embodiment of the present invention. Detailed Implementation
[0043] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.
[0044] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.
[0045] The present invention provides a method for optimizing the floating length, used to calculate the optimal floating length of the floating coupling during floating casing operations, such as... Figure 1 As shown, it includes:
[0046] Step S10: Obtain and filter well site data from the start of well cleaning to the bottom of the well. After filtering, calculate the optimized solution for drill bit position and hook load, and use the calculated data as input data. The well site data includes drill bit position, hook load, rotation speed, pump pressure, displacement, traveling block height, and torque data.
[0047] Step S20: Based on the input data, the wellbore friction coefficient is obtained through a pre-constructed rigid rod model; the wellbore friction coefficient includes the friction coefficient inside the wellbore tube and the friction coefficient outside the wellbore tube.
[0048] Step S30: The friction coefficient inside the well-through pipe and the friction coefficient outside the well-through pipe are added to the safety value to obtain the friction coefficient inside the lower casing and the friction coefficient outside the lower casing.
[0049] Step S40: Combining the friction coefficient inside the lower sleeve and the friction coefficient outside the lower sleeve, the optimal floating length is obtained through a pre-constructed floating length optimization equation.
[0050] To more clearly explain the preferred method for floating length of the present invention, the following is in conjunction with... Figure 3 The steps in the embodiments of the method of the present invention are described in detail below.
[0051] In floating casing installation, this invention first filters well depth and corresponding hook load data during well cleaning based on data from the well site data transmission system. Then, it substitutes this data into the tubing string mechanical equation (i.e., the rigid rod model) to calculate the well cleaning friction coefficient, and then adds a certain safety value as the casing friction coefficient. Next, it calculates the optimal floating length using the floating length optimization equation, and finally rechecks the hook load at the optimal floating length. The casing friction coefficient calculated using the filtered hook load data with added safety values closely approximates the actual field conditions, providing clear guidance for predicting casing hook load. Using the optimal floating length calculated from the floating length optimization equation allows the floating coupling to be placed below the critical resistance angle without significantly reducing the bottom hook load, thus increasing the hook load during installation. Checking the optimal floating length hook load mainly involves verifying whether the minimum value of the ungrouted air section is greater than zero. If a negative value is found, it is recommended to use methods such as pre-installing the floating coupling or top drive pressure to increase the axial downward pressure of the tubing string during installation. Specifically:
[0052] Step S10: Obtain and filter well site data from the start of well cleaning to the bottom of the well. After filtering, calculate the optimized solution for drill bit position and hook load, and use the calculated data as input data. The well site data includes drill bit position, hook load, rotation speed, pump pressure, displacement, traveling block height, and torque data.
[0053] In this embodiment, after wellbore completion, the well site data transmission system is used to select data on drill bit position, hook load, rotation speed, pump pressure, displacement, traveling block height, and torque from the start of wellbore completion to the bottom of the well. This data is then grouped chronologically. The data is filtered, removing drill bit position, hook load, and traveling block height data corresponding to non-zero rotation speed, pump pressure, displacement, and torque. After filtering, optimized solutions for drill bit position and hook load are calculated. The calculated data is used as input data. At this point, the drill bit position and corresponding hook load are considered wellbore completion data. Each data set corresponds to the process of one casing pipe from the connection string to the wellhead. Numerical optimization is performed on the drill bit position and hook load of each filtered group. The optimization formula is as follows:
[0054]
[0055] Where M is the optimized drill bit position, m; m iLet H be the well depth at a certain moment when the casing is run into the group, in meters; H be the optimized hook load, in kN (H is the optimized hook load, which, together with the corresponding well depth, is substituted into the rigid bar model to calculate the friction coefficient μ; H corresponds to the F of the topmost infinitesimal element of the entire tubing string in the rigid bar model). t2 );h i For the corresponding drill bit position m in the group i The hook load at the wellhead is kN; n is the number of data in the group.
[0056] Then, the wellbore friction coefficient is calculated by substituting it into the tubing mechanics equation (i.e., the rigid bar model below).
[0057] The data filtered by this invention has a smaller variance with the curves calculated from the string mechanics equations, making it easier to couple. This is because the string is not always in a state of force equilibrium, and the hook load is within a range of variation. Considering that the actual string lowering process is "acceleration-uniform speed-deceleration", it is necessary to calculate the optimized solution of the hook load during the lowering process, taking into account the influence of extreme values. The optimized solution is a given value, making it easier to couple.
[0058] Step S20: Based on the input data, the wellbore friction coefficient is obtained through a pre-constructed rigid rod model; the wellbore friction coefficient includes the friction coefficient inside the wellbore tube and the friction coefficient outside the wellbore tube.
