How to deal with drilling accidents? Be specific. Bury drill, burn drill. Treatment methods of accidents such as collapse and water leakage in the well. Don't come unless you know what to do.

Ring, the residual steel particles will precipitate downward, causing the drilling tool to be squeezed in the hole section of cemented carbide drill, as shown in Figure 8-24-( 1).

(3) When steel particles are drilled with cemented carbide instead of steel particles after casing running, when the hole section of steel particles does not exceed the length of the core pipe, it is easy for steel particles to get stuck in the drill bit due to excessive sand and water transportation. At this time, drilling accidents caused by hard strata are often serious, as shown in Figure 8-24-(2).

(4) When one-time sand blasting is used for steel particle drilling, the hole diameter is large and small, and the drilling hole is tapered. If at the beginning of the next time, the sand production is too large and the water delivery is too small, or the drilling tool stops pumping at the bottom of the hole for some reason, the steel particles will get stuck.

Figure 8-24 Schematic diagram of steel particle clamping drilling tool

(1) steel particles replace fixtures in cemented carbide drilling.

(2) Clamping when drilling with hard alloy steel particles.

4. Irregular hole wall and core, improper operation, diamond drilling or cemented carbide drilling between the drill bit and the hole wall or core diameter, the inner and outer diameters of the drill bit were seriously worn last time, the aperture was correspondingly reduced, and the hole body sizes were different; The kernel is correspondingly thickened, showing a small top and a large bottom. The next time a new drill bit is used, the outside diameter is often larger than the hole diameter; The inner diameter is smaller than the core diameter. If the drill bit runs too hard or escapes when lifting the drilling tool, the drill bit will be directly caught by the hole wall or core, as shown in Figure 8-25. If the rock is uniform, the degree of extrusion will be more serious.

In addition, in steel particle drilling, if the core is broken into pieces, it is easy to run out of the nozzle of the drill bit and squeeze between the drill bit and the hole wall due to centrifugal force.

5. The hole body is bent, and the hole wall forms a "keyway" on the convex arc surface of the inclined hole or the bent hole section, which is often worn by the drill pipe. Especially in decompression drilling, the upper drill pipe will bear tensile force, and when the drill pipe rotates under tensile force, it constantly wants to bend and rub the convex surface of the hole section, or it is often dragged on the convex surface when lifting the drilling tool. As time goes by, a longitudinal groove is formed along the hole wall, which is shaped like a keyway on a mechanical wheel. As shown in Figure 8-26.

The mechanism of "keyway" is often produced in the not-too-hard rock stratum, and it is not suitable to scrape grooves in the too-hard rock stratum. Too soft rock stratum has a high drilling speed, and it is not easy to form a firm "keyway". For drilling holes with "keyway", pull the drill pipe when lifting, and it will be vertical and straight, and naturally embedded in the groove. When the thick diameter rises to the lower end of the keyway, it is blocked and is in a tight state. If the "keyway" is deep and firm, it will cause sticking.

Figure 8-25 Squeezing between Bit, Hole Wall and Core

1- Conical hole 2- Accident drilling tool 3- Conical core

Figure 8-26 Occlusal blockage caused by keyway

1- drill pipe 2- drilling

6. The hole body is irregular, and the size of the hole changes greatly, forming a "suspension bridge" of rock powder. When the flushing fluid carries the rock powder upward, once it reaches the part with enlarged pore size, the flow velocity immediately decreases, and a part of the flushing fluid will form a vortex, so the rock powder will gradually deposit, forming a "suspension bridge", causing the drilling tool to be stuck, as shown in Figure 8-27.

Figure 8-27 Schematic diagram of rock powder "suspension bridge" sticking.

1- rock powder "suspension bridge" 2- drill pipe

Figure 8-28 Casing deflection causes drilling tools to get stuck.

1- casing 2- drilling tool

Rock powder "suspension bridge" is often produced by the following environmental forces:

(1) Rock powder "suspension bridge" is mostly formed at the change of well diameter. The more times the diameter is changed, the greater the chance of forming a "suspension bridge".

