CN103324112B - Control method of free fall optimal braking time point of heavy hook - Google Patents

Abstract

The invention relates to a control method for the optimal braking time point of the free fall of the heavy hook. The method is to measure the gravity, volume, mud liquid density, mud damping coefficient and other parameters of the heavy hook, and the measured parameters and drilling depth, Input it into the computer, and at the same time input the calculation formula related to the optimal braking time point of the free fall of the heavy hook into the computer. The software quickly calculates and optimizes to determine an optimal braking time point to ensure that the total time of the heavy hook falling is the shortest. The invention is suitable for drilling at different depths and has high efficiency in lowering the heavy hook.

Description

Control method of optimal braking time point for free fall of heavy hook

technical field

The invention relates to a control method for the optimal braking time point of the free fall of the heavy hook, specifically a method for measuring the resistance damping coefficient of the heavy hook when it moves in the drill pipe and mud fluid, and for different drilling methods. Depth, to determine the control method for the time point from free release of the heavy hook to the start of braking and the total time of release.

Background technique

Due to its high drilling efficiency, long bit life and short exploration period, diamond wireline core drilling technology is widely used in geological coring and prospecting construction, especially in deep hole and complex formation core drilling construction.

The operation of traditional fishing core drilling tools, from the start of lowering the heavy hook to the braking of the drawworks, depends on experience. The drilling depth is different, and the braking time is also different, which requires a lot of staff; the heavy hook moves in the mud , the resistance it suffers is related to the mud damping coefficient; the damping coefficient of the mud liquid is related to the density, viscosity of the mud, the shape of the heavy hook and other parameters. At present, there is no authoritative description of the damping coefficient of the mud in rope coring. The control of the lowering speed of the hook also depends on experience; if the control is not good, the lowering speed will cause impact on the core barrel and damage the core barrel, and the lower speed will not be effectively connected with the core barrel, which will affect the drilling efficiency. At present, some control technologies for the free-fall speed of heavy hooks have been disclosed in China, such as constant power automatic speed-adjusting retractable winches, electric drive control systems for well logging winches, speed control methods for free-fall hoists and devices for implementing the methods, The weak point of these technologies is: reach the falling speed of controlling heavy hook by means of installing relevant devices or control parts. In speed control, if related devices or control components are used, the cost performance of the whole set of equipment will be relatively low.

Contents of the invention

The purpose of the present invention is to solve the deficiencies of the prior art, and provide a control method for the optimal braking time point of the free fall of the heavy hook. This method does not need to install complicated devices or control components, but by measuring the The damping coefficient of the resistance encountered by the drill pipe and the mud fluid when moving, and the control method for determining the optimal braking time point of the free fall of the heavy hook through computer programming for different drilling depths.

In order to achieve the above object, the technical solution adopted by the present invention is to provide a control method for the optimal braking time point of the free fall of the heavy hook, which is operated according to the following steps:

Step 1, measure the gravity, volume and mud fluid density parameters of the heavy hook;

Step 2. Measure the mud damping coefficient at the drilling site. The equipment used in the measurement includes: a winch, a tension sensor, a fixed wheel train, a wire rope, a guide wheel and a heavy hook. and heavy hooks, tension sensors are installed on the fixed wheel train; different falling speeds of the two sets of heavy hooks are output through the winch, and the tension sensor measures the tension of the wire rope connected to the heavy hooks. According to the buoyancy, resistance, Braking force and gravity four-force balance, measure the damping coefficient of the resistance of the heavy hook in the mud, and record the data;

Step 3, measure the drilling depth, the drilling depth uses the labeling method to label each lowered drill pipe, and calculate the drilling depth by the serial number of the currently lowered drill pipe;

Step 4. Input the parameters measured in the above steps into the computer, and at the same time, input the calculation formula related to the optimal braking time point for controlling the free fall of the heavy hook into the computer, and compile the control flow of the free fall of the heavy hook in the computer. The computer process software quickly calculates and determines the optimal time point, the value of the braking force and the total time of lowering the heavy hook from free release to the start of braking; the calculation formula includes equation ⑦ as

