Method and device for analyzing safe tripping-in of well completion pipe string

Abstract

The invention relates to the technical field of oil exploration, and provides an analysis method and device for safe tripping-in of a well completion pipe string, and the method comprises the steps: obtaining the actual hook load data and well section information of an open hole section based on a drifting process; constructing a tubular column friction torque calculation model of the drifting drilling tool assembly; on the basis of the tubular column friction resistance torque calculation model, the actual hook load data of the open hole section and the well section information of the well, the well hole open hole section friction resistance coefficient is calibrated; on the basis of well section information and the well hole open hole section friction resistance coefficient, a solving model of the axial force of the well completion pipe string and a critical load value calculation model of well completion pipe string buckling are built; and on the basis of the solving model of the axial force of the well completion pipe string and the calculation model of the critical load value of buckling of the well completion pipe string, whether the well completion pipe string is safely tripped is determined. According to the method, the friction resistance coefficient in the drifting stage is determined, the invisible shaft cleaning state is known, the current friction resistance coefficient is used for evaluating the to-be-tripped well completion pipe string, and therefore operation risks and operation complexity are avoided, and the operation efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil exploration, and particularly relates to an analysis method and device for safe running of a completion string. BACKGROUND

[0002] With the vigorous development of oil exploration and development towards unconventional reservoirs such as "low, deep, non", the proportion of deep well, ultra-deep well and horizontal well drilling is increasing exponentially. In recent years, the workload of horizontal well drilling accounts for 30% of the total amount of drilled wells, and the number of deep wells is increasing exponentially. The length of the horizontal section continues to break through 3km, 4km and 5km, and 5-6km horizontal section horizontal wells will become the norm. Deep wells continue to break through 8km and 9km, and two ultra-deep wells are being implemented. Currently, the traditional vertical well and directional well "one design one well" experience method is still used to deal with deep well / horizontal well drilling, and accidents of running string operation are complex and frequent during the completion stage of ultra-long horizontal section well / ultra-deep well. The number of cases of successful completion of high-yield wells during the testing stage has increased. Therefore, it is urgent to reform the technical management mode to support oil and gas energy exploration and development. SUMMARY

[0003] To solve the above problems, the present application provides an analysis method and device for safe running of a completion string. The present application provides the following technical solutions:

[0004] In the first aspect of the present application, an analysis method for safe running of a completion string is provided, the method comprising,

[0005] Based on the running-in process, actual hook load data of the open hole section and well section information are obtained;

[0006] A pipe string friction torque calculation model of the running-in tool assembly is constructed;

[0007] Based on the pipe string friction torque calculation model, the actual hook load data of the open hole section and the well section information, the open hole section friction coefficient of the wellbore is calibrated;

[0008] Based on the well section information and the open hole section friction coefficient of the wellbore, a solution model of the axial force of the completion string and a critical load value calculation model of the buckling of the completion string are constructed;

[0009] Based on the solution model of the axial force of the completion string and the critical load value calculation model of the buckling of the completion string, it is determined whether the completion string can be safely run in.

[0010] Further, the well section information includes the actual drilling trajectory, the wellbore structure, the running-in tool assembly, the completion string combination and the drilling fluid information, and the resistance points through the running-in process, which are used to determine the position information of the tripping risk points of the deviated well section and the curved well section.

[0011] Further, the pipe string friction torque calculation model comprises a straight and inclined well section pipe string friction torque calculation model and a curved well section pipe string friction torque calculation model.

[0012] Further, the expression of the straight and inclined well section pipe string friction torque calculation model is as follows:

[0013] F t1 = BwΔL (cos α ± μsin α) + F b

[0014] F t1 is the axial force borne by the upper end of the pipe string; F b is the axial force borne by the lower end of the pipe string; α is the inclination angle; B is the buoyancy coefficient; ΔL is the pipe string length; w is the weight per unit length of the pipe string; and μ is the friction factor.

[0015] Further, the expression of the curved well section pipe string friction torque calculation model is as follows:

[0016] When the curved well section pipe string is in tension:

[0017]

[0018] When the curved well section pipe string is in compression:

[0019]

[0020] The calculation formula of Fn is as follows:

[0021]

[0022] F t2 is the axial force borne by the upper end of the curved well section pipe string when in tension; F t3 is the axial force borne by the upper end of the curved well section pipe string when in compression; F b is the axial force borne by the lower end of the pipe string; F n is the normal force of the pipe string; α top is the inclination angle of the upper end of the straight and inclined well section pipe string; α bottom is the inclination angle of the lower end of the straight and inclined well section pipe string; is the azimuth angle of the upper end of the straight and inclined well section pipe string; is the azimuth angle of the lower end of the straight and inclined well section pipe string; K is the dogleg angle; B is the buoyancy coefficient; ΔL is the unit length of the pipe string; w is the weight per unit length of the pipe string; and μ is the friction factor.