(2) Drilling holes at the bottom of natural caves.

(3) When drilling in the soft stratum, the flushing liquid is large, which washes away the hole wall and forms the over-diameter hole section.

(4) Rock blocks or other soluble rock formations, due to the dissolution of flushing fluid, the borehole is seriously over-diameter, and it is easy to form a "suspension bridge" of rock powder at the bottom of the over-diameter hole section.

7. When the casing string is deviated and the casing shoe protrudes, when the casing is used to protect the wall, the casing is not straight, or does not go down to the bedrock hard disk, or the hole body is bent after the casing is reduced, so that the casing shoe protrudes from the bottom of the hole and the lifting of the drilling tool is blocked. Especially when there is a powder taking pipe on the drilling tool, the top of the powder taking pipe is often stuck by the casing shoe. If the group is not concentric with the large-diameter connection, the above situation will be aggravated, as shown in Figure 8-28.

8. Small objects fall into holes. Due to careless operation and carelessness, small tools and objects such as chuck wrench and adjustable wrench fell into the hole and got stuck at the joint between the group and reducer, which made the drilling tool stuck.

Second, the signs before the accident

There are certain signs and characteristics before the drilling tool jam accident. Grasping these signs and taking preventive measures in time are important aspects to avoid such accidents.

1. The drilling tool has resistance during lifting and rotation, such as stagnation and bouncing. The phenomenon of "grounding" often occurs when tripping in.

2. After drilling, the core pipe and the drill bit have obvious scratches, or the large-diameter drilling tool shows that mud and mud skin are scraped out, and the debris in the powder taking pipe increases and the fragmentation increases.

3. If the block falls, the drill gets stuck, and the drill will jump when drilling, there will be a strong feeling when lifting the drilling tool; When lifting the drilling tool, it will not suddenly get stuck; You can often move a certain distance at first. In general, the backflow in the hole is normal.

4. If the exploration stone or keyway is stuck, the position of the card remains the same, and it will be stuck when running into the hole. Generally, there is no clamping force, and the well washing fluid can circulate normally. When the large-diameter drilling tool is out of contact with the blocking part, the drilling tool rotates unimpeded.

5. If the rock stratum is dislocated, the rock stratum expands and contracts when it meets water, and the drill is stuck or stuck, in addition to blocking the lifting drilling tool, the rotation resistance increases, and the pump will jump.

6. If the drill bit is directly stuck with the hole wall, the drilling tool cannot rotate, and the lifting resistance is high, so the water pump will bounce when delivering water.

7. If steel particles squeeze the drilling tool, the pump can be started at the beginning of drilling, but the return water is very small. If the hole is clean and the pump jump is not serious, lifting the drilling tool slightly will reduce the tripping degree and lowering the drilling tool will stop. If there are a lot of drilling powder and rock powder in the hole, the rotation resistance of the drilling tool is large and the pump is seriously stuck.

8. When the core and the drill bit or the broken core are squeezed between the drill bit and the hole wall, the rotation resistance of the drilling tool is large, and it is difficult to lift the drilling tool, but the pump does not trip, and sudden tripping may occur.

Third, the prevention of accidents.

There are many and complicated reasons for drilling tool sticking, so corresponding preventive measures must be taken according to specific conditions and symptoms to eliminate accidents in the bud. General prevention methods are:

1. When drilling in soft, collapsed, broken and easily slipped and dislocated strata, we should do everything possible to keep the hole wall stable.

Use mud with large specific gravity, high viscosity, small water loss and low sand content (1) for flushing. Always keep the mud with good wall-building performance to keep the integrity of the hole wall.

(2) When the drilling tool is lifted out of the hole, it should be filled with mud to keep a certain liquid column pressure on the hole wall.

(3) The flow rate of flushing fluid should not be too large, so as to avoid the soft hole wall being washed away by interest.

