A DRAFT REPORT FROM SAN BENITO RISING

Sargent Oil Field Possible Impact on Local Community & Environment

By Mary Hsia-Coron 1/11/2014

Aerial View of Sargent Oil Field

Gavilan College (pop. 7,776) Anzar High School (pop. 455)

Aromas (pop. 2,650) Gilroy (pop. 50,660) San Juan Bautista (pop. 1,862)

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Summary

Sargent Oil Field is located in the southern edge of Santa Clara County, bordered by the Pajaro River. It’s tucked away in

the bucolic, oak wooded hills, northwest of the Highway 101 and 129 interchange. Sargent is the largest oil field in Santa

Clara County, according to data from California Department of Oil, Gas and Geothermal Resources (DOGGR). It covers

an area that’s almost two square miles. Although it’s in Santa Clara County, Sargent Oil Field is situated very close to

three other counties – San Benito, Santa Cruz and Monterey.

Sargent has been operating quietly for decades, invisible to most people in nearby communities and schools. There are

currently 16 active (or potentially active) oil and gas wells, 4 injection wells, and 40 plugged or abandoned wells. There

are a number of risks associated with this oil field:

1) Its proximity to four earthquake faults makes the Sargent Oil Field one of the most seismically active oil fields in North

America. Seismic activity increases the likelihood of breaks in the oil/gas well casing and can result in leaks that

contaminate freshwater aquifers. The prevalence of landslides on the Sargent property further amplifies the risks to

oil/gas extraction infrastructure.

2) The Class II Injection Wells used to dispose of wastewater from Sargent’s oil and gas wells are of particular concern.

There are many media reports of wastewater injection wells contaminating aquifers, and even triggering earthquakes.

3) The Sargent property is currently being auctioned off as its owners have filed for bankruptcy. Future investors may

decide to maximize the return from this property’s oil and gas resources by using the latest enhanced recovery

techniques (e.g., cyclic steam injection, fracking, horizontal drilling) to extract the remaining oil and gas from old wells.

These extreme extraction techniques can be quite damaging to local aquifers and affect nearby communities and

schools -- like Aromas, South Gilroy, NW San Juan Bautista, Gavilan College, and Anzar High School.

4) If contamination of groundwater and surface water by Sargent Oil Field operations is extensive, it could potentially

affect those who live and work further west in the Pajaro River watershed – rural Pajaro residents and farmers with

domestic/irrigation wells, and perhaps even residents of Watsonville.

For hundreds of years, Native Americans gathered tar from Tar Spring Creek (some say to seal their canoes). During the

1860’s, oil and asphalt were mined at Sargent. Oil drilling techniques were introduced to Sargent in the early 1900’s.

Petroleum extraction technology has evolved rapidly. The latest well stimulation techniques (cyclic steam injection,

horizontal drilling, hydraulic fracturing, acidizing, etc.) can now syphon much of the remaining oil and gas from old wells.

Unfortunately, these techniques are also more damaging to the environment than older techniques. In a seismically active

area that’s also prone to landslides, this is potentially disastrous. Sargent Oil Field is said to be exempt from California

CEQA and no EIR has been done. This needs to be verified and, if true, rectified.

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Proximity to Local Communities and Schools

People ask where the oil and gas wells are located. The following DOGGR maps show the proximity of Sargent Oil Field

to towns and schools in the area. Many of these communities and schools rely on domestic water wells located a few

miles from Sargent Oil Field.

2.5 miles from Gavilan College, 3.5 miles from South Gilroy, 4.5 miles from Eagle Ridge Golf Club

3.5 miles from Aromas, 3 miles from Anzar High School, 4.75 miles from San Juan Bautista

Gavilan College

Sargent

Sargent

Anzar High School

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Proximity to Local Streams and Pajaro River

Three creeks flow through the Sargent Oil Field – Tar Spring Creek (formerly La Brea Creek), Pescadero Creek and

Sargent Creek. These creeks are part of the Pajaro River watershed. Contamination of surface water or underground

aquifers by Sargent Oil operations could affect residents and farmers in the Pajaro River basin.

Creeks on Sargent Property are part of Pajaro River Watershed

Aquifers and Ground Water Flow

The nationalatlas.gov web site provides maps of aquifers throughout the US. Its mapping system shows two types of

aquifers in our region: The blue area below denotes the “California Coastal Basin” aquifers. The light yellow area denotes

the “Other Rocks” aquifers which are quite shallow. Sargent Oil Field resides mostly on in the “Other Rocks” aquifers.

