Paul L. Kovach1, Julia Caldaro-Baird2, Peter J. Wynne3
(1) Barrett Resources Corporation, Denver, CO
(2) Texaco E & P, Denver, CO
(3) AEC Oil and Gas U.S.A. Inc, Denver, CO
ABSTRACT: Stagecoach Draw Field: Gas Production from the Westernmost Marine Influenced Deposits of the Lewis Seaway Transgression into Southwestern Wyoming
The 1993 discovery of Stagecoach Draw Field, southwestern Wyoming, marked the culmination of an exploration effort by Texaco E & P, targeting Upper Cretaceous marine influenced sandstones of the Almond Formation in an under-explored area of the Green River Basin. The field is located in the basinal area between the Moxa Arch and the Rock Springs Uplift in Sweetwater County. The nearest Almond Formation production lies 50 miles to the east of Stagecoach Draw field at Patrick Draw and Desert Springs fields. Stagecoach Draw is a combined structural-stratigraphic trap and marks the first commercial discovery in this area of the basin. Conceptualization of a western extent to Almond production was based on regional stratigraphic correlation and paleogeographic reconstruction of individual upper Almond Formation marginal marine sandstones. Individual parasequences prograded to the east during relative stillstands of the overall Lewis Seaway transgression. These upper Almond sandstone bodies were correlated in the subsurface to the west of the Almond outcrops at the Rock Springs Uplift. Integration of local structure and stratigraphy, and careful analysis of existing well penetrations, demonstrated the possibility an updip pinchout along the normally faulted, southeasterly plunge of the Sandy Bend Arch in the Stagecoach Draw Area. Development has proven that several reservoir compartments exist in the field. This is due to both structural and depositional segmentation. Economics are highly affected by reservoir compartmentalization, hydrocarbon content, and permeability. Post discovery drilling activity includes 28 wells. Estimated Ultimate Recovery from the gas productive compartments may approach 50 BCFG of gas equivalent.
AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado