A graphic symbol is used to indicate the location and "designation" of a well on IGS maps. The IGS Petroleum Well Symbols are similar to those used in the petroleum industry and by other geological surveys, although no recognized standard exists. A well's Symbol designation is based on its status and history. The symbol scheme employs a set of basic symbols to which "modifiers" can be added to impart additional information. This scheme is explained in the PDF file Petroleum Well Symbols Explanation.
Each graphic symbol corresponds to a Symbol Code labeled Symbol in a well's Well Header (Location Table). The symbols and associated codes are defined in the PDF file, PDMS Well Symbols Table.
In the PDMS, Well Type refers to groups of wells that match specific well completion criteria. The sorting of Well Types into groups within the PDMS is accomplished using each well's Symbol Code. The following Well Types are recognized for the purpose of searches in the PDMS Well Record Tables:
Oil
Gas
Gas Storage
Service
Strat Test (Stratigraphic Test)
Dry
Unknown