Outcrop Examination and Sequence Stratigraphy of the Lacustrine Green River Formation, Uinta Basin, Utah: Implications for Conventional and Unconventional Oil and Gas Development

Lacustrine basin systems have always been valued for their abundant conventional oil and gas reserves, but also their potential for unconventional petroleum development. Some of the largest oil and gas fields in Utah produce from the sands within the Uinta Basin’s lacustrine system, while the deeper lake sediments contain one of the largest oil shale resources in the world. In order to better understand the evolution of Utah’s Eocene Lake Uinta and to help facilitate prudent and economic development of Utah’s oil shale resource, a predictable sequence stratigraphic model of the basin’s lacustrine sediments needs to be refined.

Herein, we describe lacustrine sedimentary facies and stratigraphic stacking patterns present in the upper Douglas Creek Member and Parachute Creek Member of the Green River Formation along the NW - SE trending Evacuation Creek outcrop (about four miles long) on the eastern flank of the Uinta Basin, near the Douglas Creek Arch. In addition to this outcrop dataset, a core located about ten miles to the west was also described. These datasets provide a unique opportunity to highlight significant lateral changes in facies architecture. Furthermore, these sections were tied to additional cores in more distal lake sediments using facies type and spectral gamma ray measurements. Broadly, data collected from the Evacuation Creek outcrop sections support the regional applicability of the preliminary sequence stratigraphic model developed by Birgenheier and Vanden Berg (2011), with similarities in lake phase evolution. These sections record meter-scale shallowing upward fluctuations, with an overall shallow to deep transformation of the lake system. Also present are regionally significant variations in sediment supply that are likely climatically driven. This research provides a key dataset towards developing a regional sequence stratigraphic framework for lake evolution in the Uinta Basin.

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California