Forward Stratigraphic Modeling of the Permian of the Delaware Basin
Qiucheng Ye, Charles Kerans, W. M. Fitchen, M. H. Gardner,
M. D. Sonnenfeld, and S. Bowman
Permian platform-to-basin strata of the Delaware Basin in west Texas and New Mexico represent one of the world's most complete, best studied, and most hydrocarbon productive records of this geologic period in the world. This superb marriage of a refined stratigraphic framework and active exploration provided impetus to develop a forward stratigraphic model of this section to better predict the distribution of reservoir and seal relationships
The approximately 30 m.y. Interval modeled is composed of 2 km of platform strata and a km of basinal strata divided into 8 composite sequences (average 3 m.y. duration) and 45 high-frequency sequences (400 ky m.y. duration). A 130 km dip section through the basin margin Guadalupe/Delaware Mountain outcrop is inversely modeled to derive local tectonic subsidence and a sea level curve for the Permian. In this process, the highest and lowest shoreline positions of each sequence are interpreted based on facies descriptions, which are assumed to approximate the highest and lowest relative sea level. A eustatic sea level curve is calculated by restoring these shoreline positions and removing local tectonic subsidence using a polynomial fit to the derived relative sea level curve. The quant tatively constrained curve for the Permian contains 2nd, 3rd, and 4th order signals with the 3rd-order amplitudes as great as 180 m.
This quantitatively constrained accommodation history (calculated eustatic curve and subsidence history) are input into the PHIL forward modeling program. Model variables of sediment supply and depositional system are adjusted to match known outcrop relations. The resulting model is potentially capable of predicting stratigraphy elsewhere in the basin using only subsidence history data from the inverse model.
AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California