EIA Updates Eagle Ford Maps

The U.S. Energy Information Administration (EIA) has released new maps that include updated information for Eagle Ford derived from producing wells from January 2000- June 2014 based on The maps are categorized in the following geological parameters.

Initial GOR

This map shows the detailed production in relation to the natural gas to oil ratio (GOR) of the play.

Oil to gas ration map for Eagle Ford 2015

Play Footprint

This map shows the four boundaries of the Eagle Ford Play

  1. North - This boundary is determined by the temperatures at which oil is generated from rock and stops at 3650 feet in Frio County and counties east, and in Maverick and Zavala counties from 650 to 2900 feet.
  2. South - This boundary follows the Sligo Reef Margin.
  3. Northeast - This boundary where the lower Eagle Ford thins and grades into more silica-rich units of the Pepper Shale of the East Texas Basin
  4. West - This boundary is marked by the border with Mexico
EFS boundaries map: 2015

Elevation Contours

This structure map characterizes the depth of the play and represents the minimum drilling depth to reach the top of the Eagle Ford formation.

The Eagle Ford formation is divided into upper and lower units, and the top of the lower unit is considered the best proxy for the source rock; however, due to a lack of density and distribution of the depth to the top of the lower Eagle Ford formation, this map represents an approximation of the elevation of the top of the upper Eagle Ford unit.
Eagle Ford elevation map 2015

Thickness Contours

This map provide a rough estimate of the thickness of the play, which is used to estimate resource volumes, such as oil- or gas-in-place estimates, in combination with other information such as porosity, pressure, and geologic history.

Eagle Ford thickness map

Eagle Ford Sweet Spots Shown in EIA Well Video

The EIA (U.S. Energy Information Administration) issued findings in February 2014 showing most wells drilled in the Eagle Ford have increasingly targeted oil-rich areas since production began in 2009. The larger bubbles represent higher initial production rates.

Also readPioneer Hits Record Q4 Production in the Eagle Ford

Low GOR Wells - "Sweet Spots" in the Eagle Ford

*There is no sound associated with the animation

The animation in the video above shows the


(gas to oil ratio) of wells drilled in the Eagle Ford since 2009. Sweet spots for oil production are represented by the green bubbles, and appear along the northern portion of the play.

Oil companies in the Eagle Ford are keenly aware of this data. For instance, Pioneer Resources announced in February 2014, plans to drill 45 wells in the upper (northern) portions of the Eagle Ford Shale.

Economics of Drilling Lower GOR Wells

Certainly, the fact that more wells are being drilling for oil in the Eagle Ford shouldn't come as much of a surprise. With the current price of oil hovering around ~$100 bbl  and the stagnant price of natural gas over the past several years, the pattern simply reflects the free market.

Depth of Reservoir Has An Impact on Production Yield

The distribution of initial GORs from Eagle Ford wells generally corresponds to the depth of the reservoir. Deeper wells (up to 15,000 feet) to the southeast have higher initial GORs, or a relatively greater share of natural gas, while the shallower wells to the northwest (below 6,000 feet) have lower initial GORs, or a relatively greater share of oil.

GOR: Gas to Oil Ratio (GOR) is a term used to describe the ratio of volumetric flow of produced gas to the volumetric flow of crude oil for crude oil and gas mixture sample. If a hydrocarbon producing well produces a high GOR mixture, it is identified as a gas well. If GOR is low, it is identified as an oil well.

Read more at EIA.gov