Open-file Report No. 2 

BENZENE IN WATER 

PRODUCED FROM 

KERN COUNTY 

OIL FIELDS 

CONTAINING 

FRESHWATER 

~ DEPARrMENT OF .,, .. ~ CONSERVATION 

em~ 

RESOURCES AGENCY STATE OF CALIFORNIA, DEPARTMENT OF CONSERVATION 

DOUGLAS P. WHEELER, Secretary PETE WILSON, Governor MICHAEL F. BYRNE, Director 
BENZENE IN WATER PRODUCED FROM 

KERN COUNTY 

OIL FIELDS 

CONTAINING FRESH WATER 

by Mark T. Gamache 

Energy and Mineral Resources Engineer 

Division of Oil, Gas, and Geothermal Resources 

Sacramento 

1993 

California Department of Conservation 

Division of Oil, Gas, & Geothermal Resources 

William F. Guerard, Jr., State Oil and Gas Supervisor 
CONTENTS 

Summary ............................................................................................ 1 

Introduction ....................................................................................... 1 

Procedure ........................................................................................... 2 

Location of samples ............................................................................ 3 

Data ................................................................................................... 3 

Data analysis ....................................................................................... 3 

Statistical analysis ................................................................................ 4 

Conclusion ......................................................................................... 5 

Selected References .............................................................................. 6 

FIGURES 

Map 1. Location of oil fields sampled ................................................... 7 

Table 1. Location and related information for benzene samples ........ 8-11 

Figure 1. Scatter diagram- 0

API gravity versus benzene ....................... 12 

Figure 2. Scatter diagram - formation depth ve:rsus benzene ................. 13 

iii 
BENZENE IN WATER PRODUCED 

FROM I<ERN COUNTY OIL FIELDS 

CONTAINING FRESH WATER 

by 

Mark T. Gamache 

SUMMARY 

During the summer of 1992, a project was begun to 

sample produced water in Kern County oil fields that 

contain underground freshwater aquifers. The project 

was undertaken to make a regional comparison among 

benzene levels in such fields in an effort to assess the 

possibility of groundwater degradation. Fifty-eight 

samples were obtained from produced water, which 

came from single zones when possible. Tank farms 

were the preferred choice for taking the water samples 

when the produced water was not commingled with 

water from different zones. A tank sample is a composite sample from several wells and, therefore, more 

representative of a zone. 

Statistical analysis demonstrated a direct correlation 

between benzene amounts and the API gravity of crude 

oil and an indirect correlation between benzene 

amounts and formation depth. Linear regression of the 

data produced a best-fit line on a scatter diagram and 

allowed prediction of the amount of benzene in 

produced water when the API gravity of the oil or the 

formation depth are known. Several other variables, 

including water cut, contribute to an unexplained error 

in the linear regression. 

Although oilfield fluids might contain significant levels 

of benzene, a hazard exists only with exposure to 

humans or the environment. If a permitted injection 

zone is exempt per United States Environmental 

Protection Agency (EPA) criteria and does not include 

BENZENE IN WATER 

an underground source of drinking water, no problem 

should occur if some benzene from produced water 

enters the injection zone along with injected water. 

On the other hand, the practice of disposing of 

produced water in sumps should be questioned when 

the area contains underground freshwater aquifers, and 

the produced water has high benzene levels. The 

Regional Water Quality Control Board is phasing out 

sumps iln freshwater areas. 

The benzene data generated during this study suggest 

benzene levels are generally low in produced water, 

falling below the 0.5 mg/L Toxicity Characteristic 

Leaching Procedure regulatory level in 40 of the 58 

samples collected. 

INTRODUCTION 

From April through June 1992, a project was undertaken to sample produced water in Kern County oil 

fields to measure the amount of benzene in various 

formation waters. Oil fields with underground freshwater aquifers were targeted for the study to assess the 

possible degradation of underground sources of 

drinking water by benzene. Such oil fields generally lie 

east of Interstate 5 (I-5) in Kern County, although a 

few, such as Landslide, Yowlumne, and North Coles 

Levee, are west ofl-5 (see Map 1). Wheeler Ridge oil 

field was included in the study because it is near 

potential residential areas, and it is uncertain whether 

the field has a shallow, freshwater zone. 
Benzene is a volatile, aromatic, organic molecule found 

in the light fraction of crude oils (Haun, 1977). The 

solubility of benzene is 0.180 g/100 ml water at 25°C. 

