Using Potash Identification (PID) Plot to Distinguish Commercial Potash Mineralization

Abstract

The mineralogy of McNutt “Potash” member of the Salado Formation in SE New Mexico, is extremely complex, consisting of:

• Six (radioactive) potash minerals, only two of which are commercial.

• Radioactive, non-potash “Claystones” and “Marker Beds”.

• Four non-radioactive evaporite minerals, one of which interferes with potash milling chemistry.

Because of this complexity, traditional wireline and Logging While Drilling (LWD) Potash Assay techniques, such as Gamma Ray log to core assay transforms, linear programming, and multi-mineral analyses are not effective.

Numerous oil and gas wells, in the area, have cased hole gamma ray and neutron logs, through the Salado Evaporite, run for stratigraphic and structural correlation. The logs, from these wells could provide a rapid screening database, if used properly.

A simple screening cross-plot technique utilizing only Gamma Ray and Neutron Porosity, is proposed and successfully demonstrated for potash deposits in Michigan, Nova Scotia, and Saskatchewan, as well as SE New Mexico. This technique can be used with both open- and cased-hole petroleum well logs, as well as core hole wire-line logs, and provides discrimination of commercial potash mineralization from non-commercial (potash and non-potash) radioactive mineralization.

AAPG Datapages/Search and Discovery Article #90350 © 2019 AAPG Annual Convention and Exhibition, San Antonio, Texas, May 19-22, 2019