(4) The rotation speed of drilling tools should be reduced appropriately to reduce the impact of drill pipe on the hole wall.

(5) In case of serious collapse and shedding, clay ball wall fixation, cement grouting, casing running and polymer hole protection can be used to keep the hole wall stable.

(6) Select appropriate drilling methods, adopt reasonable bit structure and drilling parameters, and ensure that the complex interval can be passed as soon as possible from the aspects of production management and technical measures.

2. When drilling in the rock stratum with large plasticity, water swelling and shrinkage, the following measures should be taken to stop shrinkage.

(1) Use high-quality mud with small water loss, low sediment concentration and low viscosity to wash holes.

(2) Shallow holes (within 200m) are drilled without pumps.

(3) Use a ribbed drill bit to drill holes, and ensure that there is enough annular clearance between the large-diameter drilling tool and the hole wall. Make a large amount of flushing fluid unblocked, and have a certain reducing space to avoid malignant jamming of drilling tools.

(4) Strengthen the work of reaming and trimming the hole wall. After each trip, you can make a special trip to scratch your eyes If something happens, add an reamer above the drill bit and expand it while drilling, which can save the time of special drilling.

(5) Drilling with a drilling tool with a reverse bit installed on the upper part of the powder taking pipe. So that when the aperture shrinks, the reaming wall can be repaired by reverse drilling while rotating the drilling tool, as shown in Figure 8-29.

Figure 8-29 Drilling tool with countersunk bit

1- Reduced Rock 2- Joint 3- Reverse Bit (Left Thread)

3. When drilling in hard rock, the key is to prevent steel particles and broken cemented carbide from being caught.

(1) When drilling steel particles or cemented carbide with diamond, the residual steel particles or broken cemented carbide particles at the bottom of the hole must be salvaged.

(2) When steel particle drilling is changed to cemented carbide drilling, the residual steel particles in the hole must also be fished out.

(3) When cemented carbide drilling is changed to steel particle drilling, small steel particle and old steel particle drill bits should be used for the first time, and the amount of sand casting should not be too much, and the water transmission should not be too large. Moreover, when tripping in, you can't go to the bottom. When it is about 0.5m away from the bottom of the hole, start the pump to sweep the hole to prevent it from hitting the bottom and squeezing the hole.

(4) When drilling with steel particles, it is necessary to correctly control the sand delivery and water delivery. The initial sand addition should not be too much; At the end of the figure, there must be no steel particles at the bottom of the hole. Water delivery can't be big or small. In short, a certain amount of steel particles should be left at the bottom of the hole. In order to make the hole diameter change more uniform, steel particles will cause drilling opportunities where the gap between the large-diameter drilling tool and the hole wall is small.

4. In all cases, keep the hole clean.

(1) There is too much rock powder and drilling powder in the hole. When it exceeds 0.3m, it must be fished out specially.

(2) When drilling, it is generally necessary to wait for the flushing fluid to return to the orifice (except for the leaking hole) before drilling. The water pump does not work normally during drilling, so it should be stopped for maintenance. Before overhaul, the drilling tool should be lifted to a safe interval to prevent the drilling tool from being buried.

(3) When using mud, you should do a good job of purification.

(4) When the particle size of rock powder produced during drilling is large or there are cuttings, a powder taking pipe should be adopted.

(5) When drilling into the broken rock stratum, the drilling tool structure should pay attention to the following points:

A. After drilling into the severely fractured formation, the large-diameter drilling tool should be lengthened as much as possible, and the large diameter should be kept at the upper part of the severely fractured formation to reduce the possibility of sticking. After drilling through this layer, cement cementation or casing wall fixation can be used.

B. In case of possible rock falling, the milling cutter reducer joint should be adopted at the upper part of the large-diameter drilling tool. The horseshoe-shaped powder taking pipe at the upper end is used when the powder taking pipe is used; When there is no powder taking pipe to drill holes, it is forbidden to use the powder taking pipe joint.

