Drill bit selection scheme recommendation method based on mechanical specific energy

Abstract

The invention belongs to the technical field of oil-gas exploration and development, and particularly relates to a drill bit selection scheme recommendation method based on mechanical specific energy. According to the method, a database is created, drilling data of a well under construction is collected, mechanical specific energy and a drill bit benefit index are calculated in real time, the trend of the mechanical specific energy and stratum compressive strength is analyzed, and when the change rate of the mechanical specific energy is larger than the change rate of the stratum compressive strength and away from the trend, drill bit evaluation is conducted in combination with the drill bit benefit index. Whether a drill bit needs to be replaced or not is considered, the optimal mechanical specific energy of historical well drilling parameter data of the same well type, the same block and the same stratum in a database is analyzed, the cost per meter of the drill bit is combined, corresponding historical optimal drilling scheme data is selected as a recommended drill bit scheme, and then construction well operation is optimized according to the recommended drill bit scheme. Therefore, the purposes of speed increasing and efficiency increasing of well drilling production are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas exploration and development, and in particular relates to a method for recommending a drill bit selection scheme based on mechanical specific energy. Background Art

[0002] In recent years, the geological conditions faced by drilling projects have become increasingly complex, and there are more and more complex structure wells such as key wells, large displacement wells, and ultra-long horizontal section wells; there are many factors affecting underground anomalies, many uncertain factors, and it is difficult to quantify the factors. Traditional research methods can usually only give qualitative conclusions.

[0003] In the invention patent "A drilling plan intelligent recommendation method and system" with publication number CN111488384B, the objective laws implicit in the historical well data can be automatically mined. It can intelligently find well sets with similar geological conditions to the wells to be drilled from the historical data, and intelligently select the wells with the highest drilling efficiency (such as high mechanical drilling speed, complex drilling and few failures) from the well sets, and automatically recommend the corresponding drilling plan to the wells to be drilled. However, this prior art needs to analyze the block where the well to be constructed is located, perform relevant calculations based on the theoretical model, and refer to the construction plans of adjacent wells and the complex situations that arise, and the designers must formulate the most reasonable engineering design possible based on their experience.

[0004] In order to achieve the drilling goals of "safety, efficiency, high quality and low cost", the current drilling construction will adjust and optimize the drilling construction plan in real time during the drilling construction process. A large amount of data has been accumulated in production. Based on the full mining and analysis of the drilling data of historical wells in the same block, well type and layer, it is difficult to find its rules by manpower alone. Summary of the invention

[0005] The present invention provides a method for recommending drill bit selection schemes based on mechanical specific energy, and its purpose is to provide a method based on big data and mathematical statistics to analyze and process real-time data and historical data, optimize the construction scheme, reduce the occurrence of underground accidents, and speed up and increase the efficiency of drilling production.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for recommending drill bit selection scheme based on mechanical specific energy comprises the following steps:

[0008] Step 1: Create a database

[0009] The database includes drilling parameter data and historical drilling plan data of multiple historical wells in the same block, well type and formation;

[0010] Step 2: Collect drilling data of wells under construction and calculate mechanical specific energy and drill bit efficiency index in real time;

[0011] Step 3: Analyze the trend of mechanical specific energy and formation compressive strength to evaluate the drill bit

[0012] When the rate of change of mechanical specific energy is greater than the rate of change of formation compressive strength and is far from the trend, the drill bit is evaluated in combination with the drill bit benefit index to consider whether the drill bit needs to be replaced;

[0013] Step 4: Select the corresponding historical optimal drilling plan data as the recommended drill bit plan

[0014] By analyzing the minimum mechanical specific energy of historical well drilling parameter data of the same well type, same block and same formation in the database, combined with the drill bit cost per meter, the corresponding historical minimum mechanical specific energy drilling plan data is selected as the recommended drill bit plan;

[0015] Step 5: Optimize well construction operations based on the drill bit solution recommended in Step 4.

[0016] The historical drilling data in step 1 includes drilling parameters, basic data, drilling fluid information data, block plan data and downhole complex accident data.

[0017] The drilling data collected in the step 2 include drilling while drilling data: drilling parameter instrument data, trajectory calculation data, MWD inclination data, gamma data and liquid level monitoring data.

