Drill hole geology active and passive combined vibration detection method

Abstract

The invention relates to the field of geological detection of coal mine advanced detection drilling, in particular to an active and passive combined vibration detection method for drilling geology, which comprises the following steps of: recording the drilling depth during drilling while drilling in coal mine advanced detection drilling, and collecting a vibration signal generated by rock breaking of a drill bit as a passive detection signal; the lithology of a drilling point of the drill bit is analyzed according to the passive detection signal, and the lithology of a drilling section is determined according to the drilling depth; shock waves are excited in a gap controllable source excitation pipe of a continuous drill rod, reflected waves are collected to serve as active detection signals, and the geological breaking grade around a drilling section hole is analyzed according to the active detection signals; determining the collapse state of the drilling section based on the lithology of the drilling section and the geological fracture grade around the hole; and based on the collapse state, determining the risk levels of drill holding and drill breaking of the drill rod of the drilling section, and performing early warning according to the risk levels. According to the method, the drill holding and breaking conditions can be judged in real time in the drilling process, normal drilling construction is guaranteed, the drilling depth is increased, and the probability that drilling machine equipment is damaged is reduced.

Description

Technical Field

[0001] The invention relates to the field of geological detection of coal mine advance detection boreholes, and in particular to a combined active and passive vibration detection method for borehole geology. Background Art

[0002] Before tunneling and mining at the working face of a coal mine, in order to ensure the smooth progress of tunneling or mining, it is necessary to obtain information such as geological structure and hydrological disasters ahead of tunneling or mining through construction drilling. During the drilling process, due to the differences in geological conditions of different strata, different geological conditions will be encountered in the extension direction of the borehole. For example, if there are abnormalities such as harder rocks, broken soft coal seams, and collapsed holes, top drilling and stuck drilling may occur during drilling construction, which will lead to the risk of stuck drill and broken drill, resulting in the loss of drilling tools and detection equipment. Summary of the invention

[0003] The present invention aims to provide a combined active and passive vibration detection method for drilling geology, so as to detect drill sticking and drill break anomalies during the drilling process and ensure the safety of drilling equipment.

[0004] The combined active and passive vibration detection method for borehole geology in this scheme includes:

[0005] Step 1: Record the drilling depth of the coal mine advance detection drilling while drilling, and collect the vibration signal generated by the drill bit breaking the rock as a passive detection signal. Based on the passive detection signal, the lithology of the drill bit encounter point is analyzed, and the lithology of the drilling section is determined according to the increase of the drilling depth;

[0006] Step 2: In the gap between the connected drill pipes, a controllable source excitation tube is used to excite vibration waves as active detection signals, and reflected elastic waves are collected. Based on the active detection signals, the geological fragmentation level around the drilled hole is analyzed, and the geological fragmentation level of the drilling section is determined according to the increase in the drilling depth;

[0007] Step 3, determining the collapse state of the drilling section based on the lithology of the drilling section and the geological fragmentation level around the hole;

[0008] Step 4: determine the risk level of drill pipe sticking or drill breaking in the drilling section based on the collapse status, and issue an early warning based on the risk level.

[0009] The beneficial effects of this program are:

[0010] By collecting the drilling vibration signal as a passive signal during the address drilling process, and actively sending the drilling detection signal and then receiving the feedback signal as an active signal, the geological lithology parameters are analyzed based on the passive signal, and the geological integrity parameters are analyzed based on the active signal. The risk level of drill sticking and drill breakage is determined by combining the two parameters, and corresponding early warnings are issued. In the drilling process, the drill sticking and drill breakage situations can be judged in real time to ensure the normal use of the drilling facilities, reduce the probability of damage to the drilling settings, and increase the drilling depth.

[0011] Furthermore, in step 1, a vibration monitoring probe is installed in the advance detection drilling tool to directly collect the vibration signal generated by the drill bit breaking the rock during the drilling process. The processor set in the vibration monitoring probe performs Fourier transform on the collected vibration signal, and calculates the center frequency of the vibration signal, which is compared with the known rock center frequency built into the vibration monitoring probe to obtain the rock type information at the drill bit.