The specific gravity is 0.87865 and the vapor pressure 

is 75 torr at 20°C (Sax and Lewis, 1989). The principal route of exposure to benzene by humans is from 

inhaling vapor or by skin absorption. Benzene is 

moderately toxic by ingestion. The primary manifestation of disease from benzene exposure is acute, central 

nervous system depression, leukemia, aplastic anemia, 

and dermatitis if the skin is involved (Levy and 

Wegman, 1988). 

Benzene is considered to be a confirmed human 

carcinogen by the American Conference of Government Industrial Hygienists (ACGIH). It has a threshold limit value (TLV:TWA) guideline of0.1 parts per 

million (ppm). 1 The Occupational Safety and Health 

Administration (OSHA) permissible exposure limits 

(PEL:TW A) are 1.0 ppm. On March 3, 1990, the 

United States Environmental Protection Agency (EPA) 

added benzene to the list of "EP Characteristic" wastes. 

The Toxicity Characteristic Leaching Procedure test 

(TCLP) regulatory level for benzene in hazardous waste 

is 0.5 mg/L.2 

Due to intermingling, produced water can contain 

some benzene derived from crude oil. Presently, 

produced water from oilfield operations is exempt from 

EPA regulatory requirements for hazardous wastes. 

Also, produced water is disposed of by injection into 

Class II wells (i.e., disposal and enhanced oil recovery 

wells) or through placement in percolation sumps 

where some is lost through evaporation. Some produced water in the study area is fresh enough to serve 

as a source of drinking water and is added to the 

Beardsley Canal near Kern River. 

PROCEDURE 

Fifty-eight samples of produced water were analyzed 

1

This change from 10 ppm and suspected human 

carcinogen was proposed by the ACGIH in 1990, then 

published in the Threshold Limit Values and Biological 

Exposure Indices 1990-1991 booklet. 

2

California Department of Health Services, 1990. Toxicity 

Characteristic Leaching Procedure (TCLP)--A Guide for 

California Generators and Handlers of Hazardous Wastes, 

table 1, p. 6. 

2 

for benzene. Sampling was targeted on produced water 

originating from a single zone or formation. Occasionally, a sample of commingled produced water was 

taken when individual zone samples were unavailable 

or the sample had special value. Since the project's 

main purpose was to compare benzene levels from 

different formations, the sampling plan was regional in 

scope. Intensive sampling of each formation to obtain 

statistically significant average benzene levels on the 

local level was neither a part of nor the purpose of the 

study. 

Some produced-water samples were obtained from tank 

farms and some from producing wells where the oil was 

decanted (Photos 1 and 2). Tank farms were the 

preferred choice when the produced water was not 

commingled. Although processing oil and water in 

Photograph 1. A typical tank containing waste water and 

crude oil that was sampled. The oil blanket on top of the 

produced water may prevent benzene in the water from 

volatilizing. 

Photograph 2. Water from the tank was sampled by using 

the lowest access line. The produced water was allowed to 

run for a few minutes to clear the line of residue oil before 

obtaining a sample. 

DIVISION OF OIL, GAS, & GEOTHERMAL RESOURCES 
tank farms may decrease the benzene quantity in 

produced water; still, a tank sample represents a 

composite sample from several wells and, therefore, 

more representative of the formation. Tanks also 

contain the final waste product that may be injected 

into a water-disposal well or placed in a sump. 

Sampling methodology 

Water samples were placed in two, 40-milliliter glass 

vials and capped with teflon seal lids. Two hundred 

microliters of 1: 1 hydrochloric acid was added to each 

sample as a preservative. The vials were filled to the 

top, with no head space. After the samples were 

obtained, they were cooled to 4°C in the field using 

"blue ice" and kept in an ice chest. The purpose of the 

acid and refrigeration was to prevent bacterial growth 

and benzene degradation. The elimination of head 

space reduced the ability of benzene to volatilize out of 

solution. A traveling blank was also labelled and 

accompanied each sample as a negative control. The 

samples were collected according to the directions of a 

state-accredited laboratory and analyzed by the same 

laboratory using EPA-approved testing methods. Since 

the samples were liquid, the sample results can be 

compared with the TCLP regulatory level of 0.5 mg/L 

(= 0.5 ppm) for hazardous waste. 