[0018] The method for calculating the mechanical specific energy in step 2 is to use the following formula to calculate the real-time mechanical specific energy:

[0019]

[0020] Where: M se is the mechanical specific energy, unit: MPa;

[0021] W is the drilling pressure, unit is N;

[0022] Ab is the drill area, unit: mm 2 ;

[0023] N is the drill bit speed, in rpm;

[0024] T is the drill torque, in Nm;

[0025] Vp is the mechanical drilling speed, in m / h;

[0026] Where, N = rotating disk speed + screw speed (displacement Q / displacement per revolution q);

[0027] T = turntable torque * 0.7 + △PQ / ω;

[0028] The drilling pressure W, rotary table speed, rotary table torque, mechanical drilling speed, displacement Q, and pump pressure are collected from the drilling parameter instrument;

[0029] The drill area Ab is provided by the drill daily report;

[0030] The displacement per revolution q is provided by the screw configuration table;

[0031] The angular velocity ω is equal to the screw speed N;

[0032] Screw pressure drop △PQ = average pump pressure when the drilling pressure is greater than 40KN after the pump is turned on - average pump pressure when the drilling pressure is 0 after the pump is turned on.

[0033] The drill bit benefit index in step 2 is calculated using the following formula:

[0034] E b =αFV P / Cb

[0035] Where: E b is the drill bit efficiency index, unit: m 2 / (h*yuan);

[0036] Vp is the mechanical drilling speed, unit: m / h;

[0037] α is the coefficient of the equation, which is 1;

[0038] F is the total penetration of the drill bit, unit: m;

[0039] Cb is the drill bit cost, unit: Yuan.

[0040] The method for analyzing the trend of mechanical specific energy and formation compressive strength in the step three and judging that the rate of change of mechanical specific energy is greater than the rate of change of formation compressive strength and away from the trend is as follows: when the rate of change of current mechanical specific energy compared with the previous hour is more than 20% higher than the rate of change of current formation compressive strength compared with the previous hour, it is judged that the rate of change of mechanical specific energy is greater than the rate of change of formation compressive strength and away from the trend.

[0041] The specific method of evaluating the drill bit in combination with the drill bit benefit index in step 3 and considering whether the drill bit needs to be replaced is as follows: if the previous drill bit benefit index decreases by more than 50% compared with the previous hour, it is determined that the drill bit needs to be replaced.

[0042] The drill bit cost per meter in step 4 is calculated using the following formula:

[0043] C=(C b +C r *t)) / F

[0044] Where: C is the cost per meter of the drill bit, unit: yuan / m;

[0045] C b is the drill bit cost, unit: Yuan;

[0046] C r is the drilling rig operation cost, unit: Yuan / h;

[0047] t is the drilling operation time, unit: h;

[0048] F is the drill penetration, unit: m.

[0049] The specific method for selecting the drilling plan data with the corresponding historical minimum mechanical specific energy as the recommended drill bit plan in the step 4 is to obtain the characteristic value Mse of the construction well data through the values ​​of the drilling parameters of the historical wells in the same block, the same well type and the same layer established in the database in step 1; the drill bit benefit index Eb is calculated by the mechanical drilling speed Vp, the total footage of the drill bit F and the drill bit cost, and the average value of the sampling model characteristic value is obtained, and then the variance of the model value of the historical wells close to the value of the existing model is obtained according to the average value; these historical wells in the same block, the same well type and the same layer are arranged according to the variance, the smaller the variance, the smaller the discrete value, which means that it is closer to the average value, that is, the historical model data is closer to the existing model data, and then these data are arranged according to the degree of similarity, and finally the drill bit optimization plan corresponding to the minimum variance is selected.

[0050] The specific method for obtaining the characteristic value Mse of the construction well data is obtained by the following method:

[0051]

[0052] in,

[0053] N = turntable speed + screw speed, screw speed = displacement Q / displacement per revolution q;

[0054] T = turntable torque * 0.7 + △PQ / ω;

[0055] The drilling pressure W, rotary table speed, rotary table torque, mechanical drilling speed, displacement Q, and pump pressure are collected from the drilling parameter instrument;

[0056] The drill area Ab is provided by the drill daily report;

[0057] The displacement per revolution q is provided by the screw configuration table;

[0058] Angular velocity ω is equal to the screw speed;

[0059] Screw pressure drop △PQ = average pump pressure when the drilling pressure is greater than 40KN after the pump is turned on - average pump pressure when the drilling pressure is 0 after the pump is turned on;

[0060] The drill bit benefit index Eb is obtained by the following equation:

[0061] Eb=αFVp / Cb

[0062] in,

[0063] Vp is the mechanical drilling speed, unit: m / h;

[0064] α is the coefficient of the equation, which is 1;

[0065] F is the total penetration of the drill bit, unit: m;

[0066] Cb is the drill bit cost, unit: yuan;

[0067] Eb is the drill bit efficiency index, unit: m 2 / h* yuan.

