Shale-to-well energy use and air pollutant emissions of shale gas production in China

Supplementary Information (SI)

Yuan Changa*, Runze Huanga, Robert J. Riesb, Eric Masaneta

a McCormick School of Engineering, Northwestern University, Evanston 60208, USAb M.E. Rinker Sr. School of Building Construction, University of Florida, Gainesville 32611, USA

*Corresponding author. Tel: +1 847 467 2929; e-mail: yuan.chang@northwestern.edu; changyuan82@gmail.com

Number of Pages: 18 (including the cover page)

Number of Figures: 1

Number of Tables: 18

1

1. Pad preparation

1.1 Pad construction

According to the national standard “Well Site Preparation and Layout Requirement (SY/T 5466-2004)”[1], the area of the shale gas pad was estimated to be 5000 square meters (m2), and site clearing involved top soil excavation of 20 centimeters (cm) in depth. The majority of shale gas exploitation zones in China are located in rural areas where soil disposal meets fewer difficulties. The disposal distance was assumed to be 5 kilometers (km), and the thickness of gravel paving was 5cm. In addition, this study adopted a “local purchase” principle to determine material transportation distance because short-distance transportation has lower economic costs and lower energy consumption and environmental emissions. The materials consumed by the Wei201-H1 well were assumed to be produced or manufactured by nearby plants with sufficient production capacity. If there are multiple qualified plants around the well site, their distances to the well site were averaged. The distances between the well site and nearby plants were calculated by Google Earth[2] at 50 kilometers on average. It should be noted that “local purchase” was also applied to other materials, such as cement and steel casings.

The Technical Specification of Pre-spud Operation in the Northeast of Sichuan(Q/SH0020-2009) of the China Petrochemical Corporation [3] states that a 2000-m3 waste sink should be built for wells under 5000m in depth, and that the thickness of the concrete layer (C30 concrete) should above 400 millimeters (mm). Additionally, a concrete partition wall must be built to separate the waste sink into two sections and the the minimum thickness of the partition wall is 300mm. The top of the partition wall should be 500mm lower than the sink top. The sink was assumed to be rectangular (length to width ratio 1.67:1) and 3m in depth. The volume of concrete was calculated to be 446.5 m3. One cubic meter of C30 concrete consists of 406 kilogram (kg) #325 cement, 0.46m3 sand, 0.79m3 gravel [4], and 191 kg water. The density of sand and gravel is 1510 kg/m3 and 1521 kg/m3 respectively [4]. Therefore, the waste sink consumed 182 tonsi cement, 310 tons sand, 537 tons gravel, and 85 tons water. Two cement plants (Weiyuan County Cement Plant and Xinqiao Cement Plant) in Weiyuan County were chosen for cement supply, and the average transportation distance from these plants to the well was calculated (by Google Earth) to be 32 km.

1.2 Road construction

For the Wei 201-H1 well, road repairing was 2.8 km, new road construction was 65m [5]. The road repairing is assumed to be grading and compaction, while road construction also includes gravel pavement. For road construction, the top soil excavation is 20 centimeters (cm) in depth. Given that shale gas drilling involves heavy traffic, the road was assumed to have a two lane design of 6m in width [6], and the gravel paving thickness was estimated at 5 cm.

1.3 Water impoundment construction

For the Wei201-H1 well, a 7000-m3 water impoundment area was excavated. The impoundment was assumed to be rectangular (length to width ratio 5:4) and 3.5m in depth. The impoundment bottom was covered by waterproof fabric (2857m2, including 2% waste) to prevent soil contamination.

1.4 Equipment and vehiclesi The ‘ton’ used in this study is metric tonne.

2

For the earth work of pad construction, equipment productivities were obtained from the National Construction Basic Quota (GJD-101-95) [7]. Equipment productivity refers to the work completed (e.g., the volume of soil removed by a bulldozer) in one shift equipment operation (1 shift is 8 hours). For road repairing and construction, material consumption and equipment productivity data were obtained from the Budget Quota of Highway Project (JTG/T B06-02-2007) [4]. Equipment energy intensities were obtained from the National Construction Machine-Shift Costs Quota [8]. It was assumed that a 100-kW diesel generator was used to fuel the concrete mixer and the pump during waste sink construction.

For the Wei201-H1 well, the quantity of material purchase was calculated by theoretical material consumption and on-site waste [4]. The on-site waste refers to the material loss during production activities, such as during onsite conveyance of materials. The waste rate of sand was 4%, gravel was 2%, and cement was 2%, resulting in waste quantities of 51kg, 12kg, and 5kg, respectively. For the fuel consumption rate of vehicles in China, results of an existing study were used [9] (see Table S1). The equipment and vehicle specifications are shown in Table S2.

Table S1. Fuel consumption rate for heavy-duty trucks in China

Vehicle gross weight Diesel consumption(ton) (L/100km) (kg/100km)6-7 16.3 13.97-9 18.8 16.09-11 21.5 18.311-13 23.8 20.213-15 25.7 21.815-17 27.4 23.317-19 28.9 24.619-21 30.2 25.721-23 31.4 26.723-25 32.5 27.625-27 33.5 28.527-29 34.5 29.329-31 35.5 30.231-32 36 30.6>32 36 30.6

Average 24.9 21.2

Data source: Huo et al., 2012 [9].