Location of samples 

The oil fields from which samples were taken are 

shown on Map 1. The number in each circle refers to 

the number of samples taken from the field. For 

example, a single sample from Landslide oil field is 

shown in T. 11N, R. 21W., SBB&M. Information on 

each sample is given in Table 1. 

Data 

The sample data in Table 1 (beginning on page 8) are 

grouped first by zone, which is the source of the 

produced water, and secondly by oil field and area. 

The youngest and shallowest source zones are grouped 

at the top, descending into older and deeper zones near 

3

Formation depths and API gravity of zones are reprinted 

from California Oil and Gas Fields. Central California. 

Volume I. 

BENZENE IN WATER 

the bottom. Note that the Stevens zone is not the 

oldest zone, but it is the deepest zone sampled. 

If the benzene found in produced water is derived from 

the lighter fraction of crude oil, then there should be 

some correlation with the API gravity and the depth of 

the zone. Therefore, the average API gravity, average 

zone dc:!pth, and area location were added for comparative purposes.3 The benzene values were reported in 

micrograms per liter. This value was divided by 1,000 

to convert it to milligrams per liter (equal to ppm). 

The intended injection zone for the produced water is 

shown in the final column. 

Data analysis 

The Kern River zone in Kern River oil field has 

benzene values below 0.01 ppm for all samples tested. 

These values were expected, given the low oil gravity 

and the shallow depths of the Kern River zone. The 

Etchegoin and Chanac zones in Edison oil field and 

the Jewett/Pyramid HillN edder zones in Round 

Mountain and Mount Poso oil fields also produced 

comparatively low-gravity oil and waters with low 

benzene values from shallow-to-medium depths. 

The N.lain Area in Fruitvale oil field produces oil from 

several zones in the following depth order (shallowest 

to deejpest): Fairhaven, Mason-Parker, Martin, Kernco, 

and the Santa Margarita. When possible, separate 

samplc~s were taken from each. The Martin and 

Kernco samples show the highest values, approaching 

0.2 ppm benzene. 

The Reserve zone was sampled in Tejon. and Wheeler 

Ridge oil fields. The Tejon benzene value of0.0066 

ppm was the lower of the two samples and corresponds 

to the shallow zone depth ( 1,810 feet} in that area. 

The higher value of 3. 7 ppm from Wheeler Ridge is 

most likely due to the greater depth of the zone (5,600 

feet) and the increase in oil gravity from 17° API in 

Tejon to 21 o API in Wheeler Ridge. 

Produced water from the Stevens zone was sampled in 

several different oil fields, including West Bellevue, 

Bellevue, Rosedale, Canal, Canfield Ranch, North 

Coles Levee, Ten Section, and Paloma. The Stevens 

zone was also sampled as commingled fluids in 

Yowlumne and Greeley oil fields. The values ranged 

from a low of0.019 ppm to a high of 18.0 ppm, with 

3 
an average of 4.82 ppm. The data follow natural 

groupings of0.019 to 0.45 ppm, 2.0 to 3.7 ppm, 5.1 

to 6.6 ppm, and 14.0 to 18.0 ppm. There is some 

difficulty in correlating this grouping to gravity and 

depth data. If the gravity of oil and depth of the 

Stevens zone were noted for each oil well contributing 

produced water to a tank farm sample, perhaps the 

correlation would be stronger. 

Another variable is produced water cut. For example, 

the benzene value of0.019 ppm for sample 27 in 

Canfield Ranch oil field (East Gosford Area) corresponds to a 58 percent water cut. Sample 61, with a 

benzene value of2.5 ppm, was also obtained in 

Canfield Ranch (South Gosford Area) and corresponds 

to a water cut of 12 percent. Sample 10 (East Gosford 

Area), with a value of3.4 ppm, corresponds to a water 

cut of 60 percent. Therefore, the correlation of 

benzene values with water cut is weak. Water cuts 

produce random error, probably because of the varied 

sources of water. For example, water may be from the 

oil horizons and in contact with the oil, or be derived 

from water-bearing sands at different horizons from the 

oil. Also, the water might be from an enhanced oilrecovery project. 

Other variables include formation temperatures, gas 

pressure in the crude oil, quantity of benzene in oil, 

sampling process (surface versus at depth), etc. Some 

of these variables might be identified and quantified in 

a controlled, local sampling study, but the individual 

contribution of each variable to the unexplained error 

of the linear regressions calculated in this study is 

unknown. 

