The glossary of oil and gas terms is available on Eni’s web page at the address Below is a selection of the most frequently used terms.

Financial terms

Dividend Yield

Measures the return on a share based on dividends for the year. Calculated as the ratio of dividends per share of the year and the average reference price of shares in the last month of the year. Generally, companies tend to keep a constant dividend yield, as shareholders compare this indicator with the yield of other shares or other financial instruments (e.g. bonds).


Is a measure of a company’s debt, calculated as the ratio between net financial debt and shareholders’ equity, including minority interests.


Return On Average Capital Employed Is the return on average capital invested, calculated as the ratio between net income before minority interests, plus net financial charges on net financial debt, less the related tax effect and net average capital employed.


Financial discipline ratio, calculated as the ratio between operating profit and net finance charges.

Current ratio

Measures the capability of the company to repay short-term debt, calculated as the ratio between current assets and current liabilities.

Debt coverage

Rating companies use the debt coverage ratio to evaluate debt sustainability. It is calculated as the ratio between net cash provided by operating activities and net borrowings, less cash and cash-equivalents, Securities held for non-operating purposes and financing receivables for non operating purposes.

Profit per boe

Measures the return per oil and natural gas barrel produced. It is calculated as the ratio between Results of operations from E&P activities (as defined by FASB Extractive Activities - Oil&Gas Topic 932) and production sold.

Opex per boe

Measures efficiency in the oil&gas development activities, calculated as the ratio between operating costs (as defined by FASB Extractive Activities - Oil&Gas Topic 932) and production sold.

Cash flow per boe

Represents cash flow per each boe of hydrocarbon produced, less non-monetary items. Calculated as the ratio between Results of operations from E&P activities, net of depreciation, depletion, amortization and impairment and exploration expenses (as defined by FASB Extractive Activities - Oil&Gas Topic 932) and volumes of oil and gas produced.

Finding & Development cost per boe

Represents Finding & Development cost per boe of new proved or possible reserves. It is calculated as the overall amount of exploration and development expenditure, the consideration for the acquisition of possible and probable reserves as well as additions of proved reserves deriving from improved recovery, extensions, discoveries and revisions of previous estimates (as defined by FASB Extractive Activities - Oil&Gas Topic 932).

Operating activities

Average reserve life index

Ratio between the amount of reserves at the end of the year and total production for the year.

Boe (Barrel of Oil Equivalent)

Is used as a standard unit measure for oil and natural gas. From July 1, 2012, Eni has updated the conversion rate of gas to 5,492 cubic feet of gas equals 1 barrel of oil (it was 5, 550 cubic feet of gas per barrel in previous reporting periods).


Refinery process allowing the transformation of heavy fractions into lighter fractions. Conversion processes are cracking, visbreaking, coking, the gasification of refinery residues, etc. The ration of overall treatment capacity of these plants and that of primary crude fractioning plants is the conversion rate of a refinery. Flexible refineries have higher rates and higher profitability.


(or Rubber) Polymers, either natural or synthetic, which, unlike plastic, when stress is applied, return, to a certain degree, to their original shape, once the stress ceases to be applied. The main synthetic elastomers are polybutadiene (BR), styrene-butadiene rubber (SBR), ethylenepropylene rubber (EPR), thermoplastic rubber (TPR) and nitrylic rubber (NBR).

Emissions of NOx (Nitrogen Oxides)

Total direct emissions of nitrogen oxides deriving from combustion processes in air. They include NOx emissions from flaring activities, sulphur recovery processes, FCC regeneration, etc. They include NO and NO2 emissions and exclude N2O emissions.

Emissions of SOx (Sulphur Oxides)

Total direct emissions of sulfur oxides including SO2 and SO3 emissions. Main sources are combustion plants, diesel engines (including maritime engines), gas flaring (if the gas contains H2S), sulphur recovery processes, FCC regeneration, etc.

Enhanced recovery

Techniques used to increase or stretch over time the production of wells.

EPC (Engineering, Procurement, Construction)

A contract typical of onshore construction of large plants in which the contractor supplies engineering, procurement and construction of the plant. The contract is defined “turnkey” when the plant is supplied for start-up.

