Drill hole deflection prediction method based on rock mass structural surface non-contact scanning and blasting well completion method

Abstract

The invention belongs to the technical field of blasting well bodies, and particularly relates to a drill hole deflection prediction method based on rock mass structural plane non-contact scanning and a blasting well completion method.The method comprises the steps that non-contact scanning is conducted on joint fissures combined with rock mass structural planes in a well completion area, and dominant joint groups are determined; constructing a two-dimensional jointed rock mass model based on the dominant joint group, and determining each dominant joint point location in the dominant joint group based on the two-dimensional jointed rock mass model; determining a state parameter when a drill bit penetrates through each joint interface when a drilling procedure is carried out on each dominant joint point location; and when the drill bit passes through the joint fissure and unbalance loading of the drill bit occurs, the blast hole deviation rate is determined based on the state parameters and stress analysis of the drill bit. According to the method, scientific, accurate and efficient borehole deflection prediction can be carried out in the joint fissure development area.

Description

Technical Field

[0001] The invention belongs to the technical field of well-breaking and well-forming methods, and in particular relates to a drilling deviation prediction method based on non-contact scanning of rock mass structural surfaces and a blasting well-forming method. Background Art

[0002] In the process of blasting wells, drilling a large number of vertical blastholes is an essential step. However, the blastholes often deviate during the construction process, which will lead to inconsistent resistance lines at the hole mouth and bottom, and then cause problems such as rock mass refusing to blast, over-concentrated blasting or premature attenuation, which ultimately affects the formation effect of the well.

[0003] There are many factors that affect the deviation of blastholes. In addition to the manufacturing level and positioning accuracy of the rock drilling equipment itself, the axial pressure control of the drill bit, the changes in rock mass structure and rock properties will also affect the deviation of the borehole. It is particularly worth noting that this effect is more significant in areas with developed joints and fissures.

[0004] Joints and fissures can be regarded as a kind of soft rock with zero hardness, forming a special soft-hard interlayer. During the drilling process, when the drill bit encounters this soft-hard interlayer, it will be affected by unbalanced forces and torques, causing the drill bit to gradually drift, and eventually causing the borehole to deviate. For mines with more developed joints and fissures, this effect is particularly prominent and may even become the dominant factor in the deviation of the blasthole.

[0005] Accurately predicting borehole deflection is of great significance for improving rock drilling accuracy, ensuring project quality and improving construction efficiency. Through prediction, the deflection rate of the predicted borehole can be understood before drilling construction, so that the drilling design plan can be planned and adjusted more reasonably, and the rock drilling area can even be reselected if necessary.

[0006] However, the current prediction methods for borehole deviation are still imperfect. Traditional methods mainly rely on the experience of rock drillers, and make empirical judgments based on equipment models and geological conditions in the well drilling area. They lack scientificity and accuracy, and it is difficult to provide reliable data support for construction decisions.

[0007] Although some technical solutions have been proposed to solve this problem, such as the Chinese invention patent CN116677370A, which discloses a method and device for predicting the degree of borehole deviation based on historical drilling data, this solution still has obvious shortcomings: it requires a large amount of historical drilling data, including drill rod parameters, rock formation parameters and real-time parameters of historical drillings, which are difficult for most mines to obtain in a short time. In addition, this solution also requires obtaining parameters such as the real-time position and speed of the drill bit corresponding to multiple moments, but the rock drilling equipment of most mines is not intelligent enough to meet this requirement.

[0008] Especially for areas with developed joints and fissures, existing prediction methods often fail to accurately grasp their particularities, resulting in large deviations between the prediction results and the actual situation. This not only affects construction efficiency, but may also bring potential safety hazards.

[0009] Therefore, it is urgent to develop a borehole deflection prediction method specifically for areas with developed joints and fissures. Summary of the invention

[0010] In response to the problems existing in the background technology, the purpose of the present invention is to provide a method for predicting borehole deviation based on non-contact scanning of rock structure surfaces, which obtains rock joint information in the well drilling area through non-contact scanning of rock structure surfaces, including joint dip, inclination, and spacing; constructs a drill bit mechanical model for vertical downward drilling taking into account the joint occurrence, and realizes scientific, accurate, and efficient prediction of borehole deviation in areas where joints and fissures are developed.