[0023] Further, based on the pipe string friction torque calculation model, the actual hook load data of the open hole section, and the well section information, the friction coefficient of the open hole section of the wellbore is determined, comprising:

[0024] Based on the well section information, the friction factor in the pipe string friction torque calculation model is calculated by combining the finite element method, and corresponding theoretical hook load data is obtained;

[0025] The corresponding theoretical hook load data is fitted and compared with the actual hook load data of the open hole section, and the theoretical hook load data closest to the actual hook load data is determined as the target theoretical hook load data;

[0026] The friction factor corresponding to the target theoretical hook load data is the friction coefficient of the open hole section of the wellbore.

[0027] Further, the pipe string axial force solving model is:

[0028]

[0029] Wherein,

[0030]

[0031] In the formula: F i is the axial force of the upper and lower ends of the i-th pipe string unit; F i-1 is the axial force of the upper and lower ends of the i-1-th pipe string unit; N g , N are the gravity distribution and normal pressure distribution of the pipe string unit in the drilling fluid; F u is the distribution of friction on the pipe string unit; α i , α i-1 represent the inclination angles of the upper and lower ends of the i-th pipe string unit; represent the azimuth angles of the upper and lower ends of the i-th pipe string unit; We is the linear weight of the pipe string; ρ m is the drilling fluid density; ρ s is the pipe string density; ΔL is the unit length of the pipe string; β is the full angle; α is the inclination angle; δ is the vector angle; θ is the angle between the gravity direction and the normal vector; μ is the friction factor.

[0032] Further, the critical load value calculation model of the well completion pipe string buckling is as follows:

[0033] The critical sine buckling load calculation formula of the vertical well section is:

[0034]

[0035] The critical sine buckling load calculation formula of the deviated vertical well section is:

[0036]

[0037] The critical sine buckling load calculation formula of the curved well section is:

[0038]

[0039] wherein, F crv is the buckling boundary load of the straight well section, F crd is the buckling boundary load of the inclined well section, F crs is the buckling boundary load of the curved section; E is the Young's modulus of the pipe string; I is the moment of inertia of the pipe string; w is the weight per unit length of the pipe string; a is the inclination angle; r is the radial clearance between the pipe string and the wellbore; and R is the curvature radius of the wellbore.

[0040] Further, based on the wellbore open hole section friction coefficient, the completion pipe string axial force solving model, and the completion pipe string buckling critical load value calculation model, it is determined whether the completion pipe string can be safely run in, including:

[0041] the wellbore open hole section friction coefficient is substituted into the pipe string axial force solving model to calculate the axial force of the completion pipe string;

[0042] the buckling critical load value calculation model is calculated to obtain the buckling boundary value;

[0043] the completion pipe string axial force value and the completion pipe string buckling boundary value are compared to determine whether the completion pipe string is subjected to buckling;

[0044] when the corresponding drill string pipe string axial force is greater than the buckling boundary value, the completion pipe string is subjected to buckling in the section, and there is a risk that the completion pipe string cannot be safely run in; and when the corresponding drill string pipe string axial force is less than 0, it is indicated that the completion pipe string cannot be safely run in;

[0045] when the corresponding drill string pipe string axial force is less than the buckling boundary value, the completion pipe string is not subjected to buckling in the section, and the completion pipe string can be safely run in.

[0046] Further, when the completion pipe string is subjected to buckling in the section, the completion pipe string cannot be safely run in, and there is a risk that the completion pipe string is run in,

[0047] the risk of running in the completion pipe string is reduced by optimizing the completion pipe string centralizer, increasing the flow reducer, using the floating completion pipe string, or rotating the completion pipe string.

[0048] In a second aspect of the present application, an analysis device for safe running in of a completion pipe string is also provided, and the device comprises,

[0049] an acquisition unit configured to acquire actual hook load data of an open hole section and well section information based on a well running process;

[0050] a first construction unit configured to construct a pipe string friction torque calculation model of a well running drilling assembly;

[0051] a calibration unit configured to calibrate a wellbore open hole section friction coefficient based on the pipe string friction torque calculation model, the actual hook load data of the open hole section, and the well section information of the well;

[0052] a second construction unit configured to construct a solution model of the axial force of the completion string and a critical load value calculation model of the buckling of the completion string based on the well section information and the wellbore open hole section friction coefficient;

[0053] a confirmation unit configured to confirm whether the completion string can be safely run in based on the solution model of the axial force of the completion string and the critical load value calculation model of the buckling of the completion string.

