A method for establishing a horizontal well drilling parameter optimization chart

Abstract

The present invention discloses a method for establishing a horizontal well drilling parameter optimization chart, including: using a friction torque calculation model and a screw drill output model to correct drilling data; establishing a functional relationship between drill bit drilling pressure, drill bit speed and mechanical drilling speed according to a random forest algorithm; establishing a functional relationship between drill bit drilling pressure, drill bit speed and stick-slip vibration index based on a stick-slip vibration analysis model; establishing a functional relationship between drill bit drilling pressure, drill bit drilling speed and maximum drilling speed based on a wellbore cleaning prediction model; and establishing a drilling parameter optimization chart by combining the mechanical drilling speed, stick-slip vibration index, maximum mechanical drilling speed and the drill bit drilling pressure and drill bit drilling speed. The present invention establishes a drilling parameter optimization chart of drill bit drilling pressure, drill bit speed and mechanical drilling speed, stick-slip vibration index, and maximum mechanical drilling speed. The range of drilling parameters determined by the optimization chart and the mechanical drilling speed that can be obtained by the corresponding drilling parameters have a certain theoretical guiding role in improving the drilling efficiency of horizontal wells.

Description

Technical Field

[0001] The invention relates to a method for establishing a horizontal well drilling parameter optimization chart, belonging to the technical field of oil and gas drilling. Background Art

[0002] In horizontal wells, the friction between the horizontal drill string and the well wall not only reduces the transmission efficiency of drilling pressure torque, but also makes the stick-slip vibration of the drill string more intense, leading to premature failure of the lower drilling tools, seriously affecting drilling efficiency and development costs. However, during on-site drilling operations, the driller controls the drilling parameters mainly according to the drilling design or relying on work experience, without considering the friction of the well wall on the drill string, the PDC drill bit with screw, the stick-slip vibration of the drill string and the formation properties on the drilling efficiency. There are limitations in the optimization of drilling parameters and lack of theoretical basis.

[0003] Therefore, there is an urgent need for a horizontal well drilling parameter optimization chart to provide a theoretical basis for the driller to adjust the drilling parameters, prevent the stick-slip vibration of the drill string, and improve the drilling efficiency. Summary of the invention

[0004] In order to overcome the problems in the prior art, the present invention provides a method for establishing a horizontal well drilling parameter optimization chart.

[0005] The technical solution provided by the present invention to solve the above technical problems is: a method for establishing a horizontal well drilling parameter optimization chart, comprising the following steps:

[0006] Step S1, correcting drilling data using a friction torque calculation model and a screw drill output model;

[0007] Step S2, establishing a functional relationship between drill bit pressure, drill bit speed and mechanical drilling speed according to the random forest algorithm;

[0008] Step S3, establishing a functional relationship between the drill bit drilling pressure, the drill bit speed and the stick-slip vibration index based on the stick-slip vibration analysis model;

[0009] Step S4, establishing a functional relationship between the drill bit pressure on bit, the drill bit speed on bit and the maximum speed on bit based on the wellbore cleaning prediction model;

[0010] Step S5, establishing a drilling parameter optimization chart by combining the functional relationship between the mechanical penetration rate, stick-slip vibration index, maximum mechanical penetration rate, the drill bit drilling pressure, and the drill bit penetration rate.

[0011] A further technical solution is that the drilling data in step S1 includes drill bit pressure on bit and drill bit speed on bit.

[0012] A further technical solution is that the calculation formula in step S1 includes:

[0013] Drill bit drilling pressure calculation formula:

[0014]

[0015]

[0016] Where: μ i is the friction coefficient between the i-th unit and the well wall, dimensionless; α i , β i are the well inclination angle and dogleg angle at both ends of the unit, rad; L i is the length of the i-th unit cell, m; Δα i is the increment of the well inclination angle at both ends of the i-th unit body, rad; q m is the buoyant weight of the i-th unit in the drilling fluid N / m; N i is the radial support force of the i-th unit, N;

[0017] Drill bit speed calculation formula:

[0018]

[0019] Where: RPM is the drill bit speed, r / min; RPM0 is the wellhead speed, r / min; Q is the inlet flow rate, L / s; q is the flow rate per revolution of the screw drill, L / r.

