1. What is the reason for the resistance of drilling down?How to deal with it? 

The reason for the resistance of drilling down is：

1) The well collapsed after drilling.

2) The mud performance is not good, the water loss is large, the mud cake is thick, and the formation expansion causes the well diameter to shrink.

3) The diameter of the drill bit was severely worn down last time, and the new drill bit caused resistance.

4) The mud is not circulated before drilling, and the bottom is not reached when drilling down.

5) Changes in the structure of drilling tools.If you replace a large drilling tool or increase the diameter of the centralizer, it is also easy to encounter resistance to drilling down by changing the type of drill bit. 

Treatment method：

The mud must be circulated before drilling, and the performance of the mud must be treated well. The mud must be filled in accordance with the regulations during drilling, and the eyes should be drawn when encountering resistance during drilling.Can't be forced or forced down.Check the type and size of the drill bit in detail before drilling; if the size of the drill tool changes, care should be taken to prevent resistance or stuck when drilling.

2. Why do you sometimes have to circulate mud in the middle of drilling? 

1) The well has not been drilled for a long time, or the mud has not been circulated for other reasons before the last drilling, to prevent the mud performance from deteriorating and the pump cannot be turned on. 

2) The underground formation has collapsed. 

3) The performance of mud deteriorates, salt water, gypsum, etc. 

4) There is a slight leakage underground. 

5) The underground situation is complicated, and the pump often cannot be turned on. 

6) When complex deep or ultra-deep wells, as well as high-pressure oil and gas reservoirs, are serious, the mud should be treated in stages. 

If the mud is not circulated halfway, it will cause resistance to drilling down, and the pump cannot be opened after drilling down, or the pump pressure is too high to hold back the formation.

3. What is a mud short circuit?What is the reason?How to judge?

Incomplete return of mud from the drill bit is called a short circuit of mud.

The cause of the mud short circuit：

The ground high-pressure manifold (gate, flange, yuren, and welding port) is pierced or the gate is inverted.Downhole drilling tools are pierced, inverted, tripped, broken, etc.

The phenomenon of mud short circuit is：

The pump pressure drops, the displacement remains the same, and the cuttings cannot be brought out, causing the drill bit to mud-encrusted and jump, which slows down when drilling, and gets stuck when drilling is serious.

4. What is the reason for the increase in pump pressure during drilling?How to deal with it correctly?

1) The reason for the increase in pump pressure during drilling is that the well collapses, the water hole of the drilling tool is blocked, the mud performance changes, and the scraper drill bit is worn out or the scraper blade is dropped.

2) If the well collapses, a large displacement of circulating mud should be used, and the cuttings at the bottom of the well should be repeatedly scratched to clean up, and the drilling under light pressure should return to normal. If something falls in the drilling tool, the drilling tool should be drilled one by one to check whether the drilling tool is brought in when the single root is drilled. Stones and sand are brought in, the hose rubber is lost, and the rubber rubber is pressed back to the heart of the well, causing the water to block the eye. If the mud deteriorates, the drilling activity should be stopped and the drilling tool should be used to deal with the mud.

5. What is the reason for holding back drilling during drilling?How to deal with it?

The reason for holding back the drill：

1) The drill bit drills into the hard sandwich or soft-hard junction formation.

2) The drill pressure of the drill bit is too large or the drill bit is slippery.

3) Drill into gravel layers or lime caves.

4) The upper strata collapsed.

5) Something fell down the well.

6) The cone is stuck.

7) Drill bit mud bag.

Treatment method：

In the case of stratigraphic causes, the drilling pressure and rotation speed can be adjusted to eliminate them. In the case of drill bits or falling objects, drilling and inspection should be started immediately to determine the lower measures.

6. What is the reason for the jumping drill found during drilling?How to deal with it?

Jumping drilling mostly occurs when the cone drill bit is drilling, the reasons are：

1) Drilling encounters gravel layers, soft and hard interlayers, uneven texture layers (such as flint-containing), strata with cracks and holes, etc.

2) The well collapses or something falls into the well.

3) The drill bit is severely mud-packed.