[0054] In a third aspect of the present application, an electronic device is also provided, which comprises at least one processor and at least one memory data-connected with the processor, wherein,

[0055] The memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the above method.

[0056] Technical effects and advantages of the present application:

[0057] The present application determines the friction coefficient of the through-well stage to understand the invisible wellbore cleaning state, and evaluates the completion string to be run in by using the current friction coefficient, thereby avoiding operation risks, avoiding operation complexity, and improving operation efficiency.

[0058] The present method comprehensively optimizes the completion stage process, which optimizes the through-well drilling tool assembly and the through-well tripping process, optimizes the completion string design and running mode, and optimizes the auxiliary process and parameters in the completion string running process, so as to ensure that the completion string is efficiently run into the well bottom under the premise of safety, improve the completion operation efficiency, and improve the completion success rate.

[0059] The completion string safe running analysis and evaluation and optimization model formed by the present application covers conventional sandstone oil and gas reservoirs and carbonate oil and gas reservoirs, unconventional shale oil and gas reservoirs and tight oil and gas reservoirs, conglomerate oil reservoirs, coalbed methane, geothermal drilling and completion engineering, and covers 20-120 drilling rigs, and is suitable for drilling sites and remote operation centers and other scene applications.

[0060] The present method constructs a completion string safe running evaluation workflow, realizes various node technology templates with the help of professional calculation software, relies on the data collected by the drilling and completion engineering informatization system, and returns to the remote technical support decision center in the rear base, and timely carries out the completion string optimization design and the completion string running process optimization by using the present method, and ensures the safety of the wellbore.

[0061] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application can be achieved and obtained by the structures indicated in the specification and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0062] Figure 1 is an analysis method flowchart of safe running of a completion string provided by the embodiment of the present application;

[0063] Figure 2 is a schematic diagram of a pipe string friction torque calculation model provided by the embodiment of the present application;

[0064] Figure 3 is a schematic diagram of stress of a micro-element section pipe string provided by the embodiment of the present application;

[0065] Figure 4 is a schematic diagram of a Cartesian coordinate system of a micro-element section pipe string provided by the embodiment of the present application;

[0066] Figure 5 is a schematic diagram of an evaluation process of safe running of a completion string provided by the embodiment of the present application;

[0067] Figure 6 is a graph of hook load and friction of a drilling through well hook provided by the embodiment of the present application;

[0068] Figure 7a is a numerical graph of hook load and buckling of a simulated original completion pipe string provided by the embodiment of the present application;

[0069] Figure 7b is a simulation graph of hook load and buckling of a simulated original completion pipe string provided by the embodiment of the present application;

[0070] Figure 8a is a numerical graph of hook load and buckling of a simulated optimized completion pipe string provided by the embodiment of the present application;

[0071] Figure 8b is a simulation graph of hook load and buckling of a simulated optimized completion pipe string provided by the embodiment of the present application;

[0072] Figure 9 is a numerical graph of hook load and buckling of an actually running completion pipe string provided by the embodiment of the present application;

[0073] Figure 10 is a structural block diagram of an electronic device according to the embodiment of the present application. DETAILED DESCRIPTION

[0074] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0075] In order to solve the problems in the prior art, the application discloses an analysis method for safe running of a completion string, as shown in the accompanying drawings, Figure 1

[0076] Step 1: based on a running-in process, actual hook load data of a bare hole section and a running-in drilling tool assembly, i.e., a downhole completion string combination, a well trajectory, a drilling fluid density and other well section information are obtained;

[0077] Step 2: a string friction torque calculation model of the running-in drilling tool assembly is constructed;

[0078] Step 3: based on the string friction torque calculation model, the actual hook load data of the bare hole section and the well section information, a friction coefficient of the wellbore bare hole section is calibrated;

[0079] Step 4: based on the well section information and the friction coefficient of the wellbore bare hole section, a string axial force solving model and a critical load value calculation model of the completion string buckling are constructed;

[0080] Step 5: based on the friction coefficient of the wellbore bare hole section, the string axial force solving model and the critical load value calculation model of the completion string buckling, the string axial force and the completion string buckling boundary value are calculated, and based on comparison of the string axial force value and the completion string buckling boundary value, it is determined whether the completion string can be safely run in, so that the string which cannot be safely run in is optimized, so as to meet the requirement of safe running in of the string.

