Mincon’s Guide to European Geothermal Well Drilling

Understanding the Landscape of Geothermal Well Drilling in Europe

In Europe, geothermal well drilling is growing rapidly thanks to increasing demand for sustainable energy solutions. Yet, each country has its own regulatory environment, geology, and project workflow. In Central Europe, for example, permitted depths often range from 100 to 200 metres, depending on proximity to urban areas, while Scandinavia frequently sees deeper boreholes of 200 – 400 metres.

Whether you’re drilling short loops in Germany or deep installations in Finland, optimising your workflow and equipment choices can significantly impact project timelines, costs, and reliability.

Tailoring Your Approach to Local Regulations and Responsibilities

In some European countries, drillers focus solely on drilling the boreholes, while in others, they must also install the loops and grout the hole. This difference alters project priorities:

1. Drill-only contractors benefit from faster drilling speeds, allowing them to complete more installations in less time.
2. Full-service contractors may not be under time pressure for drilling equipment, but will benefit more from:

• Reliable hammers that reduce downtime.
• Fuel-efficient equipment that cuts operating costs.
• Quiet operation for compliance with residential noise regulations.

Choosing Equipment That Works With You, Not Against You

Compatibility and Simplicity Matter

Any drilling project can quickly become complex when products from various suppliers are involved, especially if you’re concerned about compatibility and interoperability. Productivity suffers when tools aren’t optimised to work together, or if you have to wait for stock from multiple providers.

Why standardise your drill string?

• Equipment compatibility reduces the risk of misalignment, failure, or inefficiency.
• A fully integrated drill string from a single supplier ensures all components – hammer, bit, and pipe – are engineered to perform together.
• Mincon offers complete systems – including drill pipe, hammers, and bits – designed for all major rigs on the market.

Efficiency Is More Than Just Speed

Drilling speed is only one factor in total project efficiency. Long-term cost savings are found in how well your hammer retains power and how often it needs maintenance or replacement.

• Longevity: Hammers with high-quality internal components maintain energy efficiency over a longer lifespan.
• Durability: Poor lubrication of internals can drastically shorten the service life of your hammer. Never use a worn or undersized drill bit, as this will result in premature wear of the hammer chuck and wear sleeve.
• Precision Engineering: Mincon hammers use proprietary heat-treated components for consistent impact power throughout the lifetime of the hammer.

Drilling in Overburden? Use the Right Casing Advance System

Stabilising Holes and Controlling Air

Geothermal well drilling isn’t always directly into rock – very often there is a softer soil layer, known as overburden. These ground conditions require stabilising the hole, which can be done by driving a metal casing into the softer ground until reaching rock. After reaching rock, it’s then possible to continue drilling through the rock until reaching the required depth for the geothermal well.

Best practice for installing casings in geothermal wells:

• Ensure your DTH hammer and bit are narrower than the casing being installed.
• For the best safety, use a casing advance system that offers air control, especially in sensitive ground conditions near adjacent structures.
• Consider using Mincon Spiral Flush Mini ring-bit systems for installing casings into rock, while retaining the industry’s best air control in all ground conditions.

In addition to offering class-leading performance with the MP40-MC hammer, Mincon’s range of Spiral Flush Mini casing advance systems offers an efficient solution for geothermal well installation. These systems are available in 3” – 5” (75 – 130mm) sizes, and have been fine-tuned in the gruelling ground conditions in Scandinavia for extreme durability and high penetration rates in even the hardest rock.

Lubrication And Water Injection: What You Might Be Overlooking

Proper lubrication isn’t optional; it’s essential.

• Use biodegradable lubricants, especially for environmentally sensitive areas.
• Avoid over-lubrication or using the wrong oil grade. Biodegradable oils like Mincon Envirosafe are designed to retain performance even in acidic groundwater, providing protection for hammer internals in even the harshest conditions.

If you’re using water injection:

• Keep water clean, and amounts are minimal.
• Adjust the oil feed to compensate for water dilution.
• Consult the manufacturer’s guidelines to prevent internal corrosion or efficiency loss.

Drill Pipe Quality: An Underrated Investment

• Poor-quality pipe can compromise your entire operation. Whether drilling 100 metres or 400, an inferior pipe leads to crooked holes, increased vibration, and excessive wear on your rig and hammer.
• Choose drill pipe manufactured using cold-drawn seamless pipe, which offers maximum straightness and strength.
• Always use drill pipe that uses hardened threads to ensure long-term durability.
• When drilling, ensure drill pipe threads are always cleaned and have the correct amount of grease – this avoids wear on the tool joints and extends pipe life.

For noise-sensitive environments, consider the Mincon Ex-Flow drill pipe, which:

• Reduces drilling noise by up to 60%.
• Cuts fuel consumption by 20%.
• Lowers drilling time by 15%.

Unlock More Performance And Reliability With A New Shank

Modern drilling requires modern shank designs. Many drill bits today still use legacy shank designs, which:

• Offer lower energy transfer.
• Pose a higher risk of failure at depth.
• Use footvalves, introducing a potential failure point.

Geothermal drills should consider upgrading to footvalveless bits, or a modern shank design such as Mincon’s MC shank, to:

• Improve energy transfer and achieve higher penetration rates.
• Eliminate footvalve breakage.
• Reduce the risk of shanking.

Full-String Optimisation: Compound Your Savings

Each component in your drill string – hammer, drill bits, casing systems, drill pipe, shock absorbers, and drilling fluids – can offer efficiency gains on its own. With a full Mincon drill string, each component’s individual savings can add up to deliver compounded savings:

1. Faster drilling = shorter project timelines, more productivity per day.
2. Lower fuel use = reduced operating costs, lower carbon footprint.
3. Less downtime = more predictable project schedules, reduced operating costs.

For drillers looking to use a single supplier, Mincon’s European network can supply all components – from hammers and bits, to fluids and drill pipe – as a complete package.

Plan For The Project… And Beyond

Whether you operate a compact rig today or plan to upgrade in the future, investing in equipment that is “future-ready” will ensure your business stays competitive. Mincon’s MP-series DTH hammers are designed to grow with your capabilities, delivering even better performance with modern compressors and rigs.

Have questions about optimising your drill setup or reducing your costs per metre?

Contact the Mincon technical team for region-specific advice and product guidance.