Method for predicting displacement of cable pumping logging in drill rod

Abstract

The invention provides a method for predicting the displacement of cable pumping logging in a drill rod. The method for predicting the displacement of the cable pumping logging in the drill rod comprises the following steps: establishing a model for predicting the displacement of the cable pumping logging in the drill rod, and establishing stress analysis of each unit through an infinitesimal method; and predicting the predicted pumping displacement of the logging tool string during pumping according to the calculated stress. The problem that in the prior art, the pumping displacement is difficult to predict in the pumping process of the logging tool string is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of well logging, and more particularly, to a method for predicting the pumping displacement of a cable in a drill pipe for well logging. Background Art

[0002] With the vigorous development of the exploration and development of unconventional oil and gas reservoirs, horizontal well drill pipe pumping well logging has become an emerging technology applied in the well logging of oil and gas wells in low-permeability reservoirs in recent years. In this technology, a well logging tool is pumped to the end of the drill pipe through a cable inside the drill pipe for hanging, and then the drill string is lifted to drive the well logging tool to move to complete the well logging operation. During the pumping operation, the control of the pumping displacement and the cable tension are two key points for safe operation. If the displacement is too small, there will be risks of cable entanglement and tool string sticking; if the displacement is too large, there will be risks of cable breakage and tool string pump-off. Therefore, before the construction operation, the cable tension should be checked and a reasonable pumping displacement should be selected.

[0003] In the prior art, the cable tension during the static start pumping process of the clustered perforating string in the horizontal well section was analyzed, and 4 stages such as "static", "start acceleration", "stable operation", and "deceleration" were divided. A calculation model for pumping thrust, acceleration, and acceleration time was established by combining mechanical analysis. However, the influence of factors such as horizontal section wellbore parameters, wellbore differences (friction coefficient changes), and cable head tension changes was not considered. At the same time, in the prior art, the conventional pump-out well logging process was also improved, and well logging tools such as a special guide shoe, a cable bypass sub, a fuse type master bushing, and a catcher were developed. And a new well logging process method was also proposed in the prior art, and a horizontal well logging technology with a bridge wet joint was formed, and good results were obtained through actual application. The prior art also:

[0004] A new model for analyzing the wellbore passing ability of the cable-pumped clustered perforating string was established to evaluate the downhole passing ability of the clustered perforating string;

[0005] A calculation model for cable tension during the pumping process of a horizontal well perforating and bridge plug combined string was proposed, but the influence of pressure and temperature on the viscous force was not considered in this model;

[0006] A control method for pumping parameters of a horizontal well perforating and bridge plug combined string was established. This method closely combines the pumping displacement with the speed of the string lowering, reducing the risk of string lowering, but the pressure loss was not considered in the model;

[0007] A new type of pumping joint was designed to solve the problem that the instrument string cannot freely reach the bottom of the well by its own gravity in a highly deviated well or a horizontal well, but the influence of drill pipe joint diameter change was not considered.

[0008] Early scholars mainly focused on well logging process methods and construction technologies, and less on the research of operation parameters and cable tension of horizontal well drill pipe pumping well logging technology.

[0009] In the prior art, during the actual logging process of a logging team, there is a problem that the pumping displacement is insufficient, resulting in the tool string getting stuck. The on-site treatment method is usually to lift the stuck logging tool string by a certain distance first, and then moderately increase the pumping displacement to push the tool string to continue descending. However, on-site, it often relies on increasing the pumping displacement. While conservatively increasing the displacement, the actual displacement is often even larger. Such a treatment result can solve part of the problem of the tool string getting stuck during lowering, but it consumes too much time. Often, the workload of lowering the tool string in one day may increase to two or three days because the size of the displacement is unknown. This greatly reduces the efficiency during on-site construction operations.