[0012] The beneficial effect is that the accuracy of lithology information can be improved through calculation.

[0013] Furthermore, in step 2, a controllable source excitation tube is used to excite vibration waves to emit elastic waves with controllable center frequency in the borehole, a vibration monitoring probe is used to receive the reflected wave signal after reflection by the formation, and the reflected elastic wave signal is processed by the built-in inversion program of the vibration monitoring probe to obtain the geological fragmentation level around the hole.

[0014] The beneficial effects are: emitting controllable vibration waves in the hole, receiving the signal after feedback in the hole, small energy excitation, smaller detection-related devices, and the emission-related instruments will not be disturbed by environmental noise.

[0015] Furthermore, in step 3, the borehole collapse threshold is determined based on the lithology of the area and the geological fragmentation level around the hole, and the risk levels of drill bit sticking and drill bit breaking are determined based on the length of the drilling section.

[0016] The beneficial effect is: since the greater the drilling depth, the longer the drill rod, there is a certain difference in the risk probability of drill bit sticking and drill bit breaking when the drill rod encounters some special drilling conditions. Therefore, the risk level is determined according to the drilling depth to improve the sensitivity of drill bit sticking and drill bit breaking detection.

[0017] Further, in step 4, the drilling section is divided into short-range and long-range according to a preset length. When it is short-range, it is determined whether the lithology parameters and the geological fragmentation level are within a first preset range. If so, a first level warning is issued; when it is long-range, it is determined whether the lithology parameters and the geological fragmentation level are within a second preset range. If so, a second level warning is issued; the length of the second preset range is less than the length of the first preset range.

[0018] The beneficial effect is: multiple drilling parameters and multiple drilling geological parameters are graded into ranges for early warning, the accuracy of graded early warning is improved, and the second preset range is set smaller than the first preset range, making the graded early warning more sensitive.

[0019] Furthermore, the preset length is 300-500 m, and the first preset range and the second preset range include sub-ranges of multiple parameters.

[0020] The beneficial effect is that it can simultaneously judge the different ranges of multiple parameters under different preset lengths, thereby improving the accuracy of graded warnings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic block diagram of an embodiment of a combined active and passive vibration detection method for borehole geology according to the present invention;

[0022] Figure 2 It is a principle block diagram of an embodiment of the active and passive combined vibration detection method for borehole geology of the present invention. DETAILED DESCRIPTION

[0023] The following is further explained in detail through specific implementation methods.

[0024] Example

[0025] Borehole geological active and passive combined vibration detection methods, such as Figure 1 and Figure 2 As shown, including:

[0026] Step 1: During the drilling process, the drilling depth is recorded in the coal mine advance detection drilling while drilling, and the vibration signal generated by the drill bit breaking the rock is collected as a passive detection signal. The lithology of the drill bit encounter point is analyzed based on the passive detection signal, and the lithology of the drilling section is determined according to the increase in the drilling depth. The lithology includes igneous rock, sedimentary rock, and metamorphic rock. Specifically:

[0027] Vibration signals generated by the drill bit breaking the rock are directly collected during the drilling process by installing a vibration monitoring probe in the advance detection drilling tool. The processor set in the vibration monitoring probe performs Fourier transform on the collected vibration signal and calculates the center frequency of the vibration signal. The center frequency of the vibration signal is compared with the known lithology center frequency built into the vibration monitoring probe to obtain the lithology information at the drill bit. The method for calculating the center frequency of the vibration signal is mainly based on the frequency characteristics of the bandpass filter or the bandstop filter. The center frequency is usually defined as the geometric mean of the bandpass filter (or bandstop filter) frequency, that is, the midpoint between the two 3dB points.

[0028] The passive signal is first filtered according to the pre-stored pump signal and then used as the passive signal. The drilling construction uses the drilling rig as the drilling power to push the drill rod in a certain direction.

