Identification and Response Strategies for Common Drilling Problems

Identification and Response Strategies for Common Drilling Problems

During drilling operations, unexpected problems are inevitable. Calmly identifying the problems and adopting correct and systematic response strategies are crucial for ensuring the smooth progress of the project. The following are key points for identifying the most common problems and basic handling procedures.

I. Drilling Difficulties or Inability to Advance (Drilling Stalls)

Identification points: The drill bit hardly moves downwards, the machine is heavily loaded, and the sound is muffled.

Response strategies:

Assess the rock formation: First, assess the rock formation based on the drilled cuttings. If it is hard, intact rock (such as granite or hard sandstone), a special drill bit (such as an alloy drill bit or roller cone drill bit) is required.

Adjust parameters: Use a "low speed, high pressure" approach and patiently grind. Ensure normal mud circulation to cool the drill bit and carry out rock cuttings.

Evaluate costs: If the hard rock layer is too thick, the penetration cost (time, drill bit consumption) may be too high. At this point, discuss with the construction team to evaluate whether to continue or consider relocating and redrilling.

II. Drill String Sticking (Drill string is stuck in the well)

Identification points: The drill string cannot rotate or be lifted, and the range of movement is extremely small.

Response strategies: Immediately stop forceful operation!

Attempt to free the stuck drill string: Within the equipment's capabilities, try alternating forward and reverse rotation, combined with gentle lifting and lowering, using vibration and torque to try to loosen it.

Analyze the cause: If it is caused by swelling of soft formations (mud cake adhesion), try pumping in clean water or a freeing agent for soaking. If it is caused by wellbore collapse or falling objects, it is more complex.

Professional handling: If conventional methods are ineffective, do not proceed recklessly. Professional personnel should use specialized tools such as impact hammers or reverse-threaded drill pipes for treatment. This process is highly technical; do not attempt to handle it yourself.

III. Mud Loss (Drilling fluid is pumped in but does not return)

Identification points: The pumped mud or water does not return to the surface, or the return volume is very small, and the fluid level in the well drops.

Response strategies:

Determine the degree of loss: Is it slow seepage or rapid loss? Rapid loss usually indicates encountering cracks or cavities. Targeted Leak Control:

Minor Leaks: Add leak-plugging materials (such as sawdust, mica flakes, fibers) to the drilling fluid, or increase the viscosity of the drilling fluid.

Severe Leaks: Use the "bridging leak control method," introducing inert materials of different particle sizes (such as walnut shells, crushed stone) to bridge and seal the leak; or use professional materials such as quick-setting cement. If sealing is not possible, it may be necessary to lower casing to isolate the leaking layer.

Adjusting Operations: When a leak occurs, reduce the pump flow rate and drilling pressure to minimize the impact on the formation.

IV. Water or Sand Influx

Identification Points: A sudden surge of a large amount of water or sand from the borehole.

Response Strategy:

Clear Water Influx: This is usually a good sign, indicating that a water-rich layer has been encountered. However, the drilling speed needs to be controlled, and drainage preparations should be made.

Sand Influx (Dangerous): Measures must be taken immediately to control the influx, usually using high-density, high-viscosity, high-quality drilling fluid, and it may be necessary to immediately lower casing and cement the wellbore; otherwise, the wellbore may be ruined.

General Response Principles:

Safety First: Any treatment must be carried out while ensuring the safety of personnel and equipment.

Maintain Communication: Maintain close communication with the on-site construction supervisor to jointly analyze the cause and determine the treatment plan.

Record Details: Record in detail the well depth, phenomena, measures taken, and results of the problem, accumulating valuable experience for subsequent operations.

Clear Boundaries: For complex and severe problems such as stuck drill pipes and serious leaks, if on-site technical capabilities are limited, external professional teams should be sought for support in a timely manner to prevent the accident from escalating.

In summary, the core approach to dealing with drilling difficulties is: accurately determine the nature of the problem, prioritize safe and reliable methods, seek professional support in a timely manner, and avoid blind risks. A clear and calm response process is an important guarantee for overcoming these difficulties and ultimately drilling a successful water well.