Hydrocarbon Accumulation Analysis by Reconstructing the Canyon-Fill Sequence using Seismic Stratigraphic Interpretation in the Central Gulf Coastal Plain of Texas

The Texas Gulf region has been extensively studied and explored due to its high volume of oil and gas accumulation. One of the most highly productive sequences in the region is the lower Wilcox Group, which was deposited during a gradually sea level rising. The high rate of Tertiary sedimentary source influx and repeatedly transgression and regression resulted in numerous reservoirs and ideal traps. Regression caused the development of incised canyon systems, and later the canyon was filled with marine shales during the transgression. The complex canyon-fill sequence makes petroleum accumulation possible. Both stratigraphic and structural trapping mechanisms are found in the study area. The stratigraphy of the Wilcox Group is divided based on the lithological data and electric logs. In order to investigate the lateral variations of erosional sequences and the distributions of thin-bed sand bodies, we correlate the well logging across the survey. The seismic sequences and related sandstones are identified on the seismic sections after the well-to-seismic tie. Finally, the complex canyon-fill system is rebuilt and the hydrocarbon accumulation pattern is analyzed by conducting seismic stratigraphic interpretation in the study area

Pre-Stack Simultaneous Inversion for Petrophysical Properties of the Lower Wilcox Erosional Remnant Sandstone Along the Texas Gulf Coastal Plain

The lower Wilcox sand deposits encased between two continuous erosional sequences are of good reservoir quality and usually gas productive. However, the distribution of sedimentation is laterally scattered and hard to interpret in seismic data. Simultaneous inversion of petrophysical parameters such as P-impedance, S-impedance, and density by the integration of pre-stack data and well logs allows us to quantitatively characterize the reservoirs, and to distinguish them from the surrounding rocks. In this study, we use pre-stack inversion of the petrophysical parameters for the gas reservoir in an analog field. For wells that are missing sonic and density logs, we estimate the parameters using the time average equation and Gardner\u27s equation, respectively. The estimation results are verified using well log correlations. Rock physics analyses are conducted to find the optimal parameters to characterize the producing sand. Our inversion results show a successful delineation of the reservoir using the Vp/Vs value. In addition, the sandstone is mapped in the crossplot of the inverted results