Oil reservoirs are classified according to their fluid type. There are three broad oil classes. In order of increasing molecular weight, they are volatile oil, black oil, and heavy oil. Heavy-oil reservoirs are of minor interest during pressure depletion because they typically yield only marginal amounts of oil because of their low dissolved-gas contents and high fluid viscosities. The distinguishing characteristic between volatile and black oils is the stock-tank-oil content of their equilibrium gases.
An equation of state (EOS) is a simplified mathematical model that calculates thermodynamic properties and the equilibrium state. To develop the EOS, we need equations that relate thermodynamic quantities in terms of pressure, molar volume, and temperature data (PVT data), and we want to eliminate any path dependence by eliminating all properties that are not state functions. Substitution of Eq. 2 into Eq. 1 by elimination of dQ (a path dependent quantity) and selection of a reversible path (such that dSG 0) gives All of the properties in Eq. 3 are state functions; thus, Eq. 3 is independent of the path or process. After combining like terms, Eq. 3 becomes For a closed system (dn 0), Eq. 4 becomes Eqs. 4 and 5 are examples of fundamental property relations. Other fundamental property relations are possible.
Natural gas is the feedstock used in most of the world's production of methanol. Methanol is a primary liquid petrochemical made from renewable and nonrenewable fossil fuels containing carbon and hydrogen. Containing one carbon atom, methanol is the simplest alcohol. It is a colorless, tasteless liquid and is commonly known as "wood alcohol." Stranded gas can be monetized by producing chemical (or fuel grade) methanol and transporting it to the market.
Compressed natural gas (CNG) transportation is used in very small systems in environmentally sensitive areas. Sometimes the gas is transported to remote filling stations for CNG-fueled vehicles. Large-scale transportation of CNG is not yet commercialized but is considered economically feasible and is being pursued actively by several companies. In the 1960s, Columbia Natural Gas of Ohio tested a CNG carrier. The ship was to carry compressed natural gas in vertical pressure bottles; however, this design failed because of the high cost of the pressure vessels.
Natural gas reserves are plentiful around the world, but many are too small or too remote from sizable population centers to be developed economically. Stranded gas is essentially gas that is wasted or unused. Estimates of remote or stranded gas reserves range from 40 to 60% of the world's proven gas reserves. The local market for gas is usually too small, or the gas field is too far from the industrialized markets. Sometimes excess gas reserves can be classified as stranded because they may result in oversupply of the market.
SPE awards recognize members for their technical contributions, professional excellence, career achievement, service to colleagues, industry leadership, and public service. International awards recognize individuals and companies who make significant technical and professional contributions to the petroleum engineering profession and to the worldwide oil and gas industry. Read the International Award Summary (pdf) to learn more about about the categories and requirements, and review the SPE International Awards Nomination Form Worksheet (pdf) for more information. Award recipients are announced in July, posted on the SPE website, and published in the Journal of Petroleum Technology. The awards are presented during ATCE.