### Question
How is the term ultra deep well defined?


### Answer
The term **ultra deep well** is defined in *42 U.S.C. § 15904* as the following:

> a well drilled with a perforated interval, the top of which is at least 20,000 true vertical depth below the datum at mean sea level

#### Citation:
  - *42 U.S.C. § 15904*
  - Heading: **CHAPTER 149-NATIONAL ENERGY POLICY AND PROGRAMS > SUBCHAPTER III-OIL AND GAS > Part A-Production Incentives**