Equation ⑧ is $\frac{{\mathrm{dv}}_2}{\mathrm{dt}}=g-\frac{f+T}{m}-\frac{k}{m}{v_2}^2;$

Equation ⑨ is $\underset{0}{\overset{t_1}{\∫}}{v}_1\mathrm{dt}+\underset{t_1}{\overset{t_2}{\∫}}{v}_2\mathrm{dt}=h;$

In the formula: m is the weight of the heavy hook, v is the falling speed, v ₁ is the speed before braking, v ₂ is the speed after braking, g is the acceleration of gravity, t is the time of falling, t ₁ is the starting time after the heavy hook is lowered. The optimal time point of braking, _t2 is the total time of the heavy hook falling, k is the mud damping coefficient, F is the buoyancy, T is the braking force, and H is the drilling depth.

The described control process of programming heavy hook free fall in computer is:

In the program, first preset the total time _t3 of the heavy hook to be 1000s; the number of cycles is n, and the initial value is n=0; the initial value of the braking time point _t1 =0s;

Determine whether the number of cycles n is less than the longest number of cycles set in the program, if not, end the cycle;

If so, then output the total time t ₂ of falling that satisfies the calculation of equation 7, 8 and 9;

Judging whether the total time _t value of the calculation is greater than the value of the number of cycles n, if not, then end the cycle;

If yes, then judge whether the calculated total falling time t ₂ is less than the preset total falling time t ₃ , if not, add 1 to the number of cycles n to re-circulate;

If so, assign the calculated total falling time t ₂ to the preset total falling duration t ₃ , assign the value of the number of cycles n to the optimal braking time point t ₁ , and then add 1 to the number of cycles n to recycle; finally, the optimal Braking time point t ₁ .

The computer process software determines the magnitude of the braking force at the start of braking, and the braking force determined by the computer should be slightly reduced in the actual braking operation to ensure that the heavy hook falls safely to the bottom of the well.

Compared with the prior art, the control method for the optimal braking time point of the free fall of the heavy hook has the following advantages:

1. In the method of the present invention, the mud damping coefficient is obtained by drilling on-site measurement, not calculated by the mud damping coefficient formula, so the mud damping coefficient of the present invention has more practical value.

2. The method of the present invention is different from lowering the heavy hook by experience in general drilling operations, but the optimal braking time point is determined through the computer flow software to quickly calculate, and then the process of lowering the heavy hook is artificially controlled. The method of the invention can be used for drilling at different depths to realize the safe lowering of the heavy hook, which can save man-hours and reduce the impact of the heavy hook lowering speed on the bottom-hole drilling tool.

3. The method of the present invention is different from the control of the free fall of the heavy hook by means of installation related devices or control components in the prior art, so the method of the present invention is simple, less investment and obvious effect.

Description of drawings

Fig. 1 is a principle diagram of testing the mud damping coefficient in the control method of the optimal braking time point of the free fall of the heavy hook in the present invention.

Fig. 2 is a control flow chart of the optimal braking time point for the free fall of the heavy hook compiled in the present invention.

Fig. 3 is the graph that the present invention tests 100 meters of drilling down the heavy hook speed, the acceleration change with displacement, time.

Fig. 4 is a graph showing the variation of the speed and acceleration of the heavy hook in the 1000-meter well drilling with displacement and time according to the present invention.

In the above figure: 1-winch; 2-tension sensor; 3 _- fixed wheel train; 4-wire rope; 5-guiding wheel; 6-well wall; 7-mud; 8-heavy hook; point; t ₂ - the total time of falling; n - the number of cycles; t ₃ - the optimal total time.

Detailed ways

The content of the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Embodiment 1: Provide a control method for the optimal braking time point of the free fall of the heavy hook, and operate according to the following steps:

Step 1. In order to determine the optimal braking time point for the free fall of the heavy hook, it is also necessary to first measure the gravity mg, volume V, and mud density ρ parameters of the heavy hook.

