The Eagle Ford Shale. What Is The Eagle Ford Shale? Map and Info
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
(Note: The following article contains some outdated material. It is preserved to show the timeline of Eagle Ford shale development.) For more Eagle Ford shale maps and current news see the links at the bottom of this page.
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 the Edwards limestone formation is just below it. 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 above it. Compared to other shale formations it is brittle and contains as much as seventy percent calcite and a high silica content with an average clay content of eleven percent. It is easily "frackable" and not sensitive to water. It has the "perfect mineralogical makeup for a shale gas play" according to Petrohawk Energy Vice President Richard Stoneburner. It just may be the next big natural gas play on a scale similar to the Haynesville shale in Louisiana. It is an oil play as well. EOG Resources has already called it the sixth largest domestic oil discovery in U.S. history.
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. They have also named a new oil prospect in Zavala county the "Red Hawk" field. 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. The Eagle Ford shale contains higher natural porosity and permeability than other shale formations.
Much of the activity in the Eagle Ford shale centers along the Sligo / Stuart City trend. The following is an older map, not indicating Eagle Ford gas and oil production.
Petrohawk Energy has recently drilled wells in both McMullen, Zavala and LaSalle county Texas. In 2009 Petrohawk 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 over 300,000 acres. Currently leasing is at a fever pitch in McMullen, Live Oak, Zavala, Webb, Dimmitt, Atascosa, Karnes DeWitt, Maverick and LaSalle counties with rates going as high as $2000 an acre. Note: Lewis Energy Group experimented with the first Eagle Ford shale horizontal wells in 2005, but lacked the expertise that Petrohawk Energy brought to the table a few years later.
Petrohawk was one of the early discoverers of the profitable Haynesville Shale in North Louisiana, Arkansas and Texas. The completion techniques they developed there proved to be just as successful in the Eagle Ford. Credit for kicking off the play is largely given to Petrohawk Energy.
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. 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. One terrific advantage that the Eagle Ford shale play has going for it is an existing oil and gas infrastructure, including proximity to pipeline networks and Gulf Coast refineries and waterways.
Petrohawk Energy, http://www.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.
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
Update: In addition to the above wells, the J.C. Martin 1850 #1H was completed on July 17th at a rate of 8.8 Mmcf/d and 50 Bc/d (9.1 Mmcfe/d) on a 24/64" choke with 3,710 psi flowing casing pressure. Near Fowlerton -Los Angeles, the STS-Palmert 944 #1-H was completed on June 17th at a rate of 9.1 Mmcf/d, on a 24/64" choke with 4,350 psi flowing casing pressure.
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
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. (See Update Below).
From Petrohawk News Release
"The very rapid success of the Hawkville Field within the Eagle Ford Shale trend has enabled Petrohawk to obtain a significant amount of geologic data pertinent to the reservoir, allowing the Company to expand into other areas of the trend where it believes the rock quality could compare favorably to Hawkville Field. While building on its acreage position in the area of the field that Petrohawk believes to be commercially productive, the Company has also acquired acreage in other areas, both along strike and updip to the shale formation in the Hawkville Field. Petrohawk currently owns or has contractual commitments to acquire approximately 210,000 net acres in the trend. The Company expects to drill several exploratory wells in the second half of 2009 to evaluate its new acreage."
Petrohawk Executive Vice President Richard Stoneburner offered the following statement back in July of 2009.“It’s going to be very, very commercial.” Speaking to IPAA and Tipro members in Houston, he said, “We’ve already proven it. With this kind of gas in place, it almost has to be (commercial).”
Well costs in the Eagle Ford continue to drop, to below $5 million currently, compared with the company’s Haynesville shale wells that are now costing about $9 million.
"The gas-in-place numbers are “so exceptional,” because the shale is some 250 feet thick over a 50-by-25-mile swath and is 100% net pay. The pressure gradient, while not as high as the Haynesville, is still “above normal” at 0.65."
Here Comes The Land Rush
Conoco Phillips Quietly Leasing Eagle Ford Shale Land
Conoco Phillips CEO Jim Mulva offered the following information to Marketwatch back in March of '09. Officials at the Houston energy firm said the company has been quietly acquiring acreage in Maverick and La Salle counties in southern Texas in the Eagleford shale region rather than paying higher costs for other oil shale acreage
Rosetta Resources has acquired 35,000 acres in southwest LaSalle and Dimmitt counties an is in the process of drilling on those leases.
The map below shows the extent of the Eagle Ford shale where oil and gas activity is taking place. It is from Ross Smith Energy Group which sells maps only to the oil and gas industry. Please do not request copies, it is the only image available.
EOG Resources has leased over 550,000 acres, much of it in the so called "oil window" of the Eagle Ford shale. They estimate that there are over 900,000 barrels of recoverable oil in that area. EOG's chief executive officer has called it one of the most significant oil discoveries in the past forty years.
The Following Eagle Ford shale map is from the Texas Railroad Commission.
NOTE: For Current Eagle Ford Shale News And Updates: See the The Eagle Ford Shale Blog for updated info on happenings this major oil and gas play as well as the latest maps of the Eagle Ford shale.