This waterway configuration is recommended where very high flushing volumes are required in harder, consolidated formations. The Style ‘XXW’ waterway configuration uses a reduced number of canal type waterways when compared to the Regular (Style ‘W’) type. The waterway canals on the Style ‘XXW’ configuration are wider than those found on both the Style ‘W’ and Style ‘XW’ configurations and typically have a width of 0.25 inch (6.3 mm). As a result, the Style ‘XW’ configuration provides a flushing capacity increase of approximately 40% over the Style ‘W’ and Style ‘T’ configurations while maintaining approximately the same bit face contact area as that of an equivalent sized core bit manufactured with the Turbo (Style ‘T’) configuration.

The benefits of the Style ‘XXW’ waterway configuration include:

• An equivalent or greater rate of penetration using lower bit loads than both the Style ‘W’ and Style ‘XW’ waterway configurations due to the Style ‘XXW’ configuration’s lower bit face contact area.
  
• The fluid pressure developed at the bit face is considerably lower than either the Style ‘W’, Style ‘T’ or Style ‘XW’ configurations and as such is less susceptible to the hydraulic lift phenomenon.

It should be noted however that the Style ‘XXW’ waterway configuration is not recommended for use in softer formations where the potential for core sample degradation exists as a result of increased circulation fluid contact. In this case, the use of either the Face Discharge (Style ‘FD’) or Slot Face Discharge (Style ‘SFD’) waterway configurations are recommended.

The Dimatec code for this waterway configuration style is ‘XXW’. (Example: A Dimatec core bit with the descriptor ‘8XXW’ in its designation would indicate that the bit is supplied with 8 extra-extra-wide canal type waterways).

This configuration is a variation of the Style ‘XW’ and is recommended where it is necessary to drill with a lower bit weight than may be achievable using a Style ‘XW’ product. While the number of waterway canals and the total flow area (TFA) are equivalent to that of the Style ‘XW’, the trapezoid-shaped waterways reduce the bit’s contact area by approximately 10%. The result is a contact area that is the same as that of an equivalently sized bit with an Extra-Extra-Wide (Style ‘XXW’) waterway configuration but without its increased TFA capacity.

This waterway configuration is recommended for use when drilling in relatively soft, unconsolidated formations and/or when using triple-tube wireline core barrel systems. Unlike core bits that are manufactured with conventional canal type waterways that eject the circulating fluid through ports on the inside diameter of the bit crown, the Face-Discharge (Style ‘FD’) configuration ejects the fluid through ports moulded into the face of the bit. The re-direction of the circulating fluid results in minimum core wash and reduces the potential for subsequent core erosion.

Each waterway element typically has a canal width of 0.25 inch (6.3 mm) with a flushing port diameter of 0.19 inch (4.8 mm).

When compared to any of the internal discharge waterway configurations, the Style ‘FD’ configuration develops relatively low fluid pressures across the bit face, even when higher circulation rates are applied.

For reference in determining the appropriate bit load, impregnated diamond core bits that are manufactured with the Style ‘FD’ waterway configuration have bit face contact areas that are similar to that of same size core bits manufactured with the Style ‘XXW’ and Style ‘T’ waterway configurations.

The Style ‘FD’ waterway configuration is available on all wireline core bits as well as on core bits with kerf widths greater than 0.34 inch (8.5 mm) that are used with conventional (non-wireline) core barrel systems.

The Dimatec code for this waterway configuration style is ‘FD’. (Example: A Dimatec core bit with the descriptor ‘8FD’ in its designation would indicate that the bit is supplied with 8 face-discharge type waterways).