Note: These terms can be found all over, via books, the internet, or by talking to your crew on location. A abnormal pressure n: pressure exerted by a formation and exceeding or falling below the normal pressure to be expected at a given depth. NS – North Sea; can also refer to the North Slope Borough, Alaska, the North Slope, which includes Prudhoe Bay Oil Field (the largest US oil field), Kuparuk Oil Field, Milne Point, Lisburne, and Point McIntyre among others. NTHF – Non-Toxic High Flash; NTU – Nephelometric Turbidity Unit; NUI – Normally Unattended Installation Oilfield Glossary. Posted on December 16, 2014 by rkingco. R. King & Co. guide to oilfield acronyms and drilling terms for royalty and minerals owners to help them understand drilling and daily cost reports from their operators.