Pajaro River

Sargent

Sargent

“Ca. Coastal Basin” aquifers Hwy

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“Other Rocks “aquifers

San Juan

Bautista

Ca. Coastal Basin aquifers

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Geologist K.S. Muir said in his USGS publication [1], that unlike some other faults, the San Andreas fault forms a barrier

for ground water flow on the wastern (Pajaro Valley) side of the fault:

Of the two fault systems in the Pajaro Valley area (the San Andreas and the Zayante-Vergeles fault …) only the San

Andreas fault has a restrictive effect on the movement of ground water. The San Andreas fault acts as a barrier

because impermeable Tertiary rocks lie on the east side of the fault ... Evidence is scanty regarding the Zayante-

Vergeles fault, but that which is available indicates that this fault does not influence the movement of ground water

in the Pajaro Valley area.

Muir shows the flow of ground water flow on the Pacific (western) side of the San Andreas fault in the following diagram

using arrows (). See below:

Aromas

Sargent

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Earthquake Faults

The Sargent Oil Field is located in one of the most seismically active areas of North America. The San Andreas Fault is

about 2 miles away from some of the active Sargent oil and gas wells. The Sargent fault traverses the Sargent Oil Field.

And the Zayante and Calaveras faults are about 5 to 6 miles away to the west and east.

Landslides

Because of its proximity to the San Andreas and Sargent faults, the hills of Sargent Oil Field are susceptible to landslides,

as seen in this 1939 photo below [2]. Landslides add greater risk of damage to Sargent’s oil/gas and injection wells.

Sargent

Pajaro River

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Sargent’s Oil and Gas Wells

There are currently 16 active oil and gas wells (type “OG Active”) on the Sargent property, and 40 plugged or abandoned

wells (type “OG Plugged”). For instructions on how to view these wells using the DOGGR online mapping system, see

Appendix A.

Example of Oil & Gas Well (“Sargent 24”)

The following DOGGR map shows an active Sargent oil and gas well named “Sargent 24”. This well is currently operated

by Patriot Resources, LLC, as are the other wells on Sargent property. This is a typical Sargent oil and gas well.

Below is the “Sargent 24” Production and Well data from DOGGR. (Click here to view this production directly.)

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The production data for the “Sargent 24” oil and gas well can also be viewed in a graphical format using the DOGGR

online mapping system (see below).

This graphical format makes it easier to visualize the quantities of oil, gas and water production from “Sargent 24” well

for a short duration in time – July 2011 through September 2013. Note the fluctuating production of barrels of oil (BBLs),

volume of gas (MCF), and barrels of water (BBLs) each month. Since oil and gas wells are drilled very deep these days,

water from very deep aquifers is pumped up with the oil and gas. These deep aquifers often contain brine, mixed with

other chemicals. This brine is typically injected back underground using Wastewater Disposal wells.

According to the Wikipedia entry on Enhanced Oil Recovery:

Enhanced oil recovery wells typically pump large quantities of brine to the surface. The brine may

contain toxic heavy metals and radioactive substances, as well as being very salty. This can be very damaging

to drinking water sources and the environment generally if not properly controlled.

EPA has issued Underground Injection Control (UIC) regulations in order to protect drinking water

sources. Enhanced oil recovery wells are regulated as Class II wells by the EPA. The regulations require well

operators to reinject the brine used for recovery deep underground in Class II Disposal Wells.

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Sargent’s Injection Wells

There are 4 injection wells located in the Sargent Oil Field. Two of these wells are “Water Disposal” injection wells (type

“WD”); one is active and the other is idle. According to the staff at DOGGR District 3 office, which supervises Sargent Oil

Field, water is often pumped out during the process of extracting oil and gas. This wastewater must be gotten rid of and

the solution in many oil fields is to inject it back underground using a wastewater disposal well.

The other two injection wells at Sargent Oil Field are “Pressure Maintenance” wells (type “PM”), which are used to

pressurize the geological formation so that nearby oil and gas wells can be productive (i.e., pump out oil and gas).

According to the DOGGR District 3 office staff, only natural gas is injected into these PM wells, no other chemicals.

Wastewater Injection Wells

According to the California DOGGR theArcGIS.com online mapping system, found at the link

http://www.arcgis.com/home/webmap/viewer.html?url=http://services.arcgis.com/jDGuO8tYggdCCnUJ/ArcGIS/rest/services/CA%20Class%20II%20Injection%20Well

s/FeatureServer/1&source=sd, the two wastewater injection wells at Sargent Oil Field are Class II Disposal Wells, regulated by

the DOGGR Underground Injection Control (UIC) program.

The dangers of wastewater injection wells, especially for surrounding aquifers, are well known and detailed in many

online articles. One sample article from ProPublica [3] states:

The boom in oil and natural gas drilling is deepening the uncertainties, geologists acknowledge. Drilling produces

copious amounts of waste, burdening regulators and demanding hundreds of additional disposal wells. Those wells —

more holes punched in the ground — are changing the earth's geology, adding man-made fractures that allow water

and waste to flow more freely.

