Solutions to Common Problems During Drilling Operations

Solutions to Common Problems During Drilling Operations

During drilling operations, encountering problems such as drilling difficulties and downhole anomalies is inevitable. Understanding their basic causes and mastering the correct approaches to address them will help solve problems promptly and effectively, ensuring the smooth progress of the project.

I. Drilling Difficulties (Slow or No Penetration)

Main Causes:

Drill bit wear or mismatch: This is the most common reason.

Encountering hard rock formations or thick gravel layers.

Poor drilling fluid (circulation fluid) performance, leading to "bit sticking" in soft formations.

Solutions:

Immediately pull out the drill string and replace the drill bit. Based on the new formation conditions, switch to a more suitable drill bit (e.g., switch to an alloy drill bit or roller cone drill bit).

Adjust the drilling fluid performance according to the formation, such as appropriately diluting and strengthening circulation for cuttings removal.

If it is indeed an extremely hard rock formation, the cost needs to be evaluated to decide whether to continue drilling with impact drilling or consider completing the well at the current location.

II. Loss of Circulation Fluid in the Well (Inflow without outflow or minimal return)

Main Causes: Encountering fractures, cavities, or highly permeable sand layers.

Solutions:

Immediately inject plugging materials into the well, such as sawdust, clay balls, or specialized plugging agents.

Increase the viscosity and density of the drilling fluid to seal the fractures.

If the loss is severe and cannot be sealed, it may be necessary to run in technical casing (temporary casing) to isolate the leaking layer, and then continue drilling with a smaller diameter drill bit.

III. Drill String Sticking (Drill string cannot be lifted or rotated)

Main Causes:

Wellbore collapse trapping the drill string.

Accumulation of cuttings burying the drill string.

Formation constriction (e.g., expansive clay).

Solutions (Core principle: Strictly prohibit forceful lifting or twisting):

Try to maintain circulation, adjust the drilling fluid performance, and cooperate with the equipment for gentle lifting, slow rotation, and movement of the drill string.

If the sticking is due to wellbore collapse, try injecting high-viscosity thick drilling fluid to stabilize the wellbore.

Complex sticking problems require specialized tools (such as jarring tools) and professional technical support should be sought promptly.

IV. Well Deviation (Drill hole is not straight)

Main Causes: Improper initial drilling, encountering inclined rock formations, improper drilling parameters. Solutions:

Before drilling, strictly calibrate the drilling rig to ensure it is level, and use "light pressure and controlled drilling" in the initial stages to ensure verticality.

If well deviation is detected, reduce drilling pressure and rotation speed, and use a stabilizer or a more stable drill string assembly to "correct the deviation."

Severe well deviation may require backfilling part of the well section before redrilling.

V. Turbid water or low water yield

Main causes:

Incomplete well cleaning (most common).

Improper placement of the filter pipe or unqualified filter material (gravel) filling.

Failure to reach the main aquifer.

Solutions:

Perform a strong and thorough secondary well cleaning, which is the preferred and most economical measure.

Check the geological records; if the filter pipe position is significantly off, professional repair may be needed.

If the depth or location is clearly incorrect, consider deepening the drilling or trying other locations if conditions permit.

Summary: Calm judgment, scientific approach

The basic logic for addressing problems is: first assess (identify the cause based on the symptoms) → then treat (start with the simplest and most economical measures) → then escalate (if ineffective, seek more professional solutions). As the owner or on-site personnel, your core role is to communicate the problem symptoms to the contractor promptly and accurately, understand their proposed solutions and cost implications, and make informed decisions together. Maintaining open communication channels is a crucial part of problem-solving.