Electroplated Diamond Single-Tube Reaming Shell
Our electroplated diamond single-tube reaming shells are purpose-built for single-tube core drilling operations and are used in conjunction with diamond core bits. Featuring a high-strength alloy steel body and an electroplated diamond working layer, these shells deliver outstanding gauge-keeping performance and drilling efficiency in hard, competent rock formations. The reaming shell OD is slightly larger than the bit OD, reaming the hole wall ahead of the bit to maintain a consistent borehole diameter and prevent the need for reaming when a new bit is run . The single-tube design also retains and limits the travel of the core lifter, making it suitable for water well drilling, geotechnical investigation, and mining exploration.
Key Advantages
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Fast penetration in hard, competent rock: The electroplated diamond layer is optimized for medium-hard to hard, intact formations, with sharp exposure that delivers significantly higher ROP than hot-pressed or sintered alternatives.
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Precision gauge control: OD is held at approximately bit OD +0.3 mm, continuously reaming the hole wall to ensure a consistent full-gauge borehole .
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Single-tube specific design: Integrates core lifter retention and travel limitation, simplifying the single-tube BHA and reducing downhole risks.
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Electroplating advantage: Strong diamond retention resists pull-out, delivering stable service life in abrasive formations with favorable overall cost-efficiency.
Available Sizes
| Nominal Diameter (mm) | Matched Bit Series | Typical Application |
|---|---|---|
| 46 / 56 / 59 | Single-tube | Shallow-hole investigation, concrete coring |
| 75 / 91 / 110 | Single-tube | Geotechnical investigation, water wells |
| 130 / 150 / 170 | Single-tube | Mining exploration, large-diameter projects |
| 220 / 278 | Large-diameter single-tube | Hydrogeological wells, bedrock reaming |
Standard single-tube reaming shell diameter range covers 46–278 mm.
Applications
This product is widely used in: water well drilling and hydrogeological well construction; solid mineral exploration and mining engineering; geotechnical investigation for highway, railway, bridge, and building foundation projects; hydropower geological exploration; concrete coring and quality verification drilling. It is particularly recommended for hard, competent formations with moderate abrasiveness, where the gauge-keeping and ROP advantages of electroplated diamond reaming shells are most pronounced.
FAQ
Q1: How much larger should the OD of an electroplated diamond single-tube reaming shell be than the matched bit, and what problems arise if the difference is too large or too small?
A1: The reaming shell OD is generally set about 0.3 mm larger than the matched bit OD. If the difference is too small, the shell cannot effectively ream the hole wall and gauge protection is lost; if too large, torque and diamond wear increase, shortening service life. Before the first run, measure the actual OD with a caliper and verify it against the bit OD for each batch.
Q2: Can a single-tube reaming shell be used with wireline coring tools, and what are the fundamental structural differences between single-tube and wireline reaming shells?
A2: No. Single-tube reaming shells are designed exclusively for single-tube assemblies. Their body dimensions, core lifter housing, and travel-limiting geometry are not compatible with wireline reaming shells, and mixing them can cause core lifter mispositioning or even downhole failure. For wireline operations, select the dedicated wireline reaming shell series; the two types are not interchangeable.
Q3: How do you determine when a reaming shell is worn out and needs replacement, and in hard abrasive formations, how should OD be measured and recorded to manage replacement intervals scientifically?
A3: Once the reaming shell OD wears below the bit OD, gauge protection is lost and the shell must be replaced immediately; otherwise a new bit will need to ream the hole on run-in, adding trips. In hard abrasive formations, measure and record the OD after every run, plot a wear curve, and use it to predict remaining life and replacement timing, avoiding downhole problems caused by a worn-out shell.