The treatment method is：

Adjust the parameters to exclude jumping drills. If the treatment is invalid, you should consider falling objects underground, start drilling to check the wear of the drill bit, and take effective measures to prevent the drill from getting stuck during the treatment process.  

7. What is the reason for the sudden drop in pump pressure during drilling?How to check?How to deal with it?

The reason for the sudden drop in pump pressure during drilling is：

The pump is broken or the water supply is not good, the pipeline is pierced and leaks, causing a short circuit cycle, the drilling tool is pierced, the drill bit is pierced, the drilling tool is broken, the ground is leaking, and the mud is invaded.

The method of inspection is：

First check the ground: the working condition of the pump, whether the water supply is good, whether the pipeline and gate are pierced or short-circuited, whether the pump pressure gauge is accurate, and then consider whether the downhole drilling tool is pierced, broken or leaking.

Treatment method：

Emergency repairs should be organized for ground reasons to remove air bubbles.The cause of the downhole drilling tool should be drilled immediately, and the drilling tool should be checked in detail. If the turntable shackle cannot be used, the drilling tool should be prevented from breaking without lifting the brake, and the well leakage should be blocked.

8. Why is the drill bit covered in mud?What is the phenomenon?How to deal with it?

Drilling into soft clay formations, the drilling speed is fast, the displacement is small, and the mud performance is not good, especially the viscosity and shear force are too high, which can easily cause mud packs.In addition, the mud shorted during drilling and continued to drill after the pump was stopped, resulting in dry drilling, which will also be a mud pack for the drill bit.

After the drill bit is mud-packed, the work is not normal. The drilling speed is significantly reduced due to drilling and jumping drills, the load on the turntable is increased, and the pump pressure is slightly increased. The movable drilling tool is stuck.

After discovering the mud pack of the drill bit, you must first scratch your eyes frequently, or at high speed, and drill under light pressure to increase the displacement.

Secondly, deal with the mud as soon as possible according to the underground and stratigraphic conditions.If the treatment is invalid, start drilling immediately. Start drilling slowly to prevent the drill from getting stuck in the event of resistance. If necessary, connect the square drill pipe to circulate the mud and draw the eye upside down.Drilling requires frequent filling of mud. If the mud cannot be filled, the square drill pipe should be connected in segments to circulate the mud.

9. What is the reason why the pump cannot be opened after drilling?What should I do with it?

The reason why the pump cannot be opened after drilling：

1) A large number of drilling tools were replaced during this drilling, and there were stolen goods in the water holes of the drilling tools that blocked the water holes of the drill bits.

2) When drilling down, things fell from the drilling tool, such as lead oil brushes, gloves, cotton yarn, etc.

3) During drilling, due to the collapse of the well wall, the mud is severely poured back, and the drill cuttings are brought into the drilling tool, blocking the water hole of the drill bit.

4) Ground pipelines or drilling tools freeze in winter.

5) The mud cake on the well wall is thick, and a large amount of cuttings are sandwiched, which is squeezed into the drill bit to block the water hole when drilling down.

6) The mud cake of the well wall is thick, so that the drill bit is covered in mud, and the mud cannot be returned up. If there is a permeable layer at the bottom, it is easy to hold back the formation.

Treatment method：

If the pump cannot be opened, the ground factors must be eliminated first, and then the underground plugging should be dealt with. The drilling tools should be moved at a large distance and the pump should be opened slowly with a small displacement. If it is invalid, part of the drilling tools should be removed and then the pump should be opened slowly with a small displacement. If it is invalid, the drilling should be started quickly to prevent the underground from deteriorating and cause the drill to get stuck.

10. What is the reason for the drop in the suspension weight of the middle finger barometer during drilling?How to deal with it?

The reason for the drop in suspension weight: one is that the weight gauge is broken, and the other is that the drilling tool is broken.

The treatment method is: first lift the drilling tool to check the pressure transmitter of the finger gauge, the rubber tube is good or bad, whether there is liquid in the meter and whether the parts in the meter are damaged, and then re-proofread the suspension weight. If the finger gauge is intact, immediately start drilling to check the drilling tool, and decide on the treatment method according to the broken condition of the drilling tool.