[0068] Beneficial effects:

[0069] The present invention evaluates the drill bit by real-time calculation and analysis of mechanical specific energy and drill bit benefit index; by analyzing the optimal mechanical specific energy of historical drilling data of the same well type, the same block and the same formation in the database, combined with the cost per meter of the drill bit, the optimal drill bit solution in the historical drilling solutions is conveniently and quickly recommended as the recommended drill bit solution; according to the recommended drill bit solution, the construction well operation is optimized, and fast and safe drilling is enabled, thereby achieving the purpose of speeding up and increasing the efficiency of drilling production.

[0070] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0072] Figure 1 It is a flow chart of the present invention.

[0073] Figure 2 It is a trend curve diagram of mechanical specific energy and formation compressive strength in an embodiment of the present invention. DETAILED DESCRIPTION

[0074] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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.

[0075] Embodiment 1:

[0076] according to Figure 1 A method for recommending drill bit selection scheme based on mechanical specific energy is shown, comprising the following steps:

[0077] Step 1: Create a database

[0078] The database includes drilling parameter data and historical drilling plan data of multiple historical wells in the same block, well type and formation;

[0079] Step 2: Collect drilling data of wells under construction and calculate mechanical specific energy and drill bit efficiency index in real time;

[0080] Step 3: Analyze the trend of mechanical specific energy and formation compressive strength to evaluate the drill bit

[0081] When the rate of change of mechanical specific energy is greater than the rate of change of formation compressive strength and is far from the trend, the drill bit is evaluated in combination with the drill bit benefit index to consider whether the drill bit needs to be replaced;

[0082] Step 4: Select the corresponding historical optimal drilling plan data as the recommended drill bit plan

[0083] By analyzing the minimum mechanical specific energy of historical well drilling parameter data of the same well type, same block and same formation in the database, combined with the drill bit cost per meter, the corresponding historical minimum mechanical specific energy drilling plan data is selected as the recommended drill bit plan;

[0084] Step 5: Optimize well construction operations based on the drill bit solution recommended in Step 4.

[0085] The present invention evaluates the drill bit by real-time calculation and analysis of mechanical specific energy and drill bit efficiency index; by analyzing the optimal mechanical specific energy of historical drilling data of the same well type, the same block and the same formation in the database, combined with the cost per meter of the drill bit, the optimal drill bit solution in the historical drilling solutions is conveniently and quickly recommended as the recommended drill bit solution; according to the recommended drill bit solution, the construction well operation is optimized and guided, enabling fast and safe drilling, thereby achieving the purpose of speeding up and increasing the efficiency of drilling production.

[0086] Embodiment 2:

[0087] according to Figure 1 The method for recommending drill bit selection scheme based on mechanical specific energy shown is different from the first embodiment in that the historical drilling data in the first step includes drilling parameters, basic data and drilling fluid information data.

[0088] In actual use, the drilling parameters include drilling parameter instrument data, trajectory calculation data, MWD inclination data, gamma data, liquid level monitoring data and block plan data. The block plan data includes drill tool assembly, drill bit selection, drilling parameters, trajectory control, precautions, etc.

[0089] Basic data include single well basic data, design data, wellbore structure, casing data, formation pressure data, production, drilling fluid, drilling tool assembly, drill bit daily data, knowledge base, formation compressive strength and engineering well history.

[0090] Drilling fluid information data includes block plan data and underground complex accident data.

[0091] This technical solution is based on big data and lays the foundation for ultimately providing reliable drill bit selection.

[0092] In this embodiment, MWD is the abbreviation of Measure While Drilling.

[0093] The historical drilling plan data in step 1 is the well history data of the well drilling and completion engineering. In actual use, the provision of the historical drilling plan data lays the foundation for ultimately providing a reliable drill bit solution.

[0094] Embodiment three:

[0095] according to Figure 1 The method for recommending drill bit selection based on mechanical specific energy shown is different from that of Example 1 in that the drilling data of the well under construction collected in step 2 includes drilling while drilling construction data: drilling parameter instrument data, trajectory calculation data, MWD inclination data, gamma data and liquid level monitoring data.

