THE AMERICAN OIL &GAS

Data Confirm Safety Of Well Fracturing

By Kevin Fisher

HOUSTON-North American oil and

gas companies and energy services

providers are following with a keen and

vested interest the news coming out of

Washington regarding the "Frac Act," a

congressional proposal to amend the Safe

Drinking Water Act to remove a 2005

Energy Policy Act exemption on hydraulic

fracturing and effectively give the U.S.

Environmental Protection Agency the authority to regulate fracturing operations.

A year or two ago, no one outside of

the upstream oil and gas industry even

knew what a hydraulic fracture was.

FIGURE 1

0

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1,000 -I

2,000 -~

3,000 -I

4,000 -I

~_~ 5,000 1

6,ooo-I

7,000 1

8,000 1

Today, senators, congressmen and journalists are discussing fracturing as if they

were career frac engineers.

A number of key questions are central

to the debate over the Frac Act. Is there a

cleaner fossil fuel available than natural

gas? Is natural gas abundant in North

America and many other parts of the

world? Has the growth of unconventional

gas in the past decade, primarily from

shale, materially added to the recoverable

gas (and sometimes oil) reserves in North

America, eliminating the need for natural

gas imports? Does this improve our energy

security? Does incremental production

create new sources of tax revenues and

local jobs? Is there a more impacting

service in low-permeability reservoirs

than hydraulic fracturing? Does hydraulic

fracturing imperil groundwater supply’?

Whoa, let’s park the pump trucks here

for a moment.

On March 17, 1949, a team comprised

of Stanolind Oil Company and Halliburton

personnel converged on a well about 12

miles east of Duncan, Ok., to perform

the first commercial application of hydraulic fracturing. Later the same day,

Halliburton fractured another well near

Holliday, Tx. The technique had been

developed and patented by Stanolind and

an exclusive license was issued to HalBarnett Shale Mapped Fracture Treatments (TVD)

,’rr~ll q "1’

201 401 601 801 1,001 1,201 1,401 1,601 1,801 2,001 2,201

Frac Stages (Sorted on Perf Midpoint)

Deepest Aquifier

Depth fracTOP

perFI OP

Perf Midpoint

perfBTM

fracBTM

 ̄ Archer

 ̄ Bosque

 ̄ Clay

 ̄ Cooke

 ̄ Culberson

 ̄ Denton

 ̄ Erath

 ̄ Hill

Hood

 ̄ Jack

 ̄ Johnson

Montague

 ̄ Palo Pinto

 ̄ Parker

Reeves

 ̄ Somervelle

Terrant

Wise

Reproduced for Halliburton Pinnacle with permission from The American Oil & Gas Reporter www.aogr.com

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liburton to perform the stimulation process.

In 1953, the license was extended to all

qualified service companies.

Since that fateful day in 1949, hydraulic

fracturing has done more to increase recoverable reserves than any other technique. In the more than 60 years following

those first treatments, more than 2 million

frac treatments have been pumped with

no documented case of any treatment

polluting an aquifer.

Recent proposals have been initiated

by Congress to limit hydraulic fracturing

in order to protect groundwater supplies.

To limit or eliminate hydraulic fracturing

would, of course, be extremely detrimental

to domestic supplies of oil and natural

gas. In most low-permeability reservoirs,

the wells simply will not produce without

the fracturing process.

As many as 90 percent of all gas wells

completed in the United States have been

fractured, and the process continues to

be applied in new and innovative ways

to boost production of American and

worldwide energy in unconventional formations, such as tight gas sands, shale

deposits and coalbeds. Conventional,

higher-quality reservoirs also benefit from

hydraulic fracturing in the form of accelerated recovery.

As a result, hydraulic fracturing is

now responsible for 30 percent of domestic

oil and natural gas reserves, and has aided

in extracting more than 600 trillion cubic

feet of natural gas and 7 billion barrels

of oil, with much more to come. According

to the National Petroleum Council, 60-

80 percent of all wells drilled in the

United States during the next decade will

require fracturing to remain viable. The

reason, simply put, is that the low-hanging

fruit in the oil and gas industry is largely

gone. Going forward, new oil and gas

supplies increasingly will have to be recovered from lower-quality and unconventional reservoirs.

The concerns around groundwater contamination raised by Congress are primarily centered on one fundamental question: Are the created fractures contained

within the target formation so that they

do not contact underground sources of

drinking water? In response to that key

concern, this article presents the first

look at actual field data based on direct

measurements acquired while fracture

mapping more than 15,000 frac jobs

during the past decade.

Unanimous Conclusion

Studies conducted by governmental

agencies and respected authorities have

unanimously concluded that hydraulic

fracturing is safe. The Environmental

Protection Agency, the Ground Water

Protection Council and the Interstate Oil

& Gas Compact Commission all have

found hydraulic fracturing nonthreatening

to the environment or public health.

As displayed on the Energy in Depth

Web site (http://www.energyindepth.com/),

the GWPC’s survey of state energy regulatory agencies flmnd no documented

cases of contaminated drinking water

linked to hydraulic fracturing. The GWPC

also concluded that state regulations were

sufficient to ensure the integrity of the

water supply. A 2002 study conducted

by the IOGCC confirmed the GWPC’s

conclusion that no evidence could be

found of contaminated drinking water

related to hydraulic fracturing.

