What conditions must be met for threaded connections?
Answer: These are the three conditions: equal dimensions, identical fastener types, and matching male and female components.

How do I inspect drilling tools?
Answer: ① Tubing body: Inspect the drill pipe for bending or ovality, ensuring there are no scratches or rust. ② Joint integrity: Check both internal and external threads, remove any debris, and clean with diesel. Verify that the sealing steps are intact and that the threads show no deformation, wear, uneven wear, or thinning. ③ Drill pipe waterways: Ensure the drill pipe waterways are unobstructed and regularly shaped, free of foreign objects. Mark and record any drill pipes found to be defective.

What are the commonly used tools for handling underground accidents?
Answer: ① male cone and female cone; ② milling shoe; ③ impact tool; ④ reverse-thread connector; ⑤ slip fishing jar; ⑥ fishing spear, safety connector, strong-magnetic fishing tool, etc.

What is the function of a safety slip? What is its maximum load capacity?
Answer: A safety slip is used to prevent pipe strings or tools without shoulders or joints from slipping and falling into the well. Insurance card The slip tool is an important auxiliary device used to prevent drill pipes from slipping out of the slips. Its maximum load capacity is 225 kN.

What are the precautions for using a lifting lug?
Answer: ① Select the correct type, structure, and load capacity of the elevator; ② Open and close the elevator properly; ③ During drilling and pulling operations, slow down the elevator as it approaches the rotary table surface; ④ Absolutely prohibit operation beyond the rated load.

What are the specific steps for drawing eyes using the “dial-and-dot” method?
Answer: When you encounter a situation where the drill string cannot be moved or advanced further and it’s absolutely necessary to make a single rotation, first apply a pressure of 20 kN to 30 kN, then rotate the turntable while monitoring the weight indicator. If the suspended weight starts to rise, immediately stop rotating the turntable. Then apply another 20 kN to 30 kN of pressure and continue rotating the turntable. Repeat this cycle until the release point has made a single rotation; at that point, lift the drill string once more. Note that you must not apply continuous pressure while rotating.

What are the specific steps involved in the “one flush, two clear, three stroke” method for eye drawing?
Answer: After connecting the single pipe and confirming that the pump is operating normally, first flush it down; then lift the drill string, rotate it to a new orientation, and flush it down again; next, lift the drill string again, rotate it, and flush it down once more.

What are the technical requirements for inspecting winches?
Answer: ① When inspecting the winch, the winch power must be disconnected, and a dedicated person must guard the air switch; ② All winch fastenings must be secure and reliable, and all guards must be fully installed; ③ All grease nipples at lubrication points on the winch must be present, and grease must be added promptly according to regulations; the fork screw bolts must be complete and operate smoothly for easy engagement and disengagement; ④ The auxiliary brake’s toothed clutch must engage and disengage smoothly, and the water lines must be clear with no leaks; ⑤ The winch chain must show no severe wear, broken pins, missing links, or cracked bushings.

What are the main advantages of chain drives?
Answer: The main advantages of chain drives include: accurate average transmission ratio; ability to operate under harsh conditions such as high temperatures, dusty environments, exposure to water, and oil splashing; small radial forces acting on the shafts and bearings; capability to transmit power between two shafts with large center distances; and a wide range of applicable speeds and power levels.

What are the main disadvantages of chain drives?
Answer: The main disadvantages of chain drives include: the transmission ratio cannot remain constant under varying conditions; they produce impact and generate significant noise during operation; they can only be used for power transmission between two parallel shafts; they have relatively high requirements for installation and maintenance; after the chain links wear, the chain tends to elongate, which can easily lead to chain derailment; and their manufacturing costs are relatively high.

What are the advantages and disadvantages of gear transmission?
Answer: The advantages of gear transmission include: it can ensure a constant instantaneous transmission ratio, providing accurate and reliable motion transmission; it has a wide range of power and circumferential speed capabilities; it boasts high load-carrying capacity; it features high transmission efficiency; and its mechanism is compact, small in size, and long-lasting.