Statistical analysis 

Multivariate correlation can be used when a variable, 

like benzene quantity in produced water, is related to 

two or more other variables such as API gravity of oil 

or formation depth of origination. 

The relative strength of correlation between variables 

can be compared by calculating the correlation coefficient r for each set of variables. The value of r indicates 

4

All statistical analyses in this section were calculated from 

equations and instructions in McGhee, J. W., 1985, 

Introductory Statistics: West Publishing Co., St. Paul, 

Minnesota p. 395-444. 

4 

whether a correlation, either positive or negative, exists 

between two variables. A positive correlation becomes 

stronger as r increases from 0 to 1. A negative correlation becomes stronger as r decreases from 0 to -1. 

The r value was calculated for three variable sets: API 

gravity of oil versus benzene quantity in produced 

water (x1

,y); formation depth of origination versus 

benzene quantity in produced water value (x2

,y); and 

API gravity of oil versus formation depth (x1 ,x2

). The r 

for (x1

,y) was 0.77, for (x2,y) 0.63, and for (x1

,x2

) 0.87. 

The values indicate a strong positive correlation 

between benzene quantity in produced water to API 

gravity and formation depth of origination. Furthermore, there is an interactive effect between API gravity 

and formation depth. 

Correlation between variables was verified statistically 

by testing for the null hypothesis of no correlation 

against the alternate hypothesis of correlation. If no 

correlation existed between the variables of interest, 

then there would be a 0.5 percent chance that a 

random sampling method collecting 58 samples would 

produce an r value of 0.337 or greater. Since the r 

values obtained for these sets of variables were far 

above 0.337, the null hypothesis is rejected and the 

conclusion is that a positive correlation exists. 

A linear regression was computed for a scatter diagram 

of API gravity versus benzene quantity, and a scatter 

diagram of formation depth versus benzene quantity 

(Figs. 1 and 2, see pages 12 and 13). The statistical 

method produces a best-fitting line to the data with the 

regression line equation y = bo + b1

x. The equation 

can be used to predict y values for specific values of x. 

The equation for each linear regression is shown on the 

scatter diagrams. 

The square of r is very important in a statistical study 

and is called the coefficient of determination (r2

). This 

value explains what percentage of data is attributed to 

the variable studied and what is not. An r value of 

0.59 is associated with the variable set, API gravity 

versus benzene quantity. This means that 59 percent 

of the samples were explained by the regression line 

(i.e., they fall within the normal population predicted 

by the mean). The other 41 percent are attributed to 

unexplained error. This suggests that other, additional 

variables account for benzene quantity besides API 

gravity. The r2 value for formation depth versus 

DIVISION OF OIL, GAS, & GEOTHERMAL RESOURCES 
benzene quantity is 0.40, meaning 40 percent of the 

data are explained by the regression line and 60 percent 

are due to unexplained error. 

This factor may be explained by looking at the reason 

why benzene is in produced water. If benzene is found 

in the lighter fractions of crude oil, it would be expected that lighter crude would contribute more 

benzene to produced water than heavier crude. This 

causal observation is supported by the strong positive 

correlation between API gravity oil and benzene 

quantity in produced water. According to Philippi 

(1965), the aromatic contents in oil increase strongly 

with depth and age of sediments, due to thermal 

maturation and time. This effect is also supported by 

the moderately strong positive correlation in this study 

between benzene quantity in produced water and 

formation depth. 

Benzene has a stronger correlation to API gravity than 

to formation depth because benzene is derived from the 

crude oil rather than from the formation. However, an 

interactive effect exists between oil and formation 

depth; therefore, there is an indirect correlation 

between the formation depth and benzene quantity in 

produced water. 

For these reasons, predictions of benzene quantity in 

produced water should be based on the linear regression of API gravity to benzene quantity, rather than to 

formation depth. However, the formation depth 

might be used as a secondary check, or even as a 

primary predictor, if API gravity is unknown. 

CONCLUSION 

The data collected in this study represent a regional 

overview of benzene in produced water from Kern 

County oil fields where underground freshwater 

aquifers are present. Statistical analyses demonstrate a 

direct, positive correlation between API gravity of oil 

and benzene in produced water. An indirect, positive 

correlation was.also demonstrated between depth of 

formation and amount ofbenzene in produced water. 

