N

Natural Gasoline and Isopentane: A mixture of hydrocarbons, mostly pentanes and heavier, extracted from natural gas, that meets vapor pressure, end point, and other specications for natural gasoline set by the Gas Processors Association. Includes isopentane that is a saturated branch-chain hydrocarbon (C5H12), obtained by fractionation of natural gasoline or isomerization of normal pentane. Natural Gas Plant Liquids: Those hydrocarbons in natural gas that are separated as liquids at natural gas processing plants, fractionating and cycling plants, and, in some instances, eld facilities. Lease condensate is excluded. Products obtained include ethane, liqueed petroleum gases (propane, butanes, propane-butane mixtures, ethane-propane mixtures), isopentane, and other small quantities of nished products, such as motor gasoline, special naphthas, jet fuel, kerosene, and distillate fuel oil. Natural Gas Processing: (1) The purication of eld gas at natural gas processing plants (or gas plants) or the fractionation of mixed NGLs to natural gas products to meet specications for use as pipeline-quality gas. Gas processing includes removing liquids, solids, and vapors, absorbing impurities and odorizing; (2) the process of separating natural gas liquids (NGL5) by absorption, adsorption, refrigeration, or cryogenics from a stream of natural gas. Natural Gas Processing Plant: Facilities designed to recover natural gas liquids from a stream of natural gas that may or may not have passed through lease separators and/or eld separation facilities. These facilities control the quality of the natural gas to be marketed. Cycling plants are classied as gas processing plants. Natural Gas Producer: A natural gas producer is generally involved in exploration, drilling, and renement of natural gas. Natural Gas Resource Base: An estimate of the amount of natural gas available, based on the combination of reserves, contingent resources, and prospective resources. Reserves may include proved, probable, and possible commercial reserves. Contingent resources include recoverable quantities from known accumulations that are not commercial. Prospective resources are those quantities of petroleum that are estimated to be recoverable from undiscovered accumulations. Natural Gas Storage: A means of providing a reserve of natural gas supplies to meet the seasonal demands of natural gas customers. Natural Gas Transportation System: The pipeline transportation system used to accept and transport natural gas. Natural Gas (Units):

Mcf: one thousand cubic feet of natural gas Mmcf: one million cubic feet of natural gas Bcf: one billion cubic feet of natural gas Tcf: one trillion cubic feet of natural gas Mmcf/d: millions of cubic feet of gas per day

Natural Gas, Wet after Lease Separation: The volume of natural gas remaining after the removal of lease condensate in lease and/or eld separation facilities, if any, and after exclusion of nonhydrocarbon gases where they occur in sufcient quantity to render the gas unmarketable. Natural gas liquids may be recovered from volumes of natural gas, wet after lease separation, at natural gas processing plants. Naturally Flowing Well: A well that can ¤ow to the surface unassisted. Naturally Occurring Radioactive Material: NORM scale, usually barium or strontium sulfate scale with very low-level radiation from atoms of uranium, thorium, and potassium in the matrix of the scale. Natural Seep: A naturally occurring hydrocarbon seep to surface. (There are over 1100 known seeps in North America.) NBP: See National balancing point. NBR: See Nitrile butadiene rubber. ND: See Nipple down. NDT: Nondestructive testing. Near Wellbore Damage: Damage to the permeability occurring within the rst few feet away from the wellbore. Neat Alcohol Fuels: Straight alcohol (not blended with gasoline) that may be in the form of either ethanol or methanol. Ethanol, as a neat alcohol fuel, does not need to be at 200 proof; therefore, it is often used at 180 to 190 proofs (90% to 95%). Most methanol fuels are not strictly “neat,” since 5% to 10% gasoline is usually blended in to improve its operational efciency. Neat Cement: Cement slurry without additives. NEB: National Energy Board for Canada. NEC: See National Electrical Code. Needle and Seat Choke: An adjustable common choke for clean (no solids) production ¤ow. Needle Valve: A low-volume, small-orice, high-pressure bleed valve. NEO: See Neoprene. Neoprene: (1) The trivial name for poly(2-chlorobutadiene). This polymer is used in the manufacture of fan belts and wet suits. The monomer, 2-chlorobutadiene (aka chloroprene), looks something like this:

(2) A ball covering and seal type. NEPA: National Environmental Policy Act. Nephelometric Turbidity Unit: A unit used in measuring water quality. An instrument called a nephelometer (from a Greek word meaning “cloudy”) measures turbidity directly by comparing the amount of light transmitted straight through a water sample with the amount scattered at an angle of 90° to one side; the ratio determines the turbidity in NTU’s. NTU measurements

can be confused by the base color of the water from stains that may not create damage in the rock. Neritic: Marine zone; the environment between low tide and the continental shelf. NESHAPs: National Emission Standards for Hazardous Air Pollutants. Net Acres: The total of the company’s fractional interest in the gross acreage position. Net Back: The amount of money received per barrel of oil equivalent produced after subtracting operating and administrative costs and royalties. Net-Back Price: The effective price to the producer of natural gas at a dened point, based on the market price for the natural gas less the charges for delivering the natural gas from the dened point to market. Net Capacity (Shipping): The number of tons of cargo that a vessel can carry when loaded in saltwater to its summer freeboard marks. Also called cargo carrying capacity, cargo deadweight, and useful deadweight. Net Gas: Total produced natural gas times net working interest in natural gas production. Net Heating Value: Assumes that the vapor produced in the combustion process stays in the gaseous phase. Net Pay: The most productive part of the pay zone. Net Pay Cutoff: The lower level to the permeability, porosity, or saturation in what is considered net pay. Net Production: (1) Natural gas and oil production that we own, less royalties and production due others. (2) The company’s share of the production after royalty and partner shares are removed. Net Pro–t Share Lease: An outer continental shelf (OCS) lease that provides for payment to the United States of a percentage share of the net prots for the production of oil and gas from the tract. The percentage share may be xed in the notice of the lease sale or may be a variable of the bid, depending on the bidding system used for the lease sale. Net Pro–ts Interest: A share of the production as calculated from the net prots of the operation. Net Receipts: The difference between total movements into and total movements out of each Petroleum Administration for Defense (PAD) District by pipeline, tanker, and barge. Net Revenue Interest: (1) That percent of the production revenue allocated to the working interest after rst deducting proceeds allocated to royalty and overriding interest. (2) That part of the proceeds less royalty payments. NETL: National Energy Technology Laboratory. Net-to-Gross Ratio: The ratio of the net pay to the gross pay. Net Tonnage: The carrying capacity of vessels as prescribed by government regulations and determined by measuring the cubic contents of the space intended for revenue earning.