[0011] To achieve the above-mentioned purpose, the present invention discloses a method for predicting borehole deflection based on non-contact scanning of rock mass structural surfaces, which performs non-contact scanning on joint fissures combined with rock mass structural surfaces in a well drilling area to determine a dominant joint group; constructs a two-dimensional jointed rock mass model based on the dominant joint group, and determines each dominant joint point in the dominant joint group based on the two-dimensional jointed rock mass model; determines the state parameters of the drill bit when it passes through each joint interface when the drilling process is performed on each dominant joint point; and determines the borehole deflection rate based on the state parameters and the force analysis of the drill bit when the drill bit passes through the joint fissures and the drill bit is overloaded.

[0012] In a preferred embodiment of the present invention, a method for non-contact scanning of joints and fissures combined with rock mass structural surfaces in a well drilling area comprises: S1, joint scanning point determination; S2, joint and fissure non-contact scanning.

[0013] In a preferred embodiment of the present invention, in S1, about 50 to 100 m of the upper and lower tunnels in the well formation area are divided as joint scanning areas, and 10 to 20 points with developed joints and fissures and no shotcrete support are selected as joint scanning points.

[0014] In a preferred embodiment of the present invention, in S2, S21, a benchmark is erected vertically on the ground in front of the measured rock mass, and the distance A between the benchmark control points is measured; S22, a smart phone or a camera is used to photograph the rock mass at two positions on the left and right, and the distance D between the lens and the measured rock mass and the distance B between the two imaging positions must satisfy the relationship: B=D / 8~D / 5; S23, a compass is used to measure the inclination and dip of the measured rock mass surface; S24, the obtained left and right views are imported into the software system, and a three-dimensional image of the rock mass surface is synthesized through benchmark calibration, pixel matching, and image deformation and bias correction; S25, the distance A between the benchmark control points and the inclination and dip of the rock mass surface are input to make the orientation, size and distance of the three-dimensional image realistic; S26, the rock mass structural surface is identified, grouped and analyzed, and the corresponding measurement results are derived to obtain the dominant joint group and its occurrence, and the occurrence includes the inclination α, dip φ, and spacing h.

[0015] In a preferred embodiment of the present invention, the method for constructing a two-dimensional jointed rock mass model comprises:

[0016] After the on-site scanning and data processing of the joints and fissures, a total of q groups of dominant joints are obtained, among which the inclination angle α of the i-th group of dominant joints is i ,tendency Spacing h i , where i∈{1,2,3,...,q}, the height of the well is H, then the number of times the drill bit passes through the i-th group of dominant joints during the drilling process is m i The calculation formula is as follows:

[0017]

[0018] The total number of times the drill bit passes through all joint groups is recorded as m, and the calculation formula is as follows:

[0019]

[0020] Combined with the occurrence of multiple groups of dominant joints obtained by non-contact scanning of the rock mass structural surface, the middle of the patio was taken as the symmetry axis, and i groups of dominant joints were arranged symmetrically according to the inclination angle and spacing to construct a two-dimensional jointed rock mass model.

[0021] In a preferred embodiment of the present invention, during the drilling process, the drill bit passes through the i-th group of dominant joints from top to bottom. i1 , O i2 ,…,O ij , where O ij represents the point when the drill bit passes through the i-th group of dominant joints for the jth time, where j∈{1,2,3,...,m i}, when the drill bit passes through point O ij When the drill rod length L in the jointed rock mass is ij The calculation formula is:

[0022]

[0023] In a preferred embodiment of the present invention, the state parameters include index parameters, joint parameters, position parameters and deflection parameters, and the index parameter k is the value of the position of the drill bit when drilling to O. ij The number of joints crossed when the point is located, k∈{1,2,3,...,m}; three joint parameters L k , α k , is the parameter of the drill bit passing through the joint for the kth time, and the four position parameters x k , y k , is the coordinate of the current state of the drill bit relative to the original design position, and the four deflection parameters Δx k , Δy k , is the deflection of the current joint to the drill bit.