[0059] In this embodiment, a stress analysis is performed on the tubing, such as... Figure 4 As shown, considering the "rigidity" of the tubing during the running-in process, a "rigid bar model" is established, taking into account the bending moment and shear force of the cross section. This model is based on the assumptions that: ① the tubing undergoes linear elastic deformation; ② the tubing is in continuous contact with the wellbore, and their axes are aligned; ③ the wellbore is rigid; ④ the tubing is subjected to uniformly distributed forces; and ⑤ the tubing interface is circular or annular. The calculation equations obtained using the rigid bar model are:
[0060]
[0061] Among them, K d C represents the wellbore curvature, ° / 30m; k The conversion factor is dimensionless, when K d When the unit is ° / 30m, C k Take 30; Δα is the change in well inclination angle, rad / m; K represents the rate of change of azimuth angle, in rad / m. α F is the rate of change of well inclination angle, rad / m; E is the elastic modulus of the tubing string, N / m²; I is the moment of inertia of the tubing string, m⁴; K is the wellbore curvature, rad / m; τ is the wellbore deflection, rad / m; F t2 F represents the axial force at the upper end of the selected infinitesimal element of the tubular column, in N; t1q represents the axial force at the lower end of the selected tubular element, in N; m This indicates the weight per unit length of the casing, in N / m; K f The buoyancy coefficient, r, is dimensionless. m This indicates the density of the drilling fluid, in kg / m³. 3 ;r s This indicates the density of the casing material, in kg / m³. 3 ; α represents the well inclination angle, rad; Δs represents the length of the micro-element, m; μ represents the friction coefficient (i.e., the friction coefficient, which affects the hook load calculated by the rigid dry model. For an actual well, most of its values in the model are fixed, and the only variable is the friction coefficient. The friction coefficient outside the pipe and the friction coefficient inside the pipe are calculated using formula (2). However, when calculating the friction coefficient inside the pipe, the selected data is the well depth of the casing and the corresponding hook load, because formula (2) is a series of micro-elements. The hook load at the top of the pipe string is calculated using the Newton iteration method. When calculating the friction coefficient outside the pipe, the well depth and hook load of the open hole section are calculated. When calculating the inside of the casing, only the previous results need to be iterated in), dimensionless; N represents the contact pressure between the pipe string and the well wall, N; ΔK represents the change in wellbore curvature at the upper and lower ends of the micro-element section, rad / m; N n N represents the uniformly distributed contact pressure along the principal normal direction; N b The uniformly distributed contact pressure in the direction of the binormal is expressed in N and M. b The torque in the secondary normal direction is expressed in N / m, and s represents the length of the selected infinitesimal element in meters. Figure 4 In These represent the directions of the secondary normal and the principal normal, respectively. Indicates the tangent direction of the tubing, q c This represents the contact force evenly distributed across the infinitesimal segments.
[0062] Step S30: The friction coefficient inside the well-through pipe and the friction coefficient outside the well-through pipe are added to the safety value to obtain the friction coefficient inside the lower casing and the friction coefficient outside the lower casing.
[0063] In this embodiment, since the wellbore string is a drill pipe, its outer diameter is much smaller than that of the casing used in the same opening, and its contact area with the well wall is much smaller. At the same time, the cross-sectional area of the casing is larger than that of the drill pipe, and the additional resistance caused by its rigidity is also greater. Therefore, the friction coefficient of the casing needs to be supplemented with a safety value on the basis of the wellbore friction coefficient.
[0064] This invention adds the calculated friction coefficients inside and outside the wellbore to a safety value to obtain the friction coefficients inside and outside the casing; wherein the safety value is calculated as follows:
[0065] σ=max(|μ min -μ|,|μ-μ max |)×150% (3)
[0066] Where σ is the safety value, and μ is the safety value. min μ, μ max 1.5 times the absolute difference among the three, dimensionless; μ is the external friction coefficient of the wellbore pipe calculated by the rigid rod model using the optimized solution of drill bit position and hook load, dimensionless; μ min The minimum external friction coefficient of the wellbore pipe calculated using only unoptimized data; μ max The maximum external friction coefficient of the wellbore is calculated using only unoptimized data.
[0067] Step S40: Combining the friction coefficient inside the lower sleeve and the friction coefficient outside the lower sleeve, the optimal floating length is obtained through a pre-constructed floating length optimization equation.
