American Oil and Gas Reporter - October 2015 - 77

duction rates after refracturing ran 80-85
percent of original IPs.

Know Your Wells
"We find that what makes a good
refrac candidate varies from area to area,
and even field to field," French allows.
He recommends looking first for underperforming wells in areas that have
consistent reservoir quality. "If you have
a 3 billion cubic-foot well surrounded by
12 Bcf wells with the same geological
characteristics, you know something is
wrong," he reasons.
Next, French advises, look at the original
completion design, and particularly those
with wide stage spacing and a higher num-

ber of clusters per stage. Then check for
wells where sand was placed in only half
the stages. This failure likely was caused
by screen-outs, high treating pressures, or
other complications, he suggests.
"If a completion stage doesn't place
sand, then no fracture propping happens,"
French comments.
He says rate transient analysis is helpful
in analyzing wells within a group to find
any with lower stimulated rock volume.
"We picked single wells that stood
alone in a section to avoid interfering
with other wells," French recounts. "In
addition, we looked for 500-foot fracture
stage spacing, minimal proppant placement, unperforated pay at the heel, high

gas in place, and convenient water availability."
Once initial candidates are identified,
French goes on, they must be checked to
ensure they can handle the stress of refracturing. He says that mechanical integrity tests can be performed on a well
to ensure it can hold the pressure. During
refracturing, pumping a trace material
will reveal where the proppant is placed,
he adds.
"It's about knowing your wells and being
able to identify the opportunities," French
sums. "We continue to learn how to get the
most out of each play. More and more, we
are going back to old wells to see how we
can improve on initial designs."
r

CPP Seen Shifting Power Generation
LONDON-The U.S. government's
Clean Power Plan (CPP) likely will result
in the loss of up to 60 gigawatts (gw) of
coal-fired electric generating capacity by
2020, according to research and consulting
firm GlobalData.
Pavan Vyakaranam, GlobalData's associate project manager covering power,
says that of the 326 gw of coal-fired
power capacity in the country, 20 gw is
expected to retire in the next five years
and a further 30-40 gw will find it difficult
to meet the emission standards set by the
Environmental Protection Agency.
Says Vyakaranam, "Despite a decline
in coal-based power generation over the
last decade, coal generated around 39 percent of U.S. electricity in 2014. With the
CPP's aim of reducing emissions by 32
percent from 2005 levels by 2030, coal-

fired generation will continue to decline.
"GlobalData believes the U.S. power
sector will try to balance low-cost natural
gas power with clean power generation
from renewable sources," Vyakaranam
continues. "In 2014, natural gas contributed
27 percent of total U.S. power generation,
hydropower accounted for 6 percent, and
other renewables, including wind, solar,
biopower and geothermal, had a 7 percent
share."
The analyst adds that while increasing
renewables will require substantial investment, some states, such as Texas and
California, have increased renewable capacity successfully and could encourage
others to follow their lead.
Vyakaranam says, "With the United
States boasting significant renewable
power potential, the CPP has created a

huge opportunity for companies in this
sector. Additionally, natural gas would
benefit with new investment, as well as
with the conversion of some coal power
plants to gas.
"On the other hand," he allows, "independent power producers and utilities
with high exposure to coal in their portfolios will lose out, particularly those
companies that operate the fleet of aging
coal power plants, since it is highly likely
these facilities will not meet the new
standards."
The analyst concludes by noting that
states have two years before they must
begin rolling out their plans, and with the
United States set for presidential elections
in 2016, the identity of the next government
will greatly influence the extent to which
the CPP is implemented.
❒

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Frac smart, recover more with Tracerco technologies
OCTOBER 2015 77

American Oil and Gas Reporter - October 2015

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