re: Tuscaloosa Marine Shale

quote:

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So what you're saying is that Delta T, or change in time, which has always meant more porosity the higher the value isn't neccessarily the case these days? Isn't that basically the measure of resistivity?

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By delta T I assume you are talking about a sonic log or equivalent measure of porosity? That has no bearing on resistivity. Porosity is the foremost key to any productive formation, and always will be. If there isn't adequate storage space in the rock then commercial quantities of oil and or gas won't exist. Permeability can be induced through fracturing but porosity cannot be induced. Resistivity measures resistance and is used to determine if a formation is hydrocarbon bearing or water bearing, among other things. The issue currently which the Indigo wells will give some indication of is what causes the lower resistivity values in their area. It is currently unknown as to whether the older logs in their area had resistivity readings influenced by carbonate, clays, etc. in the actual rock. As to the Austin Chalk, that play looks like a money maker if oil stays above $100 a barrel in select places. Anadarko is probably the foremost player through their acquisition of Union Pacific Resources Corp. They have all the data from the failed play in the 1990's which resulted in only a few select areas with commercial wells. Chesapeake was the only survivor from a host of others playing the 1990's chalk who either went broke or got bought out. I doubt lease values will be very high for either play because they are going to be so economically challenging at this stage. No one has ever to my knowledge completed a commercial TMS well. If this changes then certainly values could rise. Good chalk wells exhibit steep decline rates and will need a good oil price in the early life of the well to justify drilling.

The geologist with the Tuscaloosa blog does a good job of explaining a lot of the current challenges and activity in his write ups.