All artwork remains the property of Kirk Petrophysics and may not be reproduced in whole or part thereof in any shape or form without the express permission of Kirk Petrophysics.
Lithotarge and the Lithotarge logo is a trademark of :
Kirk Petrophysics Limited
PO Box 18051
AB23 8TZ
Aberdeen
Scotland, UK
CORE DAMAGE AND INTEGRITY
Core damage can occur during coring, recovery and handling on the surface. Surface handling is our main concern. Core integrity can be lost by flexing and rotating the liner containing core. There is also an associated loss of integrity that occurs with jarring and knocking movements when transporting the liner from drill floor to saw.
Core Damage and Liner Flexing
Core damage occurs due to flexing of the liner containing the core. The problem and consequences are often ignored due to the difficulty of obtaining difinitive proof. Below are two examples where liner flexing was noted and the direct consequences recorded. These two examples, taken from competent core samples, should effectively demonstrate that core samples are not elastic and there is an absolute necessity for good core handling and stabilisation procedures.
Hidden Annulus
The majority of recovered sediments do not have visible through annular space. In many instances there is no visible annular space at either end of the cut tube. This does not mean that there is no annulus or core with integrity within the tube length. Without utilising the lithotarge method any core with integrity would subsequently be lost and assumed to be similar to the end cut section. In our experience it is not uncommon to find upto 90% of quality core within a tube length. Selected photographs are listed to demonstrate examples of this.
Minor flexing of liner above
Below are clean faces of 'disc' fractures
Sampling Point
The pictures above show the minor flexing of a liner due to the lifting cable. The remaining pictures are taken from the area of flexing and clearly show clean disc fractures throughout the area of flexing. Top right shows an area where a sample has been taken using a hammer and chisel to illustrate rock competence.
The liner with the
core being lowered
without support
Below is the resultant core integrity = intended for strength testing!
These two samples were recorded as having no visible annulus at tube ends. Core was stabilised and cut to be inserted into Protecore for shipping by air and special analysis. Annular space clearly shows competent core with integrity hidden inside tube length.
No visible annulus before Geological sampling. Mud drainage indicates annular space and probable core integrity.