[0081] In one specific embodiment of the application, in Step 1: the actual hook load data of the running-in process refers to the hook load data recorded in the process of successfully running in to the bottom under the premise of no pump and no rotation in the running-in process of the running-in drilling string.

[0082] The well section information includes a drilled trajectory, a well structure, a running-in drilling tool assembly, a completion string combination and drilling fluid information, and position information of a tripping risk point of a straight hole section and a curved hole section through a running-in resistance point in the running-in process.

[0083] Further, the drilled trajectory, the well structure, the running-in drilling tool assembly and the drilling fluid information (i.e., the well section information) are input into the string friction torque calculation model in Step 2, the running-in operation before the completion string is tracked, the running-in resistance point in the running-in process is recorded to mark a risk well section, and the actual friction coefficient of the bare hole section is calibrated through the hook load data in the running-in process.

[0084] In one specific embodiment of the application, in Step 2: the completion string friction torque calculation model is constructed as follows:

[0085] As shown in the accompanying drawings, Figure 2 ​As shown, the force analysis of the micro unit of the downhole string is carried out, and any unit is subjected to the upper end axial force, the lower end axial force, the string weight, the normal pressure of the well wall on the string, the friction (friction force) between the well wall and the string, and the directions of these forces are respectively as shown in the figure Figure 2 As shown, the resultant force is 0, so the calculation formula of the axial force and the friction torque can be derived, that is, the string friction torque calculation model.

[0086] The string friction torque calculation model comprises a straight and inclined well section string friction torque calculation model and a curved well section string friction torque calculation model.

[0087] The expression of the straight and inclined well section string friction torque calculation model is as follows:

[0088] F t1 = BwΔL (cosα±μsinαα) + F b

[0089] In the formula, F t1 is the axial force borne by the upper end of the string; F b is the axial force borne by the lower end of the string; α is the inclination angle; B is the buoyancy coefficient; ΔL is the unit length of the string; w is the weight of the unit length of the string; and μ is the friction factor.

[0090] The expression of the curved well section string friction torque calculation model is as follows:

[0091] When the curved well section string is subjected to tension:

[0092]

[0093] When the curved well section string is subjected to pressure:

[0094]

[0095] Wherein,

[0096]

[0097] F t1 is the axial force borne by the upper end of the straight and inclined well section string; F t2 is the axial force borne by the upper end of the curved well section string when subjected to tension; F t3 is the axial force borne by the upper end of the curved well section string when subjected to pressure; F b is the axial force borne by the lower end of the string; F n is the normal force of the string; α top is the inclination angle of the upper end of the straight and inclined well section string; α bottom is the inclination angle of the lower end of the straight and inclined well section string, is the azimuth angle of the upper end of the straight and inclined well section string, is the azimuth angle of the lower end of the pipe string of the inclined straight well section; K is the dogleg angle; B is the buoyancy coefficient; AL is the unit length of the pipe string; w is the weight of the unit length of the pipe string; and μ is the friction factor.

[0098] In one specific embodiment of the present application, for step 3: determining the friction coefficient of the wellbore open hole section based on the completion pipe string friction torque calculation model, the actual hook load data of the open hole section and the well section information, comprising: step 301: based on the well section information, the friction factor in the completion pipe string friction torque calculation model is calculated by combining the finite element method to obtain the corresponding theoretical hook load data of the completion pipe string;

[0099] Step 302: fitting and comparing the corresponding theoretical hook load data with the actual hook load data of the open hole section to determine the theoretical hook load data closest to the actual hook load data as the target theoretical hook load data;

[0100] Step 303: the friction factor corresponding to the target theoretical hook load data is the friction coefficient of the wellbore open hole section.

[0101] In one specific embodiment of the present application, for step 4, based on the completion pipe string combination, the well section information and the friction coefficient of the wellbore open hole section, a completion pipe string axial force solving model and a completion pipe string buckling critical load value calculation model are constructed; wherein the finite element method is an effective calculation and analysis method, which discretizes the continuous problem into a finite structure problem. The pipe string can be decomposed into discrete beam elements, and these elements can be combined to represent the initial state of the pipe string. The finite element method can reflect the changes of the structure, boundary conditions and loads, and finally obtain a set of algebraic equations with node displacement as the unknown quantity. The advantages of the finite element method are that it can consider nonlinear factors, and it can easily add the constraints of the wellbore in the model. In addition, the physical concept of the finite element method is simple, clear and applicable, and it is widely used by foreign well-known drilling service companies.

