Emergency Guide to Common Drilling Site Problems: Sticking, Deviation, and Mud Leakage

Emergency Guide to Common Drilling Site Problems: Sticking, Deviation, and Mud Leakage

Unexpected situations are inevitable during drilling. Understanding how to quickly identify and respond to these issues can effectively reduce losses and ensure safety. Below are on-site handling methods for three of the most common problems, explained in simple language.

I. Sticking Drill Bit (Stuck Drill Bit)

Problem Assessment

* Sudden increase in machine load, accompanied by abnormal noises

* Drill pipe cannot be lifted or rotated normally

* Poor or stopped mud circulation

On-site Handling Steps

* Step 1: Stop Immediately, Initial Attempts

* Immediately stop drilling, but maintain mud circulation.

* Try gentle movements: Slowly try lifting, lowering, and reversing the drill pipe (do not pull or yank).

* Increase mud pump flow: Try using a stronger mud flow to flush the stuck area.

Step 2: Analyze the Cause, Address the Problem

* If it is determined to be trapped in loose mud:

* Prepare a thinner mud mixture. Continuous mud flushing

Try a combination of gentle lifting and slow rotation to gradually loosen the hole.

If the hole is stuck due to falling rocks or tools:

Try small up-and-down movements to find a loosening gap.

Use specialized retrieval tools.

If the hole wall has collapsed and buried the drill bit:

Immediately and continuously inject high-quality wall-protecting mud.

Consider using an unblocking agent (a special liquid that lubricates and breaks down mud cake).

Step 3: Preventive Measures

Maintain good mud performance and achieve the required wall-protecting effect.

Control drilling speed in easily collapsible formations and install casing in a timely manner.

Regularly check drill bit wear and replace them promptly.

II. Drilling Off-center (Deviated)

Problem Assessment

Drill rod is clearly not vertical.

Core sample or inclinometer shows excessive borehole deviation.

Drill rod exhibits abnormal oscillation during drilling.

On-site Correction Methods

Adjustments for minor deviation:

Backfilling correction: Backfill the borehole above the initial deviation point.

Using a shorter drill rod: Re-drill the section using a shorter drill rod for easier direction control.

Adjusting parameters: Reduce drilling pressure and rotation speed, using a "slow and steady" approach to traverse the formation.

Adding a centralizer: Install a centralizer on the drill rod to help center the drill string.

Important Principles:

"Early correction is key": The earlier deviation is detected, the easier and cheaper the correction.

When drilling in hard, inclined rock formations, anticipate deviations and proactively slow down the drilling speed.

Prevention is crucial:

Ensure the drilling rig base is absolutely level and stable before drilling.

In formations with alternating hard and soft surfaces, reduce drilling speed and pressure in advance.

Regularly check drill rod bending; replace bent drill rods immediately.

III. Significant Mud Loss (Leakage)

Problem Assessment

Rapid Drop in Mud Level in the Mud Tank

A marked reduction or cessation of mud return from the borehole.

In severe cases, this may lead to a drop in the borehole water level, causing borehole collapse.

On-site Differential Treatment

Mild Leakage (Slow Reduction):

Increase Mud Viscosity: Add thickening materials (such as cellulose) to the mud to make it "thicker".

Add Sealing Material: Add flaky or fibrous inert materials (such as sawdust or rice husks) and circulate them to the leaking layer for sealing.

Reduce Pump Pressure: Reduce the mud pumping pressure to allow the sealing material to... Time lingers in the cracks

Severe grout leakage (rapid loss):

Immediately stop circulation to prevent grout depletion.

Prepare a "thick sealing grout": Mix a large amount of sealing agent (granular and fiber mixture) with high-viscosity mud.

Quickly inject into the hole and let it stand for a period of time to allow the material to accumulate and bridge in the leaking layer.

Try starting the pump at a small flow rate and observe the effect.

Extremely large leakage or underground cavities:

Consider using cement grout or quick-setting chemical grout for sealing.

Or adopt the "casing drilling" technique, where the casing follows the drill bit closely, using the casing to isolate the leaking layer.