[0096] In actual use, the collection of drilling data from wells under construction provides a guarantee for obtaining accurate and reliable calculations of mechanical specific energy and drill bit efficiency index data.

[0097] Embodiment 4:

[0098] according to Figure 1 The method for recommending drill bit selection scheme based on mechanical specific energy shown in the embodiment is different from the embodiment 1 in that the method for calculating mechanical specific energy in step 2 is to calculate the real-time mechanical specific energy using the following formula:

[0099]

[0100] Where: M se is the mechanical specific energy, unit: MPa;

[0101] W is the drilling pressure, unit is N;

[0102] Ab is the drill area, unit: mm 2 ;

[0103] N is the drill bit speed, in rpm;

[0104] T is the drill torque, in Nm;

[0105] Vp is the mechanical drilling speed, in m / h;

[0106] Where, N = rotating disk speed + screw speed (displacement Q / displacement per revolution q);

[0107] T = turntable torque * 0.7 + △PQ / ω;

[0108] The drilling pressure W, rotary table speed, rotary table torque, mechanical drilling speed, displacement Q, and pump pressure are collected from the drilling parameter instrument;

[0109] The drill area Ab is provided by the drill daily report;

[0110] The displacement per revolution q is provided by the screw configuration table;

[0111] The angular velocity ω is equal to the screw speed N;

[0112] Screw pressure drop △PQ = average pump pressure when the drilling pressure is greater than 40KN after the pump is turned on - average pump pressure when the drilling pressure is 0 after the pump is turned on.

[0113] By adopting this technical solution, a definite value of mechanical specific energy is obtained, which lays a foundation for subsequent accurate drill bit selection recommendations.

[0114] Embodiment five:

[0115] according to Figure 1 The drill bit selection scheme recommendation method based on mechanical specific energy shown in the embodiment is different from the embodiment 1 in that the drill bit benefit index in step 2 is calculated using the following calculation formula:

[0116] E b =αFVp / Cb

[0117] Where: E b is the drill bit efficiency index, unit: m 2 / (h*yuan);

[0118] Vp is the mechanical drilling speed, unit: m / h;

[0119] α is the coefficient of the equation, which is 1;

[0120] F is the total penetration of the drill bit, unit: m;

[0121] Cb is the drill bit cost, unit: Yuan.

[0122] By adopting this technical solution, a definite value of the drill bit benefit index is obtained, which lays a foundation for subsequent accurate drill bit selection recommendations.

[0123] Embodiment six:

[0124] according to Figure 1 The method for recommending a drill bit selection scheme based on mechanical specific energy shown in the embodiment is different from that of Example 1 in that: the method for analyzing the trend of mechanical specific energy and formation compressive strength in step three and judging that the rate of change of mechanical specific energy is greater than the rate of change of formation compressive strength and away from the trend is as follows: when the rate of change of current mechanical specific energy compared with the previous hour increases by more than 20% compared with the rate of change of current formation compressive strength compared with the previous hour, it is judged that the rate of change of mechanical specific energy is greater than the rate of change of formation compressive strength and away from the trend.

[0125] This technical solution provides a quantitative method for determining the trend of mechanical specific energy and formation compressive strength, and is more operational.

[0126] Embodiment seven:

[0127] according to Figure 1 The method for recommending drill bit selection based on mechanical specific energy shown in the figure is different from that of Example 1 in that: the specific method of evaluating the drill bit in combination with the drill bit benefit index in step three and considering whether the drill bit needs to be replaced is as follows: if the drill bit benefit index drops by more than 50% compared with the previous hour, it is judged that the drill bit needs to be replaced.

[0128] The adoption of this technical solution makes it easier and more convenient to determine whether the drill bit needs to be replaced.

[0129] Embodiment eight:

[0130] according to Figure 1 The method for recommending drill bit selection scheme based on mechanical specific energy shown in the figure is different from the first embodiment in that the drill bit cost per meter in the fourth step is calculated by the following formula:

[0131] C=(C b +C r *t)) / F

[0132] Where: C is the cost per meter of the drill bit, unit: yuan / m;

[0133] C b is the drill bit cost, unit: Yuan;

[0134] C r is the drilling rig operation cost, unit: Yuan / h;

[0135] t is the drilling operation time, unit: h;

[0136] F is the drill penetration, unit: m.

[0137] The cost per meter of the drill bit is obtained by adopting the technical solution, which is simple, convenient and easy to implement.

