### MEMORANDUM

TO: Lisa Biddle, EPA

FROM: Sarah Yates, Brent Ruminski, ERG

DATE: March 3 1 , 201 5

SUBJECT: Unconventional Oil and Gas (UOG) Drilling Wastewater Memorandum

(DCN SGE 00740)

T his memorandum describes the data and methods that ERG used to compile oil and gas drilling wastewater volume s and characterization d ata for the Technical Development Document (TDD) for Proposed Effluent Limitations Guidelines and Standards for Oil and Gas Extraction ( DCN SGE00704 ). In addition to explanations of data compilation and analys e s, this memorandum provides discussions about types of oil and gas drilling fluids

, unconventional oil and gas ( UOG 1 ) drilling wastewater volumes (per well)

, UOG drillin g wastewater characteristics, and UOG drilling wastewater management practices

. The focus of this memorandum is on drilling wastewater generated by UOG wells.

Table 1 lists the tables and figures in this memorandum along with the corresponding

TDD table or figure number and underlying supporting memo from which the figure/table was generated. For those fig ures/tables ERG generated specifically for this memorandum, th e underlying data and analysis are contained in the Microsoft Excel A ttachment 1 (DCN

SGE00740.A 0 1)

. Other t ables and figures in the TDD that were not derived in Attachment 1 did not require calc ulations and/or analyses by ERG or are described in separate, supporting memoranda. Appendix F of the TDD contains a crosswalk of all tables and figures in the TDD and the name of the relevant supporting memorandum, where applicable.

This memorandum will r efer to the following terms used throughout the TDD, the supporting memoranda, and memoranda attachments:

 Unconventional oil and gas (UOG) resources 2

- crude oil and natural gas 3 produced by

wells drilled 4 into low porosity, low permeability formations. Development of UOG resources often requires hydraulic fracturing of the reservoir rock by injecting large amounts of fracturing fluid at high pressures to create a network of fissures in the rock formations, giving the oil and/or natural gas a pathway to travel to the well for extraction.

1 In the TDD

, EPA defines UOG as crude oil and natural gas produced by wells drilled into low porosit y, low permeability formations which includes s hale and tight oil and gas resources. While coalbed methane (CBM) is

sometimes referred to as an unconventional resource in literature, it is not included in EPA’s definition.

2 UOG resource types are categorized into shale and tight formations.

3 Natural gas can include “natural gas liquids,” components that are liquid at ambient temperature and pressure.

4 UOG wells may be drilled using horizontal, vertical, or directional well trajectories. Literature sometimes refers to well trajectory as “drill type”.Memorandum

March 3 1 , 201 5 Page 2

 Drilling wastewater

- the liquid waste stream separated from recovered drilling fluid (e.g., mud) and drill cuttings during the drilling process. Drilling fluid is the circ ulating fluid used in the rotary drilling of wells to clean and condition the hole and to counterbalance formation pressure.

 UOG extraction wastewater

- sources of wastewater pollutants associated with production, field exploration, drilling, well completi on, or well treatment. 5 UOG extraction wastewater includes produced water, drilling wastewater, and produced sand 6

.

 Produced water

– the water (brine) brought up from the hydrocarbon

- bearing strata during the extraction of oil and gas. This can include for mation water, injection water, and any chemicals added downhole or during the oil/water separation process. Based on the stage of completion and production the well is in, produced water can be further broken down into the following components:

o Flowback

– t he produced water generated in the initial period after hydraulic fracturing (i.e., fracturing fluid, injection water, any chemicals added downhole, and varying amounts of formation water). After the hydraulic fracturing procedure is completed and pressure is released, the direction of fluid flow reverses, and the fluid flows up through the wellbore to the surface. The water that returns to the surface is commonly referred to as “flowback.” Flowback is typically reported as a percentage of fracturing fluid volume in literature and by industry. 7

o Long

- term produced water (LTPW)

– the produced water generated during the production phase of the well after the initial flowback process. Long

- term produced water includes increasing percentages of formation water tha t make up the total volume of long

- term produced water. Long

- term produced water continues to be produced throughout the lifetime of the well and is usually reported in terms of flow rates in literature and by industry. 8

5 Stormwater is not considered a source of UOG extraction wastewater. In general, no NPDES permit is req uired for discharges of stormwater from any field activities or operations associated with oil and gas production, except as specified in 40 C.F.R. 122.26(c)(1)(iii) for discharges of a reportable quantity or that contribute to a violation of a water quali ty standard . States may impose additional requirements for management of drilling site stormwater.

6 Drilling wastewater and produced sand are not discussed in this memorandum. Additional information about drilling wastewater can be found in ERG’s Unconve ntional Oil and Gas Drilling Wastewater memorandum (DCN SGE00740).

7 ERG analyzed flowback in terms of percent of fracturing fluid volume as opposed to rate because the flow rate changes rapidly over time during flowback making it difficult to summarize.

8 ERG analyzed LTPW in terms of flow rates because these rates do not vary significantly over time. In addition, LTPW is generated over the entire life of the well, a period of time that varies significantly by well. Because well life is highly variable, E RG did not convert LTPW flow rates to a total volume.Memorandum

