Marcellus Shale Play

Several forms of bog iron (impure iron) were deposited near outcrops of the Marcellus. In the 19th century, iron ore from these deposits was used as a mineral paint pigment (Lesley, 1892). 

Rock column thickness between top of play and bottom of treatable water (feet) 2125-7650 — 

Note Information presented in this table, such as original gas-in-place and technically recoverable resources, is presented for general comparative purposes only. The ntunbers provided are based on the soiuces shown and this research did not include a resource evaluation. Rather, publicly available data was obtained from a variety of sources and is presented for general characterization and comparison with other shale gas plays. Resource estimates for any basin may vary greatly depending on individual company experience, data available at the time the estimate was performed, and other factors. Furthermore, these estimates are likely to change as production methods and technologies improve. 

Abbreviations Mcf = thousands of cubic feet NA, data not available scf = standard cubic feet Tcf = trillion cubic feet. 

The Marcellus Shale covers an area of 95,000 square miles at an average thickness of 50 to 200 feet. Whereas the Marcellus is lower in relative gas content at 60 to 100 scf/ton, the much larger area of this play compared to the other shale gas plays results in a higher original gas-in-place estimate of 

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One may consider the effect of the variability of EURs and other operational characteristics over a shale play using Monte Carlo. We describe the procedure in detail in our previous work (2). In brief, we conduct N (e.g. 5000) trials in which we select input data from their distributions at random and conduct the LCA. This results in N sets of results (e.g. carbon footprints, water footprints), which constitute distributions for those results in lieu of single point estimates. We report 80% confidence intervals (CIs) for these estimates in Table 2. From the overlap of the CIs, it is evident that there is no statistically significant difference among the carbon footprints, water footprints, and other characteristics of Barnett and Marcellus shale gases. 

As shown earlier in Figure 4.2 in Chapter 4, shale gas is present across much of the lower 48 states. Figure 4.2 shows the approximate locations of current producing gas shales and prospective shales. To date, the most active of these shales are the Barnett Shale, Haynesville/Bossier Shale, Antrim Shale, Fayetteville Shale, Marcellus Shale, and New Albany Shale. This chapter does not discuss all of the unconventional gas shales rather, discussion here is limited to these most active shale gas plays. Each of these shale gas plays or basins is different, and each has a unique set of exploration criteria and operational challenges. Because of these differences, the development of shale gas resources in each of these areas faces potentially unique challenges. The Antrim and New Albany Shales, for example, are shallower shales that produce significant volumes of formation water, unlike most of the other gas shales. Development of the Fayetteville Shale is occurring in rural areas of north-central Arkansas, while development of the Barnett Shale is focused in the area of Forth Worth, Texas, in an urban and suburban environment. 

The Marcellus Shale is the most expansive shale gas play, spanning six states in the northeastern United States. The estimated depth of production for the Marcellus is between 4000 and 8500 feet (Table 5.5). The Marcellus Shale is a Middle Devonian-age shale bounded by shale (Hamilton Group) above and limestone (Tristates Group) below (Figure 5.5). 

Up to 1500 Tcf. The average well spacing in the Marcellus Shale is 40 to 160 acres per well. The data in Table 5.5 show technically recoverable resources for the formation to be 262 Tcf, although much like the Haynesville Shale the potential estimates for this play are frequently being revised upward due to its early stage of development. 

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