Most sizes of Dimatec’s diamond impregnated core bits are offered in several different bit crown profiles. Each profile has a specific range of application depending on the drilling conditions encountered. Some of the following bit crown profiles may not be available in certain bit sizes due to the kerf width limitations of that particular bit crown.
“Kerf width” is defined as the wall thickness of the diamond bit crown measured from its inside to outside diameter.
Unless otherwise specified, this profile is the standard for all wireline core bits as well as core bits with kerf widths greater than 7 mm (0.27 inch) that are used with conventional (non-wireline) core barrel systems. This bit crown profile provides good penetration rates with relatively low bit loads. It is recommended for use in hard, consolidated formations and will usually provide better initial penetration rates than a bit with the Flat-Face (Style ‘F’) profile.
This profile is the standard for all thin-wall diamond impregnated core bits with kerf widths of 7 mm (0.27 inch) or less. It is also recommended for diamond impregnated core bits with kerf widths in the 7 to 20 mm (0.27 to 0.79 inch) range that are intended for use in predominantly fractured formations. This profile is less susceptible to in-hole damage than bits that are manufactured with the V-Ring (Style ‘V’) or the Tapered (Style ‘TP’) profiles. When applied in hard, consolidated formations, the Flat-Face profile tends to require less initial in-hole conditioning than a V-Ring profile bit but usually requires the use of higher rotational speeds during the initial break-in period in order to establish a good rate of penetration.
This profile is limited to diamond impregnated core bits with kerf widths of 8.5 mm (0.34 inch) or greater. As the Tapered Profile bit crown has a significantly higher contact area with the rock face than any of the other three standard profiles, somewhat lower penetration rates may be expected. This bit crown profile is recommended for addressing hole deviation problems encountered in wireline core drilling. It is also often used for drilling past in-hole deflecting wedges. Core bits manufactured with this profile should not be used in heavily fractured formations as the nose of these crowns are relatively fragile and as such, may be susceptible to in-hole damage. This profile is provided with either the Extra-Wide (Style ‘XW’) or the Face-Discharge (Style ‘FD’) waterway configuration.
Unless otherwise specified, this profile is the standard for all diamond impregnated core bits with kerf widths of 25 mm (0.98 inch) or greater. It is also recommended for use in highly fractured formations. The “Semi-Round” (Style ‘U’) profile is particularly well suited for use in wide-kerf core bits as it tends to distribute the bit load across the bit face more equally than either the Flat-Face (Style ‘F’) or the V-Ring (Style ‘V’) profiles. As a result, this bit crown profile will reduce the risk of “bit bouncing” during operation.
