UNDISCOVERED CONVENTIONAL ACCUMULATIONS


     The assessment of undiscovered conventional resources was conducted 
at the play level. The methodology employed required estimation of the
sizes, numbers, and types of undiscovered conventional accumulations of
oil and gas and estimation of play risk. Numerous techniques were employed 
to make these estimates. These include reservoir-simulation modeling, 
discovery-process modeling, application of analogs, and spatial analysis. 
The method provides for a systematic integration and analysis of the geologic 
factors essential for the occurrence of oil and gas, a thorough documentation 
of the analysis, and an assessment containing information on the size, depth 
distribution, and number of hydrocarbon accumulations, as well as the quantity 
of estimated resources. Two principal categories of conventional plays were
assessed: confirmed plays and hypothetical plays.

     A play was considered confirmed if one or more accumulations of 
the minimum size (1 MMBO or 6 BCFG) had been discovered in the play.
Confirmed plays were commonly assessed by extrapolation or approximation 
based on sizes, numbers, depths, drilling history, and other properties of 
known accumulations. 

     Hypothetical plays were those that were identified and defined based on
based on geologic information but for which no accumulations of the minimum 
size had, as yet, been discovered. In contrast to confirmed plays, these
hypothetical plays cannot, of course, be analyzed based on trends ofknown 
accumulations. Rather, properties of undiscovered accumulations must be 
postulated based on other types of information, including reservoir simulation
and application of analog data sets from areas of similar geologic properties 
and known oil and (or) gas accumulations.  Hypothetical plays characteristically 
carry a much broader degree of uncertainty, as recorded in the range of possible 
resources reported, than do confirmed plays. In addition to the greater range 
of reported resources, virtually all hypothetical plays carry a play-level
probability of less than one.