C, reversely rotating the cemented carbide drill bit on the upper part of the powder taking pipe. When you encounter a falling block, you can sweep it up and sweep it away.

5. Take accurate technical measures to prevent casing from blocking drilling tools.

(1) The casing must be run to the complete rock stratum and reach a certain depth.

(2) The casing must be run straight and the drilling tool must be straight.

(3) When drilling casing shoe accessories, move slowly. Don't mention it suddenly.

(4) When drilling with steel particles after casing running, large-diameter drilling tools should be avoided. Therefore, before running casing, a large-diameter drilling tool with a smaller aperture than the original one is used under guidance, and a small hole equivalent to the length of the large-diameter drilling tool is drilled with steel particles before running casing.

6. Take anti-deviation measures to reduce borehole bending and avoid "keyway" phenomenon.

7. When drilling cemented carbide or diamond, the wear of the inner diameter and outer diameter of the drill bit should be strictly controlled. The wear resistance of drill bit should be improved in the process of structural design and welding manufacture, and premature wear should be prevented in use. The excessively worn drill bit should be replaced in time.

Fourth, the handling method of the accident

After the drilling tool is blocked, it should be handled in time, otherwise it will make the accident cleaner and more serious, and then the drilling tool may be buried or broken.

Handling accidents, collectively referred to as the use of elevators and oil pressure systems to lift upwards, or the combination of series movement and rotation for handling. In the case of backwater, the flushing liquid should not stop. If it doesn't work, you should shake it with a hanging hammer or jack it. If it fails again, it will be reversed, pierced, expanded, cut and cut according to the specific conditions in the hole.

For jamming accidents caused by different reasons, the treatment methods are as follows:

(1) Handle the drilling tools that fall off and get stuck.

If the drilling tool can rotate and move up and down within a certain range, when the drilling tool is stuck, it should be handled in series. Don't forcibly pull the drilling tools, but use a little rope to make the drilling tools move in series. Turn the drilling tool with pliers, then lift the drilling tool. When it is firm, use a little rope and turn the drilling tool with pliers. The distance of lifting each time is greater than the excitation of string return, so that the drilling tool can be gradually lifted away from the orifice by repeatedly "lifting more and returning less rope".

If the serial motion processing is ineffective, the lifting scanning method can be further adopted. If the drilling tool with counter bit has been used in advance, it is very effective to lift it while driving and sweep it up after encountering resistance. If you can't get stuck when lifting and sweeping, you can use a hanging hammer to vibrate up and down. Generally, it is more effective to deal with sticking accidents with hanging hammer in shallow hole section. If it breaks in a deep hole. When the hanging hammer is invalid, it should be impacted in the hole. If the clamping part is in the middle of the drilling hole, it can be drilled back under the weighted drilling tool, such as in the hole, as shown in Figure 8-30. After being pressed in, take out the large-diameter drilling tool with short drill pipe with a tap. If the clamping part is at the bottom of the hole, use a hollow clamping vibrator to impact and vibrate, and then pick up the accident drilling tool together after the effect is achieved.

The structure of the stuck hole vibrator is shown in 8-3 1. When the vibrator is lowered into the well and the accident drilling tool and tap are twisted, the pull rod drives the lower impact joint to move downwards, so that the flange of the upper reducing joint and the groove of the upper impact joint are twisted, and the tap and accident drilling tool are twisted. When the tap is tightened, the reducer is lifted up to separate the reducing joint from the upper impact joint, and the lower impact joint is combined with the upper impact joint, so that the drilling tool can play the role of impact vibration when driving and rotating.

Figure 8-30 Drilling with Weighted Drilling Tools

1-weighted drilling tool 2-falling block 3-accident drilling tool

Fig. 8-3 1 hole vibrator structure diagram

1-Upper reducing joint 2-Pull rod 3-Upper impact joint 4-Shell

5— Lower impact joint 6— key 7— washer 8— cotter pin 9— nut 10— water pipe

11-plug wire12-packing box13-plug wire gland14-down reducing.

