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Produced Water in the Western United States: Geographical Distribution, Occurrence, and Composition

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Coproduced water is a byproduct of oil and natural gas production. Because it is in contact with hydrocarbon products and geologic formations in underground basins, it usually contains elevated concentrations of inorganic and organic constituents. This paper aims to illustrate the concentration ranges for specific contaminants and the estimated quantity of coproduced water in the Western United States. The total dissolved solids (TDS) concentration in coproduced water can vary between 1,000 mg/L and over 400,000 mg/L; however, some basins tend to have much lower median values of TDS. Sodium chloride was found to be most dominant salt found in coproduced water across all basins studied. Oil and grease, ethyl benzene, benzene, phenols, and toluene are the most common organic contaminants found in coproduced water. The total oil content in coproduced water can range from 40 mg/L to 2,000 mg/L. Understanding the composition and quantity of coproduced water is essential for assessing the viability of beneficial reuse and selecting appropriate treatment processes for the water.
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ENVIRONMENTAL ENGINEERING SCIENCE
Volume 25, Number 2, 2008
© Mary Ann Liebert, Inc.
DOI: 10.1089/ees.2007.0026
Produced Water in the Western United States:
Geographical Distribution, Occurrence, and Composition
Katie L. Benko
1,2*
and Jörg E. Drewes
2
1
U.S. Bureau of Reclamation
Denver, CO 80225-0007
Environmental Science & Engineering Division
2
Colorado School of Mines
Golden, CO 80401-1887
ABSTRACT
Coproduced water is a byproduct of oil and natural gas production. Because it is in contact with hydrocarbon
products and geologic formations in underground basins, it usually contains elevated concentrations of inorganic
and organic constituents. This paper aims to illustrate the concentration ranges for specific contaminants and the
estimated quantity of coproduced water in the Western United States. The total dissolved solids (TDS) concen-
tration in coproduced water can vary between 1,000 mg/L and over 400,000 mg/L; however, some basins tend
to have much lower median values of TDS. Sodium chloride was found to be most dominant salt found in co-
produced water across all basins studied. Oil and grease, ethyl benzene, benzene, phenols, and toluene are the
most common organic contaminants found in coproduced water. The total oil content in coproduced water can
range from 40 mg/L to 2,000 mg/L. Understanding the composition and quantity of coproduced water is essen-
tial for assessing the viability of beneficial reuse and selecting appropriate treatment processes for the water.
Key words: coproduced water; water quality; oil; natural gas; geographical distribution
239
*Corresponding author: U.S. Bureau of Reclamation, P.O. Box 25007, Denver, CO 80225-0007. Phone: 303-445-2013; Fax: 303-
445-6329; E-mail: kbenko@do.usbr.gov
INTRODUCTION
C
OPRODUCED WATER
is defined as water that is extracted
from subsurface geologic formations containing oil and
gas (Society of Petroleum Engineers, N.D.). It is estimated
that the oil and gas industry generates 10 times more water
than oil and gas (Desalination and Water Purification Tech-
nology Roadmap, 2003). Current practice for disposal of co-
produced water includes reinjection into underground for-
mations, surface discharge into receiving waters, or land
application. Reinjection is an expensive option for oil and
gas producers and can only be done when the underground
structure can accommodate the water. Surface discharge can
cause contamination of drinking water or irrigation water
supplies either underground or on the surface. When applied
to land, the excess salt commonly found in coproduced wa-
ter can make soil less permeable to air and water and reduce
the availability of nutrients in the soil (Veil et al., 2004).
The estimated amount of coproduced water generated in
the United States is between 6.1 10
6
m
3
/day and 7.8
10
6
m
3
/day (1,600 mg.day and 2,100 mg.day) (Boysen et
al., 2002; Veil et al., 2004). This amount of water is greater
than the combined daily water consumption for New York
City and Los Angeles (“More Masses Huddling, 2006; Los
Angeles Department of Water and Power, N.D.). In many
areas of the United States, fresh water supplies have been
fully allocated; therefore, additional sources of water must
be identified to meet increasing water demands (Desalina-
tion and Water . . . , 2003). In the arid regions of the West-
ern United States, treated coproduced water may relieve
stresses on conventional water supplies and provide a sta-
ble source of water during times of drought (Veil et al.,
2004). Especially the Western U.S. is currently experienc-
ing a significant growth of coproduced water production due
to the increasing interest in exploring unconventional nat-
ural gas resources (coal bed methane, oil shale, and tight gas
sands) to diversify the energy portfolio of the United States
(Stevens et al., 1998). Coal bed methane (CBM) accounts
for 7% of the total natural gas production and 8% of the gas
reserves in the United States. Development from the Rocky
Mountain states of Colorado, New Mexico, Utah, and
Wyoming accounts for nearly 8% of the total coalbed
methane production in the United States (Bryner, 2006).
Understanding the chemical characteristics of coproduced
water is important for determining appropriate treatment
technologies and optimal beneficial uses of the water. Re-
actions between dissolved constituents in the water and in-
teractions between the water and surrounding rocks or pe-
troleum can affect the composition of coproduced water
(Veil et al., 2004). The inorganic chemical characteristics
of coproduced water vary considerably depending on the ge-
ographic location and the geologic formation from which
the petroleum and water were produced. The organic con-
tent of coproduced water depends heavily on the type of hy-
drocarbon produced and exists in two forms: suspended, dis-
persed oil droplets, and dissolved organic material
(Stephensen, 1992).