[0010] Therefore, in the prior art, there is a problem that the pumping displacement during the pumping of the logging tool string is difficult to predict. Summary of the Invention

[0011] The main purpose of the present invention is to provide a method for predicting the pumping displacement of a cable in a drill pipe during logging, so as to solve the problem that the pumping displacement during the pumping of the logging tool string in the prior art is difficult to predict.

[0012] To achieve the above object, according to one aspect of the present invention, there is provided a method for predicting the pumping displacement of a cable in a drill pipe during logging, including: establishing a prediction model for the pumping displacement of a cable in a drill pipe during logging, and establishing a force analysis of each unit by the microelement method:

[0013]

[0014] Among them, G is the gravity, in N; F u is the buoyancy, in N; F sn is the wellbore contact force, in N; F sf is the wellbore friction force, in N; F su is the fluid viscous force, in N; F sp is the axial fluid pressure, in N; F sh is the cable head tension, in N; predicting the predicted pumping displacement of the logging tool string during pumping according to the calculated forces.

[0015] Further, during the calculation of the gravity G, the logging tool string is calculated as a whole, and the gravity G of the logging tool string is calculated as a concentrated force, and the calculation formula is:

[0016]

[0017] Among them, M is the total mass of the logging tool string, in kg; g is the gravitational acceleration, taking 9.8 m / s 2 ; m represents the number of tools; R j is the radius of the j-th tool, in m; LLj is the length of the j-th tool, in m; ρ is the density of the j-th tool, in kg / m 3 .

[0018] Furthermore, in the process of calculating the buoyancy force F u , the buoyancy force F is calculated by the gravity of the displaced well fluid u , and the calculation formula is:

[0019]

[0020] where ρ is the density of the pumped fluid, in kg / m 3 ; V is the total volume of the logging tool string, in m 3 ; LL j is the length of the j-th tool, in m.

[0021] Furthermore, in the process of calculating the wellbore contact force F sn , the calculation formula of F sn is:

[0022] F sn =(G - F u )sinα i (4)

[0023] where α i is the well deviation angle corresponding to the i-th unit.

[0024] Furthermore, in the process of calculating the wellbore friction force F sf , the calculation formula of F sf is:

[0025] F sf =μ f ·F sn (5)

[0026] where μ f is the friction coefficient between the logging tool string and the inner wall of the wellbore.

[0027] Furthermore, in the process of calculating the fluid viscous force F su , the calculation formula of F su is:

[0028]

[0029] where R0 is the radius of the drill pipe, in m; v g is the lowering speed of the tool string, in m / s; Q b is the pumping displacement at the wellhead, m 3 / min; μ u is the viscosity of the pumped fluid, in mPa·s; R jis the radius of the j-th tool, in m; LL j is the length of the j-th tool, in m; R m is the radius of the m-th tool, in m.

[0030] Furthermore, in the process of calculating the axial fluid pressure F sp , first calculate the bottom-hole pressure and calculate the flow rate between the gaps of each tool and the drill pipe, and then calculate the total axial fluid pressure on the tool string according to the pressure losses of the pumped fluid in the curved section, straight section pipeline and variable-diameter pipeline.

[0031] Furthermore, the pressure loss includes form drag pressure drop and frictional pressure drop.

[0032] Furthermore, in the process of calculating the cable head tension F sh , according to the wellbore trajectory, divide the cable from the wellhead to the well depth position where the perforating gun is located into k units, and through the iteration of the differential element method, the pulling force of the cable head connected to the tool string can be obtained.

