Diamond drill bit
Technical Specifications – Diamond Drill Bit Range
The tables below present key specifications for our diamond drill bit range. All bits are API 7‑1 certified and fully customizable.
Surface Set Diamond Core Bits
| Bit Diameter (mm/in) | Hole Type | Stone Size Range (SPC) | Recommended Formation | Matrix Height Options (mm) | Connection Thread |
|---|---|---|---|---|---|
| BQ (60/41.5) | Coring | 20/25 – 60/80 | Soft–hard | 7, 9, 12, 14, 16, 24 | API / Metric |
| NQ (75/54.5) | Coring | 10/15 – 60/80 | Soft–hard | 7, 9, 12, 14, 16, 24 | API / Metric |
| HQ (91/68) | Coring | 10/15 – 60/80 | Soft–hard | 7, 9, 12, 14, 16, 24 | API / Metric |
| PQ (110/90) | Coring | 10/15 – 50/70 | Soft–hard | 7, 9, 12, 14, 16, 24 | API / Metric |
| 75 | Non‑coring | 20/25 – 70/90 | Medium–very hard | 7, 9, 12, 14, 16, 24 | API REG |
| 94 | Non‑coring | 20/25 – 70/90 | Medium–very hard | 7, 9, 12, 14, 16, 24 | API REG |
| 110 | Non‑coring | 30/40 – 80/100 | Hard–very hard | 7, 9, 12, 14, 16, 24 | API REG |
| 113 | Non‑coring | 30/40 – 80/100 | Hard–very hard | 7, 9, 12, 14, 16, 24 | API REG |
| 133 | Non‑coring | 40/60 – 80/100 | Hard–extremely hard | 12, 16, 24 | API REG |
| 153 | Non‑coring | 40/60 – 80/100 | Hard–extremely hard | 12, 16, 24 | API REG |
Matrix height refers to the height of diamond‑impregnated section; taller heights provide longer service life. Surface set bits have excellent adaptability in a wide range of formations and provide high drilling efficiency even in very demanding conditions.
Impregnated Diamond Core Bits
| Bit Diameter (mm/in) | Stone Size Range (SPC) | Recommended Formation | Matrix Type | Optimal RPM Range |
|---|---|---|---|---|
| BQ (60/41.5) | 40/60 – 80/100 | Hard–very hard | O / E | 500–1,200 |
| NQ (75/54.5) | 40/60 – 80/100 | Hard–very hard | O / E | 500–1,200 |
| HQ (91/68) | 50/70 – 80/100 | Hard–extremely hard | O / E | 500–1,200 |
| PQ (110/90) | 50/70 – 80/100 | Hard–extremely hard | O / E | 500–1,200 |
Impregnated bits contain multiple layers of smaller diamonds throughout a metal matrix, offering extended life and adaptability in mixed formations. They are most frequently run in conjunction with turbodrills and high‑speed positive displacement motors that operate at 500 to 1,500 rpm.
PDC Diamond Bits (Fixed Cutter)
| Bit Diameter (in/mm) | Body Type | Blade Count | Cutter Size (mm) | Recommended Formation | Connection |
|---|---|---|---|---|---|
| 4 5/8" (117.5) | Steel / Matrix | 5 | 13 | Soft–medium | 2 7/8" API REG |
| 6" (152.4) | Steel / Matrix | 5, 6, 8 | 13 / 16 | Soft–medium hard | 3 1/2" API REG |
| 8 1/2" (215.9) | Steel / Matrix | 5, 6, 8 | 13 / 16 / 19 | Soft–medium (short parabola profile) | 4 1/2" API REG |
| 9 7/8" (250.8) | Steel / Matrix | 6 | 16 | Soft–medium | 6 5/8" API REG |
| 12 1/4" (311.15) | Matrix | 6, 8 | 16 / 19 | Medium–hard | 6 5/8" API REG |
| 17 1/2" (444.5) | Matrix | 8 | 19 | Very hard / abrasive | 7 5/8" API REG |
Note: PDC bits are not ideal for extremely hard rock like granite or basalt, where impregnated bits perform better.
Crown Profiles – Matching Bit Geometry to Formation
The crown profile of a diamond bit has a direct impact on drilling speed, hole deviation, and core recovery. We offer the following profiles to match your specific drilling conditions:
| Profile Type | Best Application | Characteristics |
|---|---|---|
| Step (STP / multi‑step) | Soft to medium, competent formations | Fastest penetration, excellent core recovery, stabilized drilling |
| Semi‑round | Hard, broken, fractured formations | Very strong, good stability, requires higher bit load |
| Conical | General purpose, good penetration | Balanced performance, stronger than stepped, not as fast ROP |
| Pilot | Soft, friable formations | Excellent core recovery, good stabilization, fragile nose |
| Biconical | Soft, unfractured formations (thick kerf) | Good penetration, fragile nose |
| Flat / round | Very hard formations | Maximum stability, lower ROP |
Innovative Technology & Key Features
Our diamond drill bits incorporate the most advanced materials science and manufacturing technologies available in the industry today.