The purpose of this study is to describe the current state
of knowledge regarding the chemical characteristics of co-
produced water from both conventional and nonconven-
tional oil and gas, including the inorganic and organic con-
tent, along with the estimated volume of water available
based on peer reviewed literature. Additionally, the scope
of interest for this paper is the Western United States, in-
cluding Montana, North Dakota, South Dakota, Wyoming,
Utah, Colorado, Nebraska, Kansas, Arizona, New Mexico,
Oklahoma, Texas, and California. The major oil and gas pro-
ducing basins in the Western U.S. are Williston, Powder
River, Big Horn, Wind River, Green River, Denver, Uinta-
Piceance, Paradox, San Juan, Raton, Anadarko, Permian,
San Joaquin, and Los Angeles (Energy Information Ad-
ministration, 2004). A basin is a geographically confined
depression in the earth’s surface, consisting of layers of strat-
ified rock, in which sediments accumulated and hydrocar-
bons may have formed (Van Dyke, 1997). This paper pro-
vides insight into the quantity and quality of coproduced
water originating from these 14 basins.
CONVENTIONAL OIL AND GAS
COPRODUCED WATER CHARACTERISTICS
Methodology
The U.S. Geological Survey (USGS) has published an ex-
tensive database containing the major ion analysis and total
dissolved solids for water from 58,706 oil and gas wells (pri-
marily from conventional oil and gas operations) from the
mainland U.S., Alaska, and offshore (Breit and Otton, 2002).
The database allows the user to download data by state or
region. For this work, data were used from Montana, North
Dakota, Wyoming, South Dakota, Utah, Colorado, Ne-
braska, Kansas, Arizona, New Mexico, Oklahoma, Texas,
and California. There were 33,189 wells considered in this
analysis (56.5% of the entries in the database where used).
The geologic basin is provided for each well in the data-
base. The data was reorganized by geologic basin, rather
than by state. For some basins, the total dissolved solids
(TDS) varied by geographical location and for these basins,
the data was further organized by state within the basin. The
minimum, median, first quartile, third quartile, and maxi-
mum values were calculated for each basin. Using the ma-
jor ion analysis provided by the USGS database, mil-
liequivalent concentrations were calculated for each ion. The
anion and cation with the largest milliequivalent concentra-
tion was considered the dominant salt in the water.
A limitation of the USGS database is that it does not ex-
plicitly state which wells produce oil and which produce nat-
ural gas, the lifecycle of the wells, the flow rate of water
from the well at the time of sampling, or the extraction tech-
nique used. Thus, the database is best used to draw general
conclusions about the water generated by the petroleum in-
dustry as a whole.
Inorganic constituents
Coproduced water is generally characterized as brackish
groundwater with elevated concentrations of total dissolved
solids. The inorganic constituents present in coproduced wa-
ter are primarily derived from the rock formations with which
the water is in contact; therefore, the water quality regarding
inorganic constituents is organized and presented by geologic
basin. Water from conventional oil and gas can exhibit a wide
range of TDS concentrations; 1,000 mg/L to over 400,000
mg/L. The TDS concentration range observed in coproduced
water represented in the USGS database is presented in a box
and whisker format with the minimum, first quartile, third
quartile, and maximum value of TDS within each basin (Fig.
1). The data is presented on a log-scale to accommodate the
large range of TDS values observed. For basins in which the
TDS varied significantly, TDS statistics were calculated for
each state occupied by the basin.
The Williston Basin exhibits the most geographical vari-
BENKO AND DREWES
240
ation by state of any of the basins studied. The TDS of wa-
ter samples within the Williston Basin are much higher for
the portion of the basin that lies in North Dakota. Ranges
of the most common inorganic constituents were obtained
for all basins (Table 1). The TDS concentration ranged from
1,000 mg/L to 400,000 mg/L, with a median value of 32,300
mg/L for all basins. Sodium and chloride were the ions gen-
erally found in the highest concentrations.
Data was not available for arsenic, boron, and silica; how-
ever, these constituents are important to consider when us-
ing and treating the water because boron and arsenic are not
removed by the majority of treatment processes and silica
can cause scaling problems in membrane processes.
The USGS Produced Waters Database was used to com-
pute the dominant salts present for each water sample ana-
lyzed. Sodium chloride was found to be the dominant salt
in over 76% of the coproduced water samples. The next most
common salts found in coproduced water are sodium bicar-
bonate and sodium sulfate (Fig. 2). Magnesium sulfate and
magnesium chloride were found in a high concentration in
the Big Horn Basin, Permian Basin, and Wind River Basin.
Organic contaminants
In contrast to the occurrence of inorganic constituents,
which are determined by the geology of a basin, the quan-
tity and characteristics of organic contaminants in copro-
duced water is impacted by a number of factors including
type of hydrocarbon product the water is in contact with,
volume of water production, artificial lift technique, and the
age of production. To date, no studies have been conducted
to quantify the impact of these factors on the organic con-
tent of coproduced water. The organic data presented here
was derived from sources that reported on the organic con-
tent regardless of location and type of product. Table 2 lists
the concentration ranges of organic material commonly
found in coproduced water from oil and gas operations. Ben-
zene, ethyl benzene, toluene, and phenol typically occur in
the highest concentration in coproduced water (Table 2).
The data presented in Table 2 does not distinguish between
water from oil operations and water from gas operations; how-
ever, water from gas production tends to have higher con-
centrations of low molecular-weight aromatic hydrocarbons,
such as benzene, toluene, ethyl benzene, and xylene, than wa-
ter from oil production (Jacobs et al., 1992). Detectable con-
centrations of volatile organics are found in 75 to 80% of all
gas coproduced water samples (Fillo et al., 1992). Semi-
volatile organics are rarely found in gas coproduced water
and are much more prevalent in oil coproduced water.
Coproduced water occurrence
The amount of water generated during oil and gas ex-
traction is not known exactly. Some states keep records of
COPRODUCED WATER OCCURRENCE AND COMPOSITION
ENVIRON ENG SCI, VOL. 25, NO. 2, 2008
241
Figure 1. Distribution of TDS in produced water by basin. (Note: the outline of the box represents the 1
st
and 3
rd
quartiles, the bar
in the box represents the median value, and the wisker length represents the minimum and maximum TDS values).
coproduced water volumes, but for other states, estimates
of water production are derived from oil/gas to water ra-
tios. A number of different sources have provided esti-
mates of coproduced water quantities (Boysen et al., 2002;
Veil et al., 2004; Bryner, 2006); however, there is a large
variation in the water quantities reported. Where multiple
values were obtained for water volume, the state reported
figure was used preferentially. The oil/gas to water ratio
was used only when a state figure was not available. The
total amount of water generated in within the basins pre-
BENKO AND DREWES
242
Table 1. Ranges of common inorganic constituents in coproduced water.