[0033] Furthermore, the mechanical analysis formula for any one unit is:

[0034] F i = F i-1 + q d gl i (μsinα i - cosα i ) (22)

[0035] where q d is the cable linear density, in kg / m; l i is the length of the i-th unit cable, in m; F i-1 is the pulling force at the upper end of the i-th unit cable, in N; F i is the pulling force at the lower end of the i-th unit cable, in N;

[0036] The pulling force F0 at the upper end of the cable of the first unit at the wellhead is composed of the wellhead cable friction force F jf and the wellhead cable tension F jk . The pulling force of the cable head is the pulling force at the lower end of the k-th unit cable. The calculation formula for the cable head tension F sh is:

[0037]

[0038] Applying the technical solution of the present invention, the cable pumping logging displacement prediction method in this application can predict the actual pumping flow rate of the logging tool string before logging by inputting wellbore trajectory, speed, tool string structure parameters, pumped fluid parameters, etc. for the risks of cable entanglement and tool string weakness being pumped off that may be encountered during the lowering process of the cable pumping logging tool string. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings, which form a part of this application, are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0040] Figure 1 A flowchart of a method for predicting the displacement of wireline pumping logging in drill pipes according to a specific embodiment of the present invention is shown;

[0041] Figure 2 A schematic diagram of the wellbore trajectory of Well M1 in a specific embodiment of this application is shown;

[0042] Figure 3 A schematic diagram of the wellbore trajectory of Well M2 in a specific embodiment of this application is shown;

[0043] Figure 4 A schematic diagram of the wellbore trajectory of Well M3 in a specific embodiment of this application is shown;

[0044] Figure 5 Shows Figure 2 A comparison chart of the calculated pumping displacement and the actual pumping displacement of Well M1 in the shown embodiment;

[0045] Figure 6 Shows Figure 3 A comparison chart of the calculated pumping displacement and the actual pumping displacement of Well M2 in the shown embodiment;

[0046] Figure 7 Shows Figure 4 A comparison chart of the calculated pumping displacement and the actual pumping displacement of Well M3 in the shown embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0047] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0048] It should be pointed out that unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs.

[0049] In the present invention, unless otherwise stated, the orientation terms such as "upper, lower, top, bottom" are usually in relation to the direction shown in the drawings or in relation to the component itself in the vertical, perpendicular or gravitational direction; similarly, for ease of understanding and description, "inner, outer" refer to the inner and outer of the contour of each component itself, but the above orientation terms do not limit the present invention.

[0050] To solve the problem that the pumping displacement is difficult to predict during the pumping process of the logging tool string in the prior art, the present application provides a method for predicting the pumping displacement of a cable in a drill pipe for logging.

[0051] As Figure 1 shown, the method for predicting the pumping displacement of a cable in a drill pipe for logging in the present application includes: establishing a prediction model for the pumping displacement of a cable in a drill pipe for logging, and establishing a force analysis of each unit by the infinitesimal method:

[0052]

[0053] Among them, G is the gravity, with the unit of N; F u is the buoyancy force, with the unit of N; F sn is the wellbore contact force, with the unit of N; F sf is the wellbore friction force, with the unit of N; F su is the fluid viscous force, with the unit of N; F sp is the axial fluid pressure, with the unit of N; F sh is the cable head tension, with the unit of N; predict the predicted pumping displacement of the logging tool string during pumping according to the calculated forces.

[0054] The method for predicting the pumping displacement of a cable in a drill pipe for logging in the present application can address risks such as cable entanglement and the tool string being pumped off at weak points that may occur during the lowering process of the cable pumping logging tool string. Before logging, predict the actual pumping flow rate of the logging tool string by inputting wellbore trajectory, speed, tool string structure parameters, pumping fluid parameters, etc.

[0055] Specifically, during the calculation of the gravity G, the logging tool string is calculated as a whole, and the gravity G of the logging tool string is calculated as a concentrated force, and the calculation formula is:

[0056]

[0057] Among them, M is the total mass of the logging tool string, with the unit of kg; g is the acceleration due to gravity, taking 9.8 m / s 2 ; m represents the number of tools; R j is the radius of the jth tool, with the unit of m; LL j is the length of the jth tool, with the unit of m; ρ is the density of the jth tool, with the unit of kg / m 3 .