Advanced matrix metallurgy – Using powder metallurgy technology coupled with decades of field experience, we have developed high‑performance matrices that are suitable for virtually all common drilling conditions. Our matrices provide the highest diamond‑holding characteristics, ensuring that stones remain in place even under extreme loads.
High‑strength, quality natural diamonds – We match our specialized matrix with the highest‑quality synthetic and unprocessed natural drilling diamonds, specifically selected for use in core bits. These diamonds have sufficient strength to handle the hardest ground conditions and result in the longest‑lasting bits.
Non‑planar interface bonding technology – Our advanced bonding technology between the diamond table and carbide substrate eliminates stress concentration, ensuring no microcracking under high loads. The result is an exceptionally durable cutter with excellent self‑sharpening capability.
Deep cobalt removal process – By removing cobalt catalyst from the diamond table, our cutters achieve superior thermal stability, meaning you can drill faster with higher RPM without burning out gauge cutters.
Optimized hydraulic nozzle placement – Through dynamic flow field simulation, we optimize the number, size, and placement of nozzles to maximize bottom‑hole cleaning, improve chip evacuation, and prevent bit balling. This significantly enhances ROP, bit life, and hole quality.
Dual‑row cutting structure – Our advanced PDC designs incorporate double rows of teeth, where the secondary row regulates cutting volume and protects the primary cutters from premature wear, significantly enhancing stability in directional wells.
Product Types – Complete Diamond Drill Bit Portfolio
We manufacture the following diamond drill bit categories for global customers:
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Surface Set Diamond Core Bits – Single layer of high‑quality synthetic or natural diamonds set on the crown. For soft to medium‑hard formations. Available in all standard DCDMA wireline sizes (BQ, NQ, HQ, PQ) and custom diameters.
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Impregnated Diamond Core Bits – Millions of diamonds distributed throughout a metal matrix for continuous self‑sharpening action. For medium‑hard to extremely hard and abrasive rock. Ideal for granite, basalt, and quartzite.
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PDC Diamond Bits (Fixed Cutter) – Synthetic diamond cutters brazed onto steel or matrix bodies. For soft to medium‑hard formations where high ROP is the priority.
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Coring vs. Non‑Coring (Full Hole) Bits – Coring bits extract intact core samples for geological analysis and resource estimation, the gold standard for mineral exploration. Non‑coring bits are designed for rapid bulk material removal in pilot holes and production drilling.
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TSP (Thermally Stable Polycrystalline) Diamond Bits – For deep drilling applications where high temperature stability is critical.
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Reaming Shells – For stabilizing the borehole and reducing wear during deep drilling. Used in combination with diamond core bits to maintain consistent hole gauge.
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Custom Bit Design – Non‑standard diameters, special thread connections (API, metric, proprietary), unique crown profiles, and custom matrix formulations. Provide your well plan and we engineer the bit.
Applications – Where Our Diamond Drill Bits Excel
Our diamond drill bits have been deployed across the full spectrum of hard rock drilling:
Mineral exploration and mining – Core drilling for mineral resource estimation and geological analysis. Diamond core drilling provides intact rock cores essential for accurate resource estimates. Impregnated bits are the workhorse for deep drilling in crystalline rock.
Oil and gas exploration (pilot holes) – Drilling pilot holes and exploratory wells to map sub‑surface formations prior to full‑scale drilling, especially in hard sedimentary or crystalline formations.
Geothermal drilling – High‑temperature rated impregnated bits with metal‑bodied matrices for drilling through granite, basalt, and other igneous rocks in geothermal fields. Thermal management and continuous diamond exposure are critical for these high‑RPM applications.
Water well drilling in hard rock – Impregnated and surface set diamond bits for municipal and agricultural wells where shallow overburden transitions to deep crystalline basement rock.
Construction and geotechnical investigations – Diamond core bits for tunnels, dams, and skyscraper foundations where accurate subsurface data is required for structural risk analysis and design validation.
Mine waste remediation, exploration, and blast hole drilling – Both coring and non‑coring diamond bits are used throughout the mine life cycle, from exploration core sampling to production blast hole drilling.
Why Choose SJ Petro as Your Diamond Drill Bit Manufacturer?
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Sinopec‑backed engineering excellence – As a direct subsidiary of Sinopec Oilfield Equipment Corporation, we are part of China’s largest oilfield industrial group. Our 314 in‑house R&D engineers and 180,000+ m² manufacturing campus provide the technical depth and production scale that independent bit manufacturers simply cannot match.
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API 7‑1 certified, every bit – Full compliance with international standards for rotary drill stem elements. Third‑party inspection (ABS, DNV, BV, SGS) is always welcome. Our certification includes API Spec 7, Spec 7‑1, Spec 7K, and Spec 5CT monogram.
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Kingdream collaboration – 40+ years of diamond bit expertise – Kingdream is a Sinopec group company with over four decades of dedicated diamond bit manufacturing history. Recognized as a national high‑tech enterprise and a leading oil drill bit manufacturer in China, Kingdream has developed advanced functional products including comprehensive drilling series, directional drilling series, hard formation drilling series, core bit series, and impregnated bit series. Through our collaboration, we bring this world‑class engineering foundation directly to you.