Number of data
Constituent Units Low High Median points considered Reference
TDS mg/L 1000 400,000 32,300 33,189 Breit and Otton, 2002
Sodium mg/L ND 150,000 9,400 33,189 Breit and Otton, 2002
Chloride mg/L ND 250,000 29,000 33,189 Breit and Otton, 2002
Barium mg/L ND 850 Unknown Unknown Breit and Otton, 2002
Strontium mg/L ND 6,250 Unknown Unknown Breit and Otton, 2002
Sulfate mg/L ND 15,000 500 33,189 Breit and Otton, 2002
Bicarbonate mg/L ND 15,000 400 33,189 Breit and Otton, 2002
Calcium mg/L ND 74,000 1,500 33,189 Breit and Otton, 2002
Note: “unknown” in table signifies information not provided by the source.
Figure 2. Dominant salts in produced water by geologic basin.
sented is estimated to vary from 106,000 m
3
/day (28 mgd)
(Veil et al., 2004) to over 1,197,000 m
3
/day (316 mgd)
(Van Dyke, 1997). Water production data, median TDS
value, and the potential for treatment was determined for
each of the major producing basins in the Western United
States (Table 3).
The potential for treatment within each basin was de-
termined based on the median TDS concentration and the
quantity of water within the basin, and is used as a pre-
liminary assessment of where desalination treatment ef-
forts should be focused on. Basins containing large quan-
tities of water with relatively low TDS are considered to
have more potential for treatment than basins producing
small quantities with elevated TDS concentrations. Addi-
tional considerations impacting the potential for reuse,
which were not considered in this study, are agricultural
activity, stream flows, population centers, and logistical
infrastructure (i.e., chemical supplies for water treatment
processes) in proximity to the water production.
COPRODUCED WATER OCCURRENCE AND COMPOSITION
ENVIRON ENG SCI, VOL. 25, NO. 2, 2008
243
Table 2. Concentration ranges of organic material in coproduced water from conventional oil and gas.
Constituent Low High Median Technique (method) Reference
TOC (mg/L) ND 1,700.000 Unknown UV Oxidation/IR (EPA 415.1) Tibbetts et al. 1992
TSS (mg/L) 1.200 1,000 Unknown Gravimetric (EPA 160.2) Tibbetts et al. 1992
Total volatile organics 0.390 35 Unknown GC/MS (EPA 1624 Rev B Tibbetts et al. 1992
(mg/L) and EPA 24 & CLP)
Total polar compounds 9.700 600 Unknown Florisil column/IR Tibbetts et al. 1992
(mg/L)
Volatile fatty acids 2000. 4,900 Unknown Direct GC/FID of water Tibbetts et al. 1992
(mg/L)
Total recoverable oil 6.900 210.0 39.800 Unknown Science Applications, 1994
and grease (mg/L)
2-Butanone (mg/L) ND 0.37 Unknown Unknown Wesolowski et al., 1986
Benzene (mg/L) ND 27 10.000 EPA Method 1624 and 624 Fillo et al., 1992
Benzoic acid (mg/L) ND 13.5 3.800 Unknown Science Applications, 1994
Bis (2-chlorethyl) ether ND 0.03 Unknown Unknown Wesolowski et al., 1989
(mg/L)
Ethyl benzene (mg/L) ND 19 1.800 EPA Method 1624 and 624 Wesolowski et al., 1989
Hexanoic acid (mg/L) ND 3.43 0.815 Unknown Science Applications, 1994
Methylene Chloride 1.410 1.71 0.179 Unknown Science Applications, 1994
(mg/L)
m-xylene (mg/L) 0.015 0.611 0.137 Unknown Science Applications, 1994
Naphthalene (mg/L) ND 0.556 0.119 Unknown Science Applications, 1994
N-decane (mg/L) ND 0.797 0.116 Unknown Science Applications, 1994
N-dodecane (mg/L) ND 2.89 0.245 Unknown Science Applications, 1994
N-hexadecane (mg/L) ND 1.11 0.298 Unknown Science Applications, 1994
N-octadecane (mg/L) ND 0.246 0.106 Unknown Science Applications, 1994
N-tetradecane (mg/L) ND 0.404 0.138 Unknown Science Applications, 1994
p-cresol (mg/L) ND 0.541 0.123 Unknown Science Applications, 1994
Phenol (mg/L) 0.009 23 NA Silylation GC/MS Tibbetts et al., 1992
Toluene (mg/L) ND 37 9.700 EPA Method 1624 and 624 Fillo et al., 1992
ND, below detection limit; unknown, information was not provided by reference.
Table 3. Coproduced water generation by geologic basin.
Median TDS Potential for
Geologic basin m
3
/day mg day
a
(mg/L)
b
treatment
Williston 18,000 4.9 132,400 Low
Powder River 370,000 97 7,300 Very high
Big Horn 360,000 94 4,900 Very high
Wind River 54,000 14 5,300 Very high
Green River 41,000 11 9,400 High
Denver 14,000 3.8 10,200 High
Uinta-Piceance 42,000 11 13,200 High
Paradox 21,000 5.6 67,000 Low
San Juan 14,000 3.6 22,700 Medium
Anadarko 34,000 8.9 132,200 Very low
Permian
c
250,000 65 89,200 Low
San Joaquin NA NA 22,700 Medium
Los Angeles NA NA 30,330 Medium
a
Boysan et al, 2002;
b
Breit and Otton, 2002;
c
for natural gas only
and for the New Mexico portion of the Permian Basin.