[0020] A further technical solution is that the specific process of step S2 is:

[0021] Step S21, dividing the training data of different strata according to geological age;

[0022] Step S22, selecting the drill bit pressure and the drill bit speed as input characteristic variables, selecting the mechanical drilling speed as the output variable, and using the random forest algorithm to learn the training data of different strata to establish a mechanical drilling speed prediction model for different strata;

[0023] Step S23: determining the functional relationship between the mechanical drilling speed, the drill bit pressure on bit, and the drill bit rotation speed according to the mechanical drilling speed prediction model for different formations.

[0024] A further technical solution is that the specific process of step S3 is:

[0025] Step S31, based on the drill string stick-slip vibration model, solving the stick-slip vibration equation under different drill bit pressures and drill bit speeds, and determining the maximum speed and the minimum speed of the drill bit slipping stage under different drill bit pressures and drill bit speeds;

[0026] Step S32, calculating the stick-slip vibration index according to the maximum rotation speed during the drill bit slippage stage and the minimum rotation speed during the drill bit slippage stage, and determining the drilling parameter control range in which stick-slip vibration does not occur;

[0027] Step S33: establishing a functional relationship between the drill bit pressure on the drill bit, the drill bit speed and the stick-slip vibration index according to the drill bit pressure on the drill bit, the drill bit speed and the stick-slip vibration index.

[0028] A further technical solution is that the drill string stick-slip vibration model is:

[0029] [M][a]+[C][v]+[K][x]=[F]

[0030] Where: [M] is the mass matrix of the drill string of the entire well section; [K] is the axial stiffness matrix of the drill string of the entire well section; [C] is the axial damping matrix of the drill string of the entire well section; [x] is the displacement matrix of each node of the drill string of the entire well section; [v] is the velocity matrix of each node of the drill string of the entire well section; [a] is the acceleration matrix of each node of the drill string of the entire well section; [F] is the resultant external force matrix of each node of the drill string of the entire well section.

[0031] A further technical solution is that the stick-slip vibration index calculation formula is:

[0032]

[0033] Where: RPM max The maximum speed during the drill slippage stage; RPM min It is the minimum speed during the bit slippage stage; RPM0 is the wellhead speed.

[0034] A further technical solution is that the specific process of step S4 is: firstly, the annular return velocity and the cuttings settling velocity are calculated, then the maximum allowable mechanical drilling speed is calculated according to the criterion that the cuttings concentration is less than 5%, and finally, the functional relationship between the drill bit drilling pressure, the drill bit speed and the maximum mechanical drilling speed is determined according to the maximum mechanical drilling speed.

[0035] A further technical solution is that the calculation formula in step S4 includes:

[0036] Annular return speed calculation formula:

[0037]

[0038] The calculation formula of cuttings settling velocity is:

[0039]

[0040] The maximum mechanical drilling speed calculation formula is:

[0041]

[0042] Where: v s is the rock cuttings settling velocity, m / s; v a is the annular return velocity, m / s; ρ s is the density of rock cuttings, kg / m 3ρ m is the drilling fluid density, kg / m 3 ;μ e D is the effective viscosity of the drilling fluid, mPa·s; h is the borehole diameter, mm; D p D is the outer diameter of the drill string, mm; s is the particle size of rock cuttings, mm; ROP max is the maximum mechanical drilling speed, m / h.

[0043] A further technical solution is that the functional relationship of the drilling parameter optimization chart is:

[0044]

[0045] In the formula: ROP max is the maximum mechanical drilling speed, m / h; RPM is the drill speed, r / min; WOB is the drill pressure; ROP is the mechanical drilling speed.