What are the main disadvantages of gear transmission?
Answer: The main disadvantages of gear transmission are its high requirements for machining and installation accuracy, high cost, and unsuitability for transmitting power between two shafts with a large center distance.

What is the primary function of a key?
Answer: Keys are primarily used to achieve circumferential fixation between a shaft and components mounted on the shaft, thereby transmitting torque.

What are the replacement criteria for wire ropes in oil drilling?
Answer: ① One entire strand of the steel wire rope is broken; ② The wear or corrosion of the outer wires exceeds 40% of the original diameter; ③ The steel wire rope is severely flattened or has severe kinks; ④ The number of broken wires within any given pitch exceeds 12.

Briefly describe how to use a dial caliper.
Answer: ① Take the vernier caliper out of its case and check whether it has a valid calibration certificate and whether the certificate is still within its validity period. ② Use a soft cloth to wipe clean the antirust oil from the measuring jaws. ③ Close the outer measuring jaws and check whether the vernier caliper reads zero; if not, record the initial error. ④ Use the outer measuring jaws to clamp the workpiece being measured, and carefully read the measurement data. ⑤ Eliminate the initial error and calculate the actual dimensions of the workpiece being measured. ⑥ Wipe the vernier caliper clean, apply antirust oil, and then place it back into its case.

What are the things to keep in mind when using a grinding wheel machine?
Answer: ① The grinding wheel must rotate in the correct direction so that the abrasive debris flies away from the wheel downward; ② After starting the machine, wait until the grinding wheel has reached its normal speed before beginning the grinding process; ③ During grinding, avoid any violent impact between the tool or workpiece and the grinding wheel, as well as excessive pressure applied to the wheel; ④ The operator should stand to the side or at an angle to the grinding wheel.

What are the safety precautions when using acetylene for gas welding?
Answer: ① The pressure of acetylene shall not exceed 0.15 MPa; ② Acetylene generator ① It must be placed at least 10 meters away from the construction site. ② When transporting oxygen cylinders, avoid collisions between them and store them in a cool place to prevent overheating, expansion, and potential accidents. ③ Regularly inspect acetylene pipelines and welding torches to prevent gas leaks.

What is the nominal drilling depth of the ZJ50DB drilling rig (using both 127mm and 114mm drill rods)?
Answer: 127mm drill pipes are suitable for depths ranging from 2,800m to 4,500m; 114mm drill pipes are suitable for depths ranging from 3,500m to 5,000m.

How do you remove an old chain?
Answer: ① Connect the connector to the chain; ② Remove the pin and link plates from the old chain; ③ Extract the chain pivot pin; ④ Use hemp rope to tighten both ends of the chain, remove the chain connector, and then lift out the old chain.

How do I install a new chain?
Answer: ① Use a pneumatic winch to lift the new chain and slowly bring it close to the sprocket; ② Thread a hemp rope through the sprocket, tying one end of the rope to the new chain; ③ Once the chain is fully seated in the sprocket, use the hemp rope to secure both ends of the chain, pulling them tight until the chain connectors can be easily attached; ④ Tighten the chain connectors until the chain pin can be smoothly inserted, then install the chain links and locking pins, and finally remove the chain connectors and the hemp rope.

What precautions should be taken when using transformer oil?
Answer: ① Store with a tightly sealed lid; ② Pay attention to changes in oil quality when using; ③ Strictly prohibit mixing in impurities, moisture, and other oils; ④ Ensure the amount injected is appropriate.

If a large rope gets caught and jumps into another pulley groove, what should be done?
Answer: First, use the kelly to secure the drill string, relieve the load on the hoisting rope, open the traveling block guard, remove the rope-stop bar, and then use two flat pry bars to gently lever the hoisting rope back into its original groove. Next, reattach the rope-stop bar or guard, and clean up the tools.

