As you can see from the map below, the Eagle Ford Shale in Frio county lies outside of the “volatile oil” and “wet gas and condensate” windows of the play. These two areas are where the most intense new oil and gas drilling activity is occurring in the Eagle Ford Shale formation. The Eagle Ford Shale in Frio county has a lower GOR ratio or “gas to oil ratio,” meaning that there is less natural gas pressure in the formation to help force valuable liquids such as crude oil and condensate out into the wellbore. Thus Frio county shale wells tend to have lower IP or initial production rates and lower EUR rates (estimated ultimate recovery,) than oil and gas wells to the south and east in the over pressured part of the Eagle Ford Shale. That being said however, Frio County has and will continue be an important area in terms of oil and gas drilling. A number of formations are prospective for hydrocarbons in Frio county, such as the Eagle Ford Shale, Austin Chalk and Pearsall Shale formations. Since the depth of the Eagle Ford shale in Frio County ranges from just over 4000′ in northern Frio County to around 8000′ in the southern end of the county, drilling costs are lower than in the southern and eastern parts of the play. Companies active in Frio county oil and gas exploration include Cabot Oil and Gas, El Paso E&P, Texas American Resources Co., Cheyenne Petroleum, EF Energy, Blackbrush Oil and Gas, Goodrich Petroleum, Maverick Energy Group, Dan A Hughes Co., Chesapeake Operating and Hess Corporation.
Oilfield Activity Around Pearsall Texas
Anyone who has recently traveled between the town of Pearsall (the county seat of Frio county,) and Cotulla on IH-35, may have noticed that there are dozens of new oil and gas businesses in that area. Pearsall had a population of around 7000 residents according to the 2001 census, however judging from the number of new businesses, the traffic on area roads and from all the new construction, the population of Frio county has most likely climbed in the past couple of years. The Frio county government is currently dealing with increased wear and tear on area roads. So far no per – well fee has been imposed on oil and gas companies to offset road and bridge wear in Frio County, but one may be considered if the amount of drilling activity picks up. (Click On Maps To Enlarge)
Many of the oil wells (green dots,) seen on the map above are old Austin Chalk wells. Most of the ones that you see on this map were drilled in the late 1980s to 1990s and have been plugged. These wells featured a very short lateral (horizontal wellbore) or two, but generally nothing in terms of the lateral length that is possible today. The technology required to horizontally drill and hydraulically fracture the Austin chalk and Eagle Ford Shale formations simply did not exist back then in the same form that it does today. After completion, many of these wells came in as so-called “barn burners,” since their large gas flares burned for days. Some of the first Austin Chalk wells in Frio county produced hundreds of barrels of oil per day. Some oil company insiders referred to these high IP (initial production,) wells as “doctor wells” because the high IP results were so good at helping lure new investors such as physicians. Sadly for both the investors and the oil companies, Frio county Austin Chalk wells did not last more than a few weeks or months before depleting to a barrel or two of oil per day. During this flurry of oil and gas production in Frio County, a number of oil and gas gathering lines and transmission pipelines were constructed to transport Austin Chalk production to market. Pipelines built for Austin Chalk production, such as the Harvest Pipeline Company’s Pearsall Mainline, are now being used to transport Eagle Ford Shale production eastward to refineries such as Valero’s in Three Rivers.
What’s in store for Frio county in terms of Eagle Ford Shale drilling? Right now oil and gas companies such as Chesapeake Energy and EOG Resources are scrambling to drill high IP and high EUR wells in the volatile oil and wet gas windows of the EFS, (to keep share prices high and fund new drilling activity with high production wells,) in addition to hold leases about to expire. Oil and gas E&P companies will balance the need to drill Eagle Ford Shale wells in Frio County with their overall objectives in the greater Eagle Ford shale play. Some leases are held by production from older Austin Chalk and other oil and gas wells, therefore there is no rush to drill on those leases. Frio county is about 1,134 square miles in size, or approximately 725,760 acres. Potentially productive Eagle Ford shale lies beneath more than half of this area, so Frio county will most likely be in the game for many years to come, as hundreds more oil and gas wells are drilled over the coming decades. As natural gas prices rise, interest in drilling the Pearsall shale will return. The Pearsall shale, a large formation containing primarily dry natural gas, also lies under much of Frio County in addition to the Eagle Ford shale.
For the office of the Frio County Clerk, law enforcement, and Tax Appraisal District, see the Frio County Government Web Site
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