[0102] During drilling operations, the entire pipe string is subjected to the friction force of the well wall, and the influence of the friction force will be reflected on the hook load. In order to facilitate calculation, the entire pipe string is divided into several microelement sections, and the influence of the friction force is superimposed after the force analysis of each pipe string microelement section. The force analysis of the pipe string microelement section is shown in Figure 3 and 4 .

[0103] Finally, the solving model of the pipe string axial force is obtained as follows:

[0104]

[0105] wherein,

[0106] In the formula: F i is the axial force of the upper and lower ends of the i-th pipe string unit; Fi-1 is the axial force of the upper and lower ends of the i-1th pipe string unit; N g , N are the gravity distribution and the normal pressure distribution of the pipe string unit in the drilling fluid; F u is the distribution of the friction on the pipe string unit; α i , α i-1 represents the inclination angles of the upper and lower ends of the i-1th pipe string unit; represents the azimuth angles of the upper and lower ends of the i-1th pipe string unit; We is the linear weight of the pipe string; ρ m is the density of the drilling fluid; ρ s is the density of the pipe string; ΔL is the unit length of the pipe string; β is the full angle; α is the inclination angle; δ is the vector angle; θ is the angle between the gravity direction and the normal vector; μ is the friction factor.

[0107] The critical load value calculation model of the well completion pipe string buckling comprises a straight well section critical sine buckling load calculation formula, an inclined straight well section critical sine buckling load calculation formula and a curved well section critical sine buckling load calculation formula, wherein,

[0108] The straight well section critical sine buckling load calculation formula is:

[0109]

[0110] The inclined straight well section critical sine buckling load calculation formula is:

[0111]

[0112] The curved well section critical sine buckling load calculation formula is:

[0113]

[0114] wherein Fcrv is the buckling boundary load of the straight well section, Fcrd is the buckling boundary load of the inclined well section, and Fcrs is the buckling boundary load of the curved section; E is the Young's modulus of the pipe string; I is the rotational inertia of the pipe string; w is the weight of the unit length pipe string; α is the inclination angle; r is the radial gap between the pipe string and the wellbore; and R is the wellbore curvature radius.

[0115] In one specific embodiment of the present application, for step 5, based on the wellbore open hole section friction coefficient, the axial force calculation model of the pipe string and the critical load value calculation model of the pipe string buckling, the axial force of the well completion pipe string and the buckling boundary value of the well completion pipe string are calculated, and based on the comparison of the axial force value of the well completion pipe string and the buckling boundary value of the well completion pipe string, it is determined whether the well completion pipe string can be safely lowered, so that the pipe string that cannot be safely lowered is optimized to meet the requirement of safely lowering the pipe string, comprising:

[0116] Step 501: substituting the wellbore open hole section friction coefficient into a pipe string axial force solving model to calculate the axial force of the completion pipe string; wherein the axial force of the completion pipe string comprises the axial force of the upper and lower ends of the preset i-th section of the completion pipe string, the axial force of the upper and lower ends of the i-1-th section of the pipe string;

[0117] Step 502: comparing the axial force value of the completion pipe string and the buckling boundary value of the completion pipe string to determine whether the completion pipe string is subjected to buckling; comprising: based on the axial force of the upper and lower ends of the i-th section of the pipe string and the axial force of the upper and lower ends of the i-1-th section of the pipe string, determining whether the completion pipe string is subjected to buckling, and determining whether the ground hook load is less than 0 when the completion pipe string is bottomed;

[0118] Wherein, determining whether the completion pipe string is subjected to buckling comprises:

[0119] obtaining the buckling boundary value based on the critical load value calculation model of the buckling;

[0120] comparing the buckling boundary value with the corresponding axial force of the completion pipe string to determine whether the completion pipe string is subjected to buckling; wherein,

[0121] when the corresponding axial force of the drill string pipe string is less than the buckling boundary value, the completion pipe string is not subjected to buckling in this section, and it is considered that the completion pipe string can be safely lowered in theory;

[0122] when the corresponding axial force of the drill string pipe string is greater than the buckling boundary value, the completion pipe string is subjected to buckling in this section, and there is a risk that the completion pipe string cannot be safely lowered; when the axial force is less than 0, it indicates that the completion pipe string cannot be safely lowered; at this time, it is considered whether the risk of lowering the completion pipe string can be reduced by optimizing the casing centralizer, increasing the drag reducer, or adopting the floating casing, the rotary casing and other process measures;

[0123] After optimization, recalculate until the model calculation shows that there is no risk of lowering, and then construction can be carried out.

