Downtime Is the Most Expensive Cost in Drilling — But Rarely Calculated

In drilling operations, cost evaluation is often focused on visible factors such as tool price, fuel consumption, or cost per meter.

However, one of the most significant cost drivers is rarely included in standard calculations:

Downtime.

 

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The Hidden Cost in Drilling Operations

Downtime refers to any period when drilling equipment is not producing effective work.

This includes:

· Tool replacement

· Equipment inspection and adjustment

· Unexpected wear or failure

· Operational interruptions

While these events may appear minor individually, their cumulative impact on productivity and cost is substantial.

 

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Why Downtime Is Often Overlooked

Fragmented occurrence

Downtime is typically distributed across multiple short interruptions rather than a single prolonged event.
As a result, it is often perceived as part of normal operations rather than a measurable cost factor.

 

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Lack of direct measurement

Many projects track:

· Tool consumption

· Drilling output (meters)

· Operating expenses

However, effective drilling time — the proportion of time spent on actual drilling versus total operational time — is not always monitored.

Without this metric, downtime remains largely unquantified.

 

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Impact on Productivity and Cost

In continuous operations such as mining and quarrying, even small inefficiencies can accumulate over time.

For example:

· Slightly longer tool change duration

· Reduced tool service life

· Minor operational interruptions

These factors can lead to:

· Decreased productive drilling hours

· Increased cost per meter

· Lower equipment utilization

Over the course of a project, the total cost associated with downtime can exceed the savings from lower-cost consumables.

 

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Price vs. Operational Efficiency

Procurement decisions are often based on initial unit price.

However, tools that result in:

· Frequent replacements

· Inconsistent performance

· Higher risk of premature failure

may increase downtime and reduce overall efficiency.

From an operational perspective, cost evaluation should consider not only purchase price, but also the tool’s impact on continuous and stable drilling performance.

 

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A More Accurate Approach to Cost Control

Effective cost control in drilling requires a shift in focus:

From:
Unit price of tools

To:
Contribution to effective drilling time

Key considerations include:

· Stability and consistency of tool performance

· Frequency of operational interruptions

· Total productive time achieved per shift

Because in drilling operations, overall efficiency is directly linked to how effectively downtime is minimized.

 

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Among various sources of downtime, tool changes are one of the most frequent and controllable factors.

The next article will examine how tool changes affect effective drilling time and overall productivity in detail.