[0029] Step 2: In the gap between the connected drill pipes, a controllable source excitation tube excites vibration waves, and the reflected elastic waves are collected as active detection signals. Based on the active detection signals, the geological fragmentation level around the drilled hole is analyzed, and the geological fragmentation level of the drilling section is determined according to the increase in the drilling depth. Specifically,

[0030] Vibration waves are excited by a controllable source excitation tube to emit elastic waves with controllable center frequency in the borehole. The reflected wave signal after reflection by the formation is received by a vibration monitoring probe. The reflected elastic wave signal is processed by the built-in inversion program of the vibration monitoring probe to obtain the geological fragmentation grade around the hole.

[0031] The inversion program's calculation and processing methods for reflected elastic wave signals include elastic wave impedance inversion and elastic wave full waveform inversion. Elastic wave impedance inversion is mainly performed by using the incident angle information of seismic rays, combined with AVO processing, eLOG logging curve editing and STRATA inversion software package. Elastic wave full waveform inversion is a non-destructive testing method. It considers most of the dynamic characteristics of the waveform signal, such as amplitude, first arrival time, spectrum characteristics, time-frequency characteristics and dispersion characteristics, and obtains the physical and mechanical parameters of the target medium through mathematical inversion methods.

[0032] The geological fragmentation level can be divided according to factors such as the integrity of the rock mass, the degree of crack development, and the size of the rock. For example, the geological fragmentation level includes extremely complete rock mass, complete rock mass, relatively complete rock mass, broken rock mass, and extremely broken rock mass. A quantitative value is set for each level to characterize it.

[0033] Step 3, based on the lithology of the drilling section and the geological fragmentation level around the hole, the collapse state of the drilling section is determined. When determining the collapse state, for example, according to the weak rock layer or geological fragmentation area, the drilling strategy and drill bit type are combined, the drilling speed is adjusted, and the collapse state is determined under the feedback of different drilling results. The collapse state includes wellbore collapse during drilling, wellbore collapse when drilling, and wellbore collapse before drilling. The borehole collapse threshold is determined in combination with the lithology of the section and the geological fragmentation level around the hole. The collapse threshold includes temperature, stress, borehole diameter, depth, spacing, and control measures during construction. The collapse threshold is determined by the fragmentation level under different lithologies to indicate that the rock mass is in an unstable state and there is a risk of collapse. The risk level of drill bit sticking and drill bit breaking is determined in combination with the length of the drilling section.

[0034] Step 4, based on the collapse status, determine the risk level of drill pipe sticking or drill breakage in the drilling section. For example, the collapse status determines that the risk level of drill pipe sticking or drill breakage in the drilling section is level three risk, and issue an early warning based on the risk level.

[0035] The drilling section is divided into short-range and long-range according to the preset length. When it is short-range, it is determined whether the lithology parameters and geological crushing level are within the first preset range. The first preset range sets the corresponding performance according to the actual lithology and crushing level. If so, a first-level warning is issued; when it is long-range, it is determined whether the lithology parameters and geological crushing level are within the second preset range. The second preset range sets the corresponding performance according to the actual lithology and crushing level. If so, a second-level warning is issued; the length of the second preset range is less than the length of the first preset range or Chengdu. The preset length is 300-500m. The first preset range and the second preset range include sub-ranges of multiple parameters, such as the numerical ranges of the crushing levels of igneous rocks and sedimentary rocks.

[0036] For example, it is also possible to judge whether there is a risk in the drilling and breaking process based on the amplitude and wave velocity. For example, if the wave velocity is slow and the amplitude is small, there is a risk of biting the drill. When the amplitude and wave velocity exceed the threshold, it is judged that the rock formation will not collapse and the risk is low. First, identify the drilling depth of the borehole, and determine the risk level of biting and bit breaking in combination with the drilling depth. Specifically, it is divided into short-range and long-range according to the preset length according to the drilling depth. The preset length is 300-500m. When it is short-range, it is judged whether the drilling parameters and drilling geological parameters are within the first preset range. If so, a first-level warning is issued. When it is long-range, it is judged whether the drilling parameters and drilling geological parameters are within the second preset range. If so, a second-level warning is issued. The length of the second preset range is less than the length of the first preset range. The second preset range is included in the first preset range. The first preset range and the second preset range include multiple parameter sub-ranges. The drilling section lithology parameters and drilling section geological integrity parameters refer to the elastic wave signals that can be collected by the instrument, such as amplitude, wave velocity, frequency, etc.