Since the well construction period is short, the embodied energy of equipment was not considered in this study. Theoretically, To calculate the embodied energy used in a process such as equipment use, the embodied energy of the equipment should be allocated based on the share of equipment use in the entire life of the equipment. Because the pad construction period is short (usually 1-2 weeks), and the use of construction equipment in hours is very low, the embodied energy of equipment allocated to shale gas pad construction is insignificant in comparison to both the total equipment embodied energy and to the shale gas well drilling energy. On the other hand, It is a rare case that the construction equipment used in drilling pad construction are exclusively used for shale gas well production. The equipment usually has multiple usage throughout its entire lifespan. This also requires the allocation of embodied energy between different equipment uses.

3

Table S2. Equipment use of shale gas pad construction

Equipment Specifications Workload Productivity Energy intensity

Energy type

(m3) (m3 shift-1)a (kg shift-1)Pad construction

Bulldozer 90kW 1000 776 59 DieselLoader 2m3 load capacity 1000 380 65 DieselTruck (soil disposal) 8-ton, 5km transport 1000 6.5m3/load 0.22kg/km DieselGrader 120kW 5000 m2 1429 m2 shift-1 55 DieselRoller 15ton 5000 m2 7143 m2 shift-1 43 DieselSprinkler truck 4000 liter capacity 5000 m2 5000 m2 shift-1 30 DieselTruck (gravel transport) 8ton, 50km transport 380 ton 8 ton/load 0.22kg/km Diesel

Road constructionBulldozer 90kW 78 776 59 DieselLoader 2m3 load capacity 78 380 65 DieselTruck (soil disposal) 8-ton, 5km transport 78 6.5m3/load 0.22kg/km DieselGrader 120kW 390 m2 1429 m2 shift-1 55 DieselRoller 15ton 390 m2 7143 m2 shift-1 43 DieselSprinkler truck 4000 liter capacity 390 m2 5000 m2 shift-1 30 DieselTruck (gravel transport) 8ton, 50km transport 30 ton 8 ton/load 0.218kg/km Diesel

Waste sink constructionTruck (# 325 Cement) Bulk cement tanker

truck, 32 km transport186 ton 10 ton/load 0.23kg/km Diesel

Truck (Sand and gravel) 8ton, 50km transport 870 ton 8 ton/load 0.22kg/km DieselConcrete mixer 1500 liter 446.5 75 m3/h 24kWh ElectricityConcrete pump 80m3/h 446.5 80 m3/h 58kWh Electricity

Road repairingGrader 120kW 16,800 m2 1429 m2 shift-1 55 DieselRoller 15ton 16,800 m2 7143 m2 shift-1 43 Diesel

Impoundment constructionExcavator 1.25m3 load capacity 7000 571 54 DieselLoader 2m3 load capacity 7000 380 65 DieselTruck 8-ton, 5km transport 7000 6.5m3/load 0.22kg/km Diesela one shift is eight hours. Equipment productivity and energy intensity data sources:[7,8,9].

1.5 Environmental emissions

Emission factors from the U.S. EPA AP-42 data set [10] were used to estimate the air pollutant emissions of equipment operation. Relevant categories were gasoline and diesel industrial engines and heavy-duty diesel trucks. When estimating the SO2 emissions of diesel and gasoline industrial engines, only SOx emissions (i.e., not SO2) per million British Thermal Units (MMBtu) of fuel use were listed in the AP-42 manual. Thus, SO2 emission factors were estimated at 90% of total SOx emissions. The energy and emissions of the pad construction equipment and vehicles are calculated in Table S3.

4

Table S3. Energy consumption and emissions of equipment use in pad constructionEquipment Energy type Consumption (kg) SO2 (kg) NOx (kg) CO2 (kg)Bulldozer Diesel 80 0.4 7 250Loader Diesel 1400 7 110 4160Truck (soil disposal) Diesel 2700 13 220 8220Bulk cement tanker truck Diesel 260 1 20 770Diesel generator (100kW) Diesel 120 0.6 10 360Grader Diesel 850 4 70 2570Roller Diesel 130 0.6 10 400Sprinkler truck Diesel 30 0.2 2 90Truck (gravel transport) Diesel 3460 17 280 10400Excavator Diesel 660 3 50 2000Total a 10,000 50 800 30,000

a May not sum to total due to rounding.

2. Well drilling

2.1 Drilling rig

The Wei 201-H1 well was assumed to use the 4000m DBS drilling rig manufactured by Sichuan Honghua Petroleum Equipment CO., LTD., a main drilling rig manufacturer in China located 200 km north of the well site. The drilling rig is driven by three 1200 kW (rating power) diesel generators. However, given that the actual power of a drilling pump is approximately 66% of the rating power and drilling pump and drawworks do not simultaneously operate [11], the actual power of the drilling rig was assumed to be 2400kW.

2.2 Drilling fluids

Three types of drilling fluids were used in the Wei201-H1 well: (1) water-based drilling fluid, (2) compressed air drilling fluid, and (3) oil-based drilling fluid [12]. The compressed air drilling fluid was not considered in this study due to its small use compared to the other two types of drilling fluid. Theoretically, the volume of drilling fluid includes the fluid in wellbore, the fluid in circulation tank, the fluid in reserve tank, and the fluid in pipeline, see equation S-2.1[13]. The national standard of Drilling Fluid Clarifying Equipment Arrangement, Installation, Operation and Maintenance (SY/T 6233-2005) [14] states that for a 4000m drilling rig, the minimum capacity of the circulation tank is 180m3, and the reserve tank is 80m3. The fluids in the mud manifold and pipeline were not considered based on the assumption that their volumes were comparatively negligible.

