ABSTRACT

Well Log-Seismic Sequence Stratigraphy Analysis is a new technology that integrates high resolution biostratigraphic and paleobathymetric data and the characteristics of the well log signatures with seismic reflection profiles. This methodology permits the biostratigrapher, geologist and geophysicist to work together to subdivide a stratigraphic section into packages of sediments bounded by chronostratigraphically significant condensed sections and their associated maximum flooding surfaces and sequence boundaries using well logs and seismic profiles. Each sequence is subdivided into smaller lithogenetic (facies linked) units called systems tracts on the basis of characteristic well-log patterns. The systems tract boundaries, are identified on well logs, marked on two-way time logs or synthetic seismograms and correlated with corresponding systems tracts that have been independently identified on the seismic profiles using seismic-stratigraphic interpretation procedures (Vail and Wornardt, 1990).

Faunal and floral abundance and diversity histograms provide critical information to make reproducible chronostratigraphic correlations (Huang and Wornardt, 1986; Shaffer, 1987; Wornardt, 1989; and Shaffer, 1990). The paleobathymetric interpretations permit the identification of rock types in relation to the depositional environment and systems tracts. The high resolution biostratigraphy is critical in integrated well log-seismic sequence stratigraphic analysis because it provides information for identifying fossil abundance and diversity peaks that are important for recognizing and correlating condensed sections and maximum flooding surfaces on well logs and seismic profiles. High resolution biostratigraphy and paleobathymetry data provides the additional data package that has heretofore been missing in seismic sequence stratigraphy. Added to the well log and seismic data set, they provide an integrated data package that permits the inexperienced person to use the concepts of seismic well log-sequence stratigraphy to develop expertise and confidence in its practice. In order to obtain consistently reliable results in well log-seismic sequence stratigraphy, a particular procedure must be fo lowed and specific data sets must be used.