Genetic Sequence Stratigraphic Analysis A New Tool for Consistent Correlation, Placement of Laterals, and Mapping Richness Zones in the Eagle Ford-Austin, Eaglebine and Bossier-Haynesville
Walter W. Wornardt
MICRO-STRAT INC., 5755 Bonhomme #406, Houston, TX 77036
When drilling in the Bossier-Haynesville and Eagle Ford-Austin it is important to accurately and consistently identify in order to correlate the same zone of richness and brittleness in two or more wells. In addition to logs and seismic, using the age-datable maximum flooding surfaces identified in each well, provides a third dataset for identification of these zones that are in-between the same age-datable time lines, the maximum flooding surfaces (MFS). This methodology reduces risk in these expensive shale wells by verifying that the lateral that is going to be drilled or has been drilled is in the correct richness or brittleness zone.
Bossier-Haynesville and Eagle Ford-Austin formations have be divided into a series of chronostratigraphic Genetic Sequences between Stage/Age and numerical age datable Maximum Flooding Surface from the base of the Haynesville (top of Smackover) Ox7 SB to the approximate top of the Bossier, Ti5 MFS and from the base of the Eagle Ford (top of Buda) the Cenomanian (Ce3) sequence boundary to the top of the Austin, the Santonian (Sa3) Maximum Flooding Surface. The depositional expression of the MFS, the condensed section, is associated with fossil abundance peaks, Transgressive systems tract, high TOC, increased organic richness and have been correlated to the sequence stratigraphic cycle chart modified after Gradstein et al, 2012.
Subsequently these flooding surfaces also provide: the time-based mapping surfaces necessary to make various types of maps, TOC, %carbonate, HI, isopach, structural, biofacies, brittleness, and fractures; unconformities with time missing: timing of faults; time based data for more accurate burial and thermal history. Sequence Stratigraphy has been proven to reduce risk in these expensive shale wells.
AAPG Search and Discovery Article #90158©2012 GCAGS and GC-SEPM 6nd Annual Convention, Austin, Texas, 21-24 October 2012