March 3 1 , 201 5 Page 3

Table 1

. List of Tables and Figures Discussed in this Memorandum

TDD Table or Figure

Number Memo Table or Figure Number and Title Memo

. Section Underlying

Supporting

Attachment

Figure C

- 1 Figure 2

. UOG Extraction Wastewater Volumes

Breakdown by Drill Type for UOG Wells in Pennsylvania (2004

– 2013) 2.1 SGE00739.A 0 3 a

Table C

- 4 Table 2

. Average Drilling Wastewater Volumes for

Horizontal and Vertical Oil and Gas Wells in Pennsylvania 2.1 SGE00739.A 0 3 a

Table C

- 5 Table 3

. UOG Drilling Wastewater Volumes Generated

per Well by Formation 2.1 SGE00740.A 0 1 b

Table C

- 10, C

- 12, C

- 14,

C

- 16, and C

- 18 Table 4

. Concentrations of Constituents in UOG Drilling

Wastewater from Marcellus Shale Wells 2.2 SGE00740.A 0 1 b

Figure D

- 2 Figure 3

. UOG Drilling Wastewater Management and

Disposal Methods 3

-- a

Figure D

- 3 Figure 4

. Management of UOG Drilling Wastewater

Generated by UOG Wells in Pennsylvania (2008

– 2013) 3 SGE00739.A 0 3 c

a

— This figure was generated by ERG for the purpose of this memorandum and the TDD but does not appear in any

attachment.

b

— These figures/tables were g enerated in this memorandum. The underlying data and analyses are contained in Attachment 1 (DCN SGE00740.A 0 1).

c

— These figures/tables were generated in another supporting memorandum (DCN SGE00739)

.

1. O VERVIEW OF O IL AND G AS D RILLING F LUIDS

Drilling fluid is the circulating fluid used during the rotary drilling of oil and gas wells to clean and condition the hole and to counterbalance formation pressure. During drilling, well
operators circulate drilling fluids down the wellbore to cool the drill bit and to remove fragments of rock (i.e ., drill cuttings) 9 from the wellbor e. O ther purposes of drilling fluids include: reduc ing friction between the drilling string and the sides of the hole, prevent ing inflow of fluids from the formation into the hole, cool ing the rotor and drill bit, transmit ting sensor readings from navigational tools, and providing stability to the borehole while drilling ( DCN SGE00090, DCN

SGE00 635 ; DCN SGE01009 ).

Figure 1 provides an overview of how oil and gas operators use drilling fluid. During the drilling process, drilling fluid (i.e., mud) is injected down the well bore where it collects the drill cuttings. The drilling fluids are circulated bac k up the well bore to the surface where the cuttings

are removed using shakers, desilters and centrifuges . The drilling fluid is then reinjected down

the wellbore. T he drilling fluids may be continuously recycled until the end of the drilling

process with this closed

- loop process while cuttings are managed and/or disposed of when they

are removed at the surface ( DCN SGE00090; DCN SGE00 635 ; DCN SGE01009 ).

9 The particles generated by drilling into subsurface geologic formations and carried out from the wellbore with the drilling fluid.Memorandum

March 3 1 , 201 5 Page 4

Source: DCN SGE00801

Figure 1 . Drilling Fluid Circulation

1.1 Types of Drilling Fluids

There are four general types of drilling fluids:

 Compressed gases ;

 Water

- based drilling fluid ;

 Oil

- based drilling fluid ; and

 Synthetic oil

- based drilling fluid

.

Operators may use a combination of these drilling fluids while d rilling a single well. The drilling fluid used typically depends on the properties of the formation, well depth, associated regulations, and cost considerations ( DCN SGE01009 ) . While drilling, operators must ensure that the weight of the drilling fluid on the bottom of the well bore exceeds the pressure within the

formation. Pressures increase as well depth increases along with the likelihoo d of encountering gas pockets . At shallow depths during well drilling , where pressure and temperature are typicallyMemorandum

March 3 1 , 201 5 Page 5

low, drillers use compres sed gases because they are the least expensive

. As the well is drilled deeper

, pressures and temperatures increase

, requiring heavier drilling fluids (e.g., fresh water,

water

- based, or oil

- based fluids ) (DCN SGE00 635 )

.

The following list provides an overview of a typical drilling process in terms of the well depth versus the type of drilling fluid that operators might use

.

1. Shallow D epths: (e.g., 0

– 1,000 feet) Pressurized air is often used to drill vertically through t he drinking water aquifer ( DCN SGE00 635 ; DCN SGE00345;

DCN SGE00280; DCN SGE00774 ; DCN SGE00090

, DCN SGE01009 )

.

2. Shallow to Medium Dep ths: (e.g., 1,000

– 3,500 feet) As the vertical section of the well is drilled deeper, operators switch over to water

- base d drilling fluids

. The purpose of the drilling fluid (e.g., cooling, stability) becomes more critical to account for increased pressure, temperature , and potential for pressurized gas pockets at these depths ( DCN SGE00 635 ).

3. Medium to Deep De pths: (e.g., 3 ,500 feet and deeper) At some depth, operators may switch to oil

- or synthetic

- based fluids as the vertical section of the well is drilled deeper and pressure , temperature , and potential for pressurized gas pockets continue to increase ( DCN SGE00 635 ). However, synthetic

- based fluids are not always used depending on the final depth and/or operator preference.

4. Formation D epth s ( i.e., Horizontal Leg ) : For horizontal ly

- or directional ly

drilled UOG wells, operators will continue to use the same drilling f luid they used at “medium to deep” depths for the directional or horizontal leg

. Operators may

use water

- , oil

- , or synthetic oil

- based drilling flu ids for this portion of the well drilling (DCN SGE00 635 )

.

Operators add chemicals to water

- and oil

- based drilling fluids to give the fluid its desired characteristics for drilling deeper, where pressure and temperature are higher relative to shallow depths. The following subsections describe the primary types of drilling fluids in more

detail

, including specific additives that may be used

.

1.1.1 Compressed Gases

Compressed or pressurized air is often used as drilling fluid for shallow wells, for drilling through the drinking water aquifer, or for rapid drilling through stable, hard rock formation s (DCN SGE00 635 )

. D ry air, nitrogen gas, mist, foam and aerated fluids are included in this
category (DCN SGE01009)

. The relatively low pressure of the gases (compared to water

- based drilling fluids) minimizes losses of drilling fluid into the ground and generates a r apid rate of penetration.