Step 2. Measure the mud damping coefficient at the drilling site. As shown in Figure 1, the equipment used for the measurement includes: winch 1, tension sensor 2, fixed wheel train 3, wire rope 4, guide wheel 5 and heavy hook 8. The drawworks 1 is sequentially connected with the fixed wheel train 3, the guide wheel 5 and the heavy hook 8 through the wire rope 4, the tension sensor 2 is installed on the fixed wheel train 3, there is mud 7 in the well wall 6, and the heavy hook 8 falls to the bottom of the well in the mud 7 .

The principle that mud damping coefficient is measured among the present invention is: heavy hook 8 falls in mud 7, and final velocity is uniform velocity, and at this moment heavy hook 8 is balanced under force; Actually mud damping coefficient is relevant with many factors, as the viscosity of mud, Density, shape of heavy objects, etc., which makes it difficult to directly measure the mud damping coefficient. In this method, the damping coefficient of the mud is not considered to be related to other factors, but it can be determined that the movement of the heavy hook 8 in the mud has the following relationship with its speed;

f＝kv ^x ①

In formula ①, f is the resistance of the heavy hook in the mud movement, k is the mud damping coefficient, v is the falling speed of the heavy hook, and x is the power exponent on the speed.

When the heavy hook 8 falls in the mud and moves at a constant speed, the gravity mg, resistance f, buoyancy F, and braking force T on the heavy hook 8 are balanced by four forces:

mg＝f+F+T ②

Among them, F=ρgV _row , f=kv ^x , ρ-mud liquid density, g-gravity acceleration, V _row is the volume of heavy hook drainage.

By setting two different falling speeds of the heavy hook, the tension of the corresponding wire rope can be measured respectively, and the damping coefficient of the mud can be obtained.

According to the formula ②, there are: $\left\{\begin{array}{c}\mathrm{mg}-f-T_1=k{v_{11}}^x\\ \mathrm{mg}-f-T_2=k{v_{\mathrm{twenty\; two}}}^x\end{array}\right.$

The simultaneous equations can be solved to get:

$x=\frac{\lg (\mathrm{mg}-f-T_1)-\lg (\mathrm{mg}-f-T_2)}{\lg v_{11}-\lg v_{\mathrm{twenty\; two}}}$ ③

$k=\frac{\mathrm{mg}-f-T_1}{{v_{11}}^x}$ ④

Calculate the damping coefficient of the mud according to formulas ③ and ④. In order to make the measured mud damping coefficient more reliable, the average value is calculated by multiple measurements, then:

$\stackrel{\‾}{k}=\frac{\underset{i=1}{\overset{\mathrm{no}}{\mathrm{\Σ}}}{k}_i}{\mathrm{no}}$ ⑤

Step 3. Determining the drilling depth. In actual engineering construction, the drilling depth uses the marking method. Carry out the label to each lowered drill pipe, as long as read out the serial number of the drill pipe to be lowered currently, the depth of drilling can be obtained according to the following formula ⑥.

H＝l×n-l′×(n-l) ⑥

In the above formula: H is the drilling depth (m), l is the length (m) of a single drill pipe, n is the label of the currently lowered drill pipe, and l' is the screwing length (m) of the drill pipe.

Step 4. Input the parameters measured in the above steps 1 to 3 into the computer, and at the same time, input the calculation formula related to the optimal braking time point for controlling the free fall of the heavy hook into the computer, and program the control of the free fall of the heavy hook in the computer. The procedure is to quickly calculate and determine the optimal time point, the value of the braking force and the total duration of the descent from the free release of the heavy hook to the start of braking through the computer process software; because the fall of the heavy hook is divided into two stages: free fall and braking. In the free fall stage, under the action of its own gravity, mud resistance and buoyancy, the heavy hook performs accelerated motion with reduced acceleration until the heavy hook falls at a constant speed; in the braking stage, the heavy hook is under the action of gravity, mud resistance, buoyancy and braking force , do deceleration motion with decreasing acceleration until the heavy hook falls at a constant speed.

