BH22 Drilling Productivity and Cost per Metre
The economic value of a drilling-air package depends on completed work and the resources used to achieve it. Comparing fuel per hour alone can conceal differences in output, waiting time and rework. A fair comparison begins with a defined job scope and consistent records.
Define the denominator first
State what counts as an accepted drilled metre. Identify whether casing, development, testing, mobilisation and abandoned or repeated work belong in the comparison. Keep drilled depth separate from accepted completed work when the contract distinguishes them.
Use the same boundary for each alternative. A compressor-only operating cost should not be compared with another supplier’s complete drilling-package cost without explaining the missing items.
Build a transparent cost record
Record fuel, equipment hire or allocated ownership cost, labour, consumables, transport and any other included cost. State the period and evidence for each. For owned equipment, explain the allocation basis rather than presenting an arbitrary hourly ownership figure as a measured expense.
Fuel intensity = fuel consumed ÷ accepted metres.
Included cost per metre = total included cost ÷ accepted metres.
Both relationships require a non-zero denominator and a consistent work boundary. They are accounting measures, not predictions of future drilling performance.
An illustrative comparison
Suppose a recorded assignment used 480 litres to complete 120 accepted metres. Its fuel intensity is 4 litres per accepted metre. If the included assignment cost was ₹60,000, the corresponding cost is ₹500 per accepted metre. These invented figures demonstrate arithmetic only; they are not Reddy Compressors prices, operating claims or industry benchmarks.
A second assignment cannot be declared better merely because its result is lower. Check formation, diameter, completion requirements, water conditions and included activities before interpreting the difference.
Show where time goes
Separate productive drilling, approved cleaning, pipe handling, planned maintenance, waiting and unplanned interruption. Do not hide non-drilling time by reporting only the fastest interval. The full record helps identify whether the next improvement concerns equipment selection, scheduling, tooling or site readiness.
Use a documented baseline before claiming savings. If several things change at once, describe the result as a package comparison rather than assigning all benefit to the compressor.
Compare purchase and rental options: submit the expected work programme and utilisation assumptions. Ask for quotations using the same scope so the commercial decision rests on comparable evidence.
Related pages: New Borewell Compressor Sales · Borewell Compressor Rentals and Hire · Used and Reconditioned Borewell Compressors
Field guide
Judge drilling by the metre, not by the hour
Hourly fuel burn and CFM tell you little about economy. What matters is what the compressor helps the rig produce: productive metres for the money spent.
Fuel per metre beats fuel per hour
| Compressor A | Compressor B | |
|---|---|---|
| Fuel use | 28 L/h | 34 L/h |
| Penetration | 10 m/h | 16 m/h |
| Fuel per metre | 2.8 L/m | 2.125 L/m |
| At ₹95/L (illustrative) | ₹266/m | about ₹202/m |
B burns more every hour but less for each metre, about ₹64 per metre cheaper. Over 10,000 productive metres that is roughly ₹6.4 lakh. These prices are an example; enter your own diesel price in the fuel calculator.
Total cost per metre
Cost per metre = (fuel + rental or ownership + labour + maintenance + bits + hammer + downtime + support) ÷ productive metres. This turns equipment choice into a lifecycle question rather than a purchase-price one.
Slow penetration costs more than the bit
For 1,000 m at 10 m/h you need 100 hours; at 15 m/h, about 66.7. The 33 hours saved are rig, compressor, wages, fuel, support vehicle and supervision.
Reliability is a productivity variable
Rig A: 20 m/h but 70% available gives 14 m/h in scheduled time. Rig B: 17 m/h at 95% gives 16.15 m/h. B drills slower and produces more hole.
- MTBF = operating time ÷ number of failures.
- MTTR = repair time ÷ number of repairs.
- Availability = MTBF ÷ (MTBF + MTTR). With 500 h and 10 h that is about 98%.
Judge a severe-duty fleet against comparable duty, not light-duty equipment.
What to trend
Pressure over time rather than one reading; penetration rate; litres per hour and litres per metre together; bit and hammer cost per metre; hours between failures. Pressure that rises while drilling slows usually points to restriction (blocked bit passages, packed cuttings), not to a healthy compressor.
Compare rental and ownership with the ownership calculator.