[0046] The present invention has the following beneficial effects: the present invention establishes a drilling parameter optimization chart of drill bit drilling pressure, drill bit rotation speed and mechanical drilling speed, stick-slip vibration index, and maximum mechanical drilling speed. The range of drilling parameters determined by the optimization chart and the mechanical drilling speed that can be obtained by corresponding drilling parameters have a certain theoretical guiding role in improving the drilling efficiency of horizontal wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a schematic diagram of the horizontal well drilling parameter optimization chart established by the present invention. DETAILED DESCRIPTION

[0048] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] A method for establishing a horizontal well drilling parameter optimization chart of the present invention comprises the following steps:

[0050] Step S1, processing the suspended weight and wellhead speed collected during the drilling process, and correcting the drill bit speed and drill bit pressure using the friction torque calculation model and the screw drilling tool output model;

[0051] The friction torque calculation model takes into account different drilling conditions when calculating the friction coefficient between the drill string and the well wall, and the drilling conditions include compound drilling and sliding drilling;

[0052] The calculation formula of drill bit drilling pressure is as follows:

[0053]

[0054]

[0055] Where: F0 is the hook load, N; μ i is the friction coefficient between the i-th unit and the well wall, dimensionless; α i , are the well inclination angle and dogleg angle at both ends of the unit, rad; L i is the length of the i-th unit cell, m; Δα i is the increment of the well inclination angle at both ends of the i-th unit body, rad; q m is the buoyant weight of the i-th unit in the drilling fluid N / m; N i is the radial support force of the i-th unit, N;

[0056] The drill bit speed calculation formula is:

[0057]

[0058] Where: RPM is the drill bit speed, r / min; RPM0 is the wellhead speed, r / min; Q is the inlet flow rate, L / s; q is the flow rate per revolution of the screw drill, L / r;

[0059] Step S2, establishing a functional relationship between drill bit pressure, drill bit speed and mechanical drilling speed according to the random forest algorithm;

[0060] Step S21, dividing the training data of different strata according to geological age;

[0061] Step S22, selecting the drill bit pressure and the drill bit speed as input characteristic variables, selecting the mechanical drilling speed as the output variable, and using the random forest algorithm to learn the training data of different strata to establish a mechanical drilling speed prediction model for different strata;

[0062] The mechanical drilling speed prediction model is related to the properties of the formation, and the mechanical drilling speed model of each formation is independent;

[0063] Step S23, determining a functional relationship between the mechanical drilling speed and the drill bit pressure and the drill bit speed according to the mechanical drilling speed prediction model of different formations;

[0064] ROP=f(WOB,RPM)

[0065] Step S3, establishing a functional relationship between the drill bit drilling pressure, the drill bit speed and the stick-slip vibration index based on the stick-slip vibration analysis model;

[0066] Step S31, based on the drill string stick-slip vibration model, solving the stick-slip vibration equation under different drill bit pressures and drill bit speeds, and determining the maximum speed and the minimum speed of the drill bit slipping stage under different drill bit pressures and drill bit speeds;

[0067] [M][a]+[C][v]+[K][x]=[F]

[0068] Where: [M] is the mass matrix of the drill string of the entire well section; [K] is the axial stiffness matrix of the drill string of the entire well section; [C] is the axial damping matrix of the drill string of the entire well section; [x] is the displacement matrix of each node of the drill string of the entire well section; [v] is the velocity matrix of each node of the drill string of the entire well section; [a] is the acceleration matrix of each node of the drill string of the entire well section; [F] is the resultant external force matrix of each node of the drill string of the entire well section;

[0069] Step S32, calculating the stick-slip vibration index according to the maximum rotation speed during the drill bit slippage stage and the minimum rotation speed during the drill bit slippage stage, and determining the drilling parameter control range in which stick-slip vibration does not occur;

[0070]

[0071] Where: RPM max The maximum speed during the drill slippage stage; RPM min is the minimum speed during the bit slippage stage; RPM0 is the wellhead speed;

[0072] The drilling parameter control range in which stick-slip vibration does not occur is determined by a stick-slip vibration index. If the stick-slip vibration index is less than 1, the drill string does not have stick-slip vibration. If the stick-slip vibration index is greater than 1, the drill string has stick-slip vibration. By controlling the drill bit drilling pressure and the drill bit speed to make the stick-slip vibration index less than 1, stick-slip vibration can be prevented.