[0138] Embodiment nine:

[0139] according to Figure 1 The method for recommending a drill bit selection scheme based on mechanical specific energy shown in the embodiment is different from the embodiment 1 in that: the specific method for selecting the drilling scheme data with the corresponding historical minimum mechanical specific energy as the recommended drill bit scheme in the step 4 is to obtain the characteristic value Mse of the construction well data through the values ​​of the drilling parameters of the historical wells in the same block, the same well type and the same layer established in the database in step 1; the drill bit benefit index Eb is calculated by the mechanical drilling speed Vp, the total footage of the drill bit F and the drill bit cost, and the average value of the sampling model characteristic value is obtained, and then the variance of the model value of the historical wells close to the value of the existing model is obtained according to the average value; these historical wells in the same block, the same well type and the same layer are arranged according to the variance, the smaller the variance, the smaller the discrete value, which means it is closer to the average value, that is, the historical model data is closer to the existing model data, and then these data are arranged according to the degree of similarity, and finally the drill bit optimization scheme corresponding to the minimum variance is selected.

[0140] Furthermore, the specific method for obtaining the characteristic value Mse of the construction well data is obtained by the following method:

[0141]

[0142] in,

[0143] N = turntable speed + screw speed, screw speed = displacement Q / displacement per revolution q;

[0144] T = turntable torque * 0.7 + △PQ / ω;

[0145] The drilling pressure W, rotary table speed, rotary table torque, mechanical drilling speed, displacement Q, and pump pressure are collected from the drilling parameter instrument;

[0146] The drill area Ab is provided by the drill daily report;

[0147] The displacement per revolution q is provided by the screw configuration table;

[0148] Angular velocity ω is equal to the screw speed;

[0149] Screw pressure drop △PQ = average pump pressure when the drilling pressure is greater than 40KN after the pump is turned on - average pump pressure when the drilling pressure is 0 after the pump is turned on;

[0150] The drill bit benefit index Eb is obtained by the following equation:

[0151] Eb=αFVp / Cb

[0152] in,

[0153] Vp is the mechanical drilling speed, unit: m / h;

[0154] α is the coefficient of the equation, which is 1;

[0155] F is the total penetration of the drill bit, unit: m;

[0156] Cb is the drill bit cost, unit: yuan;

[0157] Eb is the drill bit efficiency index, unit: m 2 / h* yuan.

[0158] This technical solution uses big data and mathematical statistics to analyze and process real-time and historical data, which helps to optimize construction plans, reduce underground accidents, and speed up and improve the efficiency of drilling production.

[0159] Embodiment ten:

[0160] according to Figure 1 and Figure 2 A recommended method for selecting a drill bit based on mechanical specific energy is shown in FIG.

[0161] The following steps are involved:

[0162] Step 1, creating a database; the database includes a number of historical scheme data; the historical scheme data includes historical drilling data and historical drilling scheme data;

[0163] Step 2: Collect the drilling data of the well being constructed, and calculate the mechanical specific energy and drill bit efficiency index in real time;

[0164] Step 3: Analyze the trend of mechanical specific energy and formation compressive strength. When the change rate of mechanical specific energy is greater than the change rate of formation compressive strength and is far away from the trend, evaluate the drill bit in combination with the drill bit benefit index to consider whether the drill bit needs to be replaced.

[0165] Step 4: By analyzing the optimal mechanical specific energy of historical drilling data of the same well type, same block, and same formation in the database, combined with the drill bit cost per meter, the corresponding historical drilling plan data is intelligently recommended as the recommended drill bit plan;

[0166] Step 5: Optimize construction well operations based on the recommended drill bit solution.

[0167] In this embodiment: the database established in step 1 includes drilling technology support platform data, basic data synchronized from the engineering intelligent support system platform, drilling fluid information technology integrated platform database involving block plan data and underground complex accident data.

[0168] Specifically, the drilling technical support platform database covers the drilling parameters while drilling during the drilling construction process: drilling parameter instrument data, trajectory calculation data, MWD inclination data, gamma data, liquid level monitoring data) and block plan data (drilling tool assembly, drill bit selection, drilling parameters, trajectory control, precautions, etc.).

[0169] The basic data synchronized from the engineering intelligent support system platform include: single well basic data, design data, wellbore structure, casing data, formation pressure data, production, drilling fluid, drilling tool assembly, drill bit daily data; knowledge base; formation compressive strength; engineering well history.

[0170] The basic data synchronized from the drilling fluid information technology integrated platform include: block plan data and underground complex accident data.