[0058] Specifically, during the calculation of the buoyancy force F u , the buoyancy force F u is calculated by the gravity of the displaced well fluid, and the calculation formula is:

[0059]

[0060] where ρ is the density of the pumped fluid, in kg / m 3 ; V is the total volume of the logging tool string, in m 3 ; LL j is the length of the j-th tool, in m.

[0061] Specifically, in the process of calculating the wellbore contact force F sn , the calculation formula for F sn is:

[0062] F sn = (G - F u ) sinα i (4)

[0063] where α i is the well inclination angle corresponding to the i-th unit.

[0064] Specifically, in the process of calculating the wellbore friction force F sf , the calculation formula for F sf is:

[0065] F sf = μ f · F sn (5)

[0066] where μ f is the friction coefficient between the logging tool string and the inner wall of the wellbore.

[0067] Specifically, in the process of calculating the fluid viscous force F su , the calculation formula for F su is:

[0068]

[0069] where R0 is the radius of the drill pipe, in m; v g is the running-in speed of the tool string, in m / s; Q b is the pumping displacement at the wellhead, m 3 / min; μ u is the viscosity of the pumped fluid, in mPa·s; R j is the radius of the j-th tool, in m; LL j is the length of the j-th tool, in m; R m is the radius of the m-th tool, in m.

[0070] Specifically, in the process of calculating the axial fluid pressure F sp , first calculate the bottom-hole pressure and calculate the flow rate between the gaps of each tool and the drill pipe, and then calculate the total axial fluid pressure received by the tool string according to the pressure losses of the pumped fluid in the bent section, straight section pipeline and variable-diameter pipeline.

[0071] Specifically, the pressure loss includes form drag pressure drop and frictional pressure drop along the length of the pipe.

[0072] Specifically, in the process of calculating the tension F of the cable head sh along the wellbore trajectory, the cable from the wellhead to the depth where the perforating gun is located is divided into k units, and through the iteration of the infinitesimal method, the tension of the cable head connected to the tool string can be obtained.

[0073] Specifically, the mechanical analysis formula for any one unit is:

[0074] F i = F i-1 + q d gl i (μsinα i - cosα i ) (22)

[0075] where q d is the cable linear density, with the unit of kg / m; l i is the cable length of the i-th unit, with the unit of m; F i-1 is the tension at the upper end of the cable of the i-th unit, with the unit of N; F i is the tension at the lower end of the cable of the i-th unit, with the unit of N;

[0076] The tension F0 at the upper end of the cable of the first unit at the wellhead is composed of the frictional force F of the cable at the wellhead jf and the cable tension F jk at the wellhead. The tension of the cable head is the tension at the lower end of the cable of the k-th unit. The calculation formula for the cable head tension F sh is:

[0077]

[0078] And the process in this application mainly includes: 1) Regarding the pumping process of the logging tool string as a uniform motion at an instant; 2) Continuously approximating the discrete wellbore trajectory; 3) Considering the influence of the deformation of the tool string passing through a large build-up section or a large dogleg severity on the pumping displacement; 4) Considering the influence of the geothermal temperature gradient on the viscosity of the pumped fluid; 5) Compiling and simulating the obtained data using Fortran code, and calculating the predicted pumping displacement by iterating from the wellhead to the bottom of the well.

[0079] In a specific embodiment of this application, based on the structural analysis and logging process analysis of the cable pumping logging tool in the downhole drill pipe, the following assumptions are made: It is assumed that the deformation of the logging tool string is elastic deformation; it is assumed that the material of the logging tool string is uniform and isotropic; it is assumed that tools with the same outer diameter are regarded as a section of beam; the entire logging tool string is regarded as a simply supported beam with variable cross-section under the action of axial force and transverse distributed load;

[0080] Establish a prediction model for the pumping logging displacement of the cable inside the drill pipe:

[0081] (1) Establish the force analysis of each unit through the infinitesimal element method:

[0082]

[0083] The detailed calculation of each force in the above formula is as follows:

[0084] (2) Gravity G. The logging tool string is regarded as a whole, and its gravity is calculated as a concentrated force.