[0073] Step S33, establishing a functional relationship between the drill bit drilling pressure, the drill bit speed and the stick-slip vibration index according to the drill bit drilling pressure, the drill bit speed and the stick-slip vibration index;

[0074] TSE=g(WOB,RPM)

[0075] Step S4, using the borehole cleaning prediction model, calculate the borehole cleaning state under different mechanical drilling speed conditions under a certain drilling fluid displacement condition (the borehole cleaning state is determined by the annular cuttings concentration, and the annular cuttings concentration is less than 5%, which means that the borehole is clean and can effectively prevent the pipe from getting stuck), establish a functional relationship between borehole cleaning and mechanical drilling speed, determine the maximum mechanical drilling speed of borehole cleaning, and establish a functional relationship between the drill bit drilling pressure, the drill bit drilling speed and the maximum drilling speed;

[0076] Step S41, firstly calculate the annular return velocity and the cuttings settling velocity;

[0077] Annular return speed calculation formula:

[0078]

[0079] The calculation formula of cuttings settling velocity is:

[0080]

[0081] Where: v s is the rock cuttings settling velocity, m / s; v a is the annular return velocity, m / s; ρ s is the density of rock cuttings, kg / m 3 ρ m is the drilling fluid density, kg / m 3 ;μ e D is the effective viscosity of the drilling fluid, mPa·s; h is the borehole diameter, mm; D p is the outer diameter of the drill string, mm;

[0082] Step S42, then calculating the maximum permissible mechanical drilling speed according to the criterion that the cuttings concentration is less than 5%;

[0083]

[0084] Where: v s is the rock cuttings settling velocity, m / s; v a is the annular return speed, m / s; D h is the borehole diameter, mm; D s is the particle size of rock cuttings, mm; ROP max is the maximum mechanical drilling speed, m / h;

[0085] Step S43, finally determining the functional relationship between the drill bit drilling pressure, the drill bit rotation speed and the maximum mechanical drilling speed according to the established mechanical drilling speed prediction model;

[0086] Step S5, establishing a drilling parameter optimization chart by combining the functional relationship between the mechanical penetration rate, stick-slip vibration index, maximum mechanical penetration rate, the drill bit drilling pressure, and the drill bit penetration rate;

[0087]

[0088] By solving the drilling parameter optimization chart equation, the optimal drilling parameters can be obtained, and the drilling parameters can also be set according to the chart for drilling.

[0089] Example

[0090] Taking the target well as an example, the logging data, wellbore structure data, drilling tool assembly data, and wellbore trajectory data of the adjacent wells are first obtained. According to the map establishment method of the present invention, the established drilling parameter optimization map is as follows: Figure 1As shown, the driller can adjust the drilling parameters according to the drilling parameter optimization chart. The optimal drilling parameters are the intersection of the stick-slip vibration index and the maximum mechanical penetration rate, the drill bit drilling pressure is 170kN, and the drill bit drilling speed is 120r / min.

[0091] The above description is not intended to impose any form of limitation on the present invention. Although the present invention has been disclosed through the above embodiments, it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A method for establishing a horizontal well drilling parameter optimization chart, characterized in that: The following steps are involved: Step S1, correcting drilling data using a friction torque calculation model and a screw drill output model; Step S2, establishing a functional relationship between drill bit pressure, drill bit speed and mechanical drilling speed according to the random forest algorithm; Step S21, dividing the training data of different strata according to geological age; Step S22, selecting the drill bit pressure and the drill bit speed as input characteristic variables, selecting the mechanical drilling speed as the output variable, and using the random forest algorithm to learn the training data of different strata to establish a mechanical drilling speed prediction model for different strata; Step S23, determining a functional relationship between the mechanical drilling speed and the drill bit pressure and the drill bit speed according to the mechanical drilling speed prediction model of different formations; Step S3, establishing a functional relationship between the drill bit drilling pressure, the drill bit speed and the stick-slip vibration index based on the stick-slip vibration analysis model; Step S31, based on the drill string stick-slip vibration model, solving the stick-slip vibration equation under different drill bit pressures and drill bit speeds, and determining the maximum speed and the minimum speed of the drill bit slipping stage under different drill bit pressures and drill bit speeds; Step S32, calculating the stick-slip vibration index according to the maximum rotation speed during the drill bit slippage stage and the minimum rotation speed during the drill bit slippage stage, and determining the drilling parameter control range in which stick-slip vibration does not occur; Step S33, establishing a functional relationship between the drill bit drilling pressure, the drill bit speed and the stick-slip vibration index according to the drill bit drilling pressure, the drill bit speed and the stick-slip vibration index; Step S4, establishing a functional relationship between the drill bit pressure on bit, the drill bit speed on bit and the maximum speed on bit based on the wellbore cleaning prediction model; The specific process of step S4 is: firstly, the annular return velocity and the cuttings settling velocity are calculated, then the maximum mechanical drilling speed allowed is calculated according to the criterion that the cuttings concentration is less than 5%, and finally, the functional relationship between the drill bit pressure on bit, the drill bit speed and the maximum mechanical drilling speed is determined according to the maximum mechanical drilling speed; Step S5, establishing a drilling parameter optimization chart by combining the functional relationship between the mechanical penetration rate, stick-slip vibration index, maximum mechanical penetration rate, the drill bit drilling pressure, and the drill bit penetration rate.