[0024] In a preferred embodiment of the present invention, the blasthole deflection rate s is:

[0025] where x m ,y m is the deflection coordinate of the borehole after passing through q groups of dominant joints.

[0026] The present invention also discloses a blasting well construction method, in which drilling construction is carried out in a joint and fissure development area in a well body, and before construction, a blasthole deviation rate s is determined by a drilling deviation prediction method based on non-contact scanning of a rock mass structural surface, and during drilling construction, the deflection of the drill bit is compensated based on the blasthole deviation rate s.

[0027] In a preferred embodiment of the present invention, the well body includes a cutting well, a ventilation well, and a chute.

[0028] The beneficial effects of the present invention are as follows: the present invention firstly adopts the non-contact scanning technology of the rock mass structural surface to obtain the dominant joints and occurrence of the rock mass in the well formation area, and then constructs a two-dimensional jointed rock mass model, and defines the drill bit state parameters including index parameters, joint parameters, position parameters and deflection parameters. By constructing a drill bit mechanical model for vertical downward drilling taking into account the occurrence of joints, the present method realizes the scientific, accurate and efficient prediction of borehole deflection in the joint and fissure development area. Since the method constructs the drill bit mechanical model based on the actual joint measurement on site, the uncertainty of the blasthole deflection prediction is significantly reduced. Compared with the traditional method, the present invention not only improves the accuracy and efficiency of the prediction, but also provides a reliable basis for drilling construction in the joint and fissure development area. In addition, the method does not need to rely on a large amount of historical drilling data and highly intelligent rock drilling equipment, has wide applicability and practical value, and provides strong support for optimizing the drilling design scheme and improving the construction quality and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of joint scanning points of the present invention;

[0030] Figure 2 It is the scanning position diagram of the joints and fissures of the present invention;

[0031] Figure 3 is a schematic diagram of a borehole passing through the i-th group of dominant joints of the present invention;

[0032] Figure 4 It is a flow chart of constructing a two-dimensional jointed rock mass model of the present invention;

[0033] Figure 5 is the elevation view of the kth joint of the present invention;

[0034] Figure 6 is a cross-sectional view of the kth joint of the present invention;

[0035] Figure 7 is the three-dimensional diagram of the k-th joint of the present invention;

[0036] Figure 8 is a coordinate system diagram of position parameters and skew parameters of the present invention;

[0037] Fig. 9 It is a force diagram of the drill bit of the present invention. DETAILED DESCRIPTION

[0038] The technical solution of the present invention (including the preferred technical solution) is further described in detail below by means of the accompanying drawings and by listing some optional 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.

[0039] The invention provides a method for predicting borehole deflection based on non-contact scanning of rock mass structural surfaces. First, non-contact scanning of rock mass structural surfaces is used to obtain the dominant joints and occurrence of the rock mass in the well formation area, and a two-dimensional jointed rock mass model is constructed based on this. The drill bit state parameters including index parameters, joint parameters, position parameters and deflection parameters are defined, and the prediction of blasthole deflection is realized by constructing a mechanical model. The invention constructs a drill bit mechanical model based on the actual measurement of joints on site, reduces the uncertainty of blasthole deflection prediction, realizes a more scientific, accurate and efficient prediction of borehole deflection, and provides a reliable basis for drilling construction in areas with developed joints and fissures. The specific technical scheme is as follows:

[0040] (1) Determination of well drilling area

[0041] The well construction area is determined based on the actual well construction needs of the mine (such as cutting wells, ventilation wells, chute wells, etc.) and combined with relevant well construction area selection principles.

[0042] (2) Joint and fissure scanning

[0043] ①Determination of joint scanning points

[0044] In the upper and lower tunnels of the well drilling area, about 50 to 100 meters are divided as joint scanning areas, and 10 to 20 points with developed joints and fissures and no shotcrete support are selected as joint scanning points.

[0045] ② Joint and fissure scanning

[0046] A. Place the benchmark vertically on the ground in front of the rock mass to be measured and measure the distance A between the benchmark control points.