Precautions for operation:

1. Before use, check the wear of various threads and impact teeth of the jar in detail to prevent new accidents.

2. When tripping in, accurately measure the excess footage on the computer, and master the elevator to prevent tripping in. When approaching the accident drilling tool, lower it slowly.

3. Before starting vibration, water should be sent to the hole to cool the vibrator and remove rock powder from the air.

4. In the process of operation, attention should be paid to the sound of the turntable, and if there is any abnormality, it should be stopped immediately for research and treatment.

5. When the shaft moves upward, it is proved that the treatment is effective and the drilling can be stopped.

After adopting the above methods to deal with the sticking fault, measures such as reaming, drilling, cutting and grinding should be considered. If the borehole is shallow and the rock drillability level is not too high. The method of large diameter expansion can be adopted; If the hole is deep and the rock is hard, small diameter drilling is generally used. Due to the vibration during drilling in Tao Xin, the fixture often loosens naturally. Accident drilling tools can be lifted with taps. If the drilling tool is clamped firmly in the case of deep hole, the accident drilling tool can be directly eliminated by splitting grinding.

(2) Handling the dislocation of probe stones or rock strata and clamping drilling tools.

The main treatment method is to remove the dislocation part of the exploration stone or rock stratum. If the accident drilling tool is equipped with a countersunk bit, the clamped object can be swept up. Otherwise, you can use the hanging cone to vibrate upwards. If the sticking cannot be released, the large diameter can be sent back to the bottom of the well, and all the drill pipes at the upper part of the large diameter can be reversed. Then use drilling tools with the same diameter to break obstacles from top to bottom, and then use taps to salvage accident drilling tools, as shown in Figure 8-32.

If the accident drilling tool is stuck and it is difficult to send it back to the bottom of the hole, first reverse the upper drill pipe, and then use the heavy drilling tool to run down. Before running weighted drilling tools, prevent blockage. According to the specific conditions in the hole, use drilling tools with the same diameter to properly sweep the hole.

Fig. 8-32 Schematic diagram of treatment of dislocation and sticking accident of rock exploration or strata.

1-same diameter drilling tool 2-rock detection 3-accident drilling tool 4-tap

(3) Treatment of drilling tool stuck in shrinkage rock

First, use the elevator to pull, and jack it up. If the above method fails, all drill pipes need to be returned. Eliminate large diameter drilling tools by cutting, splitting and grinding. Generally, methods such as expansion or infiltration are not used. In small diameter drilling, it is easy to cause double clamping because of reaming. At the same time, the clamping of drilling tools is mainly caused by lateral pressure, and the methods adopted often can not get good results.

(4) treating steel particles or broken cemented carbide particles of the extrusion drilling tool.

In general, when steel particles or broken cemented carbide particles squeeze the drilling tool, the flushing fluid can still circulate. First of all, we should increase the capacity of the pump and disperse the squeezed objects. Reduce the degree of extrusion. If the sticking is not serious, lift the drilling tool with elevator during flushing. It can be released by expanding the range of drilling tools. If it fails, you can still hang the hammer. Effective methods to deal with such accidents, especially shallow holes, are more effective. When the hole is deep or the extrusion is serious, if the elevator or hanging hammer fails, it can be treated with a vibrator in the hole.

When all the above methods are ineffective, it is necessary to use a small diameter drilling tool to penetrate the accident drilling tool to reduce the degree of extrusion, and then use a tap to salvage. If it still can't be lifted, it can be cut in sections. Generally, it is not advisable to use reaming to take it, so as to avoid double-clamping accidents.