Several. other variables, including water cut, contribute 

BENZENE IN WATER 

to the unexplained error of the linear regression. 

Benzene:: quantities can be predicted if the API gravity 

of the o:il or formation depth of origination is known 

and the linear regression equations developed from this 

study are used. 

Table 1 includes the permitted zone of injection for 

fluids containing benzene. If the permitted zone is 

exemptc~d by the EPA and doesn't contain an underground source of drinking water, there should be no 

problem if some benzene from produced water enters 

the injection zone. However, the practice of disposing 

of prodlUced water in sumps should be questioned 

when the area contains underground freshwater 

aquifers and the produced water has high benzene 

levels. 

Producc~d-water spills, by themselves or in conjunction 

with oil spills, might require further investigation. 

Oil-contaminated soil is removed routinely, 

bioremediated, and used as road mix (or otherwise 

recycled or disposed of). If produced water containing 

a large amount of benzene is spilled, the soil may 

become contaminated with benzene. However, the soil 

can bioremediate itself naturally, and the benzene can 

vaporize::. It may be beneficial to calculate a predicted 

benzene~ quantity for the produced water when such a 

spill oc<:urs. This would help to determine whether or 

not a problem exists. 

Finally, the EPA is considering a change to its policy of 

exempting oilfield waste from hazardous waste regulations. The benzene data generated from this study 

indicate: benzene levels are generally low in produced 

water (below the 0.5 ppm TCLP regulatory level in 40 

of the s;s samples collected). Therefore, these data 

suggest the appropriate decision would be to retain the 

exempt status. Such a decision could be based not only 

on the llow levels of benzene in produced water, but of 

the fact that a regulatory process is already in place for 

producc::d-water disposal. This is especially important 

as more: produced water will be subject to injection for 

disposal purposes as percolation sumps are phased out 

in areas of underground freshwater aquifers. 

5 
SELECTED REFERENCES 

California Department of Health Services, 1990, 

Toxicity Characteristic Leaching Procedure (TCLP)--A 

guide for California generators and handlers of hazardous wastes, 19 p., 1 appendix. 

California Division of Oil and Gas, 1985, California 

Oil & Gas Fields, Central California, Vol. 1. 

California Chamber of Commerce, 1990, Hazardous 

waste management, 96 p., 10 appendices. 

Editor's note, 1990, Notice of intended changes--

benzene: applied occupational environmental hygiene, 

v. 5,no. 7,p.453-463. 

Haun, J.D. 1977, Some principles of petroleum 

geology--a review, in subsurface geology--petroleum 

mining construction, Leroy, L. W. and Leroy D. 0. 

ed., Fourth Edition: Colorado School of Mines, 

Golden, Colorado, p. 234-240. 

6 

Levy, B. S., and Wegman, D. H., 1988, Occupational 

health--recognizing and preventing work-related 

disease, second edition: Little, Brown and Company, 

Boston, p. 575. 

McGhee, J. W., 1985, Introductory statistics: West 

Publishing Company, St. Paul, Minnesota, p. 395-

444. 

Philippi, G. T., 1965, On the depth, time, and 

mechanism of petroleum generation: Geochimica et 

Chosmochimica Acta, v. 29, p. 1021-1049. 

Sax, I. N., and Lewis, R. J., Sr., 1989, Dangerous 

properties of industrial materials, seventh edition, Vol. 

II: Van Nostrand Reinhold, New York, New York, p. 

364-365. 

DIVISION OF OIL, GAS, & GEOTHERMAL RESOURCES 
~t 

s 

r 

u 

s 

!5 

s 

Z7 

s 

r 

as 

s 

1' 

Z9 

1 

:so 

s 

7 

lf 

s 

1' 

lt 

' 

II 

.... 

1' 

10 

,. 

\ 

\ 

i 

i 

\ 

I )'Uit Cit(!)( ( \ 

I 

I 

l~t\ ~I~ ~~T-f'\. I 

I '® i \ ~,. loiOUHT .OOSO 

:) I \ l I ! ;~ \ I 

INDEX MAP 

CENTRAL CAUFORNIA 

SCA.I.( IN "'I.(S 

X e: R N 

/-

I 

! 

I 

OH 1411.1.S 

I .· 

!117"" ltiiW 

.. 

zs 

s 

Z7 

s 

r 

Zl 

1 

r 

z, 

s 

1' 

30 

s 

1' 

11 

s 

7 

l~ 

s 

r 

II 

'I' 

10 

... 