[0085]

[0086] Where M is the total mass of the logging tool string, kg; g is the acceleration due to gravity, taking 9.8 m / s 2 ; m represents the number of tools; R j is the radius of the jth tool, m; LL j is the length of the jth tool, m; ρ j is the density of the jth tool; kg / m 3 .

[0087] (3) Buoyancy F u . The calculation method of buoyancy is calculated according to the gravity of the displaced well fluid.

[0088]

[0089] Where ρ is the density of the pumping fluid, kg / m3; V is the total volume of the logging tool string, m 3 .

[0090] (4) Wellbore contact force F sn .

[0091] F sn =(G - F u )sinα i (4)

[0092] Where α i is the well deviation angle corresponding to the ith unit, in degrees.

[0093] (5) Wellbore friction force F sf .

[0094] F sf =μ f ·F sn (5)

[0095] Where μ f is the friction coefficient between the logging tool string and the inner wall of the wellbore.

[0096] When the logging tool string passes through the build section, the well inclination angle changes greatly at this time. The logging tool string will undergo certain deformation under the constraint of the inner wall of the wellbore. The normal pressure at points A and B will increase, and the frictional force on the logging tool string will increase. Therefore, the frictional force here should be calculated specifically. The specific structure of the logging tool string consists of multiple tools with different lengths and different outer diameters. The part of the logging tool string with the same outer diameter is regarded as a section of beam, and the entire logging tool string is connected by several beams with different outer diameters.

[0097] Determination of the deformation of the tool string:

[0098]

[0099] Among them, R is the wellbore curvature radius, m; d b is the drill pipe diameter, m; d z is the outer diameter at the midpoint of the logging tool string, m; d q is the outer diameter at the end of the tool string, m; L m is the total length of the tool string, m; y c is the deflection deformation amount generated due to the drill pipe constraint in the middle of the tool string, mm.

[0100] During the process of pumping the logging tool string into the well, the tool string is affected by its own gravity, cable tension, and friction. The logging tool string is equivalent to a simply supported beam with variable cross-section under axial tension and distributed load. According to the static equilibrium relationship, it can be obtained:

[0101]

[0102] Among them, F ay 、F by are the reaction forces at the left and right ends of the beam respectively, N; L i is the total length of the first i sections of the beam, L0 = 0, m; q i is the distributed load of the i-th section of the beam, N;

[0103] The bending moment at any point of the beam is expressed as:

[0104]

[0105] In the formula: Pi (i = 1, m) is the axial tension of the i-th section, Pi < 0, that is:

[0106]

[0107] Differential equation of the deflection curve of the beam deformation:

[0108] EI i y i ″ = -M i (x) (L i-1 ≤x≤L i ) (9)

[0109] The general solution of the differential equation is as follows:

[0110]

[0111] Where:

[0112]

[0113] To solve Equation (10), the corresponding boundary conditions and continuity conditions must also be given.

[0114] Boundary conditions:

[0115]

[0116] Continuity condition, i.e., the deflection at the variable cross-section is equal:

[0117]

[0118] Field tests show that the maximum deflection of the tool string during the running-in process occurs near the midpoint of the tool string. Therefore, for the convenience of calculation, it is assumed that the maximum deflection value occurs at the midpoint of the tool string.

[0119] If the load F p acts at the midpoint of the span of the simply supported beam, the maximum deflection of the beam also occurs at the midpoint of the beam span. Bringing back the deflection of the tool string when passing through the build section, the F p acting on the pipe string is:

[0120]

[0121] where w is the actual deflection value of the tool string when passing through the build section, in mm; EI is the flexural rigidity of the tool string.

[0122] The normal pressure considering deformation when the tool string passes through the build section can be obtained through Equation (14), and then the frictional force at this stage can be obtained through Equation (5).