1.1.2 Water

- based Drilling Fluid

Water

- based drilling fluids are more stable than compressed gases and are used at

medium depths. However, they are also more expensive to use than compressed gases. Water

-Memorandum

March 3 1 , 201 5 Page 6

based fluids include water or a water miscible fluid as the suspending medium for solids. Water

based fluids may contain the following additives (DCN SGE 00 635 ; DCN SGE01009 ):

 Gels to enhance cutting

- carrying properties ;

 Lime to control pH ;

 Polymers to prevent exces sive seepage into the f ormation;

 Salt s to increase density and conductivity to allow the operator to analyze downhole

conditions via electric currents ; and/or

 Barite (barium sulfate), as needed, to add weight to the fluid

.

1.1.3 Oil

- based Drilling Fluid

Oil

- based drilling fluids use oil as their continuous phase with water as the dispersed phase. The oil is often diesel or mineral oil

. Oil

- based fluids are more effective than water

- based

fluids at performing the primary functions of drilling fluids ; howev er, they are also more expensive. Oil

- based fluids better prot ect the formation from swelling, provide better weight

control , and degrade less rapidly than water

- based fluid. Oil

- based fluids may contain the following additives (DCN SGE 00 635 ; DCN SGE01009 ) :

 Emulsifiers to keep water and fluid together ;

 Gels to enhance cutting

- carrying properties ; and /or

 Barite, as needed, to add weight to the fluid

.

1.1.4 Synthetic oil

- based Drilling Fluid

Operators may also use synthetic oil

- based drilling fluids which are tech nically equivalent to oil

- based drilling fluids described in Section 1.1.3 in that they are designed f or dri lling at deep depths (e.g., horizontal laterals of wells ) (DCN SGE01009). However, instead of using diesel oil and/or mineral oils, synthetic oil

- based fluids use organic fluids (e.g., esters, polyeolefins, acetal, ether, and linear alkyl benzenes) that exhibit similar fluid properties as

diesel and mineral oil s. Synthetic

- oil

- based fluids have been referred as more environmentally friendly 10 than oil

- based fluids but are also more expensive ( DCN SGE01009)

. Synthetic

- based oil drilling fluids have lower toxicities, lower concentrations of certain priority polluta nts 11

, lower bioaccumulation potential, and faster biodegradation rates than oil

- based drilling fluid ( DCN SGE01006; DCN SGE01009 ). T he organic additives used in synthetic oil

- based fluids are

less toxic than the diesel and/or mineral oils used in oil

- based drilling fluids (DCN SGE01009). Synthetic oil

- based drilling fluids also result in a smaller volume of drilling wastewater that operators need to manage or dispose of

.

10 Using synthetic

- oil

- based drilling fluids results in a lower volume of wastewater that must be disposed of. They also have lower toxicities, lower concentrations of certain priority pollutants, lower bioaccumulation potential, and faster biodegradation rates than oil

- based drilling fluid.

11 These i nclude polynuclear aroma tic hydrocarbons (PAHs) that are priority pollutants in Appendix A to 40 CFR 423. These pollutants are constituents in oil

- based drilling fluids but not in synthetic oil

- based drilling fluids.Memorandum

March 3 1 , 201 5 Page 7

2. V OLUMES AND C HARACTERISTICS OF UOG D RILLING W ASTEWATER

Drilling wastewater is the liqui d waste stream separated from recovered drilling fluid 12
(mud) and drill cuttings during the drilling process

. As explained in Section 1 , operators are able

to circulate the same drilling fluid down the wellbore multiple times while drilling a single well. This is accomplished by removing the solids (i.e., drill cuttings) 13 from the drilling fluid on the well pad . However, at some point the drilling fluid is no lo nger usable and must be managed or disposed of by the operator

.

This section summarizes UOG drilling wastewater volume and characterization data from

available literature. Section 4 includes descriptions of the analyses that ERG performed to generate the data presented.

2.1 Volumes of UOG Drilling Wastewater

On a per well basis, UOG drilling wastewater accounts for a small portion of the total

UOG extraction wastewater compared to produced water. Figure 2 shows a breakdown of UOG extraction wastewater volumes generated from Marcellus shale wells in Pennsylvania based on data from Pennsylvania Department of Environmental Protection’s (PA DEP) statewide waste reports (DCN SGE00188) for all wells active between 2004 and 2013

. An explanation of how ERG generated Figure 2 is described in a separate ERG memorandum: Analysis of PA DEP Waste Reports (DCN SGE00739). 14 On average

, drilling wastewater contributes seven percent
or less of total UOG extraction wastewater on a per well basis for UOG wells in Pennsylvania

. In Figure 2 , produced water is shown as its two primary components: flowback 15 and long

- term produced water 16

. The ratio of drilling wastewater to flowback and long

- term produced water varies by formation and sometimes within the formation (DCN SGE00704).

12 As described in Section 1 , drilling fluid is the circulating fluid used in the rotary drilling of wells to clean and condition the hole and to counterbalance formation pressure.

13 The particles generated by drilling into subs urface geologic formations and carried out from the wellbore with the drilling fluid.

14 ERG analyzed the quantity and type of wastewater (e.g., drilling wastewater, long

- term produced water) as reported by operators in the PA DEP waste reports (DCN SGE0073 9).

15 Flowback is the produced water generated in the initial period after hydraulic fracturing (i.e., fracturing fluid, injection water, any chemicals added downhole, and varying amounts of formation water).

