The Eagle Ford Shale. What Is The Eagle Ford Shale? Map and Info
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 Photo: Old Abandoned School House In Eagle Ford, Texas. ( Alma Mater of Bonnie Parker, of Bonnie and Clyde Fame.) The Eagle Ford Shale derives it's name from Eagle Ford Texas where it is on the surface as clay soil. In South Texas, in the Hawkville Field area of McMullen and LaSalle County, it is turning into the next major shale gas play.
The Eagle Ford Shale Gas Play In South Texas
While many in the oil and gas industry are familiar with the Barnett Shale few know about a newly discovered natural gas reservoir called the Eagle Ford shale.
The Eagle Ford shale underlies the Austin Chalk and Edwards formation. It is considered by geologists to be the "source rock", or the original source of hydrocarbons (oil and gas) that are now found in the Austin Chalk and Edwards formation above it. It just may be the next big natural gas play on a scale similar to the Haynesville shale in Louisiana.
In a likely attempt to motivate investors, that the same oil company that "discovered" the Haynesville shale, Petrohawk Energy, has named the field where one of it's discovery wells is located the "Hawkville Field". It is now officially recognized by the Railroad Commission by that name in McMullen and LaSalle county. Often misspelled "Eagleford", the Eagle Ford Shale outcrops at the town of Eagle Ford, near Dallas Texas and reaches depths over 12,000 feet in South Texas. In LaSalle and McMullen County it produces natural gas and in Maverick and Dimmitt county it is producing oil.
For many years the Eagle Ford shale was known by drillers as a zone to watch out for and increase mud weight while drilling through on the way to other formations. "Shale gas" it was called, was more of a nuisance in South Texas gas oil and gas wells than a source of potential production. Only with the advent of directional drilling combined with hydraulic fracturing was it recognized that gas wells could be completed in some shale formations rich in natural gas such as the Barnett shale and now the Eagle Ford shale.
Petrohawk Energy has recently drilled wells in both McMullen and LaSalle county Texas. Earlier this year it completed the discovery well in the South Texas Syndicate Field in LaSalle county, near Fowlerton, Texas, the STS-241-1H and another, approximately 18 miles away in McMullen County, the Dora Martin 1-H. It has recently added 50,000 acres of leases in McMullen and LaSalle counties to the existing leasehold of 100,000 acres. Currently leasing is at a fever pitch in McMullen and LaSalle counties with rates going as high as $400+ an acre. Just a couple decades ago a large parcel could be bought for that price per acre.
Petrohawk was one of the early discoverers of the profitable Haynesville Shale in North Louisiana, Arkansas and Texas. This could very well be their next Haynesville and investors are buzzing.
Meanwhile in other areas of the Eagle Ford shale Pioneer Natural Resources, Anadarko and others are active in the Maverick Basin and as far east as Dewitt County. In Maverick county TXCO Resources, which holds leases of nearly a million acres is testing two oil shale wells and expects to report results by next year.
According to Oil and Gas Journal Pioneer Natural Resources of Dallas has drilled a horizontal well in the Eagle Ford Shale Well in Dewitt County, TX. This is approximately ninety miles from the Petrohawk well in LaSalle County. The formation extends that far but porosity is not uniform.
Pioneer Natural Resources reports that it has well logs of over one hundred and fifty wells that were drilled in past years from LaSalle County to the Gulf Coast where the Eagle Ford shale may be productive. There is a very good prospect for the Eagle Ford shale to become the next Haynesville Shale or Barnett shale. What makes it exciting in terms of investing is that there are many marginal Edwards wells that could possibly be re-entered and drilled horizontally and for a comparatively small investment turned into profitable Eagle Ford wells with pipelines and tank batteries already in place. Petrohawk Energy's discovery well is in the old South Texas Syndicate Field which already has production infrastructure in place. The South Texas Syndicate field is located 12 miles southeast of Los Angeles Texas and was first developed in the 1940's.