How many slips and safety slips should be prepared for the preparatory work before drilling begins?
Answer: There are two drill pipe slips and two drill collar slips of different sizes, one of which serves as a spare; there are also two drill collar safety slips.

How do you operate a reverse-circulation fishing basket?
Answer: ① Lower the combined drill string into the well and use the tongs to tighten all threads of the fishing basket; ② Lower the string to 1 meter above the bottom of the well, then start the pump and ensure normal circulation; ③ Disconnect the square drill pipe, drop a steel ball, start the pump for circulation, and monitor changes in pump pressure; ④ Start the rotary table, slowly lower the drill string, and after the bit reaches the bottom, apply a weight of 10–20 kN and mill forward; ⑤ After milling forward by 0.3 meters, continue milling at a weight of 5 kN; after milling forward by another 0.2 meters, stop the pump and pull out the core; ⑥ Raise the drill string by 1–2 meters, then lower it again to check whether the fish has been retrieved. Repeat the fishing operation or pull out the drill string as needed.

Can PDC drill bits be used for reaming long well sections? Why?
Answer: PDC drill bits should not be used for reaming long well sections. When using a PDC drill bit for reaming, only a few gauge teeth bear the entire drilling weight. During the reaming process, since the return velocity of the drilling fluid is slow, these gauge teeth do not receive adequate cleaning and cooling, leading to overheating and damage. In long well sections, reaming can cause the gauge teeth to become rounded, resulting in premature failure and reduced effectiveness of the drill bit.

Can PDC drill bits be used under conditions of restricted flow? Why or why not?
Answer: PDC drill bits cannot be used. This is because, when drilling with PDC drill bits, the flow rate must be kept above the minimum flow rate; otherwise, due to the low drilling fluid flow rate, the cutting teeth will not be adequately cooled and cleaned, leading to overheating and premature damage.

What safety precautions should be taken when working at heights?
Answer: ① Always wear a safety belt when working at heights, and the safety belt must undergo regular tensile strength tests; ② All tools used must be secured with tail ropes and properly fastened. After use, tools must not be left on the derrick; ③ It is strictly prohibited to use electric (or pneumatic) winches to lift personnel or to ride in traveling cars up or down the derrick; ④ Personnel from other positions who wish to access the derrick must meet the requirements for high-altitude work and obtain permission from the drilling foreman on duty.

What are the basic requirements for filling out the form?
Answer: ① The content must be complete, with accurate and truthful data; there should be no errors or omissions. ② Handwriting (in long-style Fangsong font) must be neat and legible; no alterations are allowed, and charts and diagrams must be correct and clear. ③ Use a fountain pen or ballpoint pen (blue-black or black); the use of blue ballpoint pens and pencils is strictly prohibited. ④ Data entries should be rounded to two decimal places, and units must conform to legally prescribed measurement units.

What are the requirements for completing the drilling engineering shift report?
Answer: ① The data must be complete and accurate, and the work content must be genuine; ② The handwriting must be neat, and the surface must be clean; ③ The units filled in must use legally prescribed measurement units.

What is meant by “complex downhole conditions”?
Answer: In drilling operations, when obstacles or stuck conditions occur downhole due to factors such as encountering special geological formations, improper selection of drilling fluid type and properties, or poor wellbore quality—resulting in phenomena like bit bounce, lost circulation, and well kicks during drilling—and making it impossible to maintain normal drilling and other operational activities, all these situations are collectively referred to as downhole complexities.

What are the phenomena that occur when a well leak happens?
Answer: The mud tank level is dropping; when circulating drilling fluid, the return velocity of drilling fluid at the wellhead decreases; when not circulating, the fluid level inside the well drops; with constant drilling weight, the mechanical drilling rate increases, and sometimes the drill string may experience "emptying"; the suspended weight indicator reading rises, while the drilling weight decreases, among other signs.