16 Long

- term produced water is the produced water generated during the production phase of the well after the initial flowback process. Long

- term produced water includes increasing percentages of formation water that make up the total volume of long

- term produced water.Memorandum

March 3 1 , 201 5 Page 8

Source: DCN SGE00739 ; DCN SGE00739.A 0 3

Figure 2 . UOG Extraction Wastewater Volumes Breakdown by Drill Type for UOG Wells

in Pennsylvania (2004

– 2013) (TDD Figure C

- 1)

N early all of the drilling fluid used during drilling is recovered during the drilling process

as drilling wa stewater (DCN SGE 00625). 17 The volume of drilling fluid required in the drilling

process varies with the length of the wellbore

. The longer the wellbore, the more drilling fluid is required. For example, UOG wells that are drilled horizontally typically generate higher volumes of drilling wastewater than UOG wells that are drilled vertically

. Table 2

, based on PA DEP’s waste reports from 2004 to 2013 (DCN SGE 00739) , supports these generalizations

.

Table 2

. Average Drilling Wastewater Volumes for Horizontal and Vertical Oil and Gas Wells in Pennsylvania (TDD Table C

- 4)

Resource Type Drill Type Average Drilling Fluid Volume per Well (gallons) Range of Drilling

Fluid Volume per Well (gallons) a Typical Total

Measured Depth b
(feet) Number of Data

Points

UOG (shale) Horizontal 9 3 ,000 3,2 00

– 210 ,000 10,000

– 11,000 3,055

UOG (shale) Vertical 89 ,0 00 5

, 0 00

– 210 ,000 6,000

– 7,000 209

Source: DCN SGE00739. A 0 3

a

— These ranges are based on the 10 th and 90 th percentile of volumes reported for individual wells.

b

— T otal measured depth is the true length of wellbore drilled (i.e., sum of the vertical and horizontal).

Table 3 shows volumes of drilling wastewater generated per well by UOG formation sorted from highest volume to lowest

. Existing l iterature often reports total drilling fluid volume used per well rather than the drilling wastewater volume generated per well. As previously explained , operators confirmed that nearly all of the drilling fluid is recovered during the drilling

17 Some of the drilli ng fluid volume may be lost in the cuttings, to evaporation, and/or to seepage into the formation but one operator reported these losses to be minimal.Memorandum

March 3 1 , 201 5 Page 9

process as wastewater (DCN SGE 00625 ). Therefore, Table 3 presents all volumes as drilling wastewater volumes regardless of whether it was reported as drilling wastewater or drilling fluid

in the literature

. M ost data sources reported volumes withou t an indication of the well trajectory (i.e., hori zontal, vertical, directional). As explained above, drilling fluid/wastewater volumes generally increase with the total measured depth. Therefore

, Table 3 also presents the typical total measured depths for each formation that are reported in literature

.

Table 3

. UOG Drilling Wastewater Volumes Generated per Well by Formation (TDD

Table C

- 5)

Resource Type Formation Drilling Wastewater Volume (Gallons) Typical Total

Measured Well Depth b (feet) Number of

Data Points Range (Min

– Max) Median

Shale Haynesville &

Bossier 420,000

-

1,100,000 600,000 1 3 ,000

– 1 9 ,000

5

Tight Anadarko Basin 200,000

- 420,000 310,000

-- c 2

Shale Niobrara

-- a 300,000 7

, 5 00

– 1 3 ,000 1

Shale Barnett 170,000

- 500,000 250,000 8

, 5 00

– 1 4 ,000 6

Shale Permian 84,000

- 420,000 210,000

-- c 8

Tight Cleveland

-- a 200,000

-- c 1

Tight Granite Wash

-- a 200,000

-- c 1

Shale Eagle Ford 130,000

- 420,000 160,000 6 ,000

– 1 6 ,000 7

Shale Utica

-- a 100,000 6 ,000

– 1 9 ,000 1

Tight Mississippi Lime

-- a 100,000

-- c 1

Shale Marcellus 2,400

– 170,000 92,000 7

, 300

– 13 ,000 2,072

Source: See Attachment 1 (DCN SGE00740.A 0 1)

.

a

— ERG identified only one data point for these formations. Therefore, there is no range to display.

b

— Total measured depth is the true length of wellbore drilled (i.e., sum of the vertical and horizontal).

c

— Information is unknown.

2.2 C haracteristics of UOG Drilling Wastewater

S everal categories of constituents are present in most types of oil and gas drilling

waste water (DCN SGE 00733):

Salt ( typically measured as t otal dissolved s olids or electrical conductivity); Oil and grease ; I norganic and organic compounds; and

C hemical additives used during drilling

.

ERG has identified less i nformation in the public literature on UOG drilling wastewater

characteristics , as compared to information that has been found on UOG produced water

characteristics

. All of the data ERG located on UOG drilling wastewater was specific to the

Marcellus Shale. Table 4 present s typical concentrations of select constituents that are frequently reported in UOG drilling wastewater from Marcellus shale wells

. Where multiple data points (i.e., samples) were available, Table 4 show s the range and median concentrations associated with each parameter and the associated number of data points. Constituents are grouped andMemorandum

March 3 1 , 201 5 Page 10

sorted by pollutant categories. Table 4 contains all of the drilling wastewater characterization data provided in Table C

- 10, Table C

- 12, Table C

- 14, Table C

- 16, and Table C

- 18 of the TDD

.

