Whangai Shale Formation

Whangai Fractured Oil ShaleWhangai Fractured Oil Shale
Thick marine shale sections are common to most sedimentary basins around the world. These thick marine siltstones to mudstones are also sometimes associated with high amounts of organic carbon particles, which "cook" into hydrocarbons when subjected to pressure and heat. Examples of these thick "Source Rocks" are found in many parts of North America, including the Barnett Shales of Texas, the Utica Shales in Quebec and the Horn River Shales in NE British Columbia.

Up to 600 Meters of Fractured Shale
The Whangai Formation is a poorly bedded, siliceous or slightly calcareous mudstone of Late Cretaceous age, with localized development of greensand and well bedded calcareous facies. The formation is 300 to 600m thick throughout much of the onshore East Coast Basin. The Whangai has an average TOC of 0.8% in the western, onshore sub-belt, with maximum measured values of 1.7% TOC and 336 HI. Although its TOC content is lower than the Waipawa Black Shale, the Whangai Formation has been geochemically linked to many onshore oil and gas seeps, validating its potential as an unconventional reservoir. In addition, the Formation is heavily fractured, which provides both increased reserve potential as well as natural pathways to enhance flow rates. The fact that the Formation is typically some twenty times thicker than the overlying Waipawa Black Shales, adds immensely to the overall oil and gas generation potential of the Formation.