A method and system for ensuring the core recovery of soft and hard interbedded rock

Abstract

The application discloses a kind of prompting method and system for ensuring soft and hard interbedded core recovery rate, method includes:1) collecting drilling speed, drilling speed, main system pressure and mud pump pressure parameter;2) the interval value of each parameter is respectively calculated to obtain the interval mean of each parameter;3) compare the interval mean of each parameter itself adjacent respectively, if positive and negative percentage change is greater than control threshold, then it is recorded as positive mutation or negative mutation;4) combination is judged according to the mutation of each parameter, and corresponding prompt is given.The application collects relevant data and processes data, so as to scientifically and quickly identify the mutual change of soft and hard interbedded in the process of core drilling, timely remind staff of the change event and the category of change of soft and hard rock formation, so that staff can adjust drilling strategy in time, so as to ensure the core recovery rate when soft and hard interbedded core drilling is carried out.

Description

Technical Field

[0001] This invention relates to the field of core drilling technology, and in particular to a method and system for ensuring the recovery rate of core samples from alternating soft and hard layers. Background Technology

[0002] In geological exploration and other work, a lot of manpower, material resources, financial resources and time are spent on core drilling. The fundamental purpose is to extract cores with guaranteed quality and quantity, which serve as primary physical data for geological research, mineral resource evaluation and reserve calculation in the exploration area. Therefore, the core recovery rate is a key indicator for measuring the quality of drilling.

[0003] If the rock layer has a relatively uniform density, dense structure, complete texture, high hardness, and high strength, it will have vibration and impact resistance during the drilling process, which is more conducive to core extraction. Conversely, if the rock layer is easily eroded, or has alternating soft and hard layers, it will be less conducive to core extraction.

[0004] Therefore, during the drilling process, it is necessary to pay close attention to changes in drilling parameters, such as drilling pressure, rotation speed, and drilling footage, to accurately determine the changes in the hardness of the formation, and to adjust the drilling methods and parameters in a timely manner to adapt to the drilling needs of different formations.

[0005] Currently, the main approach relies on staff to notice changes in the drilling rig's parameters and then make corresponding judgments and adjustments based on their experience. However, the experience levels of drilling rig staff vary, and they need to concentrate on observation for long periods of time, making it difficult to keep track of parameter changes at all times. If these changes are not addressed in a timely manner, it can lead to the failure to obtain core samples, resulting in a decrease in the core recovery rate. In severe cases, it can lead to the borehole being scrapped, requiring the drilling of a new hole, which can cause significant losses. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method and system for ensuring the core recovery rate of interbedded soft and hard rock, so as to solve the technical problem in the background mentioned above.

[0007] The technical solution of this invention is as follows:

[0008] A method for ensuring core recovery rate of interbedded soft and hard rock includes the following steps:

[0009] (1) Collect drilling speed, drilling speed, main system pressure and mud pump pressure parameters;

[0010] (2) Calculate the mean of each parameter's interval value by taking the mean of the interval values ​​of each parameter;

[0011] (3) Compare the mean value a of each parameter with the intervals adjacent to it. If the positive or negative percentage change is greater than the control threshold, it is recorded as a positive mutation or a negative mutation.

[0012] (4) Make a combined judgment based on the mutation of each parameter and give corresponding prompts;

[0013] If the drilling speed changes positively, the drilling rate changes negatively, the main system pressure changes negatively, and the mud pump pressure changes to zero, it indicates that the formation has hardened.

[0014] If there is a sudden positive change in drilling speed, a sudden negative change in drilling rate, a sudden negative change in main system pressure, or a sudden positive change in mud pump pressure, it indicates core blockage.

[0015] If there is a sudden negative change in drilling speed, a sudden positive change in drilling rate, a sudden positive change in main system pressure, or a sudden zero change in mud pump pressure, it indicates that the formation has softened.

[0016] Furthermore, the interval mean of each parameter in step 2 Where t0 is the end time of the previous recording interval, t1 is the interval length for calculating the mean, and f(t) is a function of the time corresponding to each parameter.

[0017] Furthermore, where t1 is 0.5s-1s, the interval mean a is calculated every 0.5s-1s.

[0018] Furthermore, the interval mean of each parameter in step 2 Where i and n are both integers, td is the sampling interval, and f(t) is a function of the time corresponding to each parameter.

[0019] Furthermore, td·n equals 0.5-1s, and n≥10.

[0020] Furthermore, the control threshold in step 3 is 6%-8%.