Water production
CBM COPRODUCED
WATER CHARACTERISTICS
Methodology
Public domain and peer reviewed papers were used to
gather data on the inorganic and organic constituents found
in coal bed methane coproduced water.
Inorganic constituents
There are significant differences in the concentrations of
major ions in coproduced water from CBM compared to
conventional oil and gas. CBM generally produces water
that has significantly lower TDS concentrations, ranging
from 300 mg/L to 15,000 mg/L (Van Voast, 2003).
Water associated with CBM has a common chemical char-
acter: minimal sulfate, calcium, and magnesium, and larger
quantities of sodium and bicarbonate (Van Voast, 2003).
Based on the solubility of calcium and magnesium in the
presence of bicarbonate, higher bicarbonate concentrations
cause calcium and magnesium to precipitate, thus explain-
ing their low concentrations in CBM coproduced water
where bicarbonate is the dominant anion (Van Voast, 2003).
There are five geologic basins that produce the majority of
the CBM in the Western U.S.: Powder River, Uinta,
Piceance, Raton, and San Juan. The TDS range for CBM
water generated in these basin is presented in Table 4. The
concentration ranges of the common ions found in CBM wa-
ter from the Powder River Basin are provided in Table 5.
Organic contaminants
The organic contaminants in water from CBM are derived
from coal. CBM coproduced water generally has no oil and
grease, and has relatively low dissolved organic carbon con-
centrations, usually varying from 2 mg/L to 10 mg/L
(Kharaka and Rice, 2003). Some of the dissolved organic
constituents known to be present in CBM water include
goitrogens, such as 2-methyl resorcinol, 5-methylresorcinol,
and hydroxypyridines. Polycyclic aromatic hydrocarbons,
such as aminophenols and aromatic amines, are also known
to leach into water from coals (Fisher and Santamaria, 2002).
To the best knowledge of the authors, no studies have at-
tempted yet to characterize dissolved organic constituents
from CBM water.
Quantity of coproduced water
The quantity and quality of coproduced water in each
basin was used to determine which basins are the most likely
candidates for treatment of coproduced water toward bene-
BENKO AND DREWES
244
Table 4. Total dissolved solids concentration for CBM producing basins.
Number of data
Basin Units Low High Mean points considered Reference
Powder River mg/L 370 1,940 15,840 47
a
Uinta mg/L 6,000 43,000 15,000 Unknown
b,c
Piceance mg/L 7,252 15,500 Unknown Unknown
d
San Juan mg/L 10,434 23,464 Unknown Unknown
d
Raton mg/L 1,100 4,600 1,500 Unknown
c,e
Unknown, reference did not provide information;
a
Rice, 2000;
b
Handbook, 2003;
c
Hightower,
ND;
d
Myers, 2005;
e
Raton Basin, 2003.
Table 5. Ranges of common inorganic constituents in coproduced water from CBM in the
Powder River Basin (Rice, 2000).
Number of data
Constituent Units Low High Mean points considered
Sodium mg/L 130 800 300 47
Chloride mg/L 6.3 64 13 47
Barium mg/L 0.14 1.6 0.62 47
Strontium mg/L 0.10 1.9 0.70 47
Sulfate mg/L ND 12 2.4 47
Bicarbonate mg/L 290 2,320 950 47
Calcium mg/L 5.9 57 32 47
ficial use. Basins exhibiting small TDS values and high wa-
ter volumes were considered to have the most potential for
reuse. The following values were compiled for water pro-
duction from CBM producing basins (Rice and Nuccio,
2000) (Table 6).
QUALITY ASSURANCE
It is noteworthy that information regarding the makeup of
coproduced water from both conventional and CBM explo-
ration are associated with a fair degree of uncertainty. Al-
though individual producers usually have a good under-
standing of quantity and quality of coproduced water from
their operations, frequently this information is not readily
available. Where possible, water quality parameters and wa-
ter quantity estimates provided in this study were obtained
from multiple sources. Additionally, these values were
checked and found to be consistent with select complete wa-
ter quality analyses from various coproduced water samples
collected and analyzed by the authors.
SIGNIFICANCE OF WATER QUALITY AND
QUANTITY TO TREATMENT
The analysis conducted in this study provides a starting
point for determining what types of treatment strategies are
appropriate for different types of coproduced water. Treat-
ment technologies need to be tailored to the types and con-
centrations of constituents present in the water, the type of
intended end-use, and the conditions under which the treat-
ment will occur. Findings of this study illustrate that the
TDS concentration of coproduced water might frequently be
unsuitable for the desired end use of the water, and desali-
nation technologies must be employed. Typical desalination
technologies that have been used or proposed to treat co-
produced water include reverse osmosis and nanofiltration,
electrodialysis, capacitive deionization, ion exchange,
chemical precipitation, and thermal or distillation processes,
and hybrid combinations of these technologies. Some of
these technologies may not be capable in achieving the de-
sired inorganic constituent removal efficiency or might ex-
hibit limitations due to the presence of organic contaminants.
Because many basins exhibit very similar water composi-
tions, appropriate treatment process combinations are
needed that meet the unique goals of coproduced water treat-
ment, such as a high degree of robustness, high water re-
covery, little need for maintenance and treatment chemicals,
minimal generation of treatment residuals, and ease of op-
eration.
Attention should also be given to certain constituents pres-
ent in the water that can be recovered and potentially sold
as a product. In some cases, these products, such as iodide,
can generate revenues that could cover the cost of the wa-
ter treatment (Xu and Drewes, 2006). Currently, informa-
tion is lacking regarding the concentrations of recoverable
products within the basins targeted in this study; these con-
stituents will need to be analyzed for on an individual ba-
sis.
