ABSTRACT
Unproved Reserves: Unproved reserves are based on geologic and/or engineering data similar to that used in estimates of proved reserves; but technical, contractual, economic, or regulatory uncertainties preclude such reserves being classied as proved. Unproved reserves may be further classied as probable reserves and possible reserves. Unproved reserves may be estimated assuming future economic conditions different from those prevailing at the time of the estimate. The effect of possible future improvements in economic conditions and technological developments can be expressed by allocating appropriate quantities of reserves to the probable and possible classications (SPE). Unsaturates: Hydrocarbon compounds of such molecular structure that they readily pick up additional hydrogen atoms. Olens and diolens, which occur in cracking, are of this type. Unsteady State: Nonconstant, in ¤uid ¤ow a condition marked by changing ¤ow properties. Unsulfonated Residue: That portion of an oil that is not acted upon when the oil is agitated with a denite amount of sulfuric acid under specied conditions. Unweighted Fluid: The base ¤uid without added salts or solids. UO: Oil viscosity. Updip: In an upward direction in a tilting formation. Updip Well: A well located higher in the structure. Upgrade Projects: Various projects that are undertaken both onshore and offshore to upgrade or replace the existing facilities to ensure continued production over a long period of time. Upgrading: The process of converting heavy oil or bitumen into synthetic crude oil. Uplift: Vertical movement of a formation to a shallower depth than when it was deposited. Upper Completion: The part of the completion above the packer. Upper Crown Plug (Subsea): A plug that ts in the bore of a subsea tree to serve as the secondary barrier against reservoir pressure. Upper Kelly Cock: A valve at the top of the kelly that can be closed in the event of an inside tubing kick or high pressures. UPS: See Uninterrupted power supply. Upset (Chemical): In a produced ¤uid stream, an upset is when chemical or physical reactions create precipitates or emulsions. Upset Connection: A pipe connection with thicker wall area at the coupling. An external upset is thicker to the outside with a consistent ID with the pipe and is called an EU or EUE. A connection upset to the inside (smaller ID but consistent OD) is an IU. Upset Digester: An upset digester does not decompose organic matter properly. An upset digester is characterized by low gas production, high volatile acid/alkalinity relationship, and poor liquids-solids separation.