Map 1. Each oil field sampled had active water disposal or waterflood injection projects. All maps were adapted from 

California Division of Oil and Gas, 1985, California Oil & Gas Fields, Central California, Volume 1. Circled numbers 

indicate the number of samples taken from each field. 

BENZENE IN WATER 7 
Table 1. Location and related information for water samples. 

PRODUCED GRAVITY DEPTH FIELD/AREA SECTION SAMP. BENZENE INJECTION 

WATER OIL ZONE TWN/RNG NUMB. VALUE ZONE 

ZONE ( 0API) (FEET) (PPM) 

KERN 10-16 400 KERN RIVER SEC. 31 20 0.0007 CHANAC/SANTA 

RIVER 28S 28E MARGARITA 

KERN 10-16 400 KERN RIVER SEC. 5 21 0.0011 CHANAC/SANTA 

RIVER 29S 28E MARGARITA. 

KERN 10-16 400 KERN RIVER SEC. 30 30 NONE KERN RIVER 

RIVER 28S 28E DETECTED 

KERN 10-16 400 KERN RIVER SEC. 25 31 0.0013 SANTA MARGARITA 

RIVER 28S 27E 

KERN 10-16 400 KERN RIVER . SEC. 6 32 NONE SANTA MARGARITA 

RIVER 29S 28E DETECTED 

KERN 10-16 400 KERN RIVER SEC. 34 39 NONE SANTA MARGARITA 

RIVER 28S 28E· DETECTED 

KERN 10-16 400 KERN RIVER SEC. 5 53 0.0071 KERN RIVER 

RIVER 29S 28E 

ETCHEGOIN 11-14 3500 POSO CREEK/ SEC. 32 40 0.0008 SANTA MARGARITA 

PREMIER 27S 27E 

ETCHEGOIN 15 3,500 ROSEDALE RANCH SEC. 35 43 NONE ETCHEGOIN 

28S 26E DETECTED 

KERN 14-22 750 EDISON/MAIN SEC. 14 28 0.0054 SCHIST 

RIVER-CHANAC 30S 29E 

CHANAC/ 14-29 750/ EDISON/MAIN SEC. 23 58 0.0005 SCHIST 

SANTA 400/ 30S 29E 

MARGARITA/ 

WICKER/NOZU/ 1,500/3,000/ 

FREEMAN-JEWETT/ 3,150/ 

WALKER/SCHIST 2,900/1,200 

CHANAC 15 1,070 EDISON/RACE SEC. 27 60 0.0047 SANTA MARGARITA 

TRACK 29S 29E 

CHANAC 14 2,290 KERN FRONT SEC. 22 54 NONE ETCHEGOIN 

28S 27E DETECTED 

CHANAC 11-15 2,500 POSO CREEK/ SEC. 8 44 NONE CHANAC 

PREMIER 28S 28E DETECTED 

CHANAC 18 3,100 FRUITVALE/ SEC. 15 46 NONE CHANAC 

MAIN 29S 27E DETECTED 

CHANAC 18 3,100 FRUITVALE/ SEC. 34 2 0.0038 UPPER KERNCO 

MAIN 29S. 27E 

8 DIVISION OF OIL, GAS, & GEOTHERMAL RESOURCES 
Table 1. (continued). Location and related information for water samples. 

PRODUCED GRAVITY DEPTH FIELD/AREA SECTION SAMP. BENZENE INJECTION 

WATER OIL ZONE TWN/RNG NUMB. VALUE ZONE 

ZONE ( 0API) (FEET) (PPM) 

