Downwind Emission Estimate for Completions
The name provides the region where the site is located (AP= Appalachian, GC= Gulf Coast, MC= Midcontinent, and RM= Rocky Mountains.
Table S4-2. Direct source methane emission measurements for Rocky Mountain Completions 3, 4 and 5 and methane emission estimates based on downwind measurements.
Completion |
Measurement van start and stop times, expressed as time from start of completion |
Tracer emission estimate (scf/m) |
Direct source emission measurement
(scf/m) |
Direct source to trace emission estimate ratio
(1.0=match) |
| |
Start |
End |
Averaged over Entire period |
Averaged over non-zero emissions |
RM-3 |
33 hr 42 min |
34 hr 35 min |
9.8±1.5 |
1.4 |
12.6 |
0.14-1.3 |
RM-3 |
34 hr 44 min |
45 hr 26 min* |
19.7±3 |
4.6 |
24 |
0.23-1.2 |
RM-4 |
27 hr 18 min |
29 hr 25 min |
37.1±5.6 |
30.4 |
32.5 |
0.82-0.87 |
RM-4 |
30 hr 37 min |
33 hr 59 min |
7.4±1.1 |
10.2 |
20.0 |
1.3-2.7 |
RM-5 |
40 hr 18 min |
44 hr 44 min |
4.4±0.7 |
19.3 |
42.6 |
4.3-9.6 |
*time period extends a few minutes past the end of the completion
Table S4-3. Direct source methane emission measurements for combined Midcontinent Completions 1 and 2 (emissions occurred concurrently on the same site) and methane emission estimates based on downwind measurements.
Completion |
Measurement van start and stop times, expressed as time from start of completion (both started at same time) |
Tracer emission estimate (scf/m) |
Direct source emission measurement
(scf/m) |
Direct source to trace emission estimate ratio |
|
Start |
End |
Averaged over Entire period |
Averaged over non-zero emissions |
MC-1 + MC-2 |
3 hr 58 min |
7 hr 34 min |
10.7±1.6 |
2.4 |
10.9 |
0.22-1.0 |
MC-1 + MC-2 |
90 hr 51 min |
93 hr 31 min |
12.1±1.8 |
13.6 |
28.8 |
1.1-2.3 |
Table S4-4. Direct source methane emission measurements for Appalachian Completion Flowback 3 (emissions from multiple sources) and methane emission estimates based on downwind measurements.
Time |
Direct emission measurements (scf) |
Dual tracer measurement
(scf per min) |
Direct/Dual tracer |
Vented flowback tank |
Separator vent |
Flare |
Total Direct
measurements
(scf per min) |
8:30-9:00 |
717 |
0 |
0 |
24 |
128 |
0.19 |
9:00-9:30 |
2800 |
0 |
0 |
92 |
290 |
0.32 |
9:30-10:00 |
2800 |
15,600 |
0 |
612 |
421 |
1.45 |
10:00-10:30 |
4400 |
10,200 |
0 |
558 |
390 |
1.07 |
10:30-11:00 |
5700 |
7,400 |
150* |
390 |
366 |
1.07 |
Total emitted |
|
|
|
50,300 scf |
47,900 scf |
1.05 |
* Flow rates to the flare were reported hourly; emission estimates were made for the flare emissions, based on methane flow to the flare and an assumed combustion efficiency of 98%
Downwind Emission Estimate for Production Sites
Table S4-5. Comparison of direct source and downwind emission estimates for production sites.
Site (# of wells on site) |
Emissions from on site measurements or estimation (scf/m) |
Tracer emission estimate (scf/m) |
Direct source to tracer emission estimate |
Pneumatic Controls and pumpsa |
Fugitivesa |
Compressorsb |
Tanksb |
Total |
MC-1 (2) |
1.41 |
0.23 |
2.23E-04 |
0.25 |
1.89 |
2.32 |
0.815 |
MC-2 (1) |
0.97 |
0.01 |
5.91E-05 |
0.01 |
0.99 |
2.00 |
0.495 |
MC-3 (3) |
1.09 |
0.29 |
5.25E-04 |
0.25 |
1.63 |
2.95 |
0.552 |
MC-4 (2) |
0.61 |
0.33 |
7.60E-06 |
1.38 |
2.31 |
3.36 |
0.687 |
MC-5 (2) |
1.41 |
0.34 |
2.31E-04 |
0.11 |
1.85 |
4.16 |
0.445 |
RM-1 (8) |
0.19 |
0.02 |
0 |
0.01 |
0.22 |
0.584 |
0.368 |
RM-2 (8) |
0.05 |
0.10 |
0 |
4.28 |
4.43 |
1.70 |
2.60 |
RM-3 (1) |
0.05 |
0.09 |
0 |
0.00 |
0.13 |
0.442 |
0.303 |
RM-4 (7) |
0.11 |
0.00 |
0 |
0.00 |
0.11 |
0.839 |
0.137 |
RM-5 (2) |
0.06 |
0.03 |
0 |
0.01 |
0.09 |
0.240 |
0.392 |
RM-6 (6) |
0.42 |
0.31 |
0 |
0.01 |
0.74 |
0.421 |
1.75 |
RM-7 (1) |
0.19 |
0.07 |
0 |
0.02 |
0.27 |
0.368 |
0.736 |
RM-8 (1) |
0.04 |
0.23 |
0 |
0.02 |
0.29 |
1.08 |
0.266 |
RM-9 (4) |
0.00 |
0.02 |
0 |
0.36 |
0.38 |
0.864 |
0.436 |
RM-10 (6) |
0.03 |
0.01 |
0 |
2.82 |
2.86 |
0.080 |
35.7 |
AP-1 (6) |
0.13 |
0.01 |
0 |
0.29 |
0.43 |
* |
* |
AP-2 (6) |
0.61 |
0.45 |
0 |
0.22 |
1.28 |
0.270 |
4.74 |
AP-3 (6) |
0.14 |
2.82 |
0 |
1.80 |
4.75 |
4.12 |
1.15 |
AP-4 (5) |
0.03 |
0.57 |
0 |
0.76 |
1.36 |
0.709 |
1.92 |
AP-5 (6) |
0.02 |
0.27 |
0 |
0.10 |
0.39 |
0.288 |
1.37 |
aBased on direct source measurements or averages of direct source measurements
bBased on emission estimation methods
*No plume captured downwind
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