On-bottom ROP measures the rate of penetration only during active drilling when the bit is engaged with the formation, excluding time for connections, surveys, reaming, and other non-drilling activities. This metric isolates drilling system performance from operational logistics, providing the clearest measure of how efficiently the drilling assembly converts energy into hole depth.
Distinction from Average ROP
Average ROP (total footage divided by total section time) includes all non-drilling activities and is heavily influenced by connection practices, survey frequency, and operational procedures. On-bottom ROP strips away these variables to reveal true drilling efficiency:
- Average ROP: 50 ft/hr (includes 30% connection time)
- On-bottom ROP: 71 ft/hr (actual drilling performance)
The gap between these metrics highlights improvement opportunities in both drilling performance and operational efficiency.
Why It Matters
On-bottom ROP is the definitive metric for comparing drilling technologies, bit designs, and parameter optimization strategies. When evaluating autonomous drilling systems or new bit technology, on-bottom ROP provides an apples-to-apples comparison unaffected by rig efficiency differences.
Hard Rock Benchmarks
In conventional oil and gas drilling, on-bottom ROP typically ranges from 50-200 ft/hr. In hard rock geothermal formations, on-bottom ROP of 10-30 ft/hr is common with conventional methods. The DOE FORGE program demonstrated that physics-based drilling optimization can achieve 400%+ on-bottom ROP improvement in granite.
Automation and On-Bottom ROP
Autonomous drilling systems deliver consistent on-bottom ROP improvement by maintaining optimal parameters throughout each stand. SPE/IADC research documents 25-48% on-bottom ROP gains with autonomous control versus manual operations (SPE/IADC 223649).