CONCLUSIONS
Understanding the chemical composition and quantity of
water available provides an idea of which areas of the West-
ern U.S. have water most favorable for treatment, leading
to beneficial use. Nearly all of the water qualities presented
would require at least minimal organics removal and de-
salination to render it for beneficial use. Because the ma-
jority of coproduced waters exhibits a rather homogeneous
composition of major ions, such as sodium, chloride, sul-
fate, and bicarbonate, desalination technologies that are al-
ready well established in the water industry like reverse os-
mosis, nanofiltration, or electrodialysis or combinations of
these processes could assure a treated water quality that
meets nonpotable and potable standards. However, some of
the basins presented here have water with such high TDS
concentrations that treatment will most likely not be cost
effective. For these basins, treatment for beneficial use is
not practical, and other options need to be investigated for
disposal. Future research should be directed toward the de-
velopment of robust, low-maintenance, easy to operate,
package treatment technologies that can be employed at the
wellhead or well clusters of oil and gas production sites.
ACKNOWLEDGMENTS
The authors thank the U.S. Bureau of Reclamation Sci-
ence and Technology program for its financial support. The
authors also thank George Breit and Jim Otton with the
USGS, John Veil with Argonne National Laboratory, John
Ford with DOE NETL, and Geoff Thyne with University of
Wyoming for their advice.
COPRODUCED WATER OCCURRENCE AND COMPOSITION
ENVIRON ENG SCI, VOL. 25, NO. 2, 2008
245
Table 6. Coproduced water generation by geologic basin.
Median TDS Potential for
Geologic basin m
3
/day mg day
a
(mg/L) treatment
Powder River 170,000 46.1 15,840 Very high
Uinta 19,000 5.1 15,000 Medium
San Juan 12,000 3.2 10,000 High
Raton 13,000 3.6 1,500 High
a
Rice and Nuccio, 2000.
Water production
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... Previous estimates for the volume of produced water generated annually have ranged between 15 to 21 billion barrels for the United States alone [1,2]. The chemical composition of produced water varies and is typically saline, containing organic and inorganic compounds from the hydrocarbon reservoir and any fluids injected for disposal or to enhance oil and gas recovery [3][4][5][6]. During the early years of oil and gas development, it was common practice to dispose of produced water on the land surface in, for example, natural drainage channels and constructed impoundments [7][8][9]. ...
... Comparison of the sump water equilibration calculations to measured groundwater data shows that some historical Buena Vista Lake Bed margin samples have Cl, Na, B, Ca, SO 4 , and HCO 3 concentrations plotting near equilibrated sump water (Fig 9), indicating the samples may largely contain produced water disposed of at the land surface. Five of these samples have NO 3 concentrations greater than about 20 mg/L as N, possibly indicating a geologic source of N. Although there are no significant geologic sources of NO 3 known in Buena Vista Valley [76], sediments derived from the Coast Ranges are thought to be a source of high NO 3 in other parts of the San Joaquin Valley [134]. ...
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Groundwater resources are utilized near areas of intensive oil and gas development in California’s San Joaquin Valley. In this study, we examined chemical and isotopic data to assess if thermogenic gas or saline water from oil producing formations have mixed with groundwater near the Elk Hills and North Coles Levee Oil Fields in the southwestern San Joaquin Valley. Major ion concentrations and stable isotope compositions were largely consistent with natural processes, including mixing of different recharge sources and water-rock interactions. Trace methane concentrations likely resulted from microbial rather than thermogenic sources. Trace concentrations of benzene and other dissolved hydrocarbons in three wells had uncertain sources that could occur naturally or be derived from oil and gas development activities or other anthropogenic sources. In the mid-1990s, two industrial supply wells had increasing Cl and B concentrations likely explained by mixing with up to 15 percent saline oil-field water injected for disposal in nearby injection disposal wells. Shallow groundwater along the western margin of Buena Vista Lake Bed had elevated Cl, B, and SO4 concentrations that could be explained by accumulation of salts during natural wetting and drying cycles or, alternatively, legacy surface disposal of saline oil-field water in upgradient ephemeral drainages. This study showed that groundwater had relatively little evidence of thermogenic gas or saline water from oil and gas sources in most parts of the study area. However, the evidence for groundwater mixing with injected disposal water, and possibly legacy surface disposal water, demonstrates produced water management practices as a potential risk factor for groundwater-quality degradation near oil and gas fields. Additional studies in the San Joaquin Valley and elsewhere could improve understanding of such risks by assessing the locations, volumes, and types of produced water disposal practices used during the life of oil fields.
... The chemical composition can change widely and is influenced by their biogeochemical origin [10]. Screening and classification of a high number of formation waters from different fuel extraction wells are reported for different areas of the planet [10][11][12][13]. Their salinity ranges between few grams to hundreds of grams per liter. ...
... Medium was prepared referring to the analysis report of oilfield water produced during fuel extraction Italy [33], that we received as confidential document. Following is reported the list of its main chemical species content: 13 Medium has been prepared through dissolution of reagent grade salts as source of the above listed chemical species in milli-Q water. So prepared media has been acidified to 1.5 pH value and sterilized by filtration on 0.22 µm membrane filter. ...
Preprint
Full-text available
Microalgae cultivation for biotechnological purposes is an expanding field. Their cultivation is usually performed on a liquid culture medium and require the presence of an energy source. Culture media are water-salt solutions containing nitrogen, sulfur, phosphate sources, with trace of transition metals. Light source supplies energy through photosynthesis process, resulting in metabolic reactions and cell growth. Thanks to the huge number of existing species and their diversity, it is possible to exploit alternative water sources with chemical and physical properties far from the commonly used freshwater media. Among these, oilfield or formation waters (AFW) are saline wastewater produced during oil drilling. They represent over 95 % of the total fluids collected from gas and oil wells during fuel extraction. This study exploits the adaptation capability of a Galdieria sulphuraria strain in different salinity conditions to build up a more feasible microalgae-based platform. Batch cultivation of G. sulphuraria was evaluated in a range from 0 to 20 g/L NaCl in terms of growth rate, metabolite content, photophysiology, and intracellular redox state. Moreover, the same strain has been tested for artificial formation water growth in semicontinuous cultivation mode. In these condition, NaCl preadaptation effect has been assessed too. Results clearly demonstrate that biomass composition is influenced from medium salinity. Strains preadapted in 0 to 20 g/L range of NaCl salinity show almost same cell growth profile and a slightly different ratio between lipids, carbohydrates, and proteins. Pigments content and photophysiology point out that variations of osmotic pressure and ionic strength in medium affect Photosystem II (PSII). Regulation of light harvesting is necessary to trigger metabolism shift toward synthesis of metabolites required in the adaptation process.