V fluid=V wellbore+V circulation tank+V pipeline+V reserve tank (S-2.1)

Where: Vfluid is the total volume of drilling fluid Vwellbore is the volume of drilling fluid in wellboreVcirculation tank is the volume of drilling fluid in circulation tankVpipeline is the volume of drilling fluid in pipelineVreserve tank is the volume of drilling fluid in reserve tank

5

2.2.1 Water-based drilling fluid

The drilling of Wei201-H1 was calculated to consume 294 m3 water-based drilling fluid based on Equation S-2.1 and the average density is 1.025 g/cm3 [12]. Since bentonite was the dominant ingredient for the water-based drilling fluid, other additives were ignored in this study [15]. The density of bentonite was assumed to be 2.4 g/cm3 [16]. Equation S-2.2 and S-2.3 [13] provide the method for calculating the bentonite and water consumption of oil-based drilling fluid. With the two equations, the bentonite consumption of the case well was calculated to be 13 metric tons and water consumption was 290 m3.

W bentonite=❑bentonite×V fluid (❑fluid−❑water )

❑bentonite−❑water (S-2.2)

VWater=❑fluidV fluid−W bentonite (S-2.3)

Where W bentonite is the weight of bentonite (ton); ❑bentonite is the density of bentonite [g (cm3)-1]; V fluid is the

volume of the drilling fluid (m3); ❑fluid is the density of drilling fluid [g (cm3)-1]; ❑water is the density of water, 1 g (cm3)-1; VWater is water consumption (ton or m3)

After the completion of well drilling, 253 m3 of water-based drilling fluid was used to deal with well loss by staying pressurized. The bentonite consumption of this well treatment was calculated at 11 metric tons and water consumption was at 250 m3.

To sum up, the total estimated consumption of the water-based drilling fluid was 547m3, bentonite was 24 metric tons, and water was 538 m3. Based on the principle of local purchase, a bentonite plant (Weirong Bentonite Plant) was located in Weiyuan County, approximately 20km to the well site.

2.2.2 Oil-based drilling fluid

The drilling of Wei201-H1 consumed 364m3 oil-based drilling fluid, and the density mainly ranged from 1.4 to 2.4g/cm3 [17]. This study assumed typical oil-based fluid compositions for China. The oil-water ratio (volume basis) was estimated to be 70:30, and 0# diesel was used. Given that oil-based drilling fluid involves various chemical additives, and lime and calcium chloride (CaCl2) have significant shares, this study focused on lime and CaCl2, and assumed a content of 75 kg and 110 kg per cubic meter drilling fluid respectively [18]. Therefore, the estimated oil-based fluid consumption included 216 tons of 0# diesel, 109 tons of water, 27 tons of lime, and 40 tons of CaCl2. After the water-based well collapse treatment, another 364 m3 of oil-based drilling fluid was used. To sum up, the total oil-based drilling fluid consumption of the Wei 201-H1 well was estimated at 727 m3, with mass composition as follows: 0# diesel is 432 tons, water is 218 tons, lime is 54 tons, and CaCl2 is 80 tons. The lime and CaCl2 were assumed to be purchased from Neijiang Weiyuan Building and Chemical Materials Plant, which is 46 km to the well site.

The transportation of bentonite, lime and CaCl2 were assumed to use 8-ton trucks, and the waste rate of bentonite was 2%, lime and CaCl2 were 3% (the waste rates in the national road construction budget quota) [4], see Table S4. The transportation energy and air pollutant emissions are shown in Table S5.

6

2.2.3 Drilling cuttings

The drilling cuttings of Wei201-H1 were estimated by the volume of the wellbore (127m3). The average density of the formation was 2123 kg/m3 [19]. The disposal was assumed to use 8-ton trucks, at a 5 km transportation distance (see Table S4). The disposal energy and emissions estimate are presented in Table S5.

Table S4. Vehicle energy intensity for drilling fluid materials transportation and cutting disposalEquipment Specifications Workload Energy intensity Energy type

(ton) (kg/km)Truck (bentonite) 8-ton, 20km transport 24 0.22 DieselTruck (lime and CaCl2) 8-ton, 46km transport 138 0.22 DieselTruck (cutting disposal) 8-ton, 5km transport 270 0.22 Diesel

Energy intensity data source: Huo et al., 2012 [9].

Table S5. Energy and emissions of drilling fluid materials transportation and cutting disposalEquipment Energy type Consumption (kg) SO2 (kg) NOx (kg) CO2 (kg)Truck (bentonite) Diesel 30 0.1 2 80Truck (lime and CaCl2) Diesel 360 2 30 1090Truck (cutting disposal) Diesel 75 0.4 6 220Total a 470 2.5 40 1400

a May not sum to total due to rounding.

2.3 Equipment for drilling fluid circulation

The Drilling Fluid Clarifying Equipment Arrangement, Installation, Operation and Maintenance (SY/T 6233-2005) [14] and the Drilling Fluid Technology Specification of the China National Petroleum Corporation [20] documents contain the equipment requirements for drilling fluid circulation and processing. In terms of a 4000m drilling rig, relevant equipment mainly includes the shale shaker (2 sets), desander, mud desilter, degasser, centrifuge, mud tank, and circulation tank. The equipment specifications stated by Sichuan Honghua Petroleum Equipment CO., LTD [21] were used for equipment electricity use estimates, see Table S6.

