Production volumes is part of the petroleum industry that is concerned with bringing gas and oil to the surface and separating, gauging, storing, and preparing it for transport. In order to conduct production activities, it is necessary to measure, estimate, and allocate the produced volumes of hydrocarbons, as well as injected fluid volume, required for hydrocarbon production as accurately as possible.
Production volumes may relate to well completions, Production strings (tubing or casing strings), and facilities on the surface like tanks, fields, leases, and so on. They are also of great importance for accounting, as well as for many analysis activities such as oilfield management and reservoir engineering.
The production volumes area of the data model allows for storage of the different types of production and injection volumes (such as estimated, measured, and allocated) that are associated with production entities such as wells, well completions, and facilities over any type of time period (such as Daily, Monthly, Yearly, and so on). In addition, production volumes can be corrected to any temperature or pressure basis.
When a well is drilled, if a zone showing commercial potential is encountered, the decision may be made to complete the well for production. A series of activities then follows to equip the well with tubing, packers, valves, pumps, and other specialized downhole facilities, depending on the unique conditions of the well to produce hydrocarbons.
Specialized equipment is installed at the surface, starting with the Christmas tree, then other surface facilities and equipment are installed to handle produced fluids beyond the wellhead through to the point of sale. Some examples of surface facilities are:
� Separation facilities to separate the oil, water, gas, and gas fluids
� Measurement facilities to determine the volume of oil, water, and gas produced and sold
� Storage facilities to store produced liquids pending disposal
� Transportation facilities to gather and dispose of produced fluids
� Treatment facilities used for gas dehydration, oil stabilization, carbon dioxide removal from gas, and water treatment among others
Surface facilities are generally remote from the reservoir and are not involved with the reservoir performance. They are normally designed by mechanical, civil, process, or petroleum engineers.
The common equipment used in the oilfield includes pressure vessels, pumps, compressors, tanks, pipes and fittings, valves, and meters. Different equipment can be assembled to create equipment systems such as flow lines, piping manifolds, gas separators, free-water knockouts, emulsion-breaking facilities, automatic custody transfer (ACT) units, vapor recovery units, pipelines, compression plants, and injection facilities.
An "allowable" is the maximum amount of gas and/or oil that a well, lease, or field is permitted to produce for a given time by a government regulatory agency, or by operational restrictions such as the capacity of the production facilities to store and transport the fluids.
An oil allowable is often expressed in barrels of oil per day (BOPD) for a given period, or as a normalized amount of barrels allowed for a certain period. There may also be other allowables for materials. For example, flow rates, GOR, pressure, temperature, number of days, and so forth.