In addition, the EPA conducted an extensive survey of hydraulic fracturing

practices and their effect on drinking

water in 2004. Focusing on very shallow

coalbed methane wells (since their extremely shallow depths would have the

highest potential of harming the water

supply), the EPA found that several factors

(fluid recovery, the small amount of chemicals contained in frac fluids, their dilution

in water, and their absorption by rock

formations) minimize the potential risks

associated with hydraulic fracturing. The

EPA agreed with the GWPC and the

IOGCC that hydraulic fracturing is safe.

More specifically, the EPA concluded that

hydraulic fracturing does not create pathways for fluids to travel between rock

formations to affect the water supply.

On May 5, 1995, Carol M. Browner,

then an EPA administrator and now energy

adviser to President Obama, stated, "There

is no evidence that the hydraulic fracturing

at issue has resulted in any contamination

or endangerment of underground sources

of drinking water."

At a state regulators conference in

Washington last February, Steve Heare,

FIGURE 2

Marcellus Shale Mapped Fracture Treatments (TVD)

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000 ~ ~ ~ ~ ~ ~

5~1 101 151 201 251 301 351

Frac Stages (Sorted on Perf Midpoint)

Deepest Aquifier

Depth fracTOP

perFI OP

Perf Midpoint

perfBTM

fracBTM

OH

II WV

HESI301980
director of EPA’s Drinking Water Protection division said, "I have no information

that states are not doing a good job

already (of protecting water supplies)."

Despite claims by environmental organizations, Heare also reported that he had

not seen any documented cases where

hydraulic fracturing was contaminating

water supplies.

ICF International recently completed

another key study that specifically addressed hydraulic fracturing activities in

the Marcellus Shale play in New York.

The study confirmed that the EPA findings

were valid and found that there would

not be any risks to drinking water from

hydraulic fracturing in the Marcellus

Shale region.

Barnett, Marcellus Data

Extensive mapping of hydraulic fracture

geometry has been performed in unconventional North American shale reserw~irs

since 2001. The microseismic and tiltmeter

technologies used to monitor the treatments

are well established, and are also widely

used for nonoil field applications such as

earthquake monitoring, volcano monitoring, civil engineering applications, carbon capture and waste disposal. Figures

1 and 2 are plots of data collected on

thousands of hydraulic fracturing treatments in the Barnett Shale in the Fort

Worth Basin in Texas and in the Marcellus

Shale in the Appalachian Basin.

More fracs have been mapped in the

Barnett than any other reservoir. The

graph illustrates the fracture top and

bottom for all mapped treatments performed in the Barnett since 2001. The

depths are in true vertical depth. Perforation depths are illustrated by the red-colored band for each stage, with the mapped

fracture tops and bottoms illustrated by

colored curves corresponding to the counties where they took place.

The deepest water wells in each of

the counties where Barnett Shale fracs

have been mapped, according to United

States Geological Survey (http://nwis.waterdata.usgs.gov/nwis), are illustrated by

the dark blue shaded bars at the top of

Figure 1. As can be seen, the largest directly measured upward growth of all of

these mapped fractures still places the

fracture tops several thousands of feet

below the deepest known aquifer level in

each county.

The Marcellus data show a similarly

large distance between the top of the

tallest frac and the location of the deepest

drinking water aquifers as reported in

USGS data (dark blue shaded bars at the

top of Figure 2). Because it is a newer

play with fewer mapped frac stages at

this point and encompasses several states,

the data set is not as comprehensive as

that from the Barnett. However, it is no

less compelling in providing evidence of

a very good physical separation between

hydraulic fracture tops and water aquifers.

Almost 400 separate frac stages are

shown, color coded by state. As can be

seen, the fractures do grow upward quite

a bit taller than in the Barnett, but the

shallowest fracture tops are still _+4,500

feet, almost one mile below the surface

and thousands of feet below the aquifers

in those counties.

The results from our extensive fracture

mapping database show that hydraulic

fractures are better confined vertically

(and are also longer and narrower) than

conventional wisdom or models predict.

Even in areas with the largest measured

vertical fracture growth, such as the Marcellus, the tops of the hydraulic fractures

are still thousands of feet below the deepest

aquifers suitable for drinking water. The

data from these two shale reservoirs clearly

show the huge distances separating the

fracs from the nearest aquifers at their

closest points of approach, conclusively

demonstrating that hydraulic fractures are

not growing into groundwater supplies,

and therefore, cannot contaminate them.

It is true that sound engineering practices make exceptional wells. But it also

can be said that sound engineering practices make for a safe environment. Today’s

combination of proven, measurementbased engineering practices, optimal fracture treatment designs and direct mapping

measurements has led to the production

success now enjoyed in low-permeability

and unconventional gas plays in the United

States and around the globe. Those same

best practices also ensure that our drinking

water supplies are protected for generations

to come. []

KEVIN

FISHER

Kevin Fisher is general manager of

Pinnacle, a Halliburton Service, and

is involved in integrating real-time

fracturing diagnostics with fracture

modeling to optimize the hydraulic

fracturing process. He began his career

with Halliburton in 1979 and served

for 14 years as a logging enginee~

field supervisog log analyst, U.S. sales

manager and global technical marketing

manage~ He joined ProTechnics as

director of sales and marketing in

1993 and Pinnacle in 2000. Fisher

holds five U.S. patents related to apectral

gamma ray, gravel pack density logging,

and tiltmeter instrumentation. He holds

a B.S. in natural science/physics from

Cameron University.

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Pinnacle

A HALLIHUHTI]H SEi~VI[:.E

9949 W. Sam Houston Parkway North

Houston, TX 77064

281-876-2323

www.pinntech.com

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