Table S6. Equipment use for drilling fluid circulationEquipment Standard requirement Power (kW)

Shale shaker (2 set) Productivity no less than 182 m3/hour 3.73Integrated desander and mud desilter

Productivity no less than 182 m3/hour 3.73

Degasser Productivity no less than 182 m3/hour 60.5Centrifuge Productivity 40 m3/hour; separation particle 5m-7m 27.5Shear pump Pump displacement 155m3/h; pump lift 32 m 55Sand pump Pump displacement 200m3/h; pump lift 36 m 55

Data source: Sichuan Honghua Petroleum Equipment CO., LTD.

The Wei201-H1 well used surface water to meet its water demand. Six 37-kW water pumps (5m3/minute) were used, four were used in hydraulic fracturing, and two were used to pump water from a nearby river to water impoundment [22].

7

2.4 On-site management and living

According to the site layout plans in the Well Site Preparation and Layout Requirements (SY/T 5466-2004) [1], there are four trailers on the well site, one each for the project manager, superintendent, drilling fluid monitor, and geology monitor. Each trailer was assumed to have two computers (320W/set) and one 40W fluorescent bulb, with 24/7 operation. Site lighting is 8kW, 12h/day.

For living activities, it is assumed that one drilling crew has 54 persons on its staff [23], and 20 dormitory rooms. The heating/cooling power is 80kW, cooking electricity is 6kW, water pump is 7.5kW [24].The total living water consumption was calculated to be 480 tons, within which cooking was 363 tons and other daily activities (such as drinking and bathing) were 117 tons [25]. Surface water of nearby rivers was the primary resource for living water use [26], and relevant pump energy was considered in Table S7.

The electricity needed for drilling fluid circulation equipment and on-site management and living activities was supplied by a diesel generator. Since the total electricity demand is 533 kW, one 350-kW and one 200-kW diesel generators are used. Based on the diesel generators of different manufacturers, such as Shanghai Diesel Engine, Volve, PerKins, and Cummins, the diesel consumption rate was estimated at 206g/kWh. For the Wei201-1, the net drilling time was 260 hours, the net well cementation, maintenance and completion time was 1170 hours, and the net hydraulic fracturing time was 30 hours [27]. The total time of the well drilling was 74 days. The estimated energy consumption and emissions of the diesel generator set are shown in Table S7.

Table S7. Energy and emissions of well drillingWork Equipment Power

load (kW)Operationa

(hour)Diesel (kg)

SO2

(kg)NOx (kg)

CO2 (kg)

Drilling Diesel generators (3600 kW rating power; 2400kW practical power)

2400 260 128,300 620 10,400 385,700

Fluid circulation+ management+ living

Diesel generators (350 kW, 1 set)

311 260 18,700 90 1500 56,200

Management + living + water transportation (7000 m3 in the impoundment)

Diesel generators (200 kW, 1 set)

176 8 340 2 30 1000

Management + living (including drilling fluid water, cement water, and living water transportation)

Diesel generators (200 kW, 1 set)

102 1480 60,900 290 4900 183,200

Management + living +water transportation +fracturing+ flowback processing

Diesel generators (350 kW, 1 set; 200 kW, 1 set)

533b 30 3400 20 300 10,200

Totalc 212,000 1000 17,000 636,000a Operation hours were estimated based on [22] and [27]. b Peak power load. 6 water pumps do not continuously work for 30 hours. c May not sum to total due to rounding.

8

3. Well cementation

3.1 Well casings

The weight of well casings was calculated by equation S-3.1 [28,29]:

Casing weight=(Outer diameter−Casingwall thickness )×Casingwall thickness×π × ρ×Casing length/1000 (S-3.1)

Where Casing weight is in kg; Outer diameter and Casing wallthickness are in mm; π is 3.14159; ρ is steel density and is 7.85 g/cm3; Casing length is in m

Based on the formula (S-3.1), the Wei 201-H1 well was calculated to consume three types of casings: 4.7 tons of surface casing, 32 tons of intermediate casing, and 121 tons of production casing. Based on the aforementioned local purchase assumption, the casings were assumed to be manufactured by Chengdu Seamless Steel Tubing Co. Ltd., and the transportation distance was calculated by Google Earth to be170km.

3.2 Cement slurry

Since the Wei 201-H1 well is 2823m in length, it was assumed that the American Petroleum Institute (API) ‘D’ class cement would be used to make the cement slurry. The water-cement ratio (volume or mass basis) is 38%, and slurry density is 1.96g/cm3 [30]. For one m3 of cement slurry, the weight of cement would be 1428 kg at the aforementioned density. The total consumption of cement slurry was calculated to be 55m3, and the cement and water consumption in the slurry were estimated at 79 tons and 30 tons respectively. The waste rate of cement was 2% [4]. A well cement plant (Sichuan Jiajiang Guiju Special Cement Plant) was selected and the transportation distance was estimated at160km by Google Earth.

3.3 Equipment and vehicles

The casings and cement were assumed to be transported by 40-ton flatbed trucks and bulk cement tanker trucks, respectively. A cementation truck was assumed to be used for cement slurry batching and pumping. See Table S8 and Table S9.

