Narrow margin drilling practices

Narrow margin drilling practices refer to practices and procedures adopted when there is only a small margin (or window) between either:

A. The lowest measured (or expected) fracture gradient in the open hole and the corresponding local ECD (while drilling ahead) and/or any induced surge pressure, or

B. The highest measured (or expected) pore pressure in the open hole and the combination of the downhole static mud weight in use and any induced swab pressure.