Santiago, Cadi1, Andrew Pepper2
(1) BP Norge, 4065 Stavanger, Norway
(2) Amerada Hess Corp, Houston, TX
ABSTRACT: Understanding Petroleum Fluid Distributions in Sedimentary Basins using Headspace Gas Data
Historically, cuttings headspace gas was a technique used as an attempt to establish maturation profiles, given the traditional view that fine-grained rocks are “impermeable”; thus the gases are regarded as in-situ. Modern concepts of petroleum migration, however, involve vertical migration through fine-grained sequences. Therefore, in young, cold sedimentary sequences where the mudrocks are well below the thermal stress levels required for significant petroleum generation, headspace gas data are now used to map migration pathways and “fronts”.
When integrated with other available geochemical data, we show that headspace gas composition and isotope profile is a powerful tool providing important information on the migration style (lateral vs. vertical migration). In some cases, where subsurface fluid samples are not collected, and the source rock is not drilled, cuttings headspace gas may be the only geochemical data collected from a well, yet it can provide critical information where data from flowline / mud gas is ambiguous.
In this paper, we compare headspace gas data from several sedimentary basins to demonstrate application of cuttings headspace gas data in exploration and production.
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.