As shown in Table 4

, TSS concentrations can vary significantly in drilling wastewater

. This is likely dependent on how efficiently the drill cuttings are removed by the operator d uring the drilling process (see Figure 1 in Section 1 )

. Operators measure d TSS c oncentrations as high

as 6 0 percent by mass in drilling wastewater

.Memorandum

March 3 1 , 201 5 Page 11

Table 4

. Concentrations of Constituents in UOG Drilling Wastewater from Marcellus
Shale Wells

Constituent Category Parameter Units Range Median/Average a Number

of Samples Number

of

Detects

Classical and

Conventional Alkalinity (as

CaCO) mg/L 110

- 42,000 1,600 11 11

Ammonia mg/L 0.98

- 35 7 8 8

BOD 5 mg/L 80

- 1,100 390 8 8

Chloride mg/L 160

- 23,000 12,000 12 12

COD mg/L 150

- 9,300 1,800 8 8

Hardness mg/L 1,400

- 46,000 4,400 12 12

Oil and Grease mg/L ND

- 150 2.5 8 4

pH S.U. 6.8

- 12 9 12 12

Phosphate mg/L 16

- 16 16 4 4

Specific

Conductance uS/cm 1,100

- 60,000 19,000 10 10

TDS mg/L 560

- 80,000 31,000 14 14

TSS mg/L 120

- 600,000 28,000 16 16

Ions Contributing

to TDS Bromide mg/L 23

- 210 110 5 5

Sulfate mg/L ND

- 1,600 220 13 10

Organic s Benzene μg/L ND

- 40 ND 20 5

Ethylbenzene μg/L

-- b 9.6 4 4

Ethylene glycol mg/L

-- 500 1 1

Toluene mg/L ND

- 0.01 ND 8 1

Xylene (m,p) μg/L ND

- 80 ND 20 8

Xylene (o) μg/L

-- b 88 4 4

Metals Aluminum mg/L 1.7

- 6,900 38 12 12

Arsenic mg/L ND

- 4.2 ND 12 6

Barium mg/L 2.6

- 2,000 13 14 14

Beryllium mg/L ND

- 0.018 ND 8 2

Boron mg/L ND

- 2.7 0.17 8 4

Cadmium mg/L ND

- 0.005 ND 8 1

Calcium mg/L 150

- 15,000 1, 3 00 13 13

Chromium mg/L ND

- 11 0.01 12 8

Cobalt mg/L ND

- 1.8 ND 8 3

Copper mg/L ND

- 17 0.83 8 6

Iron mg/L 4.2

- 18,000 86 12 12

Lead mg/L ND

- 8 0.35 12 10

Lithium mg/L ND

- 1.2 ND 8 1

Magnesium mg/L ND

- 3,600 290 12 11

Manganese mg/L ND

- 350 4.3 12 11Memorandum

March 3 1 , 201 5 Page 12

Table 4

. Concentrations of Constituents in UOG Drilling Wastewater from Marcellus
Shale Wells

Constituent Category Parameter Units Range Median/Average a Number

of Samples Number

of

Detects

Mercury mg/L ND

- 0.029 ND 8 2

Molybdenum mg/L

-- 0.1 1 1

Nickel mg/L ND

- 16 0.55 12 9

Potassium mg/L

-- b 8,800 4 4

Selenium mg/L ND

- 0.11 ND 8 3

Silver mg/L ND

- 0.01 ND 8 1

Sodium mg/L 170

- 16,000 2,900 12 12

Strontium mg/L 1.8

- 1,500 21 13 13

Zinc mg/L ND

- 38 2.1 12 10

Radioactive

Measurements Gross alpha pCi/L 17

- 3,000 130 5 5

Gross beta pCi/L 32

- 4,200 1,200 5 5

Source: See Attachment 1 (DCN SGE00740.A 0 1)

. ND

– non detect (n ot all sources report detection limit s ).

a

— Median value in the “Reported Measured/Average Value” column in the “UOG DF WW Chara. Data” tab

b

— Source only reported median value based on multiple samples

.

3. M ANAGEMENT OF UOG D RILLING W ASTEWATER

As detailed in Section D.2 of the TDD , historically, the oil and gas industry has most commonly managed UOG extraction wastewater , which includes drilling wastewater, by underground injection (DCN SGE 00704). T he UOG industry is increasingly turning to reuse/recycle

, and, in some geographic ar eas
, transfer to centralized waste treatment (CWT) facilities to manage growing volumes of UOG extraction wastewater. The National Petroleum Council (NPC) describes oil and gas drilling wastewater management in three tiers (DCN

SGE 00733 ):

Tier 1: Waste Min imization

– The generation of waste is minimized by using closed loop circulation systems during drilling , which reduces the total amount of waste that must be managed and/or disposed of in addition to minimizing costs.

Tier 2: Reuse/Recycle

– Operators can reuse/recycle drilling wastewater in subsequent drilling and/or fracturing jobs 18

.

Tier 3: Disposal

– When drilling wastewater cannot be managed via reuse/recycle,
operators must use other manage ment options, including dispos al

.

Common met hods for managing and /or disposing of drilling wastewater are listed below

and shown in Figure 3 ( DCN SGE00081 ).

18 One operator reported that treated drilling wastewater using induced gas flotation (IGF) may be used for hydraulic

fracturin g base fluid (DCN SGE00625)Memorandum

March 3 1 , 201 5 Page 13

 Transfer to a CWT facility 19 ;

 Dispos al via injection into Class II disposal well s 20 ;

 On

- site burial

– temporary fluid storage in on

- site open earthen or lined pits with

burial of residual solids after fluids are solidified, removed from the top, or evaporated ;

 Disposal via l andfill

– fluids are solidified and then contained in constructed or

natural excavations within the landfill ; and

 Land application (not shown in Figure 3 )

– sp reading over land surface where natural bioremediation is enhanced by tilling and nutrient applications

.

Figure 3

. UOG Drilling Wastewater Management and Disposal Methods (TDD Figure D

- 2)

C urrently, the most detailed publicly ava ilable source of information on drilling
wastewater management and disposal practices is specific to oil and gas extraction in Pennsylvania

. PA DEP periodicall y releases a database that captures the management of drilling wastewater generated by all oil and gas wells in Pennsylvania (DCN SGE 00739). Figure 4 shows

a timeline of d rilling wastewater management practices used by UOG operators in Pennsylvania reported for 200 8 through 2013

. As can be seen in the figure, UOG drilling fluid volumes

19 CWT facilities that accept UOG extraction wastewater are described in a separate ERG memorandum titled Analysis of Centralized Waste Treatment (CWT) Facilities Accepting UOG Extraction Wastewater (DCN

SG E00596).

