American Oil and Gas Reporter - August 2015 - 79

SpecialReport: Hydraulic Fracturing Technology
balanced perforating environment," he
adds.
Penetrating deep into the rock is only
half the battle. "We want a clear tunnel,"
Clark says. "If the total penetration is 10
inches, but seven inches of the created
tunnel are plugged with debris, the effective penetration is only three inches.
"To clean the tunnels, our charges use
patented reactive materials. After the perforating event, these materials create a
bimetallic reaction that generates thermal
and radial mechanical energy in the perforating tunnel. This energy disrupts the
formation of compacted rock during the
penetration event, allowing natural pressure surges to clean out the tunnel," Clark
relates.
The increase in clear tunnel is significant, Clark assures. "In some cases, we
see 200-250 percent increases in clear
tunnel," he reports. "In other words, the
reactive technology is doubling or tripling
the effective penetration."
In addition to cleaning the tunnel,
Clark says that in many formations, the
energy works with effective charge design
to fracture the tunnel's tip. "With a fractured tip, the subsequent pressure pumping
operation will not need nearly as much
horsepower to break down the formation,"
he says. "We have seen 20-50 percent
reductions in fracture initiation pressure."
The clean tunnels and fractured tips
can eliminate the need for the post-perforation acid jobs often used to remove
debris from the tunnels before pressure
pumping, Clark adds. "This saves a
tremendous amount of time and money
while reducing health, safety and environmental risks," he says.
In North American shale plays, the
reactive technology has improved initial
production rates and eased decline curves,
Clark reports. "In natural completions in
the Middle East, we are seeing productivity
three times higher than the previous best
wells in the field," he remarks.
While expressing pride in the reactive
charges' accomplishments, Clark says
they should be viewed as part of a bigger
system that includes the entire gun assembly. "We design systems that have
the right shot density, the right phasing,
and the right charge for the application,"
he says. "A charge phasing and shot density design intended for vertical wells
does not make sense in horizontal prefracture perforating applications. Furthermore, with traditional perforating systems,
the location of the fracture initiation, and

GEODynamics reports that perforating charges with its reactive technology (top), which
generates heat and mechanical energy after the perforation event, create longer and
clearer tunnels than conventional charges (bottom).

the number of perforations that feed the
fracture in a given cluster vary unpredictably.
"We make gun systems that place
preferential initiation points from all the
perforations in the same plane for each
cluster," he continues. "In a traditional
six-shot-per-foot system, there are two
inches between shots and they are phased
60 degrees rather than meeting on the
same plane, making it impossible for
every perforation to contribute effectively.
Our systems are designed so that when
the number of shots per cluster is selected,
every shot will feed into, and produce
from, the fracture for that cluster of perforations."

Plug and Perf Alternative
Today's commodity price environment
has sharpened operators' focus on efficiency and reliability, says Joe DeGeare,
the U.S. president of NCS Multistage.
"Operators want to know they have done
everything possible to complete the well
effectively, which means placing each
stage exactly where they want to place
it," he adds.
Precise placement can be difficult in
a plug-and-perf completion, DeGeare
says. "In a plug-and-perf scenario, the
completions are designed based on the
assumption that each cluster will be stimulated equally," he notes. "In reality, that
rarely happens. Instead, Mother Nature
takes the path of least resistance. So if
there are three sets of clusters, the frac
may go to the top cluster until the forma-

tion can no longer take any sand, then
(go to) the second cluster. The third may
not get any sand at all."
To address that problem, NCS offers
the Multistage Unlimited system. "We
put a sleeve in the casing assembly at
every point where the operator would
like to place a stage. Once the sleeves
are in place, we go in with a bottom-hole
assembly, locate the bottom sleeve, open
it by manipulating our tool, and frac that
area," DeGeare relates. "Then we repeat
the process for the remaining stages."
By eliminating the need to use and
remove plugs, DeGeare says the system
saves time. "How much time depends on
the stage count, but in the Bakken, we
have done 60-70 stage completions in
three to four days that used to take one
or two weeks," he reports.
Because the system completes each
stage at a single point, instead of several
clusters at once, DeGeare says water can
be pumped at a much lower rate, reducing
required horsepower by two-thirds.
"By fully stimulating each stage, we
have helped operators increase production," he reports. "Not everyone will see
a production increase, but some wells
have doubled in production compared
with offset wells in the same formation."
During the completion, the coiled tubing acts as a dead string that transmits
real-time pressure information to the surface, DeGeare notes. "With true at-zone
pressures, the operator can see when the
formation stops taking the proppant and
respond to prevent a screen out," he comAUGUST 2015 79

American Oil and Gas Reporter - August 2015

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