In order to reduce the physical labor intensity and improve the punching efficiency of the hanging hammer, if conditions permit, the hanging hammer is driven by a roller equipped with a pair of rollers for mechanical impact, as shown in Figure 8-33. In addition, a differential crane can be specially equipped to replace the first-class manual crane with diesel engine or intermediate shaft without drum. The structure of differential hammer crane is shown in Figure 8-34. In fact, the differential hammer machine cuts off the intermediate transmission mechanism and uses the differential instead of the intermediate shaft (or diesel engine) to hammer. When in use, it is installed between the drilling rig and the diesel engine. The rope connection method is shown in Figure 8-35. That is, one end of the bolt is stuck in an appropriate position on the hoisting wire rope; The other end bypasses the flywheel, the one lying on the flywheel winds twice, then passes through two guide pulleys, and finally is fixed on the drum with a rope clamp. When hitting, mainly through the joystick, the cone-drum clutch is combined with the drum, which can hit the hanging cone upwards.

Figure 8-33 Schematic diagram of auxiliary drum lifting hammer of drilling rig

1-Binding 2-Hanging Hammer 3-Drill Pipe Holder 4-Auxiliary Drum 5-Pulling Rope

Figure 8-34 Structural Diagram of Differential Lifting Hammer Mechanism

1-joystick 2-brake wheel 3-brake band 4-differential 5-pulley 6-flywheel

7— Wire rope 8— Guide pulley rope 9— Cone-drum clutch 10— drum wheel 1 1— fork.

Figure 8-35 Schematic diagram of connection mode of differential hammer machine.

1-diesel engine 2-belt 3-pulley 4 of hammer crane-flywheel 5-hammer crane 6-wire rope

7— rig winch 8— drill pipe 9— hanging hammer 10— crown block

(5) Treatment of drilling tools directly stuck on the hole wall

Use elevator to pull out first, but don't turn the drilling tool. Because the drilling tool rotates in the hole, the bit position changes, and the hole wall may be engraved with grooves, which increases the lifting resistance. If the elevator does not move, it can be handled by knocking and jacking according to the specific situation.

(6) Treatment of core drilling.

Generally speaking, the clamping force of core drilling is not strong, so the drilling tool is forcibly pulled out by elevator, and then the rotary drilling tool is started to release after the movable clearance is obtained. Sweep the hole again, put the thrown core into the drill bit, and then drill the hole normally.

(VII) Handling "keyway" sticking

After finding signs of "keyway" in the hole wall, the deviation should be corrected immediately, and the core tube should be extended to enlarge the hole and eliminate the "keyway". When drilling, use a drilling tool with countersink or a core pipe joint with milling blades. When the card symbol appears, drive it up and destroy the "keyway". Sometimes casing should be run to isolate the "keyway". After the "keyway" is stuck, the methods of hanging, driving and jacking are often ineffective, and sometimes a smaller drilling tool can be used to drill holes.

(8) Handling drilling tools stuck in casing shoes.

Use the core pipe nipple with the same diameter as the accident core pipe, heat its lower end and beat it into a contraction shape to make a straightener, and put the straightener into the hole along the drill pipe. Before putting the large-diameter drilling tool into the well, it must be lifted to the casing shoe accessories. In this way, the contraction opening of the straightener is inserted into the upper end of the powder taking pipe, while the tail of the straightener is still in the sleeve, and the lower diameter can be smoothly increased.

In order to eliminate the future trouble of blocking drilling tools, it is necessary to adjust the casing string or use qualified casing shoes to run the casing again.

(9) Treatment of rock powder "suspension bridge" stuck drill

First of all, increase the amount of flushing fluid and try not to let the drilling tool stop rotating. Generally speaking, it can be eliminated by flushing, string drilling and rotating drilling tools with this flushing fluid. If the sticking is serious and both the truck and the pump trip, the drill pipe at the upper part of the "suspension bridge" can be reversed, and the hole can be swept with the same diameter drilling tool. After the rock powder obstacle is removed, the lower drilling tool can be fished out.

(10) Treatment of mud skin adhesion

Alkaline water bath is a simple and effective method with low cost. The so-called alkali water bath is to inject 2%~3% soda water into the hole to soak the accident drilling tool. In the process of pressing alkaline water, tandem and rotary drilling tools should be supplemented. Usually after a few hours, you can put the card.

