Description
One of two principal methods of drilling for gas and oil; the other is rotary. Cable tool, the older method, consists of raising and dropping a heavy drill bit, suspended from the end of a cable, so that it pounds and pulverizes its way through the subsurface structures. Water in the hole keeps the cuttings in suspension for removal at intervals by bailing. Calculated Bill (Also Interim Bill or Estimated Bill) A bill for service not based on meter readings for the period being billed but based on calculations of how much gas a customer used during a particular period of time utilizing the gas consumption history of that customer and temperatures during the period. Calculated Depreciation Reserve , See THEORETICAL DEPRECIATION RESERVE.