20 Underground injection wells are described in a separate ERG memorandum titled Analysis of Active Underground Injection for Disposal Wells (DCN SGE00736).Memorandum

March 3 1 , 201 5 Page 14

generated increased substantially in 2009 due to development of the Marcellus shale. UOG operators utilized POTWs from 2008 through 201 1 to manage drilling wastewater (indicated by red in figure). However, the use of POTWs for the management of UOG drilling wastewater (and produced water) stopped after 2011. Over the same period of time, the u se of reuse/recycle

increased

.

Note: As reported in the PA DEP Waste Reports, “Other” may include storage pending disposal or reuse and other (reported as “other”).

Source: DCN SGE00739; DCN SGE00739.A 0 3

Figure 4

. Management of UOG Drilling Wastewater Generated by UOG Wells in

Pennsylvania (2008

– 2013) (TDD Figure D

- 3)

4. M ETHODOLOGY FOR TDD F IGURES /T ABLES G ENERATED IN THIS M EMORANDUM

The fol lowing two subsections describe the methodology that ERG used to generate

Table 3 (TDD Table C

- 5) and Table 4 (TDD Tables C

- 10, C

- 12, C

- 14, C

- 16, and C

- 18) in thisMemorandum

March 3 1 , 201 5 Page 15

memorandum. As previously explained, all other figures and tables (e.g., Figure 4 ) in this memorandum are described in other supporting memoranda

.

4.1 Table 3

– Drilling Wastewater Volumes Generated by UOG Wells by Formation

TDD Table C

- 5 “ UOG Drilling Wastewater Volumes Generated per Well by Formation ” ( i.e., Table 3 in Section 2.1 of this memorandum ) shows volumes of UOG drilling

fluid/wastewater generated per well for various formations . The raw data and analysis are compiled in the “UOG DF WW Volume Data” and “UOG DF WW Volume Summary” tabs in Attachment 1 (DCN SGE00740.A 0 1 ) . The following two subsections explain how ERG generated this table

.

4.1.1 UOG Drilling Wastewater Volume Data Entry

ERG entered raw UOG drilling wastewater volume data reported in literature into the

“ UOG DF WW Volume Data” tab in A ttachment 1 (DCN SGE00740.A 0 1). Where available,

d ata fields entered included: 21

 Resource type ( i.e., s hale, tight )

 Formation

 Well trajectory ( i.e., horizontal, not reported )

 Volume (gallons)

– This is the reported volume of drilling fluid used or drilling wastewater generated per well in gallons. Some references report volumes used for drilling UOG wells as opposed to wastewater generated. ERG presented the results as drilling wastewater volumes. 22

 Number of data points

– Thi s is the number of wells the volume data is based on , if reported. If not reported, ERG assigned this value as 1. In some cases, this is equivalent to the number of wells the reported data is based on. However, as explained above, not all references report ed the number of wells

.

 Reference ( i.e., DCN number )

4.1.2 UOG Drilling Wastewater Volume Summary Calculations

After entering all data in the “UOG DF WW Volume Data” tab in Attachment 1 (DCN

SGE00740.A 0 1) , ERG calculated the summary statistics that appear in th e TDD Table C

- 5 ( i.e.,

Table 3 in Section 2.1 of this memorandum) in the “UOG DF WW Volume Summary” tab. ERG

calc ulated the following for each formation reported in the “UOG DF WW Volume Data” tab:

 Minimum value

– Smallest value in the “ Volume (gallons)” column in the “UOG DF

WW Volume Data ” tab.

21 ERG marked data elements that were not included in the literature as “not reported” in A ttachment 1.

22 Based on communication with industry, ERG assumed that the volume of drilling fluid used is equal to the volume of drilling wastewater generated on a per well basis (DCN SGE 00625 ). ERG did not distinguish between reported volume of drilling fluid used and drilling wastewater generated in this analysis.Memorandum

March 3 1 , 201 5 Page 16

 Maximum value

– Largest value in the “Volume (gallons)” column in the “ UOG DF

WW Volume Data ” tab.

 Range

– Combines the minimum and maximum values into a range.

 Median value

– Median value in the “Volume (gallons)” column in the “UOG DF

WW Volume Data ” tab.

 Number of data points

– Sum of the “N umber of Data Points” column in the data i n the “UOG DF WW Volume Data ” tab.

4.2 Table s 4 and 5

– Characteristics of Select Pollutants in UOG Drilling Wastewater

TDD Table s C

- 10, C

- 12, C

- 14, C

- 16, and C

- 18 (i.e., Table 4 in Section 2.2 of this

memorandum ) show concentrations of pollutants found in UOG drilling wastewater

. The raw data and analysis are compiled in the “UOG DF WW Chara

. Data” and “UOG DF WW Chara

. Summary” tabs in Attachment 1 (DCN SGE00740.A 0 1) . The following two subsections explain how ERG generated these tables

.

4.2.1 UOG Drilling Waste water Characteristics Data Entry and Standardization

ERG entered raw characterization data reported in literature into the “UOG DF WW
Chara. Data” tab in A ttachment 1 (DCN SGE00740.A 0 1). Data fields entered included: 23

 Formation;

 Cat egory [ of pollutant ] (e.g. , classical, metal) ;

 Measured parameter;

 Reported measured/average value ( i.e., value reported in literature);

 Uncertainty (applies to radioactive constituents);

 Number of samples;

 Units;

 Reference ( i.e., DCN number ) ; and

 Notes.

Because naming conventions , terminology, and measured units differed by data source

, ERG standardized each data field to allow for comparison and summary of data across the entire

data set . The following list provide s detail s on how ERG standardized data from literature in the
“UOG DF WW Chara. Data” tab

.

