Tar Mats and Viscous Oil in Reservoirs - Decoding a Hidden, Costly Production Bottleneck

Tar mats often form in high-permeability sections of the reservoir, impacting pressure support, aquifer sweep, and well placement strategies.

• What mechanism causes the formation of the tar mat as well as the graded viscous oil above the tar mat?
• Why does the tar mat form at the current oil-water contact (OWC)?

A reservoir simulation is shown to model the formation of the tar mat and associated viscous oil. The importance of reservoir architecture and petrophysical parameters is indicated in this process, explaining areal variations in tar mats. The resulting new workflow is a rapidly emerging, powerful new method to optimize field development planning.

Speaker: Oliver Mullins

Hosted by the SPE Webinar by R&D Technical Section

10 June, 2025