What are the reasons for pulling the drill string and removing the piston?
Answer: First, bit balling; second, wellbore narrowing.

What are the main causes of mud-packed stuck drill pipes?
Answer: Dry drilling, insufficient flow rate, poor drilling fluid performance, and improper drill bit selection.

What are the phenomena of sticking and jamming?
Answer: The sticking phenomenon refers to the drill string being unable to be raised, lowered, or rotated, while pumping remains normal and pump pressure stays stable. As the duration of the stuck condition increases, the drill string’s extension gradually decreases (the sticking point moves upward).

What are the main measures to prevent sticking and jamming?
Answer: Use high-quality drilling fluids, minimize the pressure differential inside the well as much as possible, and significantly move the drill string when pausing drilling operations.

What are the different methods for dealing with stuck drill pipes due to adhesion?
Answer: ① Intense activity; ② Vibration-induced key release; ③ Soaking with key-release agent.

What is a stuck drill due to collapse?
Answer: Due to poor drilling fluid performance, excessive filtration causes the formation to become saturated and loose; or, in well sections with steep formation dips, the mudstone expands after being soaked, shedding debris into the wellbore and leading to stuck pipe.

What are the phenomena of井 wall collapse?
Answer: ① During drilling, the drill bit suddenly becomes stuck, causing pump pressure to rise—sometimes even leading to pump stalling—while the suspended weight decreases and the rotary table experiences increased load, sometimes to the point where it can no longer rotate; ② When running in or pulling out of the hole, drilling fluid flows backward, and there is resistance or sticking during both upward and downward movements.

What measures can be taken to prevent wellbore collapse?
Answer: ① Use drilling fluids with low fluid loss, high mineralization, and appropriate viscosity to prevent wellbore collapse; ② When drilling through fractured formations, appropriately increase the density of the drilling fluid; ③ Continuously circulate drilling fluid during tripping operations; ④ Avoid mud packing around the drill bit to prevent collapse caused by suction effects.

What are the phenomena of sand bridge sticking?
Answer: When the drill string is stuck while being lifted, the drill pipe cannot be rotated, the pump pressure rises or the pump becomes blocked, and sometimes it’s still possible to lower the drill string.

What are the phenomena of sand settling and bit sticking?
Answer: ① After connecting a single drill pipe or pulling out the drill string and disassembling the stand, the drilling fluid may flow back forcefully or even spout vigorously; ② When restarting the pump for circulation, the pump pressure may rise sharply or the pump may become blocked; ③ When lifting the drill string, it encounters sticking; when lowering it, it faces resistance, and it becomes increasingly difficult to raise or lower the drill string. When rotating the drill string, there is significant resistance, and in some cases, rotation becomes completely impossible.

What are the phenomena of stuck pipe due to diameter reduction?
Answer: ① The stuck point is fixed; ② Pump pressure rises during circulation; ③ It’s difficult to raise the drill string but easy to lower it; ④ The upper part of the drill pipe joint retrieved often has a soft, loose filter cake.

How can we prevent stuck pipe due to shrinkage?
Answer: ① Use high-quality drilling fluids with low solids content and low fluid loss; ② When using heavy drilling fluids, mix in oil; frequently move the drill string while it is in the wellbore to prevent sticking; ③ During running-in-the-hole operations, ream the well section where resistance is encountered to enlarge the wellbore diameter at the narrowed areas.

What should you do if a bit bounce occurs during drilling or when making a single joint connection?
Answer: The mud should be circulated immediately to pull out the drill string, and the drill tools should be inspected for defects.

During the second-stage drilling process, what should be done if the equipment malfunctions and drilling cannot continue?
Answer: First, try to circulate the drilling fluid and move the drill string as much as possible. If it’s impossible to circulate the drilling fluid or move the drill string, you can lower the drill string and apply two-thirds of the suspended weight onto the bottom of the well, causing the drill string to bend and thus preventing sticking. After troubleshooting and resolving the issue, lift the drill string and resume drilling.

