Horizontal drilling

From Wikimarcellus

In order to tap natural gas with horizontal drilling typically a drill is sent down vertically a mile or so underground and then turned at a ninety degree angle horizontally into the shale. By using horizontal drilling the drill bit can penetrates a much greater number of pockets of natural gas than it ever could with vertical drilling. On the average horizontal wells produce three to five times the amount of natural gas from vertical ones.

The shale tends to be located between approximately five and eight thousand feet below ground.

Horizontal wells are much more expensive to drill than vertical ones. Costs may run between $4 million and $7 million U.S. for a horizontal shale well. Vertical ones can be drilled for only $1-2 million U.S.

Reusable drilling rigs that cost up to $16 million apiece are generally used for horizontally drilling Marcellus shale wells. These rigs are larger-sized ones with 1,000 and 1,600 horsepower.

A business strategy sometimes employed is to drill a vertical well that can produce up $700,000 per day in production. This can be done fairly cheaply, and get some science and good data about the acerage, then go back later and do a horizontal portion to the well using a larger rig.