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Complete bit range in stock – We inventory common diamond bit sizes for immediate shipment. Custom bits for non‑standard diameters or specific formations are manufactured in 20‑30 days.
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Full material traceability – Every bit carries a unique serial number. We provide complete material certificates (EN 10204 3.1) with heat numbers, chemical composition, and mechanical properties for every diamond bit. You know exactly what you are running downhole.
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Dull bit analysis – Our accredited laboratory inspects returned bits and provides a written dull grading report identifying wear mechanisms: abrasion, impact damage, thermal degradation, or balling. This feedback loop continuously improves your bit selection.
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Formation‑specific technical consultation – Our drilling engineers can analyze your offset well data and bit records to recommend the optimal bit type, stone size, matrix hardness, and crown profile for your specific lithology—before you order.
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Competitive direct‑manufacturer pricing – No trading company markups. You pay factory‑direct prices for Sinopec‑level quality, typically 15‑25% below Western brands for equivalent API certification.
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Global logistics – We have shipped diamond bits to over 30 countries. Our export team handles all documentation: commercial invoices, packing lists, certificates of origin, and bills of lading.
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Warranty – 12 months on all diamond bits against material and workmanship defects. Bits that wear out naturally are not covered, but we do offer refurbishment services at competitive rates.
Frequently Asked Questions (FAQ)
Q1: What is the difference between surface set and impregnated diamond drill bits?
Surface set bits embed a single layer of larger diamonds on the crown. They are ideal for soft to medium formations where high ROP is the goal, but they have shorter life. Impregnated bits contain millions of smaller diamonds distributed throughout a metal matrix. As the outer diamonds wear, fresh diamonds are continuously exposed—like a self‑sharpening mechanism—giving them much longer life in hard, abrasive rock. Impregnated bits are the preferred choice for granite, basalt, and quartzite.
Q2: How do I choose the correct stone size (SPC) for my formation?
The stone size in stones per carat (SPC) determines cutting aggressiveness: smaller SPC numbers = larger, more aggressive stones for soft rock; larger SPC numbers = smaller, more numerous stones for long life in hard rock. For soft formations (clay, chalk, soft shale), use 10/15 – 20/25 SPC. For medium rock (sandstone, limestone), use 30/40 – 50/70 SPC. For hard rock (granite, basalt, quartzite), use 60/80 – 80/100 SPC.
Q3: What is the advantage of diamond drilling over tricone or roller cone bits?
In hard rock (compressive strength above 15,000 PSI), diamond bits drill faster, last longer, and produce better hole quality than tricone bits. Tricone bits crush rock through impact, which requires high weight on bit; diamond bits grind rock abrasively, requiring less weight but higher RPM. For deep, hard rock drilling, diamond bits significantly reduce the number of trips and lower cost‑per‑foot. Diamond bits are also capable of extracting intact core samples, which tricone bits cannot do.
Q4: Can diamond drill bits be repaired or refurbished?
Yes. Diamond bits can be returned to our factory for refurbishment. For surface set bits, we clean the bit, replace worn diamonds, and recertify the bit. For impregnated bits, the entire matrix layer can be replaced. Refurbished bits are tested to API 7‑1 standards and have similar performance to new bits—at approximately 40‑60% of the new bit price. This significantly lowers your long‑term drilling costs.
Q5: What RPM range should I use for a diamond bit?
Surface set bits are effective at 150‑400 RPM with moderate weight on bit. Impregnated bits require higher RPM to be effective—typically 500‑1,200 RPM—and are most often run with high‑speed mud motors or turbodrills. Running an impregnated bit at low RPM (below 300) will glaze the matrix, dramatically reducing ROP. Always consult our recommended operating parameters for your specific bit type and formation.
Q6: What is the typical lifespan of an impregnated diamond bit?
Impregnated bit life depends on formation abrasiveness, operating parameters, and run length. In hard granite, a properly run NQ impregnated bit may drill 100‑200 meters before matrix rebuild is required. In softer rock, surface set bits may drill 500‑1,000 meters. Our dull bit analysis service helps you quantify the lifespan in your specific field conditions.
Q7: Can I get a custom diamond bit for a non‑standard hole diameter or thread connection?
Absolutely. We manufacture custom diamond bits for any diameter and any thread type (API REG, API IF, API FH, metric threads, proprietary connections). Minimum order quantities apply. Provide your drilling program specifications, and our engineering team will design a bit specifically for your project.
Q8: Do you offer diamond bits for directional drilling applications?
Yes. Our PDC bits and certain impregnated bits are designed with force‑balanced cutting structures and short parabola profiles specifically for directional and horizontal wells. These bits reduce torque fluctuations, maintain toolface control, and have been successfully run in build sections and long laterals.
Q9: What documentation do you provide with each diamond bit?
Every bit is accompanied by: API 7‑1 certificate of conformance; material certificates (EN 10204 3.1) with full chemical composition and mechanical properties; dimensional inspection report; diamond grading certificate; and a hydrostatic/performance test certificate (where applicable). For international shipments, we also provide commercial invoices, packing lists, and certificates of origin.