What should be done if the pump pressure drops to 1 MP during drilling?
Answer: The surface equipment and drilling fluid performance should be checked. If no problems are found, immediately organize the drill string to be pulled out of the hole, refill the drilling fluid, and inspect the drill string.

What are the hazards of improper drilling fluid density?
Answer: (1) If the drilling fluid density is too high, it can damage the oil and gas formation, reduce the drilling rate, easily cause filter cake adhesion leading to stuck pipe, increase the likelihood of fracturing the formation, result in excessively high viscosity and shear force, consume more drilling fluid materials and power, and weaken the fluid’s resistance to contamination. (2) The hazards of having a drilling fluid density that is too low include a higher risk of well kicks, wellbore collapse, borehole shrinkage, and reduced cuttings-carrying capacity.

What are the handling principles for stuck drill accidents?
Answer: (1) Safety principle; (2) Speed principle; (3) Flexibility principle; (4) Economy principle.

Under what circumstances must the drill be pulled out of the hole when using a PDC bit?
Answer: When using a PDC drill bit, you should pull the drill string if any of the following conditions occur: pump pressure rises after applying weight on bit; mechanical drilling rate significantly decreases while formation lithology remains unchanged; debris falls into the bottomhole; operational errors lead to severe sticking or bumping of the drill string; or overall economic indicators fall below those of other types of drill bits.

Why is patience necessary when using PDC drill bits for bottom-hole shaping?
Answer: When shaping at the bottom of the well, only a few cutting teeth on the PDC drill bit are in contact with the bottom of the well. Applying excessive pressure too quickly can overload and damage these cutting teeth.

What phenomena occur when the roller bits get stuck while working at the bottom of the well?
Answer: The rotary table load has increased, causing severe chain slippage on the rotary table, resistance in the square drill pipe, and requiring reverse rotation when stopping the rotary table. Drilling speed has decreased, and the suspension weight indicator needle is swinging violently.

What phenomenon occurs when the toothed wheel on the drill bit falls off while the drill is working at the bottom of the well?
Answer: The rotary table load has increased, causing severe chain slippage on the rotary table, and the rotary table stops when reversing; drilling resistance is severe; the weight-on-bit indicator needle swings back and forth; the drilling rate has noticeably decreased or there is no penetration at all; when lifting the drill string and changing direction to probe downward, the position of the drill bit shows noticeable changes, with a height difference roughly equivalent to the height of one tooth wheel.

What phenomenon occurs when the teeth of a drill bit become polished after working at the bottom of the well?
Answer: The rotary table load has decreased; the square drill pipe is free from sticking or bouncing; the drilling rate has noticeably slowed down or there is no penetration at all; the weight indicator shows a steady reading without any fluctuations; and the pump pressure remains normal.

What are the different types of roller cone bits?
Answer: (1) Single-cone drill bit; (2) Dual-cone drill bit; (3) Cone reaming drill bit; (4) High-speed cone drill bit.

What information does the on-duty officer need to understand when taking over and inspecting the underground conditions?
Answer: ① Understand well the well depth and formation, drill string structure and suspended weight, bit usage, mud properties, and complex conditions; ② Understand the make-up length and drilling rate.

What information should the on-duty personnel hand over during shift changes?
Answer: ① The use of drill bits, drill string configuration, bit penetration depth, drilling fluid properties, and formation conditions; ② Problems encountered during this shift and precautions for the next shift; ③ Instructions from higher authorities, key measures, and complex downhole conditions; ④ Equipment maintenance and operational status.

What does personnel management mainly involve?
Answer: ① Organize production strictly according to job responsibilities; ② Organize technical problem-solving efforts and strive to tap potential and promote innovation; ③ Encourage learning and hold operational competitions; ④ Reward excellence and penalize poor performance to boost employees’ work enthusiasm; ⑤ Foster harmonious interpersonal relationships.