 Parameter Standardization and Pollutant Category Assignments

- ERG created a list of all parameters included in the various sources and consolidated parameter names to

account for different spellings or abbreviations. For example, “Co” and “Cobalt”
were standardized to “Cobalt.” Pollutant c ategories for each standard parameter name were also assigned to allow sorting of measured parameters. For example, aluminum

was assigned to the “Metals” category.

 Reported Measured/Average Value s

- In some cases, data sources indicated that minimum, median, and/or maximum values did not exceed the limit of detection. To standardize the data for aggregation, ERG assigned all reported non detect s as zero

23 ERG marked data elements that were not included in the literature as “not reported” in Attachment 1.Memorandum

March 3 1 , 201 5 Page 17

values. After analyzing the data, any zero m inimum , median , or maximum values

were converted back to non detect in the TDD and memorandum tables

.

 Wastewater Description

– ERG only used literature that specifically reported the wastewater type associated with the characterization data as drilling was tewater. However, different sources may use different terms for drilling wastewater. ERG captured wastewater desc ribed as: “pit water”, “drilling”, and “mud”.

 Unit s of Measure Standardization

– ERG converted reported pollutant concentrations

to standardize d units of measure appropriate for each parameter. For example, total suspended solids were sometimes reported as a percent . ERG converted these values to mg/ L by multiplying the percent by 1,000,000 (e.g., 38% would be converted by multiplying 0.38 by 1,000,000 to get the value of 380,000 mg/L )

.

4.2.2 UOG Drilling Wastewater Characteristics Summary Calculations

After consolidat ing and standardizing all data in the “UOG DF WW Chara. Data” tab,

ERG calculated summary statistics that appear in the “UOG DF WW Chara. Summary” tab in Attachment 1 (DCN SGE00740.A 0 1). ERG calculated the following for each parameter r eported

in the “UOG DF WW Chara. Data” tab :

 Min imum value

– Smallest value in the “ Reported Measured/Average Value ” column

in the “UOG DF WW Chara. Dat a” tab.

 Max imum value

– Largest value in the “ Reported Measured/Average Value ” column

in the “UOG DF WW Chara. Data” tab

.

 Range

– Combines the minimum and maximum values into a range.

 Median value

– Median value in the “ Reported Measured/Average Value ” column in

the “UOG DF WW Chara. Data” tab

. 24

 Number of data points

– Sum of the number of data points represented by the data in

the “UOG DF WW Chara. Data” tab

.

 Number of detects

– Sum of the n umber of data points that were not non

- detects or

zeros repre sented by the data in the “UOG DF WW Chara. Data” tab

.

5. Q UALITY C ONTROL P ROCEDURES

All of the analyses presented in this memorandum adhered to the Environmental Engineering Support for Clean Water Regulations Programmatic Quality Assurance Project Plan (PQA PP) (DCN SGE00957) and the Unconventional Oil and Gas (UOG) Supplemental Quality Assurance Project Plan (SQAPP) (DCN SGE00 958 ), including collecting, evaluating, and analyzing existing data and information about drilling fluids and drilling wastewater

.

Spe cifically, ERG used the procedures described in Section 4 of the PQAPP to gather and manage existing data in support of the UOG proposed rulemaking. ERG staff entered reference

information for relevant sources into the UOG Literature Review database. The E RG index keeper reviewed all reference information, assigned each reference a Document Control Number

24 One source (SGE00774) provided the average measured result for four samples but did not provide the individual sample results. ERG did not weight these values during the calculation of the median value.Memorandum

March 3 1 , 201 5 Page 18

(DCN ), imported the reference information into the UOG Project File Index database, and saved referenced files in the Electronic Project File folder.

ERG also used the procedures described in Section 3 of the SQAPP when collecting existing data for use in the UOG proposed rulemaking. ERG used a combination of sources, including reports, papers, and online databases from state regulatory agencies such as dep artments of environmental protection and oil and gas commissions. As shown in Table 5 in this memorandum, ERG assigned a source flag (A, B, C or D) to all references used in these analyses. ERG defines each source flag as follows:

 Source Flag A

- J ournal articles and documen ts prepared by or for a government agency (e.g., site visit reports, industry meeting notes);

 Source Flag B

- Documents prepared by a verified source 25 that include citation information (e.g., operator reports, vendor documents, university publications);

 Source Flag C

- Documents prepared by a verified source that do not include citation information (e.g., operator reports, vendor documents, conference presentations); and

 Source Flag D

- Documents prepared by a source that could not be verified and that

d o not include citation information

.

EPA and ERG followed the procedures described in Section 7.0 of the PQAPP to generate, evaluate, and analyze data using a spreadsheet. ERG conducted the following QA checks during the analyses:

 ERG performed a 20 percent check of all data entry.

 ERG performed a 100 percent check of all analyses and calculations, and documented these in the internal version of the spreadsheet.

 ERG had a senior staff member familiar with ELGs and the UOG proposed rulemaking review the resul ts from each analysis.

6. R EFERENCES

Table 5 provides DCNs and citations for references used in these analyses and their assigned source flag. Definitions for source flags are located in Section 3.0 of the SQAPP (DCN SGE00958) and also in Section 5 of this memorandum

.