Table S8. Equipment and vehicle energy intensity for shale gas well cementationEquipment Specifications Workload Productivity Energy intensity Energy typeTruck (Casings) 40-ton flatbed truck,

170 km transport158 ton 40 ton load-1 0.31kg/km Diesel

Truck (“D” class cement) Bulk cement tanker truck, 160 km transport

80 ton 10 ton load-1 0.23kg/km Diesel

Cementation truck Rating power 336kW 55 m3 1.64am3/min 31.3b kg diesel/h Diesela Practical productivity.b Practical power is calculated to be 38% of rating power.

9

Table S9. Equipment and vehicle energy and emissions in shale gas well cementationEquipment Energy type Consumption

(kg)SO2

(kg)NOx

(kg)CO2

(kg)Truck (Casings) Diesel 420 2 35 1250Truck (“D” class cement) Diesel 600 3 50 1800Cementation truck Diesel 20 0.1 1 50Totala Diesel 1040 5 90 3100

a May not sum to total due to rounding.

4. Hydraulic fracturing and well completion

4.1 Fracturing preparation

For the Wei 201-H1 well, the net fracturing time was 1817 minutes, fracturing fluid consumption was 23,655 m3, sand consumption was 960 tons (4% waste rate), and fracturing stage is 11 [22] (The horizontal wellbore of a shale gas well is always divided into multiple sections for hydraulic fracturing, and one section is called one stage). The total power of the fracturing fleet was 34,000hp, and the fracturing fleet was estimated to include 17 pumper trucks, 2 fracturing blender trucks, 1 monitoring van, and 2 manifold trucks [27, 31]. The fracturing fleet of the Wei201-H1 well was manufactured by the Sinopec Jianghan Oilfield Corporation and relevant specifications are shown in Table S10. The energy and emissions of fracturing fleet are shown in Table S11. For the sand used within the fracturing fluid, vehicle specifications and transportation impacts are shown Table S12 and Table S13.

Table S10. Specifications of fracturing fleetEquipment Type Diesel engine power (kW)

Pumper SYL2000Q-105 1680Blender SHS 10 410Monitoring van SYQ2000 12.4 (Diesel generator)Manifold truck SYG 140 -

Data source: Sinopec Jianghan Oilfield Corporation (2013).

Table S11. Energy and emissions of hydraulic fleetEquipment Practical

power(kW)

Operation(hour)

Diesel consumption(kg)

SO2

(kg)NOx

(kg)CO2

(kg)

Pumper 19050a 30.28 139,000 670 11,240 418,000Blender 547a 30.28 4000 20 320 12,000Monitoring Van 12.4 30.28 80 0.4 6 230Totalb 143,000 700 11,600 430,200a For diesel engine, the practical power is 66.7% of rating power [11], and the efficiency of the diesel engine is 35% [27].

b May not sum to total due to rounding.

Table S12.Vehicle energy intensity for fracturing fluid sand transportationEquipment Specifications Workload Productivity Energy

intensityEnergy type

Truck (sand transport) 8ton, 50km transport 1000 ton 8 ton/load 0.22 kg/km DieselEnergy intensity data source: Huo et al., 2012 [9].

10

Table S13. Energy and emissions for fracturing fluid sand transportationEquipment Energy type Consumption (kg) SO2 (kg) NOx (kg) CO2 (kg)Truck Diesel 2730 13 220 8200

4.2 Fracturing and well completion

The equipment used by flowback management was fueled by the electricity produced by the diesel generators, whose estimated energy use and air pollutant emissions were listed in Table S7.

For typical shale gas well completion in the United States methane (i.e., natural gas) emissions of per well were estimated to be 9175 Mcf, and 51% of the emissions (4662 Mcf) were flared [32]. For shale gas wells in China, the content of methane is estimated at 74.5% [33]. It is assumed that the methane released during the well completion is either flared with a combustion efficiency of 98% or vented without recovery [34]. The U.S. average flare-vent ratio (51%:49%) [32] was assumed for the well completion stage in China (see Figure S1). Probable workovers in the future were not considered, meaning that an existing production well will not be stimulated for the purpose of restoring, prolonging or enhancing the production of shale gas.

a Calculation based on the equation provided by Jiang et al., 2011[34]. Figure S1. Estimated GHG emissions from methane during shale gas well completion

5. Transportation of on-site diesel uses

For Wei 201-H1, the end uses of diesel fuel included on-site equipment, transportation vehicles, and oil-based drilling fluids. Diesel must be transported to the site for equipment and oil-based drilling fluids, 790 tons in total (calculated by summing up the aforementioned on-site uses). It was assumed that a 45000-liter tank (38 tons diesel) trailer was used to transport diesel from Weiyuan County to the well site (the nearest county from the well site). The transportation distance is approximately 5 km calculated by Google Earth. The estimated energy and air pollutant emissions of the diesel transportation are shown in Table S14.

Table S14. Energy and emissions of diesel transportationEquipment Energy type Consumption (kg) SO2 (kg) NOx (kg) CO2 (kg)Truck Diesel 64 0.3 5 190

11

6. Summary of process materials, energy and emissions

Based on the aforementioned process-based calculations, the well site process energy use, water use, and air pollutant emissions are summarized in Table S15.

Table S15. Summary of process energy, water, and air emissions estimates for an individual shale gas well in China

Well site process Diesel SO2 NOx CO2 CH4 CO2e Water(kg) (kg) (kg) (ton) (ton) (ton) (ton)

Pad preparation 10,000 50 800 30 - 30 85Well drilling 644,100 1020 17,150 640 - 640 1240Well cementation 1000 5 80 3 - 3 30Hydraulic fracturing and well completion 145,800 700 11,790 640 70 2390 23,650Totala 800,900 1780 29,800 1300 70 3060 25,000

a May not sum to total due to rounding.