[0123] (6) Fluid viscous force F su . During the pumping process of the tool string, there is an annular gap between the drill pipe and the tool string. The relative movement between the fluid in the gap and the tool string causes the tool string to be subjected to a fluid viscous force, which is determined by the following formula:

[0124]

[0125] where R0 is the radius of the drill pipe, in m; v g is the running-in speed of the tool string, in m / s; Q b is the wellhead pumping displacement, in m 3 / min; μ u is the viscosity of the pumped fluid, in mPa·s.

[0126] (7) Axial fluid pressure F sp . The tool string is pushed under the action of differential pressure. To calculate the forces on both ends of the pipe string when it is pushed, the bottom hole pressure must be calculated first. The fluid flow state in the drill pipe is laminar flow. According to the literature, the pressure at any position at the bottom of the well can be obtained:

[0127]

[0128] where p jk is the wellhead pressure, Pa; p 1i is the fluid pressure at the front end of the tool string when the tool string is lowered to the i-th well section, Pa; l i is the well depth at the front end position of the tool string when it is lowered to the i-th well section, m; H i is the vertical depth at the front end position of the tool string when it is lowered to the i-th well section, m; ρ m gH i represents the hydrostatic pressure term.

[0129] Assume that at each stepped cross-section of the tool string, the fluid velocity is consistent with the relative fluid velocity between the inner wall of the wellbore and the bridge plug gap. Then the flow rate between the gaps of each tool and the drill pipe can be calculated:

[0130]

[0131] There are pressure losses of the pumped fluid in the curved section, straight section pipe and variable diameter pipe, including the form resistance pressure drop and the frictional pressure drop as follows:

[0132]

[0133]

[0134] where, in the formula, D j is the cross-sectional area of the j-th tool, m2; h j is the height of the gap between the j-th tool and the wellbore, m; ε j is the relative eccentricity between the j-th tool and the wellbore; v F is the average fluid velocity between the pipe string and the wellbore gap, m / s; ΔP Y is the frictional pressure drop, Pa; v is the fluid velocity, m / s; L is the wellbore length, m; D is the inner diameter of the wellbore, m; f is the friction coefficient, R c is the radius of curvature of the pipe fitting, m; G i is the dogleg severity per 30 m, R ew is the Reynolds number of the water-based pumped fluid.

[0135] Substituting Equation (17) into Equation (18) and / or (19) can calculate the pressure drop at each cross-section change of the tool string. When the front-end pressure of the tool string pumped to any horizontal section unit is calculated through Equation (16), the pressure at any tool cross-section can be calculated based on the pressure drop, thereby considering the pressure loss when calculating the axial fluid pressure.

[0136] p j+1i = p ji -Δp j -Δp Y (1 ≤ j ≤ m) (20)

[0137] From this, the total axial fluid pressure on the tool string can be calculated:

[0138]

[0139] where A d is the cross-sectional area of the cable, A j is the cross-sectional area of the j-th cross-section, m 2 ;

[0140] (8) The tension F of the cable head sh . According to the wellbore trajectory, the cable from the wellhead to the well depth position where the perforating gun is located is divided into k units, and the well inclination angle is approximately constant within each analysis unit. Arbitrarily select a unit k for mechanical analysis, as Figure 5 shown.

[0141] Through mechanical analysis, it can be obtained that:

[0142] F i = F i-1 + q d gl i (μsinα i - cosα i ) (22)

[0143] where q d is the linear density of the cable, kg / m; l i is the length of the i-th unit of the cable, m; F i-1 is the tension at the upper end of the i-th unit of the cable, N; F i is the tension at the lower end of the i-th unit of the cable, N.

[0144] Among them, the tension F0 at the upper end of the cable of the first unit at the wellhead is composed of the frictional force F jf of the wellhead cable and the tension F jk of the wellhead cable. The tension of the cable head is the tension at the lower end of the k-th unit of the cable.