Section 6 Prevention and Treatment of Drilling Tool Breaking, Falling off and Drilling Accident

Drilling tool fracture refers to the fracture of various joints of drill pipe and core pipe Wainai during drilling. The accident of drilling tool falling off refers to the thread slipping at all connection parts of drilling tool, such as the tripping of drill pipe and joint, the separation of core pipe and drill bit, etc. Trip in refers to the accident that the drilling tool falls into the well during tripping in. This kind of accident is most likely to happen in drilling construction. Generally speaking, if the hole wall is stable and the hole is clean, this accident is easy to deal with. However, if the situation in the hole is complicated and the treatment method is improper, it is easy to appear the phenomenon of "accident set accident". If the rock layer on the hole wall collapses and falls off, the drilling tool will break and get stuck; Because there are rock powder and drilling powder in the hole, the treatment time is long, and the drilling tool is buried; The accident happened at the bottom of an extra-large diameter hole or in a karst cave, so it is difficult to find the person in charge of the accident; Drill pipe sticking accident caused by tripping in; Break into several sections and enter the hole, forming a "brazing" accident and so on. All the above situations increase the complexity and difficulty of handling the accident. Therefore, we should attach great importance to drilling tool fracture and drilling leakage accidents and strictly guard against them. Once it happens, it should be handled correctly in time.

I. Cause of the accident

1. The reason why the drill pipe breaks when the drill string works in the hole is that the working conditions are relatively bad, and a slender "elastic line" with good elasticity and flexibility is formed in the hole. At the same time, when the drill string works in the well, it bears the loads such as tension, compression, torsion and impact rotation, and is in a complex stress state. Therefore, once the combined stress on a certain section exceeds its strength limit, the drill pipe will break.

The main causes of drill pipe fracture are:

(1) During drilling and lifting, the drill pipe is subjected to excessive pressure, torque and tension; If the hole is bent, the bottom of the hole is not clean and the pressure is too high, the drill pipe will break.

(2) In the process of drilling, when there are accidents such as sticking, sticking steel particles, burning and burying, the rotary resistance of drilling tools increases, which may cause drilling tools to break.

(3) When handling accidents, drilling tools are often broken due to strong pulling.

(4) The working condition of the drill pipe in the hole is abnormal, such as the drill pipe itself is not straight and the rotary resistance is large; The drilling hole is severely bent and the drill pipe rotates weakly; The diameter of drill pipe differs greatly from the hole diameter, especially in serious over-diameter intervals (such as large caves, large fractures, old holes, etc. ), will lead to drill pipe fracture.

(5) Poor maintenance of drill pipes causes bending, thread damage or other hidden dangers, as well as serious wear or cracks in use. If the drill pipe is not strictly inspected and replaced in time during use, it is easy to break at the weak point once it encounters great rotational resistance during drilling.

(6) The machining quality of drill pipe is not ideal, such as the locking joint is inconsistent with the thread taper of drill pipe; Excessive concentricity deviation between drill pipe and core pipe leads to excessive bending; The rewinding slot is too deep; The bore hole in the center of the joint is too large; Unqualified drill pipe pier thickness and improper heat treatment will reduce the strength of drill pipe, and accidents such as breaking and tripping are easy to occur during use.

2. Causes of fracture of large diameter drilling tools

(1) The hole is not straight. Due to problems in formation and operation, the borehole suddenly bends. The large-diameter drilling tool broke when passing through the bend. Due to the rotating torque of drill string, the thread of large diameter drilling tool breaks at the bend.

(2) The strength of the thread part of the core pipe with smaller outer diameter is weakened when the core pipe wall is worn thin, and it will be twisted off at the weak point when encountering greater rotation resistance during drilling.

(3) There are defects in drilling tool thread processing, threads are not processed in batches, or the processing quality of various drilling tool threads of different processing units is often different. After connection, it may be too loose or too tight. In fact, not all threads are laborious, which leads to stress concentration and fracture. Or after connection, the drilling tool is not concentric, so that it is bent or not straight, and it is easy to break when it is used too hard.