7. Indirect energy use and air pollutant emissions--- Input-output LCI model for China

Based on the economic IO technique and publicly accessible data on sectoral energy and environmental performance in China, the energy consumption and air pollutant emissions of the supply chains providing raw materials and fuels to the well site were estimated. For the theoretical details of IO model, please refer to Heijungs and Suh [

35],and Hendrickson et al.,[36

].

The China IO LCI model developed in this study was based on the 2007 China input-output table [37], which is the latest benchmark data of the Chinese national economy. For the data source, processing and assumptions of the model development, such as sectoral energy and environmental coefficients calculation, please see Chang et al. 2011 [38] for full details.

The values of material inputs into the shale to well system were estimated by material quantity and 2007 sales price. The unit price and on-site waste rate of each material were obtained from the Budget Quota of Highway Project (JTG/T B06-02-2007) [4]. Since the I-O table was compiled by producer price, the producer price of each material was estimated by the share of producer price in purchaser price of each materials purchased by construction sector [39]. In other words, the producer price value of each material input was used in the IO LCI model. The materials were assumed to be produced from the corresponding sectors in the 2007 China I-O table that are listed in Table S16 [37]. Table S17 shows the embodied energy and emissions of the material inputs for the Wei201-H1.

12

Table S16. Estimated value of raw materials and fuels consumed in onsite well developmentMaterial Actual

weight (ton)Unit price(yuan/ton,2007)

Purchaser price value(104yuan, 2007)

Share of producer price in purchaser price(%)

Producer price value(104yuan, 2007)

Corresponding sectors

Sand 1267 33 4.2 94 4 Manufacture of brick, stone and other building materials

Gravel 957 36 3.4 94 3.2 Manufacture of brick, stone and other building materials

Cement (#325) 182 320 5.8 98.6 5.7 Manufacture of cement, lime and plasterCement (D class) 80 860 6.8 98.6 6.7 Manufacture of cement, lime and plasterWaterproof fabric 2857 m2 5 yuan/m2 1.4 81.5 1.2 Manufacture of chemical fiberCasing 158 5610 88.4 99 88 Rolling of steelBentonite 24 620 1.5 95.6 1.4 Mining and processing of nonmetal ores

and other oresLime 54 105 0.6 98.6 0.56 Manufacture of cement, lime and plasterCaCl2 80 1615 13.3 55.8 7.2 Manufacture of basic chemical raw

materialsDiesel 800 4900 392 96.4 378 Processing of petroleum and nuclear fuel

8. Data quality assessment

Based on the guideline of data quality assessment in the ISO 14044 standard [40], Table S18 provides a data quality assessment for the major input data employed in this study. The data are categorized into general data and well-specific data. Since one of the aims of this study is to establish a hybrid LCI framework for the energy use and air pollutant emissions of a typical shale to well system in China, the general data are relatively stable and should be put in low priority for update by future studies. Comparatively, the well-specific data can vary from well to well and should be updated with well-specific data in future studies that apply this framework to specific wells or regional and national estimates.

Given that the source of the general data are primarily national standards, quota, or government publications, the general data were deemed to be reliable and to have medium or high geographical coverage. Some national standards were published several years ago, but they focus on mature technologies, such as the earthwork in construction, and were deemed applicable for current practices.

The well-specific data are mainly derived from the drilling company report, standards, and technical handbooks. The data are specific to the Wei201-H1 well and should be updated in other case studies. As a result, the well-specific data are not as reliable as the general data, and have relatively low geographical and temporal coverage. Compared with general data, the shale to well energy and air emissions of shale gas production in China (the final results of this study) are more sensitive to well-specific data. This can be seen in the contribution analyses for the shale to well energy use, air pollutant emissions and water consumption, which were generally dominated by onsite drilling activities.

Since national standards, quotas, government statistics, and drilling company reports are authoritative and reliable data sources, the general data and well-specific data in this study have high precision and completeness. However, due to the data scarcity on fugitive and flaring GHG emissions of China shale gas wells, the adoption of U.S. shale gas well data to an extent contributes to study uncertainty. Also,

13

splitting the aggregated sectoral energy and emissions data to match the finer sectors in IO table causes uncertainty in model results. In terms of data reproducibility, the detailed data sources, processing, assumptions, and calculations illustrated in this study allow other researchers to reproduce the reported results.

Given that shale gas development in China is at an initial stage focusing on trial well drilling, the shale gas well production data of different wells are not available, which precludes the estimation of parameter ranges (e.g., max, medium, min). Therefore, in this study we compared our model results with U.S. shale gas well values. Researchers can quantitatively analyze the variations of energy and emissions of China shale gas production when more data are released by governmental authorities, drilling companies, and researchers.

An important caveat for this study is that this study is best interpreted as initial but rough estimates of the magnitudes of emissions and energy use that are likely based on China’s well types, materials supply chains, and fuel supplies. Study results are specific for the trial-stage (2011-2015) shale gas production in China. Model parameters such as fracturing water usage and oil-based drilling fluid consumption should be updated to reflect future technology maturation and representative supply chains when more data become available.