... Produced water is a byproduct of oil and gas extraction that contains a wide range of impurities, including salts, oil, grease, and surfactants [1][2][3]. Produced water contains non-ionic surfactants that are added to hydraulic fracturing fluids (HFFs) [4,5] to control the viscosity of the fracturing fluid and alter the surface tension to assist in fluid recovery [6,7]. Specific details of composition and concentrations of the surfactants added to HFF are poorly described due to proprietary formulations of HFFs [4,8]. ...
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Produced water from unconventional oil and gas reservoirs often contains non-ionic surfactants that are added to the hydraulic fracturing fluid to facilitate water release and enhance gas production. This study investigates the impact of currently used surfactants (i.e., nonylphenol ethoxylates (NPEOs) and octylphenol ethoxylates (OPEOs)) and proposed alternative surfactants on the performance of membrane distillation (MD) for produced water treatment. The impact of NPEOs and OPEOs on wetting of PTFE membranes was studied as a function of their concentrations and ethoxylate (EO) chain length in a lab-scale DCMD system. Additionally, alternative surfactants, including linear alcohol ethoxylates (LAEs), branched secondary alcohol ethoxylates (BAEs), and alkyl polyglycosides (APGs), were evaluated for their potential to replace NPEOs and OPEOs. Experimental results indicate that the increase in the number of EO units in NPEOs decreased their tendency to cause membrane wetting by reducing their interaction with hydrophobic surfaces. It was also observed that LAEs and APGs that are environmentally friendly alternatives did not cause membrane wetting. This study provides valuable insights into the underlying mechanisms of surfactant-membrane interactions and offers guidelines for surfactant alternatives that can potentially improve hydraulic fracturing and lower environmental concerns while facilitating the use of MD for produced water treatment and recovery.
... Table I showed the metal contents of iron, zinc, nickel, cadmium and lead to be higher than NESEREA and WHO acceptable limits for water utilizations. The high concentration of lead is of concern because of its health effect on human and the environment (Benko and Drewes, 2008). Table 2 shows PAH distribution for the fourteen PAHs that were detected at the gas-phase for 2-6 rings PAHs. ...
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Produced water from four Delta State Community flow-stations [Ogulaha (A), Sokobolor (B), Iyokiri (C) and Okirika (D)] 10 miles apart were analyzed. They contain 35.26ppm polycyclic aromatic hydrocarbon for A, 4.57ppm for B, 60.68 for (C) and 53.00 for (D). pH values were 8.10 for A, 8.20 for B, 8.10 for C and 8.10 for D, tuibidity values were 63NTU for A, 51 for B, 47 for C and 66 for D. BOD and COD were (310.00, 121.00, 201.31 and 231.21)ppm and (810.00, 710.00, 913.00 and 810.00) ppm respectively for samples A, B, C, and D. Total organic carbon (mg/l) was 30.00, 154.00, 23.00 and 240.00 for the samples A, B, C and D. The metal concentrations of iron, zinc, nickel, cadmium and lead were higher than accepted limits of World Health Organisation (WHO) and National Environmental Standard and Regulation Enforcement Agency (NESREA) while copper, chromium and manganese were within acceptable limits.
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This study critically reviews the impact of hydraulic fracturing on water management and quality, emphasizing environmental, economic, and sustainability challenges. Hydraulic fracturing, essential for extracting hydrocarbons from unconventional reservoirs, requires significant water volumes, often competing with local water demands. The study explores the use of produced water as an alternative to freshwater, examining its potential to alleviate water scarcity while mitigating environmental risks. It identifies key challenges such as contamination from hydraulic fracturing fluids, harmful substances in produced water, and groundwater migration. Additionally, the review highlights advanced water treatment technologies, including reverse osmosis and thermal methods, for addressing the high salinity and toxicity of wastewater. Strategies for recycling and reusing produced water are analyzed to reduce freshwater dependency and improve operational efficiency. The paper also discusses innovative approaches like alternative fracturing fluids and non‐aqueous additives to further enhance sustainability. Findings underscore the critical need for comprehensive water management strategies that balance resource extraction with environmental protection. Recommendations include stricter regulations, technological advancements, and adopting best practices to minimize ecological and public health risks. By addressing these challenges, the study aims to contribute to sustainable hydraulic fracturing operations that ensure the long‐term viability of unconventional oil and gas development.
Conference Paper
Oil and gas production uses large volumes of water for injection during polymer flooding and hydraulic fracturing operations. The same operations generate large volumes of wastewater, of which produced formation water and flowback water make up the dominant volumes. The availability of fresh water is a growing challenge in many regions of the world and major oil companies take these challenges seriously and recognize their need to preserve fresh water. They report operations in water-scarce areas in their annual sustainability reports and they strive to reduce and ideally eliminate freshwater intake for their operations by increasing recycling capacity. Reusing high salinity water for hydraulic fracturing and polymer flooding applications is a challenge as high salinity water negatively impacts the economics and success rate of these treatments as the apparent viscosity of standard HPAM is affected by the high salinity. Desalination of these high salinity water sources can be executed by thermal desalination techniques which are not cost effective at these large water volumes. Altering the HPAM polymer by adding ATBS or AMPS monomer instead will enhance the viscosity and stability of the polymer solutions at high salinity. These sulfonated polymers showed excellent performance in using saline water in hydraulic fracturing operations, where friction reduction during injection and proppant carrying capacity are the main requirements. When using the right fraction of ATBS/AMPS monomers in the polymer, high salinity (even combined with high temperature) reservoirs can be flooded with sulfonated polymer solutions to obtain increased recovery as indicated by a field case.