[0047] B. Use a smartphone or camera to take photos of the rock mass at two positions, such as Figure 2 The distance D between the lens and the measured rock mass and the distance B between the two imaging positions must satisfy the relationship: B = D / 8 ~ D / 5.

[0048] C. Use a compass to measure the inclination and dip of the rock surface.

[0049] D. Import the acquired left and right views into the software system, and synthesize the three-dimensional image of the rock surface through operations such as benchmark calibration, pixel matching, and image deformation and polarization correction.

[0050] E. Input the distance A between the benchmark control points and the inclination and dip of the rock mass surface to make the orientation, size and distance of the three-dimensional image realistic.

[0051] F. Identify, group, and analyze rock mass structural surfaces, derive corresponding measurement results, and obtain dominant joint groups and their occurrence (inclination α, dip φ, spacing h).

[0052] (3) Construction of two-dimensional jointed rock mass model

[0053] After the on-site scanning and data processing of the joints and fissures, a total of q groups of dominant joints are obtained. The inclination angle α of the i-th group of dominant joints is i ,tendency Spacing h i , where i∈{1,2,3,...,q}. The height of the well is H, and the number of times the drill bit passes through the i-th group of dominant joints during the drilling process is m i The calculation formula is as follows:

[0054]

[0055] In the formula, [] is the rounding symbol.

[0056] The total number of times the drill bit passes through all joint groups is recorded as m, and the calculation formula is as follows:

[0057]

[0058] The spatial distribution of joints is random and uncertain, so the jointed rock mass must be abstracted. Combined with the multiple groups of dominant joints obtained by non-contact scanning of the rock mass structural surface, the middle of the skylight is taken as the symmetry axis, and i groups of dominant joints are arranged symmetrically according to the inclination and spacing to construct a two-dimensional jointed rock mass model, such as Figure 4 shown.

[0059] During the drilling process, the point where the drill bit passes through the i-th group of dominant joints from top to bottom is O i1 , O i2 ,…,O ij ,like Figure 3 As shown, O ij represents the point when the drill bit passes through the i-th group of dominant joints for the jth time, where j∈{1,2,3,...,m i}. When the drill bit passes through point O ij When the drill rod length L in the jointed rock mass is ij The calculation formula is:

[0060]

[0061] (4) Definition of state parameters when the drill bit passes through each joint interface

[0062] The state parameters when the drill bit passes through each joint interface are composed of index parameter, joint parameter, position parameter and deflection parameter. ij The drill bit will enter each joint interface in sequence. ij When the drill bit is positioned, 12 parameters are used to describe the current state of the drill bit, including (k, L k , α k , x k ,y k , Δx k , Δy k , ).

[0063] Where k is the index parameter, that is, the drill bit drills to O ij The number of joints crossed when the point is located, k∈{1,2,3,...,m};

[0064] L k , α k , is the joint parameter, i.e., the parameter of the drill bit passing through the joint for the kth time;

[0065] x k , y k , is the position parameter, which represents the coordinate of the current state of the drill bit relative to the original design position, where the positive y direction of the coordinate system is due north, the positive x direction is due east, and x is k and is the displacement and rotation angle of the drill bit on the xoy plane, y k and is the displacement and rotation angle of the drill bit on the yoz surface. It is easy to know that when k = 1,

[0066] Δx k , Δy k , is the deflection parameter. The positive y direction of this coordinate system is the inclination of the drill bit passing through the joint for the kth time, and the positive x direction is the direction of the drill bit passing through the joint for the kth time, which represents the deflection effect of the current joint on the drill bit. The state parameters are as follows: Figure 5-8 shown.

[0067] (5) Prediction of blasthole deviation

[0068] When the drill bit passes through the joints and fissures, the front working surface contacts rocks of different hardness at the same time, so the force is uneven, the line of action of the resultant force does not coincide with the axis of the drill bit, and the drill bit is overloaded. When the drill bit encounters a joint for the kth time while drilling from the upper tunnel downward, the force analysis of the drill bit is as follows: Fig. 9 shown.

