Tool accessories are defined per tool class.  They define the allowable items in the Accessory Inventory.

 

Any item that is not a drillstring component (e.g. a bit, drill collar, etc) is regarded to be an Accessory.  Effectively, there are two types of accessories:

 

1.Accessory items that belong to, and are run in hole, with a drillstring component. For example: motor stabilizer sleeve, MWD transmitter, MWD sensor package etc.  In addition to logistics (date on location, date off location), utilization hours can also be tracked.  To achieve this, the accessory must be added to the relevant tool detail data on the BHA tally.  Currently this can be done for bits, mud motors, and MWD.  For an accessory to be added to the tool detail data, it must be defined for the correct tool class.

2.Other items that must be tracked, such bit breakers, MWD unit or even shipping baskets or containers.  These items should not be added to the tool detail data, but they are part of the inventory on location and can be included in Backload Lists.

 

Further reading: Using and maintaining lookup data.