[0037] Based on the disordered phase of the reflected wave, the short wave arrival time, the amplitude accounting for half of the relative peak value, and the drilling in the coal seam or mudstone or shale section, it can be identified as a high-risk area prone to collapse.

[0038] During the rock crushing process, if the rock collapses, the drill rod will be buried, which will cause the gravel to be discharged in time. Adding water will cause the fine slag to become mud. If the drill is not detected in time and construction continues, it will cause the drill to break. This embodiment collects the drilling vibration signal as a passive signal during the address drilling process, and actively sends the drilling detection signal and then receives the feedback signal as an active signal. The drilling address parameters are analyzed based on the active signal, and the drilling address parameters are analyzed based on the passive signal. The two parameters are combined to determine the risk level of drill holding and drill breaking, and corresponding early warnings are issued. The drill holding and drill breaking situations can be judged in real time during the drilling and mining process, ensuring the normal use of the drilling facilities, reducing the probability of damage to the drilling settings, and increasing the drilling depth.

[0039] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A combined active and passive vibration detection method for borehole geology, characterized in that: include: Step 1: Record the drilling depth of the coal mine advance detection drilling while drilling, and collect the vibration signal generated by the drill bit breaking the rock as a passive detection signal. Based on the passive detection signal, the lithology of the drill bit encounter point is analyzed, and the lithology of the drilling section is determined according to the increase of the drilling depth; Step 2, exciting vibration waves with a controllable source excitation tube in the gap between the connected drill pipes, collecting reflected elastic waves as active detection signals, analyzing the geological fragmentation level around the drilled hole based on the active detection signals, and determining the geological fragmentation level of the drilling section according to the increase in the drilling depth; Step 3, determining the collapse state of the drilling section based on the lithology of the drilling section and the geological fragmentation level around the hole; Step 4: determine the risk level of drill pipe sticking or drill breaking in the drilling section based on the collapse status, and issue an early warning based on the risk level.

2. The method for combined active and passive vibration detection of borehole geology according to claim 1, characterized in that: In step 1, a vibration monitoring probe is installed in the advance detection drilling tool to directly collect the vibration signal generated by the drill bit breaking the rock during the drilling process. The processor set in the vibration monitoring probe performs Fourier transform on the collected vibration signal, and calculates the center frequency of the vibration signal, which is compared with the known rock center frequency built into the vibration monitoring probe to obtain the rock type information at the drill bit.

3. The combined active and passive vibration detection method for borehole geology according to claim 2 is characterized by: In step 2, a controllable source excitation tube is used to excite vibration waves to emit elastic waves with controllable center frequency in the borehole, a vibration monitoring probe is used to receive the reflected wave signal after being reflected by the formation, and the reflected elastic wave signal is processed by the built-in inversion program of the vibration monitoring probe to obtain the geological fragmentation level around the hole.

4. The combined active and passive vibration detection method for borehole geology according to claim 3 is characterized by: In step 3, the borehole collapse threshold is determined based on the lithology of the area and the geological fragmentation level around the hole, and the risk levels of drill bit sticking and drill bit breaking are determined based on the length of the drilling section.

5. The combined active and passive vibration detection method for borehole geology according to claim 4 is characterized by: In step 4, the drilling section is divided into short-range and long-range according to a preset length. When it is short-range, it is determined whether the lithology parameters and the geological fragmentation level are within a first preset range. If so, a first level warning is issued; when it is long-range, it is determined whether the lithology parameters and the geological fragmentation level are within a second preset range. If so, a second level warning is issued; the length of the second preset range is less than the length of the first preset range.

6. The combined active and passive vibration detection method for borehole geology according to claim 5, characterized in that: The preset length is 300-500m, and the first preset range and the second preset range include sub-ranges of multiple parameters.

Images