Steps Toward a “Best Practices” Protocol - Induced Seismicity Potential in Energy Technologies - page 133

TABLE 6.2 Seven Questions Forming a Profile of a Seismic Sequence

Earthquakes
Clearly NOT
Induced

Earthquakes
Clearly
Induced

I
Denver,
Colorado

II
Painesville,
Ohio Ques tion

Background Seismicity

1 Are these events the first known

earthquakes of this character in the
region?

NO YES YES NO

Temporal Correlation

2 Is there a clear correlation between

injection and seismicity?

NO YES YES NO

Spatial Correlation

3a Are epicenters near wells (within

5 km)?

NO YES YES YES?

3b Do some earthquakes occur at or

near injection depths?

NO YES YES YES?

3c If not, are there known geologic

structures that may channel flow to
sites of earthquakes?

NO YES NO? NO?

Injection Practices

4a Are changes in fluid pressure at

well bottoms sufficient to encourage
seismicity?

NO YES YES YES

4b Are changes in fluid pressure at

hypocentral locations sufficient to
encourage seismicity?

NO YES YES? NO?

TOTAL “YES” ANSWERS 0 7 6 3

SOURCE: Davis and Frohlich (1993).

Using this protocol as a foundation, the committee has adapted the protocol's set
of seven steps in Table 6.3 to illustrate a set of parallel activities, with steps 2 through 7
undertaken essentially concurrently, as opposed to sequentially, to help manage and miti-
gate induced seismicity from injection associated with EGS. Viewing a protocol as a set of
parallel activities is useful not only for general project management but also for the ability
it provides to reassess the protocol through time as circumstances of an energy project
change and more data are acquired. This resulting matrix form can be used as a template
to develop an appropriate protocol to mitigate the potential to induce seismicity in other