[0021] This invention also provides a system for implementing the above method, including a PLC and connected to it a speed sensor, a displacement sensor, a pressure sensor A, a pressure sensor B, an alarm, an HMI (human-machine interface), and a prompter; the speed sensor is used to monitor the drilling speed of the drill rod, the displacement sensor is used to monitor the drilling speed of the drill rod, the pressure sensor A is used to monitor the hydraulic pressure of the main system of the drilling rig, and the pressure sensor B is used to monitor the hydraulic pressure of the mud pump; the alarm is an audible and visual alarm, used to prompt the operator about the current formation conditions and the operating status of the drilling rig, and the HMI is used to display the data of each sensor and set drilling parameters.

[0022] Furthermore, the indicator consists of three groups of lights of different colors, corresponding to three working conditions: hardening of the formation, core plugging, and softening of the formation.

[0023] The advantages of this invention are:

[0024] This invention scientifically and quickly identifies the mutual changes between soft and hard strata and the state of the core entering the core tube during drilling by collecting and processing relevant data. It promptly alerts the staff to the occurrence and type of changes in soft and hard rock strata, allowing them to adjust drilling strategies in real time and thus ensure the core recovery rate when drilling cores in soft and hard strata. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the system structure of the present invention. Detailed Implementation

[0026] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0027] like Figure 1 As shown:

[0028] A method for ensuring core recovery rate of interbedded soft and hard rock includes the following steps:

[0029] First, data on drilling rotation speed, drilling rate, main system pressure, and mud pump pressure are collected. When the drilling rig encounters alternating layers of soft and hard rock, the different geological characteristics of these layers will cause significant changes in these parameters, including drilling rotation speed, drilling rate, main system pressure, and mud pump pressure. Moreover, these changes are systematic; therefore, it is crucial to understand these variable parameters first.

[0030] Then, the interval values ​​of each parameter are averaged to obtain the interval mean of each parameter. This is because even in a constant geological formation, the values ​​of these parameters fluctuate, making direct comparison impossible. Therefore, they must first be averaged. This patent provides two methods for averaging:

[0031] The first type:

[0032] Interval mean of each parameter Where t0 is the end time of the previous recording interval, t1 is the interval length for calculating the mean, and f(t) is a function of each parameter corresponding to time. This processing method involves taking a definite integral of the function curve of each parameter corresponding to time within an interval, and then dividing it by the length of the interval to obtain the mean within that interval. The advantage is that the calculation is relatively accurate and can effectively avoid the interference of outliers. However, it requires a relatively large amount of computation from the system, and the collected interval time should not be too long. t1 is 0.5s-1s, and the interval mean a is calculated every 0.5s-1s.

[0033] The second type:

[0034] Interval mean of each parameter Where i and n are both integers, td is the sampling interval, and f(t) is a function of the time corresponding to each parameter. This method collects a value in a very short time, and then collects multiple values ​​at intervals and divides by the number of collections to obtain the average. For example, a value is selected every 100 milliseconds for accumulation, and then divided by the total number of values. This is similar to the first method, except that it does not need to calculate all values. Similarly, considering the accuracy issue, td·n equals 0.5-1s, and n≥10. That is to say, the sum of all intervals of collecting values ​​cannot exceed 0.5-1s, and the minimum number of values ​​cannot be less than 10.

[0035] Next, we compare the mean value 'a' of each parameter with the mean value 'a' of its adjacent intervals. If the positive or negative percentage change is greater than the control threshold, it is recorded as a positive or negative mutation. Since the parameters of the drilling rig will also fluctuate within a small range under normal circumstances, a control threshold needs to be set. Based on our company's multiple experiments, we believe that 6%-8% is more appropriate, which is neither too sensitive nor too sluggish, and the accuracy rate can reach more than 95%.

[0036] Finally, the system combines and judges the changes in various parameters and provides corresponding prompts.

[0037] If the drilling speed changes positively, the drilling rate changes negatively, the main system pressure changes negatively, and the mud pump pressure changes to zero, it indicates that the formation has hardened.

[0038] If there is a sudden positive change in drilling speed, a sudden negative change in drilling rate, a sudden negative change in main system pressure, or a sudden positive change in mud pump pressure, it indicates core blockage.

[0039] If there is a sudden negative change in drilling speed, a sudden positive change in drilling rate, a sudden positive change in main system pressure, or a sudden zero change in mud pump pressure, it indicates that the formation has softened.

[0040] The present invention also provides a system for implementing the above method, including a PLC and connected thereto a speed sensor, a displacement sensor, a pressure sensor A, a pressure sensor B, an alarm, an HMI human-machine interface, and a prompter; the speed sensor is used to monitor the drilling speed of the drill rod of the drilling rig, the displacement sensor is used to monitor the drilling speed of the drill rod of the drilling rig, the pressure sensor A is used to monitor the hydraulic pressure of the main system of the drilling rig, and the pressure sensor B is used to monitor the hydraulic pressure of the mud pump.