[0124] In the embodiment of the application, the buckling boundary value obtained from the buckling boundary value calculation model is compared with the axial force of the pipe string calculated in step 301; when the pipe string force (axial force of the pipe string) exceeds the buckling boundary value, it indicates that buckling occurs in this section.

[0125] Based on the above judgment process: whether the pipe string appears buckling.

[0126] During the process of lowering the completion pipe string, the ground hook load is continuously monitored by using the parameters, the lowering process is optimized for the abnormal hook load point, and the rotary lowering and circulation parameters are adapted.

[0127] During the actual well completion string running process, track the actual hook load data and compare it with the hook load data of the theoretical model. Analyze the actual obstruction points encountered during drilling and recommend measures such as repeated movement and pump flushing on site. If it still cannot pass, comprehensively analyze the reasons and consider cementing in place or pulling out the well completion string.

[0128] This method comprehensively optimizes the well completion stage procedures. First, it optimizes the drilling tool assembly and well tripping procedures. Second, it optimizes the design and running-in method of the completion string. Third, it optimizes the auxiliary procedures and parameters during the running-in process of the completion string. This ensures that the completion string is run into the bottom of the well efficiently under safe conditions, thereby improving the efficiency of well completion operations and increasing the success rate of well completion.

[0129] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0130] This invention relates to a method for improving the safe running of completion strings, used to optimize the design of completion strings and the running procedures and parameters. For example... Figure 5 As shown, the basic information required for tubing mechanics and tubing friction torque modeling is first obtained from drilling daily reports, logging tools, and drilling fluid performance data. Theoretical hook loads for different friction coefficients are established. Simultaneously, actual wellbore hook loads are obtained from drilling parameter instruments and logging tools to confirm the friction coefficient of the open hole section. Based on the obtained open hole friction coefficient, mechanical calculations and analysis of the casing string and a calculation model for the critical buckling load are performed to confirm whether the casing string buckles or whether the surface hook load is zero when it reaches the bottom. If buckling occurs or the hook load is zero, the casing string structure or running process is optimized, and the previous step is repeated until buckling is confirmed to be non-existent and the surface load is not zero. The specific application steps are as follows:

[0131] By using real-time data transmitted back from the Internet of Things, the drilling process of the drill string is tracked after drilling is completed, and the friction coefficient of the open hole section is formed.

[0132] The well cleaning process and tripping process of a certain well are tracked as follows: Drilling daily data, drilling parameter data, logging data and drilling fluid performance data are input into the tubing friction torque calculation model. The well cleaning operation before the completion tubing is tracked, and the obstruction points during the well cleaning process are recorded to mark the risk sections. The actual open hole friction coefficient is calibrated by the actual hook load data of the open hole section during the well cleaning process.

[0133] like Figure 6 As shown, the blue solid line represents the theoretical hook load for tripping the drill string, the green line represents the theoretical hook load for running the drill string, the blue dots represent the actual hook load for tripping the drill string during well cleaning, and the green dots represent the actual hook load for running the drill string during well cleaning. By comparison, it can be found that there are multiple sections of resistance below 2800m, and the hook load fluctuates greatly. The actual friction coefficient of the open hole section is checked to be around 0.4.

[0134] Considering the well trajectory and well structure data, the force and hook load data of the completion string are calculated according to the friction coefficient, as shown in FIG. 7, it can be seen that the spiral buckling exists during the running of the completion string, and the hook load is negative after the completion string is run in, which indicates that there is not enough load to overcome the friction, and the running of the string has a great risk.

[0135] (2) The completion string running procedure is recommended by using the string mechanics calculation method and optimizing the completion string combination structure, as shown in FIG. 8;

[0136] It is suggested that the well is drilled to a friction coefficient of 0.35 or less, or a float casing is used, and the hook load diagram and force of the float casing are calculated, and the running risk is greatly reduced.

[0137] (3) The running procedure and parameters of the string into the well are corrected in time by using the real-time return data during the running of the completion string.