2. A method for establishing a horizontal well drilling parameter optimization chart according to claim 1, characterized in that: The drilling data in step S1 include the drilling pressure and drilling speed of the drill bit.

3. A method for establishing a horizontal well drilling parameter optimization chart according to claim 2, characterized in that: The calculation formula in step S1 includes: Drill bit drilling pressure calculation formula: Where: μ i is the friction coefficient between the i-th unit and the well wall, dimensionless; α i , β i are the well inclination angle and dogleg angle at both ends of the unit, rad; L i is the length of the i-th unit cell, m; Δα i is the increment of the well inclination angle at both ends of the i-th unit body, rad; q m is the buoyant weight of the i-th unit in the drilling fluid N / m; N i is the radial support force of the i-th unit, N; Drill bit speed calculation formula: Where: RPM is the drill bit speed, r / min; RPM0 is the wellhead speed, r / min; Q is the inlet flow rate, L / s; q is the flow rate per revolution of the screw drill, L / r.

4. The method for establishing a horizontal well drilling parameter optimization chart according to claim 1, characterized in that: The drill string stick-slip vibration model is: [M][a]+[C][v]+[K][x]=[F] Where: [M] is the mass matrix of the drill string of the entire well section; [K] is the axial stiffness matrix of the drill string of the entire well section; [C] is the axial damping matrix of the drill string of the entire well section; [x] is the displacement matrix of each node of the drill string of the entire well section; [v] is the velocity matrix of each node of the drill string of the entire well section; [a] is the acceleration matrix of each node of the drill string of the entire well section; [F] is the resultant external force matrix of each node of the drill string of the entire well section.

5. The method for establishing a horizontal well drilling parameter optimization chart according to claim 1, characterized in that: The stick-slip vibration index calculation formula is: Where: RPM max The maximum speed during the drill slippage stage; RPM min It is the minimum speed during the bit slippage stage; RPM0 is the wellhead speed.

6. The method for establishing a horizontal well drilling parameter optimization chart according to claim 1, characterized in that: The calculation formula in step S4 includes: Annular return speed calculation formula: The calculation formula of cuttings settling velocity is: Maximum mechanical drilling speed calculation formula: Where: v s is the rock cuttings settling velocity, m / s; v a is the annular return velocity, m / s; ρ s is the density of rock cuttings, kg / m 3 ρ m is the drilling fluid density, kg / m 3 ;μ e D is the effective viscosity of the drilling fluid, mPa·s; h is the borehole diameter, mm; D p D is the outer diameter of the drill string, mm; s is the particle size of rock cuttings, mm; ROP max is the maximum mechanical drilling speed, m / h.

7. The method for establishing a horizontal well drilling parameter optimization chart according to claim 1, characterized in that: The functional relationship of the drilling parameter optimization chart is: In the formula: ROP max is the maximum mechanical drilling speed, m / h; RPM is the drill speed, r / min; WOB is the drill pressure; ROP is the mechanical drilling speed.

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