Steps Toward a “Best Practices” Protocol - Induced Seismicity Potential in Energy Technologies - page 132

the answers of this ten-point criteria list for three injection wells. The wells listed include
an existing injection well located in Texas, a proposed injection project in Quebec, and the
injection well located at Rocky Mountain Arsenal in Denver with questions answered “as
if injection had not yet taken place.”
The authors note, “In actuality, if one were to propose injection at a site near Denver
today, the existence of the earthquake activity between 1962 and 1972 would alter the
profile, and there would be six or more 'yes' answers” (p. 214). The authors go on to say,
“At the Tracy, Quebec site we find five 'yes' answers. . . . We would thus conclude that the
situation is more similar to Denver than the Texas Gulf Coast” (p. 214).
d id i injection i nduce the o bserved e arthquake ( s ): s even -p oint c hecklist
The list of seven questions from Davis and Frohlich (1993) again evaluates four factors
related to possible cause: background seismicity, temporal correlation, spatial correlation,
and injection practices. In Table 6.2 the seven questions are listed and are specifically phrased
so that a “yes” answer would indicate underground injection induced the earthquake(s) and
a “no” answer would indicate the earthquake(s) were not caused by injection.
Two injection wells are evaluated in Table 6.2. The well in Denver, Colorado, was
the injection well at the Rocky Mountain Arsenal, which was definitely shown to be the
cause of induced earthquakes in the mid-1960s. The Painesville, Ohio, well, also known
as the Calhio well, which was injecting liquid waste from agricultural manufacturing, was
investigated as a cause of earthquakes and revealed ambiguous results; the scientists who
examined the data could not make a certain correlation between the injection well and the
earthquakes, in part due to historical (natural) seismic activity in the area. 1
An Example Best Practices Protocol for Induced Seismicity Associated with Enhanced
Geothermal Systems
As an example of a protocol used in projects expected to result in induced seismicity, the
Department of Energy (DOE) has published a best practices protocol for addressing
the potential of induced seismicity associated with the development of enhanced geo-
thermal systems (EGS) (Majer et al., 2012). The steps that a developer might follow in that
protocol are summarized in Box 6.1. The DOE states that this protocol is not intended as a
proposed substitute to existing local, state, and /or federal regulations but instead is intended
to serve as a guideline for the systematic evaluation and management of the anticipated
effects of the induced seismicity that are expected to become related to the development
of an EGS project.
1 For example, see www.dnr.state.oh.us/geosurvey/earthquakes/860131/860131/tabid/8365/Default.aspx.