18 CFR 270.101 - General definitions.
(a) NGPA definitions. Terms defined in the Natural Gas Policy Act of 1978 (NGPA) will have the same meaning for purposes of this subchapter as they have under the NGPA, unless further defined in this subchapter.
(b) Subchapter H definitions. For purposes of this part:
(1) NGPA means the Natural Gas Policy Act of 1978.
(2) Surface location means the point on the Earth's surface from which drilling of a well is commenced except that in the case of a well drilled in permanent surface waters, “the Earth's surface” means the mean elevation of the surface of the water.
(3) Jurisdictional agency means the state or federal agency identified in § 270.401.
(4) Tight formation gas means natural gas that a jurisdictional agency has determined to be produced from a designated tight formation.
(5) Designated tight formation means the portion of a natural gas bearing formation that was:
(i) Designated as a tight formation by the Commission, pursuant to section 501 of the NGPA, or
(ii) Determined to be a tight formation pursuant to section 503 of the NGPA.
(6) Occluded natural gas produced from coal seams means naturally occurring natural gas released from entrapment from the fractures, pores and bedding planes of coal seams.
(7) Natural gas produced from Devonian shale means natural gas produced from fractures, micropores and bedding planes of shales deposited during the Paleozoic Devonian Period.
(8) Shales deposited during the Paleozoic Devonian Period can be defined as either:
(i) The gross Devonian age stratigraphic interval encountered by a well bore, at least 95 percent of which has a gamma ray index of 0.7 or greater; or
(ii) One continuous interval within the gross Devonian age stratigraphic interval, encountered by a well bore, as long as at least 95 percent of the selected Devonian shale interval has a gamma ray index of 0.7 or greater (but if the interval selected is more than 200 feet thick, the bottom and top 100 foot portions must meet the five percent test independently).
(9) Gamma ray index means when measuring the Devonian age stratigraphic interval, the gamma ray index at any point is to be calculated by dividing the gamma ray log value at that point by the gamma log value at the shale base line established over the entire Devonian age interval penetrated by the well bore.
(10) Mcf means one thousand cubic feet of natural gas at 60 degrees Fahrenheit under a pressure equivalent to that of 30.00 inches of mercury at 32 degrees Fahrenheit, under standard gravitational force (980.665 centimeters per second squared).
(11) Data well means a well for which permeability and/or pre-stimulation production rate data are available for a pay section in the formation for which a tight formation designation is being sought.