[0145] F0 = F jk + F jf (23)

[0146] F x = F sh (24)

[0147] Using the differential element method for iteration, the tension of the cable head connected to the tool string can be obtained:

[0148]

[0149] Analyze the force on the logging tool string during pumping in the drill pipe according to the formula calculated in the above steps. According to the calculated force, the predicted pumping displacement of the logging tool string during pumping can be predicted.

[0150]

[0151] Moreover, in this application, the upper end of the logging tool string is connected to the logging cable, and the lower end is connected to the logging tool. The logging tool contains tools such as a logging module, a flexible joint, a centralizer, and a suspension nipple.

[0152] In a specific embodiment of this application, calculate based on the on-site parameters of the example well, and compare the measured displacement on site with the theoretically calculated displacement to verify the correctness of the pumping displacement control equation established in this article. Among them, the well depth of Well M1 is 3945 m, and the vertical depth is 2340 m; the maximum well deviation angle is 91.8°, located at 3225 m at the bottom of the well; the maximum dogleg severity is 5.01° / 25 m, located at 2600 m of well depth. The well depth of Well M2 is 3968 m, and the vertical depth is 2190 m; the maximum well deviation angle is 90.1°, located at 2912.05 m; the maximum dogleg severity is 4.98° / 25 m, located at 2259 m of well depth. The wellbore trajectories of Wells M1 and M2 are as Figure 2 , Figure 3 shown. The tool string parameters are shown in Table 1, and other construction parameters are shown in Table 2.

[0153] Moreover, as Figures 4 to 6 shown, Figure 4 is a schematic diagram of the wellbore trajectory of Well M3; Figure 5 is a comparison chart of the calculated pumping displacement and the actual pumping displacement of Well M1; Figure 6 is a comparison chart of the calculated pumping displacement and the actual pumping displacement of Well M2; it can be seen that the calculated pumping displacement and the actual pumping displacement are consistent both in terms of quantity value and trend, further verifying the effectiveness of the present invention.

[0154] Figure 7It is a comparison chart of the calculated pumping displacement and the actual pumping displacement for Well M3. The on-site measured results and the software displacement prediction results are compared as shown in the above figure. It can be seen from the figure that when the tool string is lowered to 2300 m, the pump is started at the wellhead, and the pump is stopped at 4128 m. The changing trend of the displacement measured on-site is basically consistent with the software prediction results. When reaching 2830 m, the software gives a recommended pumping displacement of 38 L / S, while the on-site pumping displacement is 33 L / S. The on-site pumping displacement is less than the displacement given by the software, and the tool encounters resistance when being lowered and cannot pass through. Later, the on-site team lifted the tool string and slowly increased the displacement to pass through the 2830 m well depth. When the tool string enters the horizontal section, the pumping displacement predicted by the software basically remains unchanged, which is basically consistent with the on-site measured results. The comparative analysis shows the effectiveness of the pumping displacement prediction model and the software.

[0155] In summary, from this example, it can be seen that the technology of the present invention can better predict the pumping displacement during the pumping process of the logging tool string.

[0156] Table 1 Related parameters of the tool string

[0157]

[0158] Table 2 Related parameters of logging

[0159]

[0160] Obviously, the above-described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0161] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless otherwise clearly specified in the context, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0162] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above drawings are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0163] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for predicting the pumping logging displacement of a cable inside a drill pipe, characterized in that Including: Establish a prediction model for the pumping displacement of the cable in the drill pipe during logging, and establish the force analysis of each unit through the infinitesimal element method: Among them, G is the gravity, with the unit of N; F u is the buoyancy force, with the unit of N; F sn is the wellbore contact force, with the unit of N; F sf is the wellbore frictional resistance, with the unit of N; F su is the fluid viscous force, with the unit of N; F sp is the axial fluid pressure, with the unit of N; F sh is the cable head tension, with the unit of N; Predict the predicted pumping displacement of the logging tool string during pumping according to the calculated force.