We measured organic compound emissions from a produced-water, evaporative disposal facility's oil-water separation vault in May 2022 and March-May 2023. Produced water is water pulled from the subsurface of a well along with the oil and natural gas; some produced water is disposed of by allowing it to evaporate from surface impoundments. The vault measured in this study separated residual oil from produced water before evaporative disposal. Because the vault's surface contained many potential small emission sources, we used a large plastic chamber to cover the entire vault and simultaneously capture all emissions. We also measured organic compounds in ambient air upwind and downwind of the vault and estimated emissions via a backward Lagrangian stochastic model (Windtrax). The total non-methane organic compound (TNMOC) emission rate from the vault ranged from 0.27 to 3.05 kg/h, averaging 1.99 kg/h in 2022 and 0.49 kg/h in 2023. The average TNMOC emission rate determined by the bLS method was 48% higher than the emission rate determined by the chamber method in 2023 (average of 0.73 kg/h). Still, the range of the chamber results fell within the range of TNMOC emissions from the model. Methanol emissions were much higher than the bLS method, averaging 85.3 g/hr, but were highly variable. We surmise that the water condensation on the chamber retained methanol and biased the results low. The extrapolated annual average emissions of methane, TNMOC, and methanol from the vault were 0.1, 15.5, and 1.4 U.S. tons/yr, respectively, within the range of emissions from uncontrolled oil storage tanks. The extrapolation considers bias in the chamber method and differences across the two years of measurements.Implications: The findings from our study indicate that emissions of non-methane organic compounds (TNMOC) from the oil-water separation vault at the produced-water evaporative disposal facility exhibit significant variability between years, with a notable decline in average emissions from 2022 to 2023. The higher emission rates recorded using the backward Lagrangian stochastic (bLS) model compared to the chamber method suggest that further investigation into measurement techniques is warranted to ensure accurate assessments of emissions. Additionally, the substantial variability in methanol emissions highlights the need for more controlled conditions during sampling to avoid potential biases. Overall, these results imply that while emissions from the vault are within the range of those from uncontrolled oil storage tanks, there is an ongoing necessity for improved monitoring and regulatory practices to mitigate environmental impacts associated with produced water disposal.
Article
Full-text available
Produced water is the largest waste byproduct from the oil and gas industry with elevated levels of salts, metals, and organic constituents. This comprehensive review summarizes (1) the potential impact, (2) produced water management, and (3) identifies current research thrust areas in future efforts. Complementary treatment systems involving chemical and biological techniques offer significant advantages. The review emphasizes the application of these technologies and their performance in meeting regulatory standards. Cost, energy consumption, chemical use, and operational complexity are recognized challenges in both the water treatment industry and the oil and gas industry. It highlights the need for further research and for the optimization of processes to enhance their efficiency. The integration of conventional methods with advanced treatment processes is also explored, with a vision toward developing hybrid systems for improved treatment efficiency. Overall, complementary systems show great promise for the treatment of produced water, but further advancements, sustainability considerations, and integration with other technologies are essential for their successful implementation in large-scale applications. Maintaining expertise and awareness of water treatment issues in the oil and gas industry can help reclamation identify new technologies and solutions to technical challenges that may benefit the oilfield water treatment industry.
Article
Full-text available
Decisions concerning the disposal or use of waters produced during the production of coal bed methane (CBM) are typically made based on water quality as expressed by the water's salinity and/or inorganic ionic constituency. The quality of CBM water is frequently evaluated in terms of its suitability for irrigation. Water that has an acceptable salinity and sodium adsorption ratio (SAR) is considered safe for surface discharge and for potential injection into a drinking-water aquifer. It is important to remember, however, that water associated with coal seams, independent of its inorganic constituents, may contain dissolved organics and other constituents at levels that may adversely affect human health and the environment. It is well known that coal, lignite, or coaly materials present in aquifers used as drinking-water supplies are associated with adverse or potentially adverse human health effects. Water produced from coal- associated aquifers has been linked, or is suspected to be linked, to goiter, Balkan Endemic Nephropathy (BEN), multiple sclerosis, and increased rates of cancer morbidity and mortality. Water-soluble organic compounds found in coals include goitrogens such as the hydroxyphenols resorcinol, 2-methyl resorcinol, and 5-methylresorcinol (orcinol), as well as hydroxypyridines. Well waters containing polycyclic aromatic hydrocarbons (PAHs), aniline, aminophenols, and aromatic amines leached from low-rank Pliocene coals may be the cause of, or a contributing factor to, BEN, an incurable interstitial nephropathy that is believed to have killed more than 100,000 people in the former Yugoslavia alone. There are few, if any, systematic and comprehensive analyses of dissolved organic compounds in CBM-produced water. Prudence suggests that the dissolved organic constituents in CBM-produced water should be systematically characterized, and their potential for harm to human health and the environment be evaluated before potentially harmful chemicals are discharged to the environment or released to drinking-water aquifers.
Chapter
Produced water is the single largest volume source of waste produced by the oil and gas industry. These waters are generated as a result of crude oil and natural gas production, including both onshore and offshore sources. Unconventional sources of natural gas, such as coalbed methane also generate water upon production of the gas. Produced waters are also generated along with the withdrawal of natural gas from underground storage reservoirs.