Petrohawk Energy, petrohawk.com lists the following in it's annual report: " We also recently announced the successful discovery of a new shale play in South Texas. The objective reservoir is the Eagle Ford Shale found at a depth of approximately 11,000 feet to 12,000 feet and with thickness of approximately 250 feet. We currently have approximately 150,000 net acres leased in the play. Our first well, the South Texas Syndicate #241-1H, had an initial production rate of 9.1 million cubic feet of natural gas equivalent per day (Mmcfe/d). We currently are drilling our second well and have budgeted to keep one rig active in the field for the balance of 2008 and 2009"
Note something very significant from the news release from Petrohawk Energy "thickness of 250 feet". That is quite thick compared to some areas of the Barnett Shale currently being produced. The discovery well's 9.1 equivalent million cubic feet of natural gas includes 250 barrels of condensate per day and 7.6 million cubic feet of natural gas. The condensate production is calculated as gas to come up with the 9.1 equivalent, but by all standards this well is a very prolific producer.
The South Texas Syndicate well was drilled horizontally at a depth of 11,300' with a lateral length of 3200'. A frac job was performed, pumping over two million pounds of sand into the Eagle Ford Formation in ten stages. Petrohawk estimates drilling and development costs to run between five and seven million dollars per well. source
Leasing of large swaths of McMullen and LaSalle county for Eagle Ford shale drilling is already underway. The first activity will likely be on larger tracts of land and as the field is proven, then the smaller landowners. Since it is highly possible that the Eagle Ford shale may be productive under a large portion of LaSalle and McMullen Counties of Texas it could be an economic bonanza for the area.
UPDATE. The following is from Oil and Gas Journal and From Petrohawk's News Releases
Petrohawk Energy Corp., Houston, reached total depth at Donnell-1H, third well in its Eagle Ford discovery area in LaSalle County, Tex. It completed the second well in the field in January. The Dora Martin-1H, 14 miles west of the discovery well that has been named Hawkville field, tested at 8.3 MMcfd on a 22/64-in. choke with 4,610 psi flowing casing pressure. Petrohawk ran 12 frac stages in its 4,300-ft lateral at 11,00 ft true vertical depth. "
The Donnell #1H was completed on February 20th at a rate of 3.6 Mmcf/d and 395 barrels of condensate per day (Bc/d), or 6.1 Mmcfe/d, on a 19/64" choke with 3585# flowing casing pressure. The Brown Trust #1H was completed on March 26th at a rate of 8.1 Mmcf/d and 200 Bc/d (9.3 Mmcfe/d) on a 24/64" choke with 4210# flowing casing pressure. Production data from the four wells completed to date indicates lower initial annual decline rates, and a flatter hyperbolic decline, than those observed in other shale plays."
Petrohawk also has stated that the quality of gas and condensate from the Eagle Ford shale in LaSalle and McMullen exceeds that of almost any other shale gas reservoir discovered.
"Other encouraging aspects of the core analysis of these two wells include the following: average total organic content (TOC) between 4.4% and 4.7%; total porosity ranges between 9.4% and 10.7% average permeability ranges between 1,110 and 1,280 nanodarcies; gas saturation ranges between 83% and 85%; and estimated free gas in place per section between 180 and 210 Bcf. These measurements, as they relate to other shale plays, suggest that the Eagle Ford Shale in this particular area is one of the highest quality shale reservoirs discovered to date in the United States."
This is exciting news indeed. They also state that the costs associated with drilling an Eagle Ford shale well have come down over sixty percent since the first wells. They now have two rigs working in the play. They have upgraded their estimates of the potential of Eagle Ford horizontal wells to between 5.5 and 7 Bcfe per well.
Based on gas in place data derived from the core analysis, along with the performance of wells completed to date, Petrohawk is raising its internally estimated ultimate recovery assumption for wells in this play to a midpoint of 5.5 Bcfe per well, with a range of 4 to 7 Bcfe/well. Exploration of the extent of the play will continue with pilot holes being drilled. Currently the amount of leased acres controlled by Petrohawk stands at 160,000 and growing.
The map below shows only the areas of the Eagle Ford shale currently being developed, not the full extent of the actual formation which goes as far north as Dallas.
The Following map shows other gas shales in the United States. The Eagle Ford Shale is not even on the map but it well be big news in the coming months. When natural gas prices rise exploration will increase even more.
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