[0041] The alarm is an audible and visual alarm, used to alert the operator to the current formation conditions and drilling rig operating status. The HMI (Human Machine Interface) is used to display data from various sensors and set drilling parameters.

[0042] A Programmable Logic Controller (PLC) is a digital electronic device specifically designed for industrial applications. It employs a programmable memory to store instructions for performing logical operations, sequential control, timing, counting, and arithmetic operations, controlling various types of machinery or production processes through digital or analog inputs and outputs.

[0043] Working principle: The PLC receives input signals from speed sensor, pressure sensor A, and pressure sensor B through I / O ports, and receives position values ​​from displacement sensor through communication port. Then, based on the control thresholds and sampling parameters preset in the HMI (Human Machine Interface), and combined with the logic program stored in the PLC (mainly the mean processing algorithm, comparison algorithm, and judgment algorithm, the methods of which are given in the text; the programming method is existing technology, and technicians can program accordingly according to the processing program method), the PLC processes these signals and outputs signals to external devices such as alarms and prompts through I / O ports, as well as outputting the calculated position values, speed, pressure, and other data to the HMI.

[0044] To help staff monitor the situation, the indicator consists of three groups of lights of different colors, corresponding to three working conditions: hardening of the formation, core plugging, and softening of the formation. This allows for timely adjustments to the drilling rig to ensure core recovery rate.

[0045] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A method for ensuring the soft and hard interlayer core recovery rate, characterized in that, Includes the following steps: (1) Collect drilling speed, drilling speed, main system pressure and mud pump pressure parameters; (2) Calculate the mean of each parameter's interval value by taking the mean of the interval values ​​of each parameter; (3) Compare the mean value a of each parameter with the intervals adjacent to it. If the positive or negative percentage change is greater than the control threshold, it is recorded as a positive mutation or a negative mutation. (4) Make a combined judgment based on the mutation of each parameter and give corresponding prompts; If the drilling speed changes positively, the drilling rate changes negatively, the main system pressure changes negatively, and the mud pump pressure changes to zero, it indicates that the formation has hardened. If there is a sudden positive change in drilling speed, a sudden negative change in drilling rate, a sudden negative change in main system pressure, or a sudden positive change in mud pump pressure, it indicates core blockage. If there is a sudden negative change in drilling speed, a sudden positive change in drilling rate, a sudden positive change in main system pressure, or a sudden zero change in mud pump pressure, it indicates that the formation has softened.

2. The method of claim 1, wherein the method is characterized by: Interval mean of each parameter in step 2 where t0 is the end time of the previous recording interval, t1 is the interval length for which the mean is calculated, and f(t) is a function of the parameter at the corresponding time.

3. The method of claim 2, wherein the method further comprises: determining the thickness of the soft and hard layers; and determining the thickness of the soft and hard layers in the core sample. Where t1 is 0.5s-1s, the interval mean a is calculated every 0.5s-1s.

4. The method of claim 1, wherein the method further comprises: determining a target core recovery rate for the soft and hard alternating layer core; and determining a target core recovery rate for the soft and hard alternating layer core. Interval mean of each parameter in step 2 where i and n are integers, td is the interval of the samples, and f(t) is the function of the parameter at the corresponding time.

5. The method of claim 4, wherein the method further comprises: The td·n is equal to 0.5-1s, and n≥10.

6. The method of claim 1, wherein the method further comprises: The control threshold in step 3 is 6%-8%.

7. A system for implementing the method of claim 1-6 for ensuring the core recovery of soft and hard interbedded rock, characterized in that: The system includes a PLC and connected speed sensors, displacement sensors, pressure sensors A and B, an alarm, an HMI (human-machine interface), and a prompter. The speed sensors monitor the drilling speed of the drill rod, the displacement sensors monitor the drilling speed of the drill rod, pressure sensor A monitors the hydraulic pressure of the main system of the drilling rig, and pressure sensor B monitors the hydraulic pressure of the mud pump. The alarm is an audible and visual alarm used to alert the operator to the current formation conditions and the operating status of the drilling rig. The HMI displays the data from each sensor and allows setting drilling parameters.

8. The system for ensuring the soft and hard interlayer core recovery according to claim 7, wherein: The indicator consists of three groups of lights of different colors, corresponding to three working conditions: hardening of the formation, core plugging, and softening of the formation.

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