14

S17. Estimated embodied energy and air pollutant emissions of materials and fuels used onsite for shale gas well developmentSectors Total

energyCoal Coke Crude

oilGasoline Kerosene Diesel Fuel oil Natural

gasElectricity SO2 NOx CO2eb

(kg ce)a (kg) (kg) (kg) (kg) (kg) (kg) (kg) (m3) (kWh) (kg) (kg) CO2 (ton) CH4 (kg)

(ton)

Mining and processing of nonmetal ores and other ores

1560 2070 110 290 22 6 70 24 50 2060 18 8 5 170 9

Processing of petroleum and nuclear fuel

569,100 877,000 32,700 659,600 4800 1000 13,900 12,500 37,800 436,500 4300 1600 1100 29,200 1800

Manufacture of basic chemical raw materials

14,690 19,900 1120 3030 110 30 300 250 930 17,350 150 50 40 320 48

Manufacture of chemical fiber 1840 2080 120 430 14 3 40 35 90 2430 16 7 4 40 5

Manufacture of cement, lime and plaster

24,100 33,700 1230 1900 190 50 570 590 540 27,000 290 160 80 410 90

Manufacture of brick, stone and other building materials

12,780 15,500 640 1380 100 26 310 310 334 13,590 130 80 40 240 46

Rolling of steel 227,240 205,000 89,430 21,970 1180 320 3080 1880 2600 220,000 1540 510 350 3830 450

Totalc 851,300 1,155,300 125,300 688,600 6400 1400 18,300 15,600 42,300 718,900 6500 2400 1600 34,100 2480a kg ce is kilogram coal equivalent. 1 kg ce=29,271 kilojoules (kJ).b conversion is based on the 2007 IPCC AR4 factors [41].c May not sum to total due to rounding.

15

S18. Input data summary and data quality assessment

Data input Source Geographical coveragea

Temporal coverageb

Representative-nessc

Precision Completenessd Reproducibilitye Uncertaintyf

General data

Drilling pad dimension National standard Medium/High High High Medium/High High High LowProductivity and energy intensity of construction equipment

National quota Medium/High High High Medium/High High High Low

Transportation vehicles Assumption High Medium Medium Medium Medium High MediumMaterial price National quota High High High High High High LowEnergy intensity of vehicles Existing literature Medium High Medium Medium Medium/High High Medium2007 China IO coefficientsf National Bureau of

StatisticsMedium High High High High High Low

Sectoral energy consumptionf China statistical yearbook High High High Medium/High Medium/High Medium/High MediumSectoral emissionsf China statistical yearbook

and World input-output database

High High Medium Medium Medium/High Medium/High Medium

Well-specific data

Drilling pad infrastructures Drilling company report High High Medium/High Medium/High Medium/High High LowMaterial type and consumption Drilling company report,

technical handbook, assumption

Medium/High Medium Medium Medium Medium/High High Medium

Material transportation distance Assumption of local purchase

High Low Low/Medium Medium Medium High Medium

Drilling machine, equipment and specifications

Drilling company standard and Manufacturer report

Medium/High Medium /High Medium Medium/High Medium/High High Low/Medium

Fracturing water consumption Drilling company report Low/Medium Medium Medium High High High LowWell specifications (e.g., depth, wellbore diameters)

Drilling company Medium/High Low/Medium Medium High Medium/High High Low

Fugitive methane and flaring emissions in well completion

Originally from U.S. EPA and was modified by the methane content of Shale gas in Sichuan basin

Medium Medium Medium Medium Medium High Medium

a The geographical difference of the input data. High geographical coverage indicates low geographical difference.b The temporal difference of the input data. High temporal coverage indicates low temporal difference.c The degree to which the data set reflects the true population of interest.d Percentage of flow/system that is measured or estimated.e The extent to which information about the methodology and data values would allow an independent practitioner to reproduce the results reported in the study.f Data used by IO LCI model to calculate the embodied energy/emission coefficients for materials (e.g., kg coal equivalent(ce)/yuan; g SO2/yuan).

16

References

17

1 []National Development and Reform Commission of the People's Republic of China. Well site preparation and layout requirement (SY/T 5466-2004). Beijing; 2004.

2 []Google Inc., Google Earth; 2013. < http://www.google.com/intl/zh-CN/earth/index.html>.3 []China Petrochemical Corporation Standard. Technical specification of pre-spud operation in the northeast of

Sichuan(Q/SH0020-2009). Beijing; 2009.4 []Ministry of Transport of the People's Republic of China. Budget quota of highway project (JTG/T B06-02-

2007). Beijing; 2007. 5 []PetroChina Southwest Oil & Gasfield Company. Well drilling project announcement for the south Sichuan gas

well Wei201-H1. Luzhou; 2010. <http://www.weiyuan.gov.cn:81/Article/Ggfw/Glgg/201011/7613.html>.6 []Ministry of Transport of the People's Republic of China Standard. Technical standard of highway engineering

(JTJ001-97). Beijing; 1997. 7 []Ministry of Construction of the People's Republic of China. National construction basic quota (GJD-101-95).

Beijing: China Planning Press; 1995. 8 []Ministry of Construction of the People's Republic of China. National construction machine-shift costs quota.