In the free fall phase, according to Newton's second law:

$\mathrm{<span\; class="notranslate">\; mg</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; m</span>}\frac{{\mathrm{<span\; class="notranslate">\; dv</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; dt</span>}}$

Arranging the deformation can be obtained:

$\frac{{\mathrm{dv}}_1}{\mathrm{dt}}=g-\frac{f}{m}-\frac{k}{m}{v_1}^2$ ⑦

In the braking phase, according to Newton's second law:

$\mathrm{<span\; class="notranslate">\; mg</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; m</span>}\frac{{\mathrm{<span\; class="notranslate">\; dv</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; dt</span>}}$

Arranging the deformation can be obtained:

$\frac{{\mathrm{dv}}_2}{\mathrm{dt}}=g-\frac{f+T}{m}-\frac{k}{m}{v_2}^2$ ⑧

The depth of the heavy hook during the entire falling process is known, v ₁ is the speed of the heavy hook in the free fall phase, v ₂ is the speed of the heavy hook in the braking phase, and the time from lowering the heavy hook to braking is set to be optimal At the braking time point t ₁ , the time for the heavy hook to fall to the bottom of the core barrel is the total time t ₂ of the fall, and the relationship is as follows:

$\underset{0}{\overset{t_1}{\&Integral;}}{v}_1\mathrm{dt}+\underset{t_1}{\overset{t_2}{\&Integral;}}{v}_2\mathrm{dt}=h$ ⑨

Since the heavy hook is in the falling stage, there are constraints of the three equations of formulas ⑦, ⑧ and ⑨, so after multiple n plus 1 cycle calculations by the computer, a series of braking time point t ₁ values are given, and a series of falling can be obtained The total time t ₂ value, from this series of falling total time t ₂ values, select the braking time point t ₁ value corresponding to the minimum falling total time t ₂ value, which is the optimal braking time during the free fall process of the heavy hook point.

The control flow of the optimal braking time point of the free fall of the heavy hook in the present invention is shown in Fig. 2, the total time length of the heavy hook falling is preset t ₃ =1000s, the number of cycles of the initial value is set to n=0, and the initial value is optimally controlled Moving time point t ₁ =0s; Judgment whether the number of cycles n is less than 1000, if not, then end the cycle, if so, then output the total time t ₂ of the calculation that satisfies equations ⑦, ⑧ and ⑨; determine the total time t of the calculation of the whereabouts Whether the value of ₂ is greater than the value of the number of cycles n, if not, end the cycle; if so, judge whether the calculated total falling time t ₂ is less than the preset total falling time t ₃ , if not, add 1 to the cycle number n and re-cycle ; If so, assign the total falling time t ₂ to the preset total falling duration t ₃ , assign the numerical value of the number of cycles n to the optimal braking time point t ₁ , and then add 1 to the number of cycles n to re-circulate; N plus 1 cycle calculation, given a series of braking time point t ₁ value, you can get a series of calculated total falling time t ₂ value, from this series of total falling time t ₂ value, select the smallest total falling time The braking time point _t1 value corresponding to the time _t2 value is the optimal braking time point in the heavy hook free fall process. The computer displays the final optimal braking time point t ₁ .

The present invention simulates drilling 100 meters and drilling 1000 meters, the programming program shows the curves of the free-falling speed and acceleration of the heavy hook with time and displacement as shown in Figures 3 and 4, and the computer shows that drilling 100 meters is the best. The braking time is 16 seconds and the optimal braking time is 161 seconds for drilling 1000 meters.

In actual work, input the data measured in steps 1 to 3 into the program, and the computer will quickly display the optimal braking time point for lowering the heavy hook; then lower the heavy hook and time it to reach the optimal braking time point At this time, the braking force is output through the winch until the heavy hook is lowered to the bottom of the well smoothly. After confirming that the heavy hook is placed, the drawworks is reversed to lift the drilling tool.

