Glossary

Artefact images

Artefacts are non-geological features found on borehole images and dipmeters that do not represent the original formation state. They are the difference between an image and what we imagine is the original undisturbed state prior to violation by the bit. They arise from a range of processes, activities and abnormal conditions that include: acquisition, drilling, logging, processing and the effects of the borehole and physics of the measurement. They can be severe to the point that interpretation is not possible. In some cases, e.g. borehole breakout and drilling induced tension fractures, however, they allow interpretations to occur.

BOURKE, L. T., 1989. Recognizing artifact images of the Formation Microscanner. Paper WW, in 30th annual logging symposium transactions. Society of Professional Well Log Analysts, 25.

LOFTS, J. C. and BOURKE, T. 1999. The recognition of artefacts from acoustic and resistivity borehole devices. In: LOVELL, M. A., WILLIAMSON, G and HARVEY, P. K. (eds.) Borehole Imaging: Applications and Case Histories. Geological Society Special Publication No. 159, 59-76.