Beijing: China Architecture & Building Press; 2001.9 []Huo H, He KB, Wang M, Yao ZL. Vehicle technologies, fuel-economy policies, and fuel-consumption rates of

Chinese vehicles. Energy Policy 2012;43:30-6.10 []U.S. Environmental Protection Agency. Emissions factors & AP 42, compilation of air pollutant emission

factors; 1995. <http://www.epa.gov/ttnchie1/ap42/>.11 []Wang HS. Working load of offshore drilling rig and characteristics of generators. China Shiprepair

2007;20(3):48-50.12 []Nie JS, Wang HP, Wang FY. Drilling technology of the highly deviated horizontal shale gas wells in Changing-

Weiyuan area. Drilling & Production Technology 2013;36(3):118-20.13 []Zhao JZ, Zhang GL. Drilling engineering practical technical manual. Beijing: China Petrochemical Press; 2007. 14 []National Development and Reform Commission of the People's Republic of China. Drilling fluid clarifying

equipment arrangement, installation, operation and maintenance (SY/T 6233-2005). Beijing; 2005.15 []Clark CE, Han J, Burnham A, Dunn JB, Wang M. Life-cycle analysis of shale gas and natural gas

(ANL/ESD/11-11). Technical report. Lemont, IL: Argonne National Laboratory; 2011.16 []Chen P. Well drilling and completion. Beijing: Petroleum Industry Press; 2005. 17 []Zhao CQ, Feng B, Liu SB, Zeng FK, Fan CY, Leng YH. Horizontal well cementation for shale gas well in

Sichuan basin. Nat Gas Ind 2012;32(9):1-5.18 []Zhou KJ, Hao JF. Drilling engineering design. Dongying: China University of Petroleum Press; 2010. 19 []Chen SB, Zhu YM, Wang HY, Liu HL, Wei W, Fang JH. Shale gas reservoir characterisation: a typical case in

the southern Sichuan Basin of China. Energy 2011;36: 6609-16.20 []China National Petroleum Corporation. Drilling fluid technology specification; 2010.

<http://www.pxwt.net/goodsid/wenzhangview/594843.html>.21 []Sichuan Honghua Petroleum Equipment CO., LTD. Drilling rig ( ZJ40/2250DBS) specifications; 2013.

<http://www.hhcp.com.cn/product/Products_1_4000_ZJ40DBS.asp>.22 []Li LG. Status quo and practice of Sichuan basin shale gas exploitation. Presentation in the 11th U.S.-China Oil

& Gas Industry Forum. Chengdu; 2011. <http://www.uschinaogf.org/Forum11/chinesepresentations11.html>.23 []Wang GY. Research on the international operations strategies of China drilling sector. Shandong Economy

2007;140(3):64-6. 24 []Kang T, Guo SC, Xu ZH, Xiong DH. Application of the IFC6 energy-efficient generator in drilling rig. Energy

Conservation of Oil Fields 1999;(4):22-5.25 []National Pollution Investigation Office. Pollutants generation and reduction manual for urban livings in China.

Beijing; 2008.26 []Chen LR, Wang R, Zeng ST, Yu SY. State quo and improvement of drinking water quality for the drilling crew

of east Sichuan Drilling Corp. Chemical Engineering of Oil & Gas 2000;(6):329-30.27 []Wu HC. Application of modern hydrofracturing technology and equipment to petroleum/gas recovery efficiency

improvement. Presentation in the 2012 Power Transmission and Control (PTC)-Asia Forum. Shanghai; 2012. 28 []General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China,

Standardization Administration of the People's Republic of China. Seamless steel tubes for structural purposes (GB/T 8162-2008). Beijing; 2008.

29 []General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China, Standardization Administration of the People's Republic of China. Dimensions, shapes, masses and tolerances of seamless steel tubes (GB/T 17395-2008). Beijing; 2008.

30 []American Petroleum Institute. Specification for cements and materials for well cementing (10A/ISO 10426-1). Washington, D.C.; 2010.

31 []Petroleum Business News. The shale gas horizontal well construction of Chuanqing drilling corporation; 2011. <http://www.pbnews.com.cn/system/2011/07/19/001341628.shtml>.

32 []U.S. Environmental Protection Agency. Greenhouse gas emissions reporting from the petroleum and natural gas industry; 2010. < http://www.epa.gov/ghgreporting/documents/pdf/2010/Subpart-W_TSD.pdf >.

33 []Li YX, Zhang DW, Zhang JC. Criteria and significance to designate shale gas an independent mining resource. Nat Gas Ind 2012;32(7):1-6.

34 []Jiang MH, Griffin WM, Hendrickson C, Jaramillo P, VanBriesen J, Venkatesh A. Life cycle greenhouse gas emissions of Marcellus shale gas. Environ Res Lett 2011;6(July-September):034014.

35 []Heijungs R, Suh S. The computational structure of life cycle assessment. Dordrecht: Kluwer Academic Publishers; 2002.

36 []Hendrickson C, Lave L, Matthews S. Environmental life cycle assessment of goods and services: an input–output approach. Washington, DC: RFF Press; 2006.

37 []National Bureau of Statistic. 2007 China input-output table. Beijing: China Statistics Press; 2009.38 []Chang Y, Ries JR, Wang YW. The quantification of the embodied impacts of construction projects on energy,

environment, and society based on I–O LCA. Energy Policy 2011;39(10):6321-30.39 []Lenzen M, Kanemoto K, Moran D, Geschke A. Mapping the structure of the world economy. Environ Sci

Technol 2012;46(15):8374-81.40 []International Organization for Standardization (ISO). Environmental management — life cycle assessment —

requirements and guidelines (ISO 14044:2006(E)). Geneva; 2006.41 []Solomon S, Qin D, Manning M, Chen Z, Marquis M, Averyt KB, et al. Contribution of working group I to the

fourth assessment report of the Intergovernmental Panel on Climate Change. Cambridge: Cambridge University Press; 2007.