[0171] In the historical scheme data, the basis for drill bit selection is:

[0172] The selection of drill bit type is related to the efficiency of mechanical rock breaking during drilling, thus affecting the drilling cost of a well. The selection of drill bit needs to refer to the geological characteristics. Analysis of formation anti-drilling characteristics: Based on the description of formation layers and existing well data, the drillability analysis results are combined with geological data and formations. It is assumed that the lateral differences in the anti-drilling characteristics of each formation are relatively small.

[0173] The recommended drill bit types for different formation drillability values ​​and the corresponding relationship between drill bit types and formation levels are shown in Table 1. Different types of drill bits are suitable for formations of different properties. Therefore, according to the formation's drilling resistance, the drill bit type of the designed well section can be reasonably selected to achieve high drilling speed, high footage, and low cost in actual drilling.

[0174] Table 1 Correspondence between drill bit type and formation level

[0175]

[0176] In this embodiment: in step 2, the drilling data of the well being constructed is collected, and the mechanical specific energy and the drill bit benefit index are calculated in real time;

[0177] Specifically, the downhole drilling parameters include: drilling parameter instrument data, trajectory calculation data, MWD inclinometer data, gamma data, liquid level monitoring data, etc. The platform completes the automatic collection of on-site downhole data (collection methods include: WITS, DateBase, File), real-time encrypted transmission, data management, data release, data analysis and other applications, laying the foundation for information construction.

[0178] Real-time calculation of mechanical specific energy and drill bit benefit index, where the mechanical specific energy calculation formula is:

[0179]

[0180] Where: M se is the mechanical specific energy, unit: MPa;

[0181] W is the drilling pressure, unit is N;

[0182] Ab is the drill area, in mm 2 ;

[0183] N is the drill bit speed, in rpm;

[0184] T is the drill torque, in Nm;

[0185] Vp is the mechanical drilling speed, in m / h;

[0186] Drill bit speed N = turntable speed + screw speed (displacement Q / displacement per revolution q);

[0187] Drill bit torque T = turntable torque * 0.7 + △PQ / ω;

[0188] The drilling pressure W, rotary table speed, rotary table torque, mechanical drilling speed Vp, displacement Q, and pump pressure are collected from the drilling parameter instrument;

[0189] The drill area Ab is provided by the drill daily report;

[0190] The displacement per revolution q is provided by the screw configuration table;

[0191] Angular velocity ω is equal to drill bit speed N;

[0192] Screw pressure drop △PQ = average pump pressure when the drilling pressure is greater than 40KN after the pump is turned on - average pump pressure when the drilling pressure is 0 after the pump is turned on.

[0193] The drill bit benefit index calculation formula is:

[0194] E b =αFVp / Cb

[0195] In the formula, E b is the drill bit efficiency index, unit: m2 / h / yuan;

[0196] Vp is the mechanical drilling speed, in m / h;

[0197] α is the coefficient of the equation, which is 1;

[0198] F is the total penetration of the drill bit, in m;

[0199] Cb is the drill bit cost, unit: RMB / piece;

[0200] In this embodiment: Step 3 analyzes the trend of mechanical specific energy and formation compressive strength. When the change rate of mechanical specific energy is greater than the change rate of formation compressive strength and is far away from the trend, the drill bit is evaluated in combination with the drill bit benefit index to consider whether the drill bit needs to be replaced;

[0201] Specifically, the mechanical specific energy and formation compressive strength curve is drawn in real time (see Figure 2), analyze the trends of mechanical specific energy and formation compressive strength. When the rate of change of mechanical specific energy is greater than the rate of change of formation compressive strength and is far away from the trend, specifically including: when the rate of change of current mechanical specific energy compared with the previous hour is more than 20% higher than the rate of change of current formation compressive strength compared with the previous hour, it is judged that the rate of change of mechanical specific energy is greater than the rate of change of formation compressive strength and is far away from the trend.

[0202] When the mechanical specific energy change rate is greater than the formation compressive strength change rate and is far away from the trend, the drill bit is evaluated in combination with the drill bit benefit index, specifically including: if the current drill bit benefit index drops by more than 50% compared with the previous hour, it is judged that the drill bit needs to be replaced.