[0138] Finally, the well is drilled several times and the oil content of the drilling fluid is increased to reduce the friction coefficient to about 0.35, and the actual running hook load data are as shown in FIG. 9, wherein the green points are the actual running hook load, the green line is the theoretical running hook load, and the red line is the theoretical buckling value: Figure 9

[0139] The application also provides an analysis device for safe running of a completion string, the device comprising,

[0140] An acquisition unit is configured to acquire actual hook load data of a bare hole section and well section information based on a well drilling process;

[0141] A first construction unit is configured to construct a string friction torque calculation model of a well drilling assembly;

[0142] A calibration unit is configured to calibrate a friction coefficient of a wellbore bare hole section based on the string friction torque calculation model, the actual hook load data of the bare hole section and the well section information of the well;

[0143] A second construction unit is configured to construct a completion string axial force solving model and a critical load value calculation model of completion string buckling based on the well section information and the friction coefficient of the wellbore bare hole section;

[0144] A confirmation unit is configured to confirm whether the completion string can be safely run in based on the completion string axial force solving model and the critical load value calculation model of completion string buckling. As to the device in the above embodiment, the specific manner in which the units perform operations has been described in detail in the embodiment related to the method, and will not be described in detail here.

[0145] Based on the above disclosure, the application also provides an electronic device. As shown in FIG. 10, Figure 10 ​As shown, the electronic device of the embodiments of the present disclosure includes at least one processor and only one memory electrically connected with the processor, wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method steps as executed by the controller.

[0146] Finally, it should be noted that: the above only for the preferred embodiments of the present application, and not for the purpose of limiting the present application, although the foregoing embodiments of the present application have been described in detail, for those skilled in the art, it still can be modified, or part of the technical features of the equivalent replacement, within the spirit and principles of the present application, any modification, equivalent replacement, improvement, etc., should be included within the scope of the present application.

Claims

1. An analytical method for the safe running of completion tubing, characterized in that, The method includes, Based on the well cleaning process, obtain actual hook load data and well section information for the open hole section; Construct a calculation model for the frictional torque of the tubing string in a wellbore drilling assembly; Based on the tubing friction torque calculation model, the actual hook load data of the open hole section, and the well section information, the friction coefficient of the open hole section of the wellbore is calibrated. Based on well section information and the friction coefficient of the open hole section of the wellbore, a solution model for the axial force of the completion string and a calculation model for the critical load value of the completion string buckling are constructed. Based on the solution model of the axial force of the completion string and the calculation model of the critical load value of the buckling of the completion string, it is confirmed whether the completion string can be safely lowered.

2. The analytical method for safe running of completion tubing according to claim 1, characterized in that, The well section information includes the actual drilling trajectory, well structure, drilling tool assembly, completion string assembly, and drilling fluid information, as well as the location information of the points of obstruction encountered during the well cleaning process, used to determine the location of risk points for tripping in and out of inclined and curved well sections.

3. The analytical method for safe running of completion tubing according to claim 1, characterized in that, The calculation model for tubing friction torque includes a calculation model for tubing friction torque in inclined and straight well sections and a calculation model for tubing friction torque in curved well sections.

4. The analytical method for safe running of completion tubing according to claim 3, characterized in that, The expression for the calculation model of friction torque of the tubing in the inclined and straight well section is as follows: F t1 =BwΔL(cosα±μsinα)+F b In the formula, F t1 F is the axial force acting on the upper end of the tubular string. b α is the axial force on the lower end of the tubing string; B is the well inclination angle; ΔL is the buoyancy coefficient; w is the length of the tubing string; μ is the friction coefficient.

5. The analytical method for the safe running of completion tubing according to claim 3, characterized in that, The expression for the calculation model of friction torque of the tubing in the curved well section is as follows: When the tubing string is under tension in a curved section: When the tubing string is under pressure in a curved section: The formula for calculating Fn is: Among them, F t2 F is the axial force exerted on the upper end of the tubing string when it is under tension in a curved section. t3 F represents the axial force exerted on the upper end of the tubing string when it is under pressure in a curved section. b F is the axial force acting on the lower end of the tubular string. n For the normal force of the tubing; α top α is the inclination angle at the upper end of the inclined and straight section of the tubing; bottom The inclination angle is the lower end of the tubing string in the inclined and straight section of the well. The azimuth angle of the upper end of the inclined and vertical well section tubing; ΔL is the azimuth angle of the lower end of the inclined and vertical well section; K is the dogleg angle; B is the buoyancy coefficient; ΔL is the length of the well string; w is the weight per unit length of the well string; μ is the friction coefficient.

