Oil Production Potential of the Upper Cretaceous Tuscaloosa Marine Shale (TMS)
John F. Sinclair
Encana Oil and Gas, 14001 N. Dallas Parkway, Suite 1100, Dallas, TX 75240
The Tuscaloosa Marine Shale (TMS) is a marine source rock located in Southern Mississippi and the Florida Parishes of Louisiana. The TMS is thought to be equivalent to the Eagleford Shale of South Texas and Central Louisiana. Lithology is a mixture of muds, silts and carbonates which have been influenced by the ancestral Mississippi River and the impact of rising and falling sea levels on this delta system.
The author became aware of the TMS play in the 1990’s through industry publications that focused on the 1970’s pioneering work of Alfred Moore. The influence of Mr. Moore’s work had such an impact on the commercial ventures in this play that Encana chose to name its first producing field the Alfred C. Moore Field. Mr. Moore was responsible for the first commercial attempts to fracture stimulate vertical TMS wells and he recognized the need for induced fracturing way ahead of his time.
Subsequent to Alfred Moore’s work, Unocal, UPRC, Worldwide Petroleum and Petroquest drilled horizontal wells from 1991 to 2004 attempting to commercialize the TMS with barefoot completions. There was no commercial success, but the drilling and production efforts did indicate that the TMS was capable of flowing oil without stimulation and gave industry encouragement that the TMS could become commercial.
From 2007 to 2008 Encore Operating took the next step and became the first company to drill and fracture stimulate horizontal wells. Early drilling problems and cost overruns limited the size of the stimulations, but Encore was able to show a step change in EUR’s with their completion efforts on 3 horizontal wells.
Encana gained entry in the play through a JV with Denbury Resources which had acquired Encore’s interest in the TMS. To date (March 29, 2012) Encana has completed 1 previously drilled horizontal well, drilled and completed 2 horizontal wells, drilled one well which is waiting on completion and currently drilling its 4th horizontal well. Encana has drilled, cased and completed the longest lateral and has established the largest initial production to date from the formation. Coring and logging evaluations indicate that the TMS is a complex reservoir, with multiple rock types and combinations of porosity, all with varying natural fracture densities. Based on what has been seen, the TMS is unique in its own right and the information gathered appears to be contrary to current wisdom of log and core evaluations from existing unconventional fields.
AAPG Search and Discovery Article #90158©2012 GCAGS and GC-SEPM 6nd Annual Convention, Austin, Texas, 21-24 October 2012