An approximately 160-kilometer (99 mile) long 2D section of the Wyoming-Utah thrust belt and the Wind River Basin, including the La Barge and Tip Top gas fields, has been modeled using the advanced technologies of structural restoration and petroleum systems modeling. The model is based on publiclyavailable data. Due to the highly complex tectonic history of the area, characterized by extensive thin-skinned thrusting as well as basement-involved flexural movements, a detailed structural restoration was carried out using the software package 2D Move.

The structural restoration accounts for lateral sediment transport, i.e., erosion and re-sedimentation, and flexural isostasy effects.

A petroleum-systems model was created using the paleo-geometries derived from the structural restoration. Modeling of the temperature/pressure history, as well as maturation and petroleum migration, was carried out using the TecLink application of the PetroMod software package.

The resulting model provides detailed insight into the history of the petroleum systems in the area, with a special focus on the La Barge and Tip Top gas fields near the eastern margin of the Wyoming-Utah thrust belt. Several petroleum systems, and a source of CO₂, occur stacked in this area. Detailed migration simulations with source rock tracking revealed that the occurrence of gas and condensate can only be explained with the presence of very effective sealing lithologies.

The combination of structural restoration and petroleum systems modeling is a very powerful tool for the analysis of petroleum systems in tectonically complex environments. An approved workflow has been established for this purpose.

Map of the area with location of the section ( after Knight et al., 2000, modified.).

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Present-day Input Geometry

Simulations Output: Petroleum migration (vectors).

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