[0203] In this embodiment: Step 4 analyzes the optimal mechanical specific energy of historical drilling data of the same well type, same block, and same formation in the database, and intelligently recommends corresponding historical drilling plan data as a recommended drill bit plan in combination with the drill bit cost per meter;

[0204] Specifically, the calculation formula for the drill bit cost per meter is:

[0205] C=(Cb+Cr*t)) / F

[0206] Where: C is the cost per meter of the drill bit (unit: yuan / m);

[0207] Cb is the drill cost, in yuan;

[0208] Cr is the drilling rig operating cost, unit: RMB / h;

[0209] t is the drilling operation time, unit: h;

[0210] F is the drill penetration, unit: m.

[0211] Analyze the optimal mechanical specific energy and drill bit cost per meter of historical drilling data of the same well type, same block and same formation in the database. The optimal mechanical specific energy is the closest between the mechanical specific energy and the formation compressive strength, and the drill bit cost per meter is the lowest. Match and obtain the optimal data of several historical schemes in the database as the drill bit construction scheme to be selected;

[0212] Calculate the similarity between each candidate drilling plan and the drilling data of the well being constructed, sort each candidate drilling plan, and obtain a sorted plan group;

[0213] Arrange the data in the collection according to similarity, including:

[0214] (1) Intersect the wells in the corresponding sets to obtain historical plan data whose data are close to the drilling data of the wells under construction obtained by detection.

[0215] (2) The variance of various data from historical wells in the same block, well type, and layer is calculated. The average value of the existing characteristic values ​​is first obtained, and then the variance of the model characteristic value of the historical scheme data that is close to the existing model characteristic value is obtained based on the average value of the existing model characteristic value.

[0216] (3) Arrange these similar historical scheme data according to variance. The smaller the variance, the smaller the discrete value, which means it is closer to the average value. This means the similarity between the historical model and the existing model in the same block, well type, and layer. Then, arrange these data according to the similarity and recommend the optimal construction scheme data.

[0217] In this embodiment: Step 5 optimizes the construction well operation according to the recommended drill bit solution.

[0218] Specifically, the present invention is applicable to the drilling stage of oil exploration drilling projects, and can intelligently recommend drilling construction plans to enable fast and safe drilling.

[0219] In the absence of conflicts, technicians in this field can combine the relevant technical features in the above examples according to actual conditions to achieve corresponding technical effects. The specific combinations are not described here one by one.

[0220] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0221] In addition, the descriptions of "first", "second", etc. in the present invention are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0222] The above are only preferred embodiments of the present invention. The present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features disclosed herein. Any simple modification, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for recommending drill bit selection scheme based on mechanical specific energy, characterized in that: The following steps are included: Step 1: Create a database The database includes drilling parameter data and historical drilling plan data of multiple historical wells in the same block, well type and formation; Step 2: Collect drilling data of wells under construction and calculate mechanical specific energy and drill bit efficiency index in real time; Step 3: Analyze the trend of mechanical specific energy and formation compressive strength to evaluate the drill bit When the rate of change of mechanical specific energy is greater than the rate of change of formation compressive strength and is far from the trend, the drill bit is evaluated in combination with the drill bit benefit index to consider whether the drill bit needs to be replaced; Step 4: Select the corresponding historical optimal drilling plan data as the recommended drill bit plan By analyzing the minimum mechanical specific energy of historical well drilling parameter data of the same well type, same block and same formation in the database, combined with the drill bit cost per meter, the corresponding historical minimum mechanical specific energy drilling plan data is selected as the recommended drill bit plan; Step 5: Optimize well construction operations based on the drill bit solution recommended in Step 4.

2. A method for recommending drill bit selection scheme based on mechanical specific energy according to claim 1, characterized in that: The historical drilling data in step 1 includes drilling parameters, basic data, drilling fluid information data, block plan data and downhole complex accident data.

3. The method for recommending drill bit selection scheme based on mechanical specific energy according to claim 1, characterized in that: The drilling data collected in the step 2 include drilling while drilling data: drilling parameter instrument data, trajectory calculation data, MWD inclination data, gamma data and liquid level monitoring data.

4. The method for recommending drill bit selection scheme based on mechanical specific energy according to claim 1, characterized in that: The method for calculating the mechanical specific energy in step 2 is to use the following formula to calculate the real-time mechanical specific energy: Where: M se is the mechanical specific energy, unit: MPa; W is the drilling pressure, unit is N; Ab is the drill area, unit: mm 2 ; N is the drill bit speed, in rpm; T is the drill torque, in Nm; Vp is the mechanical drilling speed, in m / h; Where, N = rotating disk speed + screw speed (displacement Q / displacement per revolution q); T = turntable torque * 0.7 + △PQ / ω; The drilling pressure W, rotary table speed, rotary table torque, mechanical drilling speed, displacement Q, and pump pressure are collected from the drilling parameter instrument; The drill area Ab is provided by the drill daily report; The displacement per revolution q is provided by the screw configuration table; The angular velocity ω is equal to the screw speed N; Screw pressure drop △PQ = average pump pressure when the drilling pressure is greater than 40KN after the pump is turned on - average pump pressure when the drilling pressure is 0 after the pump is turned on.