"There is no certainty at all in any of this, and whoever tells you the opposite is not telling you the truth," said Stefan Finsterle, a leading hydrogeologist at Lawrence Berkeley National Laboratory who specializes in understanding the properties of rock layers and modeling how fluid flows through them. "You have changed the system with pressure and temperature and fracturing, so you don't know how it will behave."

A ProPublica review of well records, case histories and government summaries of more than 220,000 well inspections found that structural failures inside injection wells are routine. From late 2007 to late 2010, one well integrity violation was issued for every six deep injection wells examined — more than 17,000 violations nationally. More than 7,000 wells showed signs that their walls were leaking. Records also show wells are frequently operated in violation of safety regulations and under conditions that greatly increase the risk of fluid leakage and the threat of water contamination.

Structurally, a disposal well is the same as an oil or gas well. Tubes of concrete and steel extend anywhere from a few hundred feet to two miles into the earth. At the bottom, the well opens into a natural rock formation. There is no container. Waste simply seeps out, filling tiny spaces left between the grains in the rock like the gaps between stacked marbles.

An additional risk of wastewater injection wells is their potential for triggering earthquakes. A Scientific American article

describes this phenomenon in places like Oklahoma where earthquakes used to be rare [4]:

In the area near Prague, Okla., where wastewater from oil and gas production has been injected down disposal wells

for decades, a series of earthquakes broke out following the massive magnitude 8.8 earthquake off the coast of the

Maule region of Chile in 2010. For months the grounds in Oklahoma periodically shook, culminating in a destructive

5.7 magnitude quake in November 2011.

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Example of Wastewater Injection Well (“Gulf-James W. Rea Jr Et Al 2”)

The DOGGR map below shows the location of one active wastewater injection well on the Sargent property, operated by

Patriot Resources, LLC. This injection well is categorized by DOGGR as a Class II Disposal well.

The following DOGGR well information shows that this wastewater injection well (named “Gulf-James W. Rea Jr. Et Al

2”) is located in Santa Clara county. But it’s particularly worrisome for residents and farmers in the Chittenden area of

Highway 129 (San Benito county) who have domestic/irrigation wells just 1.5 to 2 miles away from this injection well.

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The following injection data for “Gulf-James W. Rea Jr. Et Al 2” can be viewed directly by clicking here. If you scroll down

the data file, you’ll see that the well has been in continuous operation since 1981 to the present day (latest report is

November 2013. Below are excerpts of this production data for the starting period and the most recent period. Note the

volume of Water and Pressure in the monthly entries below under “Injection Data”.

:

: (data continued below)

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Where to Get More Information

The data in this report about Sargent Oil Field’s wells was obtained from the DOGGR database. Readers should go to the

online DOGGR web site to validate and further research this, and other, data. Instructions on how to access and use the

DOGGR Online Mapping System are provided in Appendix A, on the next page.

Additional information about the risks of injection wells, and about the geology and hydrology of the area surrounding

Sargent Oil Field can be found in these online resources:

1) Geology and Ground Water of the Pajaro Valley Area, Santa Cruz and Monterey, California, by K. S. Muir, U.S.

Geological Survey, 1972 http://pubs.usgs.gov/of/1973/0199/report.pdf

2) Geology of the San Juan Bautista Quadrangle, by John Eliot Allen, State of Calif. Division of Mines, 1946 https://archive.org/stream/geologyofsanjuan00allerich#page/n3/mode/2up

3) Injection Wells – The Poison Beneath Us, by Abrahm Lustgarten , article in ProPublica, June 21, 2012 http://www.propublica.org/article/injection-wells-the-poison-beneath-us

4) Injection Wells Spawn Powerful Earthquake, by David Biello, article in Scientific America, July 12, 2013 http://www.scientificamerican.com/article.cfm?id=drilling-and-pumping-wells-spawn-powerful-earthquakes

5) Pajaro Watershed Flood Protection Plan, by CSU Monterey Bay Students in Robert Curry’s Class, 2003 http://www.pajarowatershed.org/archive/uploads/Flood%20Protection/Watershed%20Studies/Curry%20Flood%20Protection%20Plan%202003.pdf

6) Geohydrology of Recharge and Seawater Intrusion in the Pajaro Valley, Santa Cruz and Monterey Counties,

California, by US Geological Survey, by Randall T. Hanson, 2003 http://pubs.usgs.gov/fs/fs-044-03/pdf/fs-044-03.pdf

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Appendix A -- How to Use the DOGGR Online Mapping System

You can find data about oil and gas wells throughout California by going to the web site of the California Dept. of Oil, Gas

and Geothermal Resources (DOGGR), or by clicking here. At this site, select “Find” and then “Find by Address” to search

for oil and gas wells in the vicinity that you wish to research. You can also search by the location of your computer.

Select "Help" for a legend of the different well symbols and to see the well types (below).

NOTE: The submission of well information to the DOGGR mapping system is currently

voluntary, so not all wells in California are shown. This voluntary policy may change

with the implementation of new regulations by DOGGR.