EPCI (Engineering, Procurement, Commissioning, Installation)

A contract typical of offshore construction of complex projects (such as the installation of production platforms or FPSO systems) in which the global or main contractor, usually a company or a consortium of companies, supplies engineering, procurement, construction of plant and infrastructure, transport to the site and all preparatory activities for the start-up of plants.

FPSO vessel

Floating, Production, Storage and Offloading system made-up of a large capacity oil tanker including a large hydrocarbon treatment plant. This system, moored at the bow in order to maintain a geostationary position, is in fact a temporary fixed platform linking the underwater wellheads to the treatment, storage and offloading systems onboard by means of risers from the seabed.

Green House Gases (GHG)

Gases in the atmosphere, transparent to solar radiation, can consistently trap infrared radiation emitted by the earth’s surface, atmosphere and clouds. The six relevant greenhouse gases covered by the Kyoto Protocol are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF6). GHGs absorb and emit radiation at specific wavelengths within the range of infrared radiation determining the so called greenhouse phenomenon and the related increase of earth’s average temperature.

Infilling wells

Infilling wells are wells drilled in a producing area in order to improve the recovery of hydrocarbons from the field and to maintain and/or increase production levels.


Liquefied Natural Gas obtained through the cooling of natural gas to minus 160 °C at normal pressure. The gas is liquefied to allow transportation from the place of extraction to the sites at which it is transformed and consumed. One ton of LNG corresponds to 1,400 cubic meters of gas.

Mineral Potential (Potentially recoverable hydrocarbon volumes)

Estimated recoverable volumes which cannot be defined as reserves due to a number of reasons, such as the temporary lack of viable markets, a possible commercial recovery dependent on the development of new technologies, or for their location in accumulations yet to be developed or where evaluation of known accumulations is still at an early stage.

Natural gas liquids

Liquid or liquefied hydrocarbons recovered from natural gas through separation equipment or natural gas treatment plants. Propane, normal-butane and isobutane, isopentane and pentane plus, that used to be defined natural gasoline, are natural gas liquids.

Oil spills

Discharge of oil or oil products from refining or oil waste occurring in the normal course of operations (when accidental) or deriving from actions intended to hinder operations of business units or from sabotage by organized groups (when due to sabotage or terrorism).

Olefins (or Alkenes)

Hydrocarbons that are particularly active chemically, used for this reason as raw materials in the synthesis of intermediate products and of polymers.


Agreements stipulated between partners regulate the right of each to its share in the production of a set period of time. Amounts different from the agreed ones determine temporary over/underlifting situations.

Proved reserves

Proved oil and gas reserves are those quantities of oil and gas, which, by analysis of geoscience and engineering data, can be estimated with reasonable certainty to be economically producible from a given date forward, from know reservoirs, and under existing economic conditions. The project to extract the hydrocarbons must have commenced or the operator must be reasonably certain that it will commence the project within a reasonable time.


Quantities of oil and gas and related substances anticipated to be economically producible, as of a given date, by application of development projects to known accumulations. In addition, there must exist, or there must be a reasonable expectation that will exist, the legal right to produce or a revenue interest in the production, installed means of delivering oil and gas or related substances to market, and all permits and financing required to implement the project. Reserves can be: (i) developed reserves quantities of oil and gas anticipated to be through installed extraction equipment and infrastructure operational at the time of the reserves estimate; (ii) undeveloped reserves: oil and gas expected to be recovered from new wells, facilities and operating methods.


Clause included in natural gas transportation contracts according to which the customer for which the transportation is carried out is bound to pay for the transportation of the gas also in case the gas is not transported.


Clause included in natural gas purchase contracts according to which the purchaser is bound to pay the contractual price or a fraction of such price for a minimum quantity of the gas set in the contract also in case it is not collected by the customer. The customer has the option of collecting the gas paid and not delivered at a price equal to the residual fraction of the price set in the contract in subsequent contract years.


The term upstream refers to all hydrocarbon exploration and production activities. The term mid-downstream includes all activities inherent to oil industry subsequent to exploration and production. Process crude oil and oil-based feedstocks for the production of fuels, lubricants and chemicals, as well as the supply, trading and transportation of energy commodities. It also includes the marketing business of refined and chemicals products.


Intervention on a well for performing significant maintenance and substitution of basic equipment for the collection and transport to the surface of liquids contained in a field.