b'Proved reserves . . . . . . . . . . . . . . . . Estimated quantities of crude oil, natural gas and natural gasliquids that geological and engineering data demonstrate withreasonable certainty to be economically recoverable in futureyears from known reservoirs under existing economic andoperating conditions, as well as additional reserves expected tobe obtained through confirmed improved recovery techniques,as defined in SEC Regulation S-X 4-10(a)(2).Proved developed reserves . . . . . . . . Those proved reserves that can be expected to be recoveredthrough existing wells and facilities and by existing operatingmethods.Proved undeveloped reserves . . . . . . Those proved reserves that are expected to be recovered fromfuture wells and facilities, including future improved recoveryprojects which are anticipated with a high degree of certaintyin reservoirs which have previously shown favorable responseto improved recovery projects.Stratigraphy . . . . . . . . . . . . . . . . . . The study of the composition, relative ages and distribution oflayers of sedimentary rock.Stratigraphic trap . . . . . . . . . . . . . . A stratigraphic trap is formed from a change in the characterof the rock rather than faulting or folding of the rock and oilis held in place by changes in the porosity and permeability ofoverlying rocks.Structural trap . . . . . . . . . . . . . . . . A topographic feature in the earths subsurface that forms ahigh point in the rock strata. This facilitates the accumulationof oil and gas in the strata.Structural-stratigraphic trap . . . . . . . A structural-stratigraphic trap is a combination trap withstructural and stratigraphic features.Trap . . . . . . . . . . . . . . . . . . . . . . . A configuration of rocks suitable for containing hydrocarbonsand sealed by a relatively impermeable formation throughwhich hydrocarbons will not migrate.Undeveloped acreage. . . . . . . . . . . . Lease acreage on which wells have not been drilled orcompleted to a point that would permit the production ofcommercial quantities of natural gas and oil regardless ofwhether such acreage contains discovered resources.6'