2. The method for predicting the displacement of wireline pumping logging in drill pipe according to claim 1, wherein, In the process of calculating the gravity G, the logging tool string is calculated as a whole, and the gravity G of the logging tool string is calculated as a concentrated force. The calculation formula is: Where M is the total mass of the logging tool string, in kg; g is the acceleration due to gravity, taken as 9.8 m / s 2 ; m represents the number of tools; R j is the radius of the j-th tool, in m; LL j is the length of the j-th tool, in m; ρ is the density of the j-th tool, in kg / m 3 .

3. The method for predicting the displacement of the cable pumping logging in the drill pipe according to claim 1, wherein When calculating the buoyancy force F u the buoyancy force F is calculated by the gravity of the displaced well fluid u and the calculation formula is: where ρ is the density of the pumped fluid, in kg / m 3 ; V is the total volume of the logging tool string, in m 3 ; LL j is the length of the j-th tool, in m.

4. The method for predicting the displacement of the cable pumping logging in the drill pipe according to claim 1, wherein, During the calculation of the wellbore contact force F sn the calculation formula of F sn is as follows: F sn =(G - F u )sinα i (4) where α i is the well deviation angle corresponding to the i-th unit.

5. The method for predicting the pumping logging displacement of the cable inside the drill pipe according to claim 1, wherein In the process of calculating the shaft wall frictional resistance F sf , F sf is calculated by the following formula: F sf = μ f · F sn (5) where μ f is the friction coefficient between the logging tool string and the inner wall of the wellbore.

6. The method for predicting the logging displacement of the cable pumped in the drill pipe according to claim 1, wherein, During the calculation of the viscous force F of the fluid su , F su is calculated according to the following formula: where R0 is the radius of the drill pipe, unit: m; v g is the running-in speed of the tool string, unit: m / s; Q b is the pumping displacement at the wellhead, m 3 / min; μ u is the viscosity of the pumped fluid, unit: mPa·s; R j is the radius of the j-th tool, unit: m; LL j is the length of the j-th tool, unit: m; R m is the radius of the m-th tool, unit: m.

7. The method for predicting the logging displacement of the cable pumped in the drill pipe according to claim 1, characterized in that, During the calculation of the axial fluid pressure F sp in the process, first calculate the bottom hole pressure and the flow rate between the gaps of each tool and the drill pipe, and then calculate the total axial fluid pressure received by the tool string according to the pressure losses of the pumped fluid in the bent section, straight section pipe and reduced diameter pipe.

8. The method for predicting the displacement of the cable pumping logging in the drill pipe according to claim 7, characterized in that, The pressure loss includes form drag pressure drop and frictional pressure drop.

9. The method for predicting the logging displacement of the cable pumped in the drill pipe according to any one of claims 1 to 8, characterized in that During the calculation of the tension F of the cable head sh in the process, according to the wellbore trajectory, the cable from the wellhead to the well depth position where the perforating gun is located is divided into k units, and through the iteration of the infinitesimal element method, the tension of the cable head connected to the tool string can be obtained.

10. The method for predicting the logging displacement of the cable pumped in the drill pipe according to claim 9, wherein The mechanical analysis formula for any unit is: F i = F i-1 + q d gl i (μ sin α i - cos α i ) (22) The upper end tension F0 of the cable of the first unit at the wellhead consists of the wellhead cable friction force F jf and the wellhead cable tension F jk The cable head tension is the lower end tension of the cable of the k-th unit. The calculation formula for the cable head tension F sh is as follows: where q d is the cable line density, in kg / m; l i is the cable length of the i-th unit, in m; F i-1 is the tensile force at the upper end of the cable of the i-th unit, unit: N; F i is the tensile force at the lower end of the cable of the i-th unit, unit: N.

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