MASON- 18 3,100 FRUITVALE/ SEC. 21 29 NONE MASON-PARKER 

PARKER MAIN 29S 27E DETECTED 

MARTIN 22 3,250 FRUITVALE/ SEC. 22 8 0.19 ETCHEGOIN 

MAIN 29S 27E 

KERN CO 15-22 3,600 FRUITVALE/ SEC. 28 3 0.13 MIDDLE KERNCO 

MAIN 29S 27E 

KERN CO 15-22 3,600 FRUITVALE/ SEC. 14 22 0.0024 ETCHEGOIN 

MAIN 29S 27E 

KERN CO 15-22 2,600 FRUITVALE/ SEC. 22 9 0.0006 ETCHEGOIN 

MAIN 29S 27E 

CHANAC/ 18 3,100/ FRUITVALE/ SEC. 27 6 0.0088 MARTINj.KEJ.WCO 

SANTA 4,500 MAIN 29S 27E 

MARGARITA 

SANTA 16 715 DEER CREEK SEC. 27 52 0.0078 SANTA M..ABGARITA 

MARGARITA 22S 27E 

SANTA 16 1,550 TEJON/WESTERN SEC. 32 13 NONE FRUITVALE/ 

MARGARITA 11N 20W DETECTED ~ ~ 

RESERVE 17 1,810 TEJON/ SEC. 12 55 0.0066 RESERVE 

SOUTHEAST 10N 19W 

RESERVE 21 5,600 WHEELER RIDGE/ SEC. 36 33 3.7 RESERVE 

WINDGAP 11N 20W 

OLCESE 14 2,300 ANT HILL SEC. 22 47 NONE OLCESE 

29S 29E DETECTED 

CHANAC/ 13-16 1,070/ EDISON/RACE SEC. 34 48 6.3 RaJND lUNfAlN/ 

SANTA *41 1,830/ TRACK 29S 29E JEWETT 

MARGARITA/ 

NOZU/*JEWETT 3,260/4,570 

JEWETT 22 1,750 ROUND MOUNTAIN/ SEC. 20 16 NONE JEWETT/ 

MAIN 28S 29E DETECTED PYRAMID HILL 

PYRAMID 18-19 1,500 ROUND MOUNTAIN/ SEC. 7 18 0.017 PYRAMID HILL 

HILL COFFEE CANYON 28S 29E 

PYRAMID 16-19 1,500/ ROUND MOUNTAIN/ SEC. 7 56 NONE PYRAMID HILL/ 

HILL/ COFFEE CANYON 28S 29E DETECTED VEDDER 

VEDDER 1,650 

VEDDER 16 1,390 ROUND MOUNTAIN/ SEC. 1.6 57 0.0012 VEDDER 

PYRAMID 28S 29E 

* API gravity is 41 for the Jewett zone. 

BENZENE IN WATER 9 
Table 1. (continued). Location and related information for water samples. 

PRODUCED GRAVITY DEPTH FIELD/AREA ·sECTION SAMP. BENZENE INJECTION 

WATER OIL ZONE TWN/RNG NUMB. VALUE ZONE 

ZONE ( 0API) (FEET) (PPM) 

