‘‘Proved undeveloped reserves’’ . . . . . . Those proved reserves that are expected to be recovered from future wells and facilities, including future improved recovery projects which are anticipated with a high degree of certainty in reservoirs which have previously shown favorable response to improved recovery projects. ‘‘Shelf margin’’ . . . . . . . . . . . . . . . . . The path created by the change in direction of the shoreline in reaction to the filling of a sedimentary basin. ‘‘Stratigraphy’’ . . . . . . . . . . . . . . . . . . The study of the composition, relative ages and distribution of layers of sedimentary rock. ‘‘Stratigraphic trap’’ . . . . . . . . . . . . . . A stratigraphic trap is formed from a change in the character of the rock rather than faulting or folding of the rock and oil is held in place by changes in the porosity and permeability of overlying rocks. ‘‘Structural trap’’ . . . . . . . . . . . . . . . . A topographic feature in the earth’s subsurface that forms a high point in the rock strata. This facilitates the accumulation of oil and gas in the strata. ‘‘Structural-stratigraphic trap’’ . . . . . . . A structural-stratigraphic trap is a combination trap with structural and stratigraphic features. ‘‘Submarine fan’’ . . . . . . . . . . . . . . . . A fan-shaped deposit of sediments occurring in a deep water setting where sediments have been transported via mass flow, gravity induced, processes from the shallow to deep water. These systems commonly develop at the bottom of sedimentary basins or at the end of large rivers. ‘‘Three-way fault trap’’ . . . . . . . . . . . . A structural trap where at least one of the components of closure is formed by offset of rock layers across a fault. ‘‘Trap’’ . . . . . . . . . . . . . . . . . . . . . . . A configuration of rocks suitable for containing hydrocarbons and sealed by a relatively impermeable formation through which hydrocarbons will not migrate. ‘‘Undeveloped acreage’’ . . . . . . . . . . . . Lease acreage on which wells have not been drilled or completed to a point that would permit the production of commercial quantities of natural gas and oil regardless of whether such acreage contains discovered resources. 6