25 ERG considered sources as “verified” if we were able to find information about the author outside of the reference document. ERG primarily verified information by looking for company/organization websites that confirmed the author’s affiliation with the UOG industryMemorandum

March 3 1 , 201 5 Page 19

Table 5 . References

DCN Reference Citation Source Flag a

SGE00010 U.S. DOE. Office of Fossil Energy NETL. April 2009. A

SGE00081 American Petroleum Institute (API). 2009. Environmental Protection for Onshore

Oil and Gas Production Operations and Leases. (July). Available online at: http://www.api.org/~/media/Files/Policy/Exploration/API_RP_51R.ashx. B

SGE00090 NYS DEC ; Leff, Eugene. 2011. Supplemental Generic Environmental Impact

Statement on the Oil, Gas, and Solution Mining Regulatory Program. New York State Department of Environmental Conservation (NYSDEC). A

SGE00188 O'Connell, James, ERG.2014. Penn sylvania Department of Environmental

Protection’s (PA DEP) Statewide Oil and Gas Waste Reports. (December)

. A

SGE00276 U.S. EPA. 2012. Meeting with XTO Energy, Inc. about Unconventional Oil and

Gas Sanitized. A

SGE00280 U.S. EPA. 201 3 . Site Visit Report Anadarko Petroleum Corporation Marcellus

Shale Gas Operations. ( January 9 ). A

SGE00298.A18 Don Warlick. 2012. Water Management for Shale Plays An Overview of the

Niobrara Shale. Warlick Energy. C

SGE00345 Lewis, Aurana. 2012. Wastewater Generation And Disposal From Natural Gas

Wells in Pennsylvania. Duke University. B

SGE00368 US EPA Region 3. 201 2 . Key Documents About Mid

- Atlantic Oil and Gas

Extraction. Available online at: http://www.epa.gov/region3/marcellus_shale/ A

SGE00368.A 0 1 US EPA Region 3. 2013. Key Documents About Mid

- Atlantic Oil and Gas

Extraction. Available online at: http://www.epa.gov/region3/marcellus_shale/pdf/responses2info

- req5

- 12

- 11/swepi255

- 508.pdf A

SGE00428 ERG. 2013. Notes on Penn State Webinar: The Utica Reservoir. B

SGE00625 US EPA. 201 5 . Site Visit Report Southwestern Energy Fayetteville Shale

Operations. Sanitized. A

SGE00635 US EPA. 2012. Site Visit Report Chesapeake Energy Corporation Marcellus Shale

Gas Operations Sanitized. A

SGE00639 Nicot et al. 2012. Oil & Gas Water Use in Texas: Update to the 2011 Mining

Water Use Report. Univ of TX at Austin. (September) B

SGE00641 Nicot, Jean

- Philippe. 2013. Geographical, Geological, and Hydrogeological

Attributes of Formations in the Footprint of the Eagle Ford Shale. A

SGE00691 U.S. Environmental Protection Agency (U.S. EPA). 2013. Summary of the

Technical Workshop on Water Acquisition Modeling: Assessing Impacts Through Modeling and Other Means. (September). A

SGE00704 U.S. EPA. 2015. Technical Development Document f or Proposed Effluent

Limitations Guidelines and Standards for Oil and Gas Extraction. Office of Water Engineering and Analysis Division. A

SGE00732 Huffmyer, Russell and Gehucheten. 2013. Recovering Valuable Byproducts from

Oil and Gas Wastes. HDR Engineering, Inc. IWC

- 13

- 37. (November 17). B

SGE00733 National Petroleum Council (NPC). 2011. Waste Management Paper #2

- 24.

Technology Subgroup of the Operations & Environment Task Group. (September 15). B

SGE00739 ERG. 201 5 . Analysis of Pennsylvania Department of Environmental Protection’s

Oil and Gas Waste Reports. AMemorandum

March 3 1 , 201 5 Page 20

Table 5 . References

DCN Reference Citation Source Flag a

SGE00739.A 0 3 ERG. 2015. Analysis of Pennsylvania Department of Environmental Protection’s

Oil and Gas Waste Reports

- Attachment 3

- Data Calculations. A

SGE00774 Ziemkiewicz, Paul. 2013. Water Quality Literature Review and Field Monitoring

of Active Shale Gas Wells. Phase I: Assessing Environmental Impacts of Horizontal Gas Well Drilling Operations. West Virginia Department of Environmental Protection. (Feb. 15). B

SGE00801 Argonne National Laboratory (ANL). 2011. Drilling Waste Management

Information System. A

SGE00957 Eastern Research Group, Inc. 201 3 . Environmental Engineering Support for Clean

Water Regulations Programmatic Quality Assurance Project Plan (PQAPP)

. A

SGE00958 Eastern Research Group, Inc. 2014. Unconventional Oil and Gas (UOG)

Supplemental Quality Assurance Project Plan (SQAPP)

. A

SGE00986 Rost, J. (2010). Municipal Authority of the City of McKeesport Analysis of Gas

Well Wastewaters as Required Under the PA DEP Administrative Order Dated October 23, 2008 (File 2). A

SGE00987 Rost, J. (2010). Municipal Authority of the City of McKeesport Analysis of Gas

Well Wastewaters as Required Under the PA DEP Administrative Order Dated October 23, 2008 (File 1). A

SGE01006 U.S. EPA. 2000. Development Document for Final Effluent Limitations

Guidelines and Standards for Synthetic

- Based Drilling Fluids and Other Non

Aqueous Drilling Fluids in the Oil and Gas Extraction Point Source Category.

EPA

- 821

- B

- 00

- 013. (Decem ber). A

SGE01009 Caen, R., Darley, H.C.H., and G. R. Gray. 2011. Composition and Properties of

Drilling and Completion Fluids. 6 th edition. Gulf Professional Publishing: Waltham, MA. B

a

— ERG defines each source flag as follows:

 Source Flag A

- J ournal articles and documents prepared by or for a government agency (e.g., site visit reports, industry meeting notes);

 Source Flag B

- Documents prepared by a verified source that include citation information (e.g., operator reports, vendor documents, university publications);

 Source Flag C

- Documents prepared by a verified source that do not include citation information (e.g., operator reports, vendor documents, conference presentations); and

 So urce Flag D

- Documents prepared by a source that could not be verified and that do not include citation

information.A TTACHMENT 1: UOG D RILLING W ASTEWATER V OLUME AND C HARACTERI ZATION
D ATA E XCEL F ILE (DCN SGE00740.A 0 1)