When the heavy hook is lowered to the bottom of the well, there must be a certain speed limit, neither too large nor too small. For the sake of safety, the value of the optimal braking force can be determined according to the computer process, and the value of the braking force can be slightly reduced during actual operation. One point to ensure that the heavy hook falls safely to the bottom of the well.

The method of the present invention does not need to install complicated devices or control components, and only needs to quickly calculate and determine the optimal braking time point through computer flow software. The method can be used for drilling at different depths to realize safe lowering of the heavy hook, which can save man-hours and reduce the impact of the excessive speed of lowering the heavy hook on the bottom-hole drilling tool.

Claims (3)

1. A control method for the optimal braking time point of the free fall of the heavy hook, characterized in that: operate according to the following steps: Step 1, measure the gravity, volume and mud fluid density parameters of the heavy hook; Step 2. Measure the mud damping coefficient at the drilling site. The equipment used in the measurement includes: a winch, a tension sensor, a fixed wheel train, a wire rope, a guide wheel and a heavy hook. and heavy hooks, tension sensors are installed on the fixed wheel train; different falling speeds of the two sets of heavy hooks are output through the winch, and the tension sensor measures the tension of the wire rope connected to the heavy hooks. According to the buoyancy, resistance, Braking force and gravity four-force balance, measure the damping coefficient of the resistance of the heavy hook in the mud, and record the data; Step 3, measure the drilling depth, the drilling depth uses the labeling method to label each lowered drill pipe, and calculate the drilling depth by the serial number of the currently lowered drill pipe; Step 4. Input the parameters measured in the above steps into the computer, and at the same time, input the calculation formula related to the optimal braking time point for controlling the free fall of the heavy hook into the computer, and compile the control flow of the free fall of the heavy hook in the computer. The computer process software quickly calculates and determines the optimal time point, the value of the braking force and the total time of lowering the heavy hook from free release to the start of braking; the calculation formula includes equation ⑦ as Equation ⑧ is $\frac{{\mathrm{dv}}_2}{\mathrm{dt}}=g-\frac{f+T}{m}-\frac{k}{m}{v_2}^2;$ Equation ⑨ is $\underset{0}{\overset{t_1}{\&Integral;}}{v}_1\mathrm{dt}+\underset{t_1}{\overset{t_2}{\&Integral;}}{v}_2\mathrm{dt}=h;$ In the formula: m is the weight of the heavy hook, v is the falling speed, v ₁ is the speed before braking, v ₂ is the speed after braking, g is the acceleration of gravity, t is the time of falling, t ₁ is the starting time after the heavy hook is lowered. The optimal time point of braking, _t2 is the total time of the heavy hook falling, k is the mud damping coefficient, F is the buoyancy, T is the braking force, and H is the drilling depth. 2. A method for controlling the optimal braking time point of the free fall of the heavy hook according to claim 1, characterized in that: the control flow for programming the free fall of the heavy hook in the computer is as follows: Set the total time _t3 of the heavy hook falling to 1000s; the number of cycles is n, and the initial value is n=0; the initial value of the braking time point _t1 =0s; Determine whether the number of cycles n is less than the longest number of cycles set in the program, if not, end the cycle; If so, then output the total time t ₂ of falling that satisfies the calculation of equation 7, 8 and 9; Judging whether the total time _t value of the calculation is greater than the value of the number of cycles n, if not, then end the cycle; If yes, then judge whether the calculated total falling time t ₂ is less than the preset total falling time t ₃ , if not, add 1 to the number of cycles n to re-circulate; If so, assign the calculated total falling time t ₂ to the preset total falling duration t ₃ , assign the value of the number of cycles n to the optimal braking time point t ₁ , and then add 1 to the number of cycles n to recycle; finally, the optimal Braking time point t ₁ . 3. The control method for the optimal braking time point of free fall of a heavy hook according to claim 1, characterized in that: the computer process software determines the braking force to start braking, and when the actual braking During operation, the braking force determined by the computer should be slightly reduced to ensure that the heavy hook falls safely to the bottom of the well.