[0068] In this embodiment, to improve the hook load and efficiency during the lowering process, an additional coefficient can be added to place the floating coupling below the critical resistance angle without significantly reducing the hook load at the bottom of the well, thereby increasing the hook load during the lowering process. The preferred equation for the floating length is:
[0069]
[0070] Among them, F x Let be the sum of the hook load from i = 30m (i = 30, 60, ..., z) down to the bottom of the well, kN; z be the bottom depth, m; x be the optimized floating length, m; y be the floating length when the floating coupling is placed at the critical resistance angle; function f is the friction calculation model, and this paper uses the rigid rod model mentioned earlier; n is the correction value, which satisfies the requirement that the difference between the bottom hook load and the hook load at the critical resistance angle when the optimized floating length is reached should not exceed n. Taking n as an example, a value of 3% means that the hook load from the optimized floating length down to the bottom of the well is reduced by 3% compared to the maximum value, and the hook load is greater than 3% throughout the entire process, thereby improving the downing efficiency and reducing the occurrence of resistance during the downing process, kN; η is the optimization solution, and x is the optimal floating length when η is maximized.
[0071] After calculating the optimal floating length, it needs to be checked again because the maximum hook load of the floating section is reached when the casing is lowered to the critical resistance angle. Beyond this point, the hook load will decrease. It is necessary to check whether the minimum value for lowering the ungrouted air section is greater than zero. If a negative value is found, it is recommended to use methods such as pre-installing floating couplings or top-drive downward pressure to increase the axial downward pressure on the casing column during actual construction, as detailed below:
[0072] Step S40 is followed by step S50, which involves setting a minimum value for approval for the ungrouted air section:
[0073] Based on the optimal floating length, check if the minimum value of the ungrouted air section is less than zero. If so, the non-top-drive drilling rig adopts a pre-connection floating coupling method to avoid difficulties in lowering the air section. The top-drive drilling rig uses a top-drive downward pressure method to increase the axial downward pressure of the casing string to achieve the expected optimal floating length. Specifically, based on the optimal floating length, the hook load at the wellhead when the entire casing string reaches the optimal floating length is calculated using the rigid rod model. If this hook load is equal to 0, the non-top-drive drilling rig adopts a pre-connection floating coupling method to avoid difficulties in lowering the air section. The top-drive drilling rig uses a top-drive downward pressure method to increase the axial downward pressure of the casing string to achieve the expected optimal floating length. The pre-connection floating coupling method means connecting the floating coupling when the hook load at the wellhead is a set kN (preferably 10kN in this invention).
[0074] The floating length optimization system of the second embodiment of the present invention is used to calculate the optimal floating length of the floating coupling in floating casing operations, such as... Figure 2 As shown, the system includes:
[0075] The data filtering module 100 is configured to acquire and filter well site data from the start of well cleaning to the bottom of the well, and calculate the optimized solution for drill bit position and hook load after filtering, and use the calculated data as input data; the well site data includes drill bit position, hook load, rotation speed, pump pressure, displacement, traveling block height, and torque data;
[0076] The friction coefficient calculation module 200 is configured to obtain the well cleaning friction coefficient based on the input data and through a pre-constructed rigid rod model; the well cleaning friction coefficient includes the friction coefficient inside the well cleaning pipe and the friction coefficient outside the well cleaning pipe.
[0077] The coefficient weighting module 300 is configured to add the friction coefficient inside the well pipe and the friction coefficient outside the well pipe to the safety value respectively to obtain the friction coefficient inside the lower casing and the friction coefficient outside the lower casing.
[0078] The floating length acquisition module 400 is configured to combine the internal friction coefficient of the lower sleeve and the external friction coefficient of the lower sleeve to obtain the optimal floating length through a pre-constructed floating length optimization equation.
[0079] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process and related descriptions of the system described above can be found in the corresponding processes in the foregoing method embodiments, and will not be repeated here.
[0080] It should be noted that the floating length optimization system provided in the above embodiments is only an example of the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the modules or steps in the embodiments of the present invention can be further decomposed or combined. For example, the modules in the above embodiments can be merged into one module, or further divided into multiple sub-modules to complete all or part of the functions described above. The names of the modules and steps involved in the embodiments of the present invention are only for distinguishing the various modules or steps and are not considered as an improper limitation of the present invention.
[0081] A third embodiment of the present invention provides a floating length optimization device, comprising at least one processor and a memory communicatively connected to at least one of the processors; wherein the memory stores instructions executable by the processor to implement the above-described floating length optimization method.
[0082] A computer-readable storage medium according to a fourth embodiment of the present invention stores computer instructions for execution by the computer to implement the above-described preferred method for floating length.
[0083] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process and related descriptions of the floating length optimization device and computer-readable storage medium described above can be found in the corresponding processes in the foregoing method embodiments, and will not be repeated here.
[0084] Those skilled in the art will recognize that the modules and method steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. The programs corresponding to the software modules and method steps can be placed in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium known in the art. To clearly illustrate the interchangeability of electronic hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in electronic hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the invention.
[0085] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent in such process, method, article, or apparatus / device.
[0086] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.
