American Oil and Gas Reporter - January 2015 - 112

croseismic acquisition and real-time processing must be able to
provide direct feedback to the engineers managing the frac job.
When done properly, this intimacy enables a higher level of
adaptive fracture management, which allows the frac engineer to
make better-informed RTO decisions that can dramatically improve stage by stage performance of every well so as to maximize production while minimizing stimulation cost. It also provides the information required to update the geomechanical model so that changes in the reservoir that occur during stimulation
can be factored into the rest of the operation.
Second, the microseismic exercise must be designed with an
acquisition geometry that will provide the most robust detection
and location of microseismic events. Using surface geophones
to detect P and S wave events, especially for deep reservoirs, is
proving not to be feasible and leads to severe detection limits along
with very significant errors in locating microseismic events.
While we will never have the luxury of the experimental geometry afforded to the medical profession (e.g., the CT scanner that
surrounds the patient), we must start making measurements that:
* Have the correct geometry and aperture to detect multiple
wave paths for the P and S wave events;
* Remove the severe challenges the near-surface creates for
detecting smaller events, and for S-waves in particular; and
* Address the accurate dual detection of P and S waves in
the subsurface.
This requires that the operator fully integrate the microseismic exercise into the field development plan so that nearby ver-

tical wells can be drilled in patterns and used as deep observation wells during drilling and stimulation of horizontals within
the grid of vertical wells that have been completed already.
Extraction Factory Model
The practice of drilling stand-alone observation wells needs
to be modified to merge the microseismic exercise into a more
efficient extraction factory model for shale development. This will
be especially true in a lower price environment, where the standalone observation wells could become cost-prohibitive.
Taking this approach also will allow the operator to be more
efficient in how he contracts microseismic services, so that a longterm monitoring approach can be used rather than the on-call approach, which is much less efficient and more costly over the long
term. Tightly integrating microseismic field crews into the factory process also will improve the performance of microseismic
acquisition and processing as the crew becomes intimate with the
particular reservoir (Figure 2).
Finally, the operator needs to start using dynamic reservoir models instead of the traditional static models that are standard in the
business. In my experience doing shock wave research work, we
had to model the world in Eulerian (deformed) coordinates versus Lagrangian (undeformed) coordinates because shock waves
deform the rocks through which they travel (e.g., in explosions,
nuclear tests and meteor impacts).
Now that operators are fracturing reservoirs intensely during
stimulation, they need to start thinking about RTO updates to the

FIGURE 2
Phase I Vertical Well Drilling

Phase II BSI and WTI Imaging

Phase III Horizontal Drilling

Target Shale Formation

Drill vertical walls in an initial spacing with the
same rigs: Optimize the vertical drilling process

Use the vertical wells to characterize the
reservoir: Upgrade data resolution

Phase IV Stimulation and Microseismic

Use adjacent vertical wells to monitor
frac jobs: Optimized imaging

Observation Wells

This 3-D field model demonstrates the shale factory approach
where vertical wells are drilled in an initial pattern and then are

112 THE AMERICAN OIL & GAS REPORTER

Drill horizontal wells using the same approach:
Better crew efficiency by focusing on one task

Phase V Infill Drilling

Plan rolling infill well programs based on the data
from the initial program

used as observation wells during the development of horizontal
wells.
American Oil and Gas Reporter - January 2015

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