Unconventional Reservoirs
America was built by innovation and determination, so it is not surprising that today’s demand for new energy supply is driving U.S. companies like EQT to explore innovative energy frontiers and pioneer new drilling technologies. EQT is at the forefront of tapping into unconventional reservoirs for what were once unrecoverable energy resources. Whether drilling deep into Huron or Marcellus Shale or tapping into more shallow coalbed methane, EQT applies the latest, most efficient drilling technologies to effectively and economically respond to the nation’s call for new energy supply.
EQT Production’s drilling has been concentrated in four major plays: Huron, coalbed
methane, Berea and Marcellus. EQT drills low risk development wells into reservoirs
that are known to be productive.
Shale
Shale, the most common sedimentary rock, is a finely-grained mineral formation made of clay or mud.
Natural gas rests within porous, vertical "fractures" within the shale. Conventional wells, with vertical boreholes, intersect very few fractures, but a horizontal well can intersect a larger number of fractures and thus produce a higher yield of natural gas.
Huron Shales
EQT has recently focused drilling on the Huron play, where the company has approximately
2.2 million acres. The company drilled 357 horizontal wells in the Huron Shale in
2008, an increase from five wells drilled in 2006 and 88 in 2007. This resulted
in a dramatic increase in production sales growth rate.
Marcellus Shale
Geologists familiar with the Appalachian Basin have known for years about the Devonian black shale called the Marcellus. The Marcellus Shale is organically rich shale that lies nearly a mile or more beneath the surface throughout much of Ohio, West Virginia, Pennsylvania and New York. The Marcellus Shale has in recent years emerged
as a potential major contributor to the natural gas supply of the United States - large enough to be spoken of as a "super giant" gas field. With more than 400,000 acres, 1 Tcfe 3P reserves and up to 6.9Tcfe of unrisked reserve
potential in the Marcellus Fairway, EQT is a leading player in the Marcellus Shale.
Tight sand
Like shale, tight sands gases are trapped in low-porosity and nearly impermeable sandstone or limestone formations. While natural gas in conventional reservoirs has typically been extracted quite easily and at a lower cost, until recently, a great deal more effort and expense has been required to extract gas from tight sands formations.
Because horizontal wellbores can intersect more of the gas deposits located within the tight sands, this relatively new drilling technique is proving to be a more economically-viable method of draining tight sands gases as well as other unconventional reservoir gases. For EQT, horizontal drilling in tight sands represents a significant portion of our Appalachian production activity.
Berea Sandstone
In 2008, EQT drilled 24 wells in the emerging Berea sandstone play. The company
has approximately 800,000 acres in the Berea play, where it expects to drill 20-25
wells in 2009. Berea wells are also drilled horizontally with air. While these are
slightly more costly to drill than horizontal shale wells, they produce proportionally
more gas per well.
Coalbed methane
Coalbed methane (CBM) is a form of natural gas found in coal beds situated 1,000 to 3,500 below the ground’s surface. EQT is a leading CBM producer in Appalachia, with 2.0 Tcfe in 3P reserves.