What factors affect drilling speed?
Answer: These include drill bit type, formation, drilling parameters, drilling fluid properties, and operational practices.

What drilling engineering factors affect gas logging?
Answer: (1) The effects of drill bit diameter and drilling speed; (2) The effects of drilling fluid viscosity and density; (3) The effect of drilling fluid flow rate; (4) The presence of oil or crude oil mixed in the drilling fluid.

What are the influencing factors of drilling time logging?
Answer: (1) The influence of drill bit type and its condition—whether new or old; (2) The influence of drilling fluid properties and flow rate; (3) The influence of drilling techniques and methods; (4) The influence of human factors, primarily the level of operational skill of the driller, which affects drilling time.

What factors influence wellbore deviation, and which of these play the primary role?
Answer: The factors influencing well deviation include geological factors, drill string configuration, drilling technology measures, the operator’s technical proficiency, and the quality of equipment installation. Among these, geological factors and the structure of the lower drill string play the primary roles.

What are the advantages of downhole power drilling tools compared to rotary drilling?
Answer: The main advantages are: higher mechanical drilling speed, improved working conditions for the drill string, resulting in fewer drill-string failures and longer service life; the use of cheaper and lighter drill pipes is also possible; furthermore, it overcomes the power consumption associated with rotating drill strings, making it particularly suitable for special operations such as directional drilling, multi-stage wells, and well workovers.

What is the purpose of conventional core sampling?
Answer: ① Identify oil- and gas-bearing formations, understand the distribution and characteristics of hydrocarbon content and reservoir features, and determine basic data such as lithology, physical properties, thickness, and area of these formations; ② Construct stratigraphic geological profiles and study lithofacies as well as the characteristics of source rocks and reservoir rocks; ③ Understand the relationship between lithology and electrical properties.

Why does failure in most drill pipes occur in the section within 1.2 meters of the connection?
Answer: Because the stiffness of the connection and the thickened section is greater than that of the main body, a weak link subjected to alternating stresses is formed at the section where the cross-section changes. This is why most drill pipes fail within 1.2 meters of the connection.

What factors cause pure fatigue failure in drill pipes?
Answer: (1) Fatigue failure occurring under the action of long-term alternating stresses; (2) When a bent drill pipe is lowered into the well, or when the square drill pipe itself is bent, rotating the drill string will inevitably induce significant alternating stresses, leading to fatigue failure; (3) If the crown block, rotary table, and wellhead are not properly aligned, bending stresses will also be induced in the square drill pipe and drill pipes, causing them to suffer fatigue failure.

What is drilling time logging?
Answer: Drilling time logging is the process of using a timer to record and document the time required to drill a specified unit of footage; it is typically expressed in “minutes per meter.”

What methods are currently mainly used to detect cementing quality?
Answer: The primary methods used for detection are acoustic amplitude logging, acoustic variable-density logging, and borehole temperature logging.

What are the main methods and objectives of well completion testing?
Answer: Well completion testing primarily includes electrical logging, radioactive logging, and engineering logging. The purpose is to inspect the wellbore quality and cementing quality, providing a basis for accurate perforation.

What are the wellbore preparations required before logging?
Answer: (1) Before logging, it is essential to thoroughly circulate the drilling fluid to ensure uniformity and stable performance throughout the wellbore. (2) Sections where the drill string encounters resistance or gets stuck must be treated to guarantee that the logging operation proceeds safely and smoothly.

What are the common causes of increased pump pressure during drilling?
Answer: The possible causes of increased pump pressure include wellbore collapse, excessively high drilling rate, poor cuttings-carrying capacity of the drilling fluid, blockage of the drill bit’s water jets, uneven density of the drilling fluid, mud packing around the drill bit, changes in rock lithology, dulling or detachment of the blades on scraper-type drill bits, and exhaustion of the active cutting surfaces on diamond or PDC drill bits, leading to grinding of the matrix.