[0069] Fig. 9 Medium F d is the axial pressure on the drill bit, N; M1 is the rotational resistance moment of the rock surface on the drill bit, N·m; M2 is the bending moment of the drilling tool system, N·m; α k is the joint inclination, °; ​​F s 、F Z , N are the sliding resistance, rotation resistance and support force of the rock surface on the drill bit teeth, N; the drill bit radius is R, m; the drill rod length is L k .

[0070] The force analysis of the drill bit yields the following results:

[0071] F s sin(α k +θ yozk )+Ncos(α k +θ yozk )=F d (4)

[0072] M1=F Z R (5)

[0073] M2=(Ncos(α k +θ yozk )+F s sin(α k +θ yozk ))R (6)

[0074] The drill bit is continuously moved downward by the propulsion force of the drilling rig. As the depth increases, the number of drill rods also increases. At this time, the axial pressure on the drill bit is:

[0075] F d =F t +m1g+ρL k πR 2 (7)

[0076] Where: F t is the drilling rig thrust, N; m1 is the mass of moving parts such as thruster, impactor, drill bit, etc., kg; ρ is the density of drill pipe.

[0077] And the sliding resistance F s Satisfy the following formula:

[0078] F s =fN (8)

[0079] Where: f is the friction coefficient.

[0080] The force on the drill bit in the vertical direction of the drill bit on the yoz surface is F y, the bending moment on the yoz surface is M2, and its calculation formula is as follows:

[0081] F y =F s cos(α k +θ yozk )-Nsin(α k +θ yozk ) (9)

[0082] Where: R is the drill bit radius, m.

[0083] According to the stress characteristics of the drill bit, the deformation of the drill bit is simplified to the deformation of the beam under simple load, and according to the formula corresponding to deflection and bending moment in material mechanics, the displacement Δy of the drill rod on the yoz surface k and the rotation angle Δθyoz k for:

[0084]

[0085] Where: EI is the drill pipe bending coefficient.

[0086] Ignoring the influence of rock properties, the rotation resistance torque M1 and the drill bit shaft pressure F d The relationship is as follows:

[0087]

[0088] Where e and u are the proportional coefficient and exponent provided by the rock drill.

[0089] According to the formula corresponding to deflection and bending moment in material mechanics, the displacement Δx of the drill rod on the xoy surface is k and corners for:

[0090]

[0091] From the above, it can be seen that when the drill bit reaches the k+1th joint, considering the inclination of the joint, the calculation formula of its position parameter is as follows:

[0092]

[0093] θyoz k+1 =θyoz k +Δθyoz k (17)

[0094] θxoy k+1 =θxoy k +Δθxoy k (18)

[0095] Will As the initial value, iterate in sequence according to equations (15) to (18), and finally calculate the coordinate value x after the borehole passes through the last joint m ,y m , which is the deflection coordinate of the borehole after passing through q groups of dominant joints. The blasthole deflection rate s can be calculated by the following formula:

[0096]

[0097] Those skilled in the art will readily appreciate that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, combinations, replacements, improvements, etc. made within the spirit and principles of the present invention are included within the protection scope of the present invention.

Claims

1. A method for predicting borehole deflection based on non-contact scanning of rock mass structural surfaces, characterized in that: In the well drilling area, non-contact scanning is performed on the joints and fissures combined with the rock mass structural surface to determine the dominant joint group; a two-dimensional joint rock mass model is constructed based on the dominant joint group, and each dominant joint point in the dominant joint group is determined based on the two-dimensional joint rock mass model; the state parameters of the drill bit when passing through each joint interface during the drilling process for each dominant joint point are determined; when the drill bit passes through the joint fissure and the drill bit is overloaded, the blasthole deflection rate is determined based on the state parameters and the force analysis of the drill bit.

2. The method for predicting borehole deflection based on non-contact scanning of rock mass structural surface according to claim 1 is characterized in that: The method for non-contact scanning of joints and fissures combined with rock mass structural surfaces in a well drilling area includes: S1, determining joint scanning points; S2, non-contact scanning of joints and fissures.