6. The analytical method for safe running of completion tubing according to claim 3, characterized in that, Based on the aforementioned tubing friction torque calculation model, actual hook load data of the open hole section, and well section information, the friction coefficient of the open hole section is calibrated, including: Based on well section information, the friction coefficient in the tubing friction torque calculation model is assigned a value using the finite element method to obtain the corresponding theoretical hook load data. The corresponding theoretical hook load data is fitted and compared with the actual hook load data of the naked eye segment, and the theoretical hook load data that is closest to the actual hook load data is determined as the target theoretical hook load data. The friction coefficient corresponding to the target theoretical hook load data is the friction coefficient of the open hole section of the wellbore.

7. The analytical method for the safe running of completion tubing according to claim 1, characterized in that, The solution model for the axial force of the tubular column is as follows: in, In the formula: F i F represents the axial force at the upper and lower ends of the i-th tubular unit. i-1 N represents the axial force at the upper and lower ends of the (i-1)th tubular unit. g N represents the gravity distribution and normal pressure distribution of the tubing unit in the drilling fluid, respectively; F u The distribution of frictional forces on the tubular unit; α i α i-1 Represents the well inclination angle at the upper and lower ends of the i-th tubing unit; Represents the azimuth angles of the upper and lower ends of the i-th column element; We is the column line weight; ρ m ρ is the density of the drilling fluid. s ΔL is the density of the tubing string; β is the full angle; α is the well inclination angle; δ is the vector angle; θ is the angle between the gravity direction and the normal vector; μ is the friction coefficient.

8. The analytical method for the safe running of completion tubing according to claim 1, characterized in that, The calculation model for the critical load value of the completion string buckling is as follows: Formula for calculating the critical sinusoidal buckling load of the vertical well section: Formula for calculating the critical sinusoidal buckling load of the inclined and vertical well section: Formula for calculating the critical sinusoidal buckling load of a curved well section: Among them, F crv For the buckling boundary load of the vertical well section, F crd For the buckling boundary load of the inclined shaft section, F crs α is the buckling boundary load of the curved section; E is the Young's modulus of the tubing string; I is the moment of inertia of the tubing string; w is the weight per unit length of tubing string; α is the well inclination angle; r is the radial clearance between the tubing string and the wellbore; R is the radius of curvature of the wellbore.

9. The analytical method for safely running completion tubing according to claim 1, characterized in that, Based on the solution models for the friction coefficient of the open hole section, the axial force of the completion string, and the buckling calculation of the completion string, it is confirmed whether the completion string can be safely run in, including: Substitute the friction coefficient of the open hole section of the wellbore into the solution model for the axial force of the completion string to calculate the axial force of the completion string. The critical load value calculation model for buckling of the completion string is used to calculate and obtain the buckling boundary value; By comparing the axial force value of the completion string with the buckling boundary value of the completion string, it can be determined whether the completion string is buckling under stress. When the axial force of the corresponding drill string is greater than the buckling boundary value, the completion string is buckled in that section, and there is a risk that the completion string cannot be safely run in. When the axial force of the corresponding drill string is less than 0, it means that the completion string cannot be safely run in. When the axial force of the corresponding drill string is less than the buckling boundary value, the completion string does not buckle in that section and can be safely lowered into the well.

10. The analytical method for safely running the completion string according to claim 9, characterized in that, If the completion string buckles in that section under stress, making it unsafe to run the completion string, or if running the completion string poses a risk, then... The risks associated with running the completion string can be reduced by optimizing the completion string stabilizer, adding drag reducers, and using floating or rotating completion string runs.

11. An analytical device for the safe running of a well completion string, characterized in that, The device includes, The acquisition unit is used to acquire actual hook load data and well section information of the open hole section based on the well cleaning process; The first building unit is used to build a calculation model for the friction torque of the tubing in the well drilling tool assembly; The calibration unit is used to calibrate the friction coefficient of the open hole section based on the tubing friction torque calculation model, the actual hook load data of the open hole section, and the well section information. The second construction unit is used to construct a solution model for the axial force of the completion string and a calculation model for the critical load value of the completion string buckling based on the well section information and the friction coefficient of the open hole section of the wellbore. The confirmation unit is used to confirm whether the completion string can be safely lowered into the well based on the solution model of the axial force of the completion string and the calculation model of the critical load value of the buckling of the completion string.

12. An electronic device comprising at least one processor and at least one memory, the memory being data-connected to the processor, wherein, The memory stores instructions executable by the at least one processor, which, when executed by the at least one processor, enables the at least one processor to perform the method of any one of claims 1-10.

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