Geothermal Drilling Rig Penetration Rate Record: CMD100 in Jilin City, 2013
Executive Summary
In August 2013, a geological exploration team in Jilin City, Jilin Province set out to drill a deep geothermal well through hard granite and metamorphic rock. They chose the CORTECH® CMD100 intelligent truck-mounted rig and ran a positive-circulation pneumatic DTH hammer process. The campaign became a benchmark for rate: the rig drilled 192 m in a single 8-hour shift, averaging 24 m per hour, and finished the hole to 2,004.42 m — refreshing China's record for the deepest positive-circulation pneumatic DTH hammer run by a full hydraulic rig. The hole opened at Φ311 mm, finished at Φ190 mm, at 90° inclination, with verticality and wall stability meeting design requirements.
Project Background & Challenge
Hard crystalline rock is the rate killer:
- Hard granite and metamorphic rock: high hardness and strong abrasiveness demand high torque, usable rotation speed and efficient rock breaking — the exact opposite of soft sediment drilling.
- Traditional process limits: conventional methods in this lithology were slow on footage and hard on tooling, with bits and rods wearing out between rounds.
- Geothermal depth target: the exploration team needed a deep, straight, stable hole to evaluate the geothermal reservoir — not just a fast run.
The team needed a rig that could deliver both high rate *and* depth through abrasive crystalline rock.
Our Solution
The crew deployed the CMD100 intelligent truck-mounted rig, pairing its 100 t-class hoisting and top-drive torque with positive-circulation pneumatic DTH hammer drilling:
- Truck-mounted mobility: the intelligent vehicle-mounted rig moved between site and road quickly, suiting a focused exploration campaign.
- Top-drive torque envelope: the 105 mm thru-hole top drive delivers 27,500 Nm at low speed (0–100 rpm) and 9,700 Nm at high speed (0–300 rpm) — enough to drive the DTH hammer through abrasive rock and still carry the rod string at depth.
- Positive-circulation air DTH: compressed air powers the hammer and clears cuttings, keeping the bit face clean and penetration high.
- Straight-hole control: drilled vertical at 90°, with verticality and wall stability held to design.
Key Results
| Metric | Value |
|---|---|
| Final depth | 2,004.42 m |
| Opening diameter | Φ311 mm |
| Final diameter | Φ190 mm |
| Hole inclination | 90° (vertical) |
| Best single-shift advance | 192 m in 8 hours |
| Average penetration rate | 24 m/h |
| Process | Positive-circulation pneumatic DTH hammer |
| Rig | CORTECH CMD100 intelligent truck-mounted |
| Record | Deepest positive-circulation air DTH run by a Chinese full hydraulic rig |
For the full technical specifications of the CORTECH® CMD100, see the CMD100 product page.
Customer Value & ROI
- Rate that compresses schedule: 192 m in an 8-hour shift and a 24 m/h average directly cut rig days on a hard-rock geothermal hole — rig time is the largest cost in deep exploration.
- Depth without losing quality: the same run that set the rate record also set the national depth record (2,004.42 m) while holding verticality and wall stability to design.
- Proven in the worst lithology: granite and metamorphic rock is where rate claims go to fail; the CMD100's performance here is directly transferable to other hard-rock geothermal or mineral programs.
- A benchmark for deep geothermal: the case has become a reference for deep geothermal exploration with vehicle-mounted full hydraulic rigs.
FAQ
What penetration rate did the CMD100 achieve in hard rock?
In the August 2013 Jilin City geothermal well, the rig advanced 192 m in a single 8-hour shift — an average of 24 m per hour — drilling through granite and metamorphic rock with positive-circulation pneumatic DTH hammer drilling.
How deep can positive-circulation air DTH drilling go?
In this campaign the CMD100 reached 2,004.42 m, refreshing the Chinese national record for the deepest positive-circulation pneumatic DTH hammer run by a full hydraulic rig.
What is a truck-mounted (vehicle-mounted) drilling rig?
A truck-mounted rig carries the drilling machine on a road-going vehicle chassis, so it can relocate quickly between sites without separate towing — valuable for focused exploration campaigns such as this geothermal program.
What formations were drilled in the 2013 Jilin City well?
The well mainly penetrated hard granite and metamorphic rock — high hardness, strong abrasiveness — which is why the DTH hammer rate (rather than conventional mud rotation) was the decisive factor.
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