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Eagle Ford Shale >> Overview

Eagle Ford Shale Overview

What is the Eagle Ford Shale?

The Eagle Ford Shale is a hydrocarbon producing formation of significant importance. It is capeabe of producing both gas and more oil than other traditional shale plays.  It contains a much higher carbonate shale percentage: upwards of 70% in south Texas. It becomes shallower and the shale content increases as it moves to the northwest.

The high percentage of carbonate makes it more brittle and “fracable”.  The Eagle Ford Shale play trends across Texas from the Mexican border up into East Texas, roughly 50 miles wide and 400 miles long with an average thickness of 250 feet.  It is Cretaceous in age resting between the Austin Chalk and the Buda Lime at a depth of approximately 4,000 to 12,000 feet.  It is the source rock for the Austin Chalk and the giant East Texas Field according to the RRC.

Eagle Ford Shale Operators/Companies

Eagle Ford Shale Drilling Activity By County - Updated Weekly

Eagle Ford Shale Rig Activity - Updated Weeky

Eagle Ford Shale Counties

Eagle Ford Shale Drilling Activities By County

Eagle Ford Wellbore Design


Eagle Ford Shale Strat Column 

Eagle Ford Shale Strat

The map below shows the three windows of the Eagle Ford Shale.  The area in green is the oil window.  To the southeast in orange is the condensate window, followed by the gas window in red.  An important aspect to this play is well cost.  The shallowest point of the Eagle Ford is located in Zavala and Maverick counties of the oil window.

Eagle Ford Shale Sweet Spot Map

According to a presentation from Harris Cander of BP, the Eagle Ford shale liquid's sweet spot is within the southern portion of Karnes and Gonzales.

Eagle Ford Shale Sweet Spot

This is the cheapest area to drill in the basin and is only 4,000 feet deep.  The majority of the oil window is at a depth of 6,000 feet, which is still relatively shallow when compared to other U.S. plays.  The oil window is deeper to the northeast where depths of 1,200 feet are seen. 

The condensate window, like the oil window, is shallow to the southwest.  In this area, depths of 6,000 to 10,000 feet are seen. It gets deeper toward northeast.  The gas window is very deep, ranging from 12,000 to 14,000 feet. This part of the play is not economic at this time.

Eagle Ford Shale Map


Eagle Ford Shale Thickness Map

Eagle Ford shale thickness varies significantly.  The thickest areas are focused around Webb, Dimmit and Maverick Counties.  The picture below shows these variances. 

Eagle Ford Shale Map

It is important to pay close attention to the dark areas of this map.  During the U.S. land grab, most of the Eagle Ford Shale interest was purchased at the southwestern portion of the play.  The shale is thickest here, which attracted the first exploration and production companies.  Because the play deepens to the northeast, well pressures increase. 

This is why the best wells in the play are located in Gonzales County.  The area of increased shale thickness in the southeastern aspect of the county are higher pressured and in a sweet spot.  EURs improve to the southeast because of higher gas content closer to the condensate window.