VEDDER 13 2,800 ROUND MOUNTAIN/ SEC. 14 17 NONE OLCESE 

SHARKTOOTH 28S 28E DETECTED 

VEDDER 15-16 1,750 MOUNT POSO/ SEC. 29 23 0.0017 PYRAMID HILL/ 

MAIN 26S 28E VEDDER 

VEDDER 15-16 1,750 MOUNT POSO/ SEC. 9 24 0.0065 PYRAMID HILL/ 

MAIN 27S 28E VEDDER 

VEDDER 15-16 1,750 MOUNT POSO/ SEC. 22 25 0.0042 PYRAMID HILL/ 

MAIN 27S 28E VEDDER 

VEDDER 15-16 1,500 MOUNT POSO/ SEC. 26 26 NONE VEDDER 

DORSEY 27S 28E DETECTED 

VEDDER 15-16 1,500 MOUNT POSO/ SEC. 22 49 NONE VEDDER 

DORSEY 27S 28E DETECTED 

VEDDER 15-16 1,500 MOUNT POSO/ SEC. 26 50 NONE VEDDER 

DORSEY 27S 28E DETECTED 

VEDDER 16 2,400 MOUNT POSO/ SEC. 20 15 NONE OLCESE 

DORSEY 27S 28E DETECTED 

WHARTON/ 23-35 5,500/ MOUNTAIN VIEW/ SEC. 21 59 3.5 CHANAC/ 

NOZU/ 7,300/ MAIN 31S 29E SANTA MARGARITA 

OLCESE 7,000 

STEVENS/ 34-36 8,300/ GREELEY SEC. 7 42 5.1 ETCHEGOIN 

OLCESE/ 10,530/ 29S 26E 

RIO BRAVO 11,300 

STEVENS 31 12,190 LANDSLIDE SEC. 24 34 .45 STEVENS 

11N 24W 

ETCHEGOIN 29-34 10,400 YOWLUMNE SEC. 3 35 6.6 STEVENS 

/STEVENS /11,200 12N 22W 

ETCHEGOIN 29-34 10,400 YOWLUMNE SEC. 4 36 5.2 STEVENS 

/STEVENS /11,200 12N 22W 

STEVENS. 33-35 7,000 BELLEVUE/MAIN SEC. 35 14 2.9 STEVENS 

29S 26E 

STEVENS 28-35 7,800 WEST BELLEVUE SEC. 33 4 2.2 STEVENS 

29S 26E 

STEVENS 28-35. 7,800 WEST BELLEVUE SEC. 32 45 2.1 STEVENS 

29S 26E 

10 DIVISION OF OIL, GAS, & GEOTHERMAL RESOURCES 
Table 1. (continued). Location and related information for water samples. 

PRODUCED GRAVITY DEPTH FIELD/AREA SECTION SAMP. BENZENE INJECTION 

WATER OIL ZONE TWN/RNG NUMB. VALUE ZONE 

ZONE ( 0API) (FEET) (PPM) 

STEVENS 32 5,800 ROSEDALE/MAIN SEC. 23 41 5.5 ETCHEGOIN 

29S 26E 

STEVENS 32 5,800 ROSEDALE/MAIN SEC. 15 51 2.0 ETCHEGOIN 

29S 26E 

STEVENS 35 8,050 CANAL SEC. 14 11 2.4 ETCHEGOIN 

30S 25E 

STEVENS 33 7,900 CANFIELD RANCH/ SEC. 13 27 0.019 ETCHEGOIN 

EAST GOSFORD 30S 26E 

STEVENS 33 7,900 CANFIELD RANCH/ SEC, 19 10 3.4 ETCHEGOIN 

EAST GOSFORD 30S 27E 

STEVENS 29-34 7,950 CANFIELD RANCH/ SEC. 26 61 2.5 STEVENS 

SOUTH GOSFORD 30S 26E 

STEVENS 33-49 8,000 NORTH COLES SEC. 33 38 5.9 STEVENS 

LEVEE 30S 25E 

STEVENS 32-60 7,950 TEN SECTION/ SEC. 24 19 3.7 SAN JOAQUIN/ 

MAIN 30S 25E ETCHEGOIN 

STEVENS 32-60 7,950 TEN SECTION/ SEC. 30 5 14.0 SAN JOAQUIN/ 

MAIN 30S 26E ETCHEGOIN 

STEVENS 35,..55 10,000 PALOMA/MAIN SEC. 10 37 18.0 ETCHEGOIN 

32S 26E 

BENZENE IN WATER 11 
~ 

a.. 

a.. 

>-

r-

-

rz 

<I: 

:::::> 

0 

w 

z 

w 

N 

z 

w 

a:J 

20 

19 

18 

17 

16 

15 

14 

13 

12 

II 

10 

9 

8 

7 

6 

5 

4 

3 

2 

LINEAR REGRESSION OF 0API GRAVITY TO 

BENZENE QUANTITY IN PRODUCED WATER 

y:- 3.596 + 0.237 X 

. .. 

0~---~----~--~~~---T--~~~---~---~---~-------

10 /~5 / -I 

-2 

-3 

-4 

/ 

/ 

/ 

/ 

/ 

GRAVITY OIL (

0 API) 

Figure 1. The benzene quantity in produced water can be predicted by using the slope formula of the line. When the 

API gravity of the crude oil is known, that value can be substituted for the variable x and the predicted value y calculated. 

12 DIVISION OF OIL, GAS, & GEOTHERMAL RESOURCES 
20 

19 

18 

17 

16 

15 

14 

:E 13 

0.. 

0.. 

........ 12 

>- It 1-

1- 10 z 

<{ 9 :::::> 

CJ 

w 8 

z 

w 7 

N 

z 6 

w 

CD 5 

4 

3 

2 

-I 

-2 

LINEAR REGRESSION OF FORMATION DEPTH 

TO BENZENE QUANTITY IN PRODUCED WATER 

y: -0.946 + 0.000655 X. 

\ 

, 

.. 

6000 8000 10000 12000 

FORMATION DEPTH (FEET) 

Figure 2. The benzene quantity in produced water can be predicted using the formation depth. When the formation 

depth is known, that value is substituted for the variable x in the slope formula and the benzene value y calculated. 

BENZENE IN WATER OFR02(4-95-GSR1-2C) 13