Time of Migration of Oil and Gas

Abstract

Time of migration may be determined by an analysis of: (1) compaction, which is a function of depth of burial and governs the of primary migration or expulsion of hydrocarbons out of the source beds; (2) of regional tilt, which initiates lateral or secondary migration; (3) of formation of traps; (4) hydrostatic pressure which governs the gas capacity of traps and determines the earliest of final accumulation; (5) saturation or bubble-point pressure, which is a function of depth of burial at of migration and fixes the of final accumulation; (6) history of lithologic development, that is, of cementation and mineralization, of development of secondary porosity, et cetera. Each of these factors indicates the approximate of migration and accumulation. An interpretation of the composite picture gives the time of migration. Application of these relationships in Alberta, Canada, indicates that accumulation of oil and gas in the Upper Devonian reservoirs of Nisku (D2) and Leduc (D3) age occurred during Colorado (Upper Cretaceous) time. As a result of this study, it has been possible to suggest the source of some Alberta crude oils.