3. The causes of drilling tools falling off are: tripping, throwing and tripping. The reason is:

(1) The threads of drilling tools are improperly matched, and they are too loose or too tight after connection; Some thread ends are not well protected; When the threads are misaligned, the force is distorted, resulting in thread deformation, early wear, depression and other phenomena, which makes the thread fit between the drill pipe and the joint loose and the drilling tool trips due to slipping.

(2) When tripping suddenly, the upper drill pipe reverses, resulting in the bit tripping.

Figure 8-6 1 fishing line pipe

(1) Simple fishing line:1-drill pipe 2-locking joint 3-upper joint.

4— Fishing sleeve 5— Lower joint 6— Guide rope joint

(2) Schematic diagram of core fishing pipe:1-drill pipe 2-locking joint 3-upper joint.

4— Locking joint 5— Short drill pipe 6— Fishing pipe 7— Locking joint 8— Lower joint

(2) Handling of cable and instrument clamping accidents

During inclinometer or logging, when the instrument and cable are stuck in the hole and cannot be pulled up, they should not be pulled up forcibly, so as not to break the cable and fall out of the hole, which will aggravate the accident.

There are two ways to deal with this jam accident.

1. This is a special tool for cutting reducing joint with core pipe, as shown in Figure 8-62. When in use, connect the reducing joint with the core pipe, pass the cable through the hole, then connect it with the drill pipe and slowly lower it to the head of the instrument, and gently cover it, so that the instrument can be introduced into the core pipe by pulling the cable, and then the instrument and cable can be lifted out of the hole after the plug is squeezed out.

Figure 8-62 Processing of Cutting Reducing Joint and Core Pipe

1-Cutting reducer 2-cable hole 3-core pipe 4-drill pipe 5-cable 6-instrument

2. When the instrument is severely stuck in the hole, handle it with the salvage cable connector, as shown in Figure 8-63. When in use, loosen all cables on the winch, insert the wire rope ferrule on the cable joint along the cable, then connect the cable joint with the drill pipe, then tighten the cable and slowly lower the drilling tool. When descending, if the cable is forced downward, it can be gently strung together to prevent the cable from being clamped tightly. When the ferrule is lowered to 5~ 10m away from the instrument in the hole, slowly lift the drilling tool. If you are strong, you can move up and down continuously and slowly pick up the instruments squeezed in the hole. If the lifting fails, the cable connector can be lowered to the top of the instrument, and the cable will be pulled off at the lower part with a strong pull, and the rest can be taken out together with the core sleeve.

Figure 8-63 Treatment of Cable Joints

1-upper joint 2-iron wedge 3-steel wire rope (diameter 9 ~12mm) 4-lower joint.

5. Size and specification of explosive barrel:

The general calculation method can be calculated according to the volume formula, namely:

The volume of explosive cartridge V=C/r (15- 1).

The length of the cartridge is L=4V/πd2 (15-2).

Where: c-explosive quantity;

R—— the specific gravity of explosives;

D—— Inner diameter of explosive tube

Matters needing attention

1. After probing the hole, put the explosive cartridge into the hole;

2. When initiating, it is absolutely forbidden to stand around the jack and in the inclined direction of the casing (referring to the inclined hole);

3. In order to prevent the explosion from damaging the bottom of casing, the position of explosive cartridge should be lower than the lower end of casing1~1.5m;

The weight of the blasting cylinder is relatively light, and heavy objects can be hung under the blasting cylinder.

5. When blasting, the blasting regulations should be strictly observed and must be operated by skilled blasting personnel;

6. In order to give full play to the blasting effect, the shaped charge explosion tube can be designed according to the vibration direction;

7. For the reliability of explosion, two electric detonators with the same resistance should be connected in parallel in an explosion tube;

8. The sealing performance of the explosive tube should be tested on the surface first.

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