Page 35 - Fundamentals of Gas Shale Reservoirs

CONCLUSIONS 15
are that influence the actual estimated ultimate recover ◦ Thermally mature, Ro >1.1%, ideally 1.1–1.4% (Types
(EUR) per well, which is a central aspect of assessing the II and III kerogen), >0.7% (Type I kerogen ). Kerogen
economic viability of a shale gas play. Therefore, an appre­ type is a function of depositional environment.
ciation of the methods for assessing likely well recovery is ◦ Thick (minimum of 100 ft).
central to identifying economic shale gas plays. In the event ◦ Porosity >5%
that such methods are not currently reliable, then it seems it • Technically recoverable (although not necessarily eco­
would be an area worthy of considerable research. nomically recoverable) shale gas resources are abun­
In addition to EUR/well, the cost of production has the
potential to vary greatly from country to country and hence dant across the globe. They are also located in a very
wide range of geographical regions, and in many of the
influence whether shale gas will be significance in each nations with the highest energy consumption.
respective area. Although some of the published sources allude
to the relative cost of production, a more quantitative approach • For certain nations, shale gas has the potential to reduce
would be beneficial for identifying opportunities‐specific energy prices and reduce dependence on other nations,
regions. It is expected that as the industry develops slowly in and hence impacts on both the political and economic
each respective region, that drilling services will become more outlook.
competitive, and hence reduce the cost of production. • The environmental concerns identified have the poten­
Due to the vast shale gas resource globally, there is consid­ tial to halt development in many regions. Furthermore,
erable attention being drawn to the industry. However, a should the industry fail to address the environmental
current concern for the global adoption of gas production issues at all levels, then there may not only be an impact
from shales is the lack of non‐US production examples on the environment but also on public perception and
on which to consider the economic viability in other regions. hence political support for the industry, and hence a
As such, shale gas remains quite speculative on a global scale. favorable regulatory environment.
Gas prices, the growth of new markets for gas consumption • Technological developments are a major reason why
(i.e., transport), and technology are likely to have a major the production of gas from shale has become possible.
impact on the future of shale gas in other countries. As such, the future growth of the industry is likely to
relate closely to technological developments that further
improve well yield and the duration of well yield.
1.9 CONCLUSIONS • The prospects for and significance of shale gas vary

considerably by country, irrespective of the absolute
• Key geological characteristics of a successful shale gas TRR estimate and production costs. It seems industry
play include the following: success also requires high local demand for gas, a lack
◦ Organic rich, minimum TOC of 2%, although suc­ of existing large‐scale conventional gas production,
cessful US shale gas plays have average TOC of 12% and an existing gas distribution network. The United
◦ Low clay content (<50%)/high brittle mineral content States is a good example of the potential for shale gas
(>40%). Generally associated with marine shales under such favorable conditions.