Claims
1. A method for optimizing the floating length, used to calculate the optimal floating length of the floating coupling in floating casing operations, characterized in that, The method includes the following steps: Step S10: Obtain and filter well site data from the start of well cleaning to the bottom of the well. After filtering, calculate the optimized solution for drill bit position and hook load, and use the calculated data as input data. The well site data includes drill bit position, hook load, rotation speed, pump pressure, displacement, traveling block height, and torque data. Step S20: Based on the input data, the wellbore friction coefficient is obtained through a pre-constructed rigid rod model; the wellbore friction coefficient includes the friction coefficient inside the wellbore tube and the friction coefficient outside the wellbore tube. Step S30: The friction coefficient inside the well-through pipe and the friction coefficient outside the well-through pipe are added to the safety value to obtain the friction coefficient inside the lower casing and the friction coefficient outside the lower casing. Step S40: Combining the friction coefficient inside the lower sleeve and the friction coefficient outside the lower sleeve, the optimal floating length is obtained through a pre-constructed floating length optimization equation.
2. The method for optimizing the floating length according to claim 1, characterized in that, Acquire and filter well site data from the start of wellbore cleaning to the bottom of the well. Then calculate the optimal solution for drill bit position and hook load. The method is as follows: Data on drill bit position, hook load, and traveling block height corresponding to non-zero rotation speed, pump pressure, displacement, and torque were filtered out. The collected data were then grouped according to time sequence and traveling block height, with each group corresponding to the process of a casing pipe from connection to the wellhead. Numerical optimization was performed on the drill bit position and hook load of each group after filtering. The optimization formula is as follows: ； Where M is the optimized drill bit position; H represents the well depth at which the casing is run down in the group at a certain moment; H represents the optimized hook load. For the corresponding group The hook load at the wellhead; n is the number of data in the group.
3. The method for optimizing the floating length according to claim 1, characterized in that, The preferred equation for the floating length is: ； in, Let z be the sum of the hook loads from the start of the run to the bottom of the well, and z be the depth measured at the bottom of the well. For optimal floating length, The floating length when the floating coupling is placed at the critical drag angle, a function This is a friction calculation model, i.e., a rigid bar model. This is a correction value. To find the optimal solution, solve... Maximum This is the optimal floating length.
4. The method for optimizing the floating length according to claim 1, characterized in that, The friction coefficient inside the wellbore and the friction coefficient outside the wellbore are added to a safety value, respectively, by the following method: The friction coefficient inside the wellbore and the friction coefficient outside the wellbore are added to a safety value to obtain the friction coefficient inside and outside the lower casing; wherein, the safety value is calculated as follows: ； in, For a safe value, , , 1.5 times the absolute difference between the three; The external friction coefficient of the wellbore is calculated using a rigid bar model to obtain the optimal solution for drill bit position and hook load. The minimum external friction coefficient of the wellbore tube calculated using only unoptimized data; The maximum external friction coefficient of the wellbore is calculated using only unoptimized data.
5. A preferred method for floating length according to any one of claims 1-4, characterized in that, Step S40 is followed by step S50. Based on the optimal floating length, the hook load at the wellhead when the entire casing string reaches the optimal floating length is calculated using the rigid rod model. If the hook load is equal to 0, the non-top drive drilling rig adopts the method of connecting the floating coupling in advance to avoid difficulties in lowering the air section. The top drive drilling rig adopts the method of top drive downward pressure to increase the axial downward pressure of the casing string in order to achieve the expected optimal floating length. The method of connecting the floating coupling in advance means connecting the floating coupling when the hook load at the wellhead is the set value.
6. A floating length optimization system for calculating the optimal floating length of a floating coupling during floating casing operations, characterized in that, The system includes: The data filtering module is configured to acquire and filter well site data from the start of well cleaning to the bottom of the well, and then calculate the optimized solution for drill bit position and hook load. The calculated data is used as input data. The well site data includes drill bit position, hook load, rotation speed, pump pressure, displacement, traveling block height, and torque data. The friction coefficient calculation module is configured to obtain the wellbore friction coefficient based on the input data and through a pre-constructed rigid bar model; the wellbore friction coefficient includes the friction coefficient inside the wellbore tube and the friction coefficient outside the wellbore tube. The coefficient weighting module is configured to add the friction coefficient inside the well tube and the friction coefficient outside the well tube to the safety value respectively to obtain the friction coefficient inside the lower casing and the friction coefficient outside the lower casing. The floating length acquisition module is configured to combine the internal friction coefficient and the external friction coefficient of the lower sleeve to obtain the optimal floating length through a pre-constructed floating length optimization equation.
7. A device for optimizing the floating length, characterized in that, include: At least one processor; and a memory communicatively connected to at least one of the processors; The memory stores instructions that can be executed by the processor to implement a preferred method for floating length as described in any one of claims 1-5.
8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that are executed by a computer to implement a preferred method for floating length as described in any one of claims 1-5.