Friday, May 8, 2009

More Horizontal Drilling In South Texas

Some (for example Petrohawk) think the Cretaceous Eagle Ford Shale may be Texas' next big shale gas play. In typical fashion, a vertical well is first drilled, cored, logged and tested. The vertical well is used for control, or as a standard by which to evaluate horizontal wells drilled nearby. The vertical well can be re-entered, or offset and then a new well bore is "kicked-off" and drilled laterally, or horizontally into the most prospective-looking layers of shale, often as far as 4-5,000 feet.

"Horizontal" is actually an over-simplification. What the operators try to do is drill parallel to bedding so the well bore stays in the preferred stratigraphic interval. That may not always be as simple as it sounds. The trick is steering the drill bit while the well is drilling. And this is where the services the Dallas-based consulting company Horizontal Solutions International come in.

Once the well has been drilled, the well is cased and cemented. The data is evaluated and a frac treatment (hydraulic fracturing) is planned. The horizontal section is then perforated and selectively "fraced", usually in stages. Then the well is opened up tested and often produced at exceptionally high rates of gas flow. Imagine having 4,000 feet of perforations in your pay zone! "Old-time" geologists and engineers can only dream with envy at modern technology.

If you would like more information on steering a horizontal well, contact me at


By OGJ editors
HOUSTON, May 5 -- St. Mary Land & Exploration Co., Denver, is drilling the horizontal section of its first operated well targeting Cretaceous Eagle Ford shale.

The company cored the Eagle Ford in a vertical hole in the Maverick County well before plugging back and kicking off the lateral. It will run a microseismic study as it fracs the well.

The company plans to drill three more horizontal Eagle Ford wells later in 2009 and will continue participating with TXCO Resources Inc. and Anadarko Petroleum Corp. in the joint venture that targets the Pearsall and Eagle Ford shales.

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