3. The method for predicting borehole deflection based on non-contact scanning of rock mass structural surface according to claim 2 is characterized in that: In S1, about 50 to 100 m of the upper and lower tunnels in the well drilling area were divided as joint scanning areas, and 10 to 20 points with developed joints and fissures and no shotcrete support were selected as joint scanning points.

4. The method for predicting borehole deflection based on non-contact scanning of rock mass structural surface according to claim 2 is characterized in that: In S2, S21, a benchmark is erected vertically on the surface in front of the measured rock mass, and the distance A between the benchmark control points is measured; S22, a smart phone or camera is used to take pictures of the rock mass at two positions on the left and right, and the distance D between the lens and the measured rock mass and the distance B between the two imaging positions must satisfy the relationship: B=D / 8~D / 5; S23, a compass is used to measure the inclination and dip of the measured rock mass surface; S24, the obtained left and right views are imported into the software system, and a three-dimensional image of the rock mass surface is synthesized through benchmark calibration, pixel matching, and image deformation and bias correction; S25, the distance A between the benchmark control points and the inclination and dip of the rock mass surface are input to make the orientation, size and distance of the three-dimensional image realistic; S26, the rock mass structural surface is identified, grouped, and analyzed, and the corresponding measurement results are derived to obtain the dominant joint group and its occurrence, and the occurrence includes the inclination α, dip φ, and spacing h.

5. The method for predicting borehole deflection based on non-contact scanning of rock mass structural surface according to claim 1 is characterized in that: Methods for constructing a two-dimensional jointed rock mass model include: After the on-site scanning and data processing of the joints and fissures, a total of q groups of dominant joints are obtained, among which the inclination angle α of the i-th group of dominant joints is i ,tendency Spacing h i , where i∈{1,2,3,...,q}, the height of the well is H, then the number of times the drill bit passes through the i-th group of dominant joints during the drilling process is m i The calculation formula is as follows: The total number of times the drill bit passes through all joint groups is recorded as m, and the calculation formula is as follows: Combined with the occurrence of multiple groups of dominant joints obtained by non-contact scanning of the rock mass structural surface, the middle of the skylight is taken as the symmetry axis, and i groups of dominant joints are arranged symmetrically according to the inclination angle and spacing to construct a two-dimensional jointed rock mass model.

6. The method for predicting borehole deflection based on non-contact scanning of rock mass structural surface according to claim 5 is characterized in that: During the drilling process, the point where the drill bit passes through the i-th group of dominant joints from top to bottom is O i1 , O i2 ,…,O ij , where O ij represents the point when the drill bit passes through the i-th group of dominant joints for the jth time, where j∈{1,2,3,...,m i }, when the drill bit passes through point O ij When the drill rod length L in the jointed rock mass is ij The calculation formula is:

7. The method for predicting borehole deflection based on non-contact scanning of rock mass structural surface according to claim 1 is characterized in that: The state parameters include index parameters, joint parameters, position parameters and deflection parameters. The index parameter k is the value of the position of the drill bit when drilling to O. ij The number of joints crossed when the point is located, k∈{1,2,3,...,m}; three joint parameters L k , α k , is the parameter of the drill bit passing through the joint for the kth time, and the four position parameters x k 、θxoy k ,y k ,θyoz k is the coordinate of the current state of the drill bit relative to the original design position, and the four deflection parameters Δx k , Δy k , Δθxoy k , Δθyoz k is the deflection of the current joint to the drill bit.

8. The method for predicting borehole deflection based on non-contact scanning of rock mass structural surface according to claim 1 is characterized in that: Hole deviation rate s: where x m ,y m is the deflection coordinate of the borehole after passing through q groups of dominant joints.

9. A method for blasting wells, characterized in that: The blasthole deflection rate s is determined based on the drilling deflection prediction method based on non-contact scanning of rock mass structural surface as described in claims 1-8, and compensation is performed based on the blasthole deflection rate s during drilling.

10. The blasting well construction method according to claim 9, characterized in that: The well body includes a cutting well, a ventilation well and a chute.

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