Chapter
Concomitant with the production of oil from North Sea oilfields is the recovery of water associated with the oil in the reservoir. Produced oil and water are usually separated on the production platform before the oil is pumped ashore via a pipeline. The separated water is discharged overboard into the sea. In 1990 approximately 159 × 106 tons of produced water were discharged in the UK sector of the North Sea (HMSO, 1991). The current study is concerned with the detailed characterization of produced waters on the Murchison (block 211/19) and Hutton TLP (block 211/28) platforms in the Northern North Sea, both of which are operated by Conoco (UK) Limited. The proportion of water to oil production during the lifetime of the reservoir is not constant. In the early stages of production from the reservoir, the water cut is low (zero to a few percent) with a constant increase until production is no longer economically feasible (80% or so). During the lifetime of a reservoir water-injection (water flooding) is usually practiced during part of the production with “breakthrough” water contributing to the produced water. Both Murchison and Hutton have been under water flood for several years; Murchison has been under pressure maintenance (water flood) since 1981 and Hutton since 1985. Currently Murchison produces 180,000 barrels per day (bpd) and Hutton 130,000 bpd of water. Produced waters discharged from these platforms comprise a variable mixture of formation water, injection water and deck drainage, which may include lubricating oil, grease and diesel from leaks and spillages.
Article
One of the key missions of the U.S. Department of Energy (DOE) is to ensure an abundant and affordable energy supply for the nation. As part of the process of producing oil and natural gas, operators also must manage large quantities of water that are found in the same underground formations. The quantity of this water, known as produced water, generated each year is so large that it represents a significant component in the cost of producing oil and gas. Produced water is water trapped in underground formations that is brought to the surface along with oil or gas. It is by far the largest volume byproduct or waste stream associated with oil and gas production. Management of produced water presents challenges and costs to operators. This white paper is intended to provide basic information on many aspects of produced water, including its constituents, how much of it is generated, how it is managed and regulated in different settings, and the cost of its management.
Article
Formation waters associated with coalbed methane have a common chemical character that can be an exploration tool, regardless of formation lithology or age. Effectively devoid of sulfate, calcium, and magnesium, the waters contain primarily sodium and bicarbon- ate and, where influenced by water of marine association, also contain chloride. The distinct geochemical signature evolves through the processes of biochemical reduction of sulfate, enrichment of bicarbonate, and precipitation of calcium and magnesium. Cation exchange with clays may also deplete the dissolved calcium and magnesium, but is not prerequisite. Low sulfate/bicarbonate ratios characterize these waters and are also common but less pronounced with occurrences of conventional oil and gas. Waters rich in sulfate, calcium, and magnesium occur in many coalbed aquifers but are not found in association with methane. Users of total dissolved solids data should ensure that the val- ues reflect adjustments of bicarbonate concentrations to simulate evaporation residues. Results that erroneously sum the entire bi- carbonate content can be far too high in these bicarbonate-rich wa- ters, thereby exacerbating the issues of disposal. Evaluations of prospects and choices of exploration targets can be enhanced by an added focus on the geochemical signature that should be expected in association with methane. Knowledge of the geo- chemical signature may also be useful in the commonly protracted testing of wells. The appearance of high sulfate concentrations in water analyses can justify early curtailment of test pumping and can prompt the siting of subsequent drill holes farther from areas of recharge.
Article
This report presents the results of a nationwide characterization program for produced waters from underground natural-gas-storage operations. In all, seven produced-water samples from seven different sites were collected and analyzed. The results of the program indicate that the characteristics and volumes of production waters from storage facilities are highly variable, site-specific, and most likely dependent on the characteristics of the storage formation. In general, the produced waters from storage facilities sampled in the program contained volatile organics and, to a lesser degree, selected semivolatile organics. Selected minor and trace elements also were present in the produced-water samples. Chloride and total dissolved solids were the most-predominant conventional parameters detected. Produced waters did not generally exhibit current RCRA hazardous-waste characteristics. The predominant method used to dispose of these waters is underground injection into Class II wells regulated under the Safe Drinking Water Act.
Article
Coal-bed methane (CBM) wells currently produce close to one billion bbl of water annually and deliver about 8% of total natural gas in the USA. The salinity of this produced water generally is lower than that of water from conventional petroleum wells; salinity commonly is 1,000-20,000 mg/L, but ranges from 200 to 150,000 mg/L TDS. Most CBM wells produce Na-HCO3-Cl type water that is low in trace metals and has no reported NORMs. This water generally has no oil and grease and has relatively low (2-10 mg/L) dissolved organic carbon (DOC), but its organic composition has not been characterized in detail. The water is disposed of by injection into saline aquifers, through evaporation and/or percolation in disposal pits, road spreading, and surface discharge. Water that has low (<1,000 mg/L TDS) salinity and sodium adsorption ratio (SAR) is considered acceptable for irrigation, surface discharge and for injection into freshwater aquifers. Because groundwater associated with coal, especially with lignite and subbituminous coal, is known to contain a variety of toxic or potentially toxic organics, including hydroxyphenols and PAHs, the organic and inorganic compositions of CBM waters should be systematically characterized and their potential for harm to human health, crops and the environment carefully evaluated prior to its addition to existing water supplies. As an alternative to costly disposal, lower salinity produced water from high-yield CBM wells is being considered for reclamation. The treated water would be a valuable new water resource, especially in the arid western USA. The feasibility and cost of reclaiming produced water to meet irrigation, industrial and drinking water standards was evaluated in a 10 gpm pilot field study. The estimated treatment cost was high at about 0.39/bbl (3,000/acre-ft) for potable water, but would be substantially lower and competitive for irrigation and industrial uses in some arid regions of the USA.
Article
Produced water management has become one of the key factors to sustainable development of natural gas/oil resources. The substantial quantities of saline water present intractable environmental threats and also increase oil/gas production costs through produced water disposal such as deep well reinjection. Developing high-efficient and flexible treatment systems that can be operated at low costs is of high interests for producers and state regulators. Beneficial use of produced water could represent a new water resource especially for areas with inadequate existing supplies. Furthermore, some produced waters generated are also characterized by elevated concentrations of recoverable constituents, for example iodide. Recovering iodide from brine could offer additional benefits besides providing methane gas, reusing produced water, or reducing brine disposal volume.