5. The method for recommending drill bit selection scheme based on mechanical specific energy according to claim 1, characterized in that: The drill bit benefit index in step 2 is calculated using the following formula: E b =αFVp / Cb Where: E b is the drill bit efficiency index, unit: m 2 / (h*yuan); Vp is the mechanical drilling speed, unit: m / h; α is the coefficient of the equation, which is 1; F is the total penetration of the drill bit, unit: m; Cb is the drill bit cost, unit: Yuan.

6. The method for recommending drill bit selection scheme based on mechanical specific energy according to claim 1, characterized in that: The method for analyzing the trend of mechanical specific energy and formation compressive strength in the step three and judging that the rate of change of mechanical specific energy is greater than the rate of change of formation compressive strength and away from the trend is as follows: when the rate of change of current mechanical specific energy compared with the previous hour is more than 20% higher than the rate of change of current formation compressive strength compared with the previous hour, it is judged that the rate of change of mechanical specific energy is greater than the rate of change of formation compressive strength and away from the trend.

7. The method for recommending drill bit selection scheme based on mechanical specific energy according to claim 1, characterized in that: The specific method of evaluating the drill bit in combination with the drill bit benefit index in step 3 and considering whether the drill bit needs to be replaced is as follows: if the previous drill bit benefit index decreases by more than 50% compared with the previous hour, it is determined that the drill bit needs to be replaced.

8. The method for recommending drill bit selection scheme based on mechanical specific energy according to claim 1, characterized in that: The drill bit cost per meter in step 4 is calculated using the following formula: C=(C b +C r *t)) / F Where: C is the cost per meter of the drill bit, unit: yuan / m; C b is the drill bit cost, unit: Yuan; C r is the drilling rig operation cost, unit: Yuan / h; t is the drilling operation time, unit: h; F is the drill penetration, unit: m.

9. The method for recommending drill bit selection scheme based on mechanical specific energy according to claim 1, characterized in that: The specific method for selecting the drilling plan data with the corresponding historical minimum mechanical specific energy as the recommended drill bit plan in the step 4 is to obtain the characteristic value Mse of the construction well data through the values ​​of the drilling parameters of the historical wells in the same block, the same well type and the same layer established in the database in step 1; the drill bit benefit index Eb is calculated by the mechanical drilling speed Vp, the total footage of the drill bit F and the drill bit cost, and the average value of the sampling model characteristic value is obtained, and then the variance of the model value of the historical wells close to the value of the existing model is obtained according to the average value; these historical wells in the same block, the same well type and the same layer are arranged according to the variance, the smaller the variance, the smaller the discrete value, which means that it is closer to the average value, that is, the historical model data is closer to the existing model data, and then these data are arranged according to the degree of similarity, and finally the drill bit optimization plan corresponding to the minimum variance is selected.

10. A drill bit selection method based on mechanical specific energy as claimed in claim 9, characterized in that: The specific method for obtaining the characteristic value Mse of the construction well data is obtained by the following method: in, N = turntable speed + screw speed, screw speed = displacement Q / displacement per revolution q; T = turntable torque * 0.7 + △PQ / ω; The drilling pressure W, rotary table speed, rotary table torque, mechanical drilling speed, displacement Q, and pump pressure are collected from the drilling parameter instrument; The drill area Ab is provided by the drill daily report; The displacement per revolution q is provided by the screw configuration table; Angular velocity ω is equal to the screw speed; Screw pressure drop △PQ = average pump pressure when the drilling pressure is greater than 40KN after the pump is turned on - average pump pressure when the drilling pressure is 0 after the pump is turned on; The drill bit benefit index Eb is obtained by the following equation: Eb=αFVp / Cb in, Vp is the mechanical drilling speed, unit: m / h; α is the coefficient of the equation, which is 1; F is the total penetration of the drill bit, unit: m; Cb is the drill bit cost, unit: yuan; Eb is the drill bit efficiency index, unit: m 2 / h* yuan.

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