Volcanic stratigraphy from ditch cutting analysis

Ditch cuttings from wells penetrating flood basalt sequences provide the most commonly available lithological data from which an assessment of the volcanic stratigraphy at a specific location can be made. Many advances in recent years have been made in regards the geophysical response of volcanic facies from down-hole tools however, a similar development in regards to ditch cutting analysis and classification is not apparent. We propose a fresh approach in an attempt to quantify some of the accuracy issues commonly attributed to cuttings. The approach presented comprises a simple analysis workflow and non-genetic classification system that aims to encompass broadly the expected lithologies found in a flood basalt volcanic succession. From this classification system a simplified log output can be produced and subsequently interpreted. The major benefits include a simplistic transparent approach, easily integrated into the real time drilling workflow along with a visual output again easily integrated with well logs and any other stratigraphically constrained information. A move towards a unified approach is required before regional comparisons and synthesis can be undertaken with confidence.