Anadarko Petroleum Corporat ion 2-1 Trinity Consultants 

## 2. REPRESENTATION OF MODELED SOURCES

2.1. EMISSIONS SOURCES AND POTENTIAL TO EMIT

The	sources	of	emissions	for	the proposed	project	primarily	con sist	of	internal	combustion	engines, painting	operation,	we lding	operation,	dust	collectors,	mud‐deg assing,	water	blasting	operation, miscellaneous	equipment,	and	fue l	storage	tanks.		For	the	suppo rt	vessels,	the	only	emission	sources are	internal	combustion	engines and	fuel	storage	tanks.		Anadar ko	will	use	the	“worst‐case” potential‐to‐emit	scenario	among	all	the	operating	scenario	dis cussed	in	the	Section	3	for	assessing air	quality	impacts	to	demonstra te	compliance	with	the	Class	I Increments,	AQRVs	an d	Class	II	SILs. This	will	give	Anadark o	the	flexibility	to	d rill	and	operate	at any	location	within	the	worse‐case	lease block	(nearest	to	respective	Cla ss	I	and	Class	II	areas)	or	at any	other	location	f urther	away	from	a

Class	I	area	withi n	the	“wedge.”

As	described	in	the	Section	3	of this	report,	the	project	inclu des	six	possible	opera ting	scenario	or	an equivalent	combination	thereof. Refer	to	Section	3	for	the	det ails	of	each	operati ng	scenario	and	the proposed	air	emission	sources	and their	operating	conditions	as sociated	with	it.

Among	all	the	support	v essels,	the	supply	bo ats	will	be	very	fr equently	used.		All	other	support

vessels	such	as	well	evaluation	v essels,	stimulation	vessels,	t ugs,	and	barges,	will	be	used	in	a specific	operating	scenario.		Mo reover,	the	supply	boats	genera te	higher	emissions when	they	are	in transit	arriving/departing	from the	drill	ship	than	emissions	g enerated	when	the	s upply	boats	are located	adjacent	to	the	drill	sh ip	during	loading/unloading	ope rations.		The	other	support	vessels generally	generate	more	emission s	during	performing	operations in	the	vicinity	of	the	drill	ship when	compared	against	the	emission s	generated	during	their	tran sit.		Hence,	placing	a	supply	boat

source	at	a	distance	of	25	nautical	miles	from	the	worst‐case	d rillship	location	i n	the	direction	of nearest	receptor	should represent	the	worst case	support	vessel emission	scenario	for	air dispersion	modeling	analysis.		T he	worst‐case	support	vessels	e missions	(i.e.,	su pply	boats	with highest	PTE)	were	utilized	for this	modeling analysis.

For	performing	air	dispersion	an alysis,	maximum	total	emissions (i.e.,	sum	of	the	drillship	and supply	boat	emissions)	for	eac h	pollutant	were	considered.		Tab le	2‐1	compares	the	emissions	from different	operational	scenarios	an d	modeled	emission	rates.		Th e	modeled	emission	rates	represent the	worst	case	combination	among the	different	operating	scenar io.

Table 2

‐ 1. Emission Rates Comparison

Pollutant Source Emission Rates (lb/hr)

Model

ed Gas
Flowbac
k

Scenario Oil
Flowback

Scenario Stimulat

ion
Vessel

Scenario General
Well Completi

on Scenario Well
Evaluatio

n Vessel

Scenario Drilling

NO x Supply

Boats	 84 42 42 42 84 42 84
Drill ship	 540 566 582 575 513 573 534
Total 624 608 624 617 597 615 618Anadarko Petroleum Corporat ion 2-2 Trinity Consultants Pollutant Source Emission Rates (lb/hr)

Model

ed Gas
Flowbac
k

Scenario Oil
Flowback

Scenario Stimulat

ion
Vessel

Scenario General
Well Completi

on Scenario Well
Evaluatio

n Vessel

Scenario Drilling

PM 10 Supply

Boats	 3 1 1 1 2 1 2
Drill ship	 27 26 26 10 9 10 10
Total 30 27 25 11 11 11 12

SO 2 Supply
Boats	 0.5	 <0.1	 <0.1	 <0.1	 0.1	 <0.1	 <0.1

Drill ship	 1.5	 <2	 <1	 <0.5	 0.4	 0.4	 0.4

Total 2 <2 <1 <0.5 2 0.5 0.5

CO Supply

Boats	 100 29 29 29 58 29 58

Drill ship	 1,000	 1,062	 779	 191	 177	 181	 182 Total	 1,100 1,091 809 220 235 210 240



### 2.2. Q/D ANALYSIS

Anadarko	has	completed	a	Q/d	calculation	to	assess	potential	im pacts	of	the	proposed	drilling	and well	completion	operations	on	the	nearest	Class	I	area.		The	Q/ d	analysis	compares	the	ratio	of	the sum	of	proposed	annualized	maximum	24‐hour	emission	rates	of	al l	visibility	impairing	pollutants (in	tons	per	year)	and	the	distan ce	to	the	neares t	Class	I	area (in	km)	to	a	threshold	value	of	10,	as determined	by	the	FLM.		The	“Q”	i s	the	combined	emissions	incre ase	from	a	source	of	SO 2 ,	NO X , PM 10 ,	and	H 2 SO 4 in	tons	per	year	(tpy)	based	on	the	maximum	hourly	emissions	a nd	“d”	is	the

nearest	distance	to	a	Class	I area	in	km	from	the	source. 11 Emissions	from	sou rces	that	operate intermittently	or	seasonally	wil l	be	adjusted	to	account	for	ye ar	round	operation .			The	emissions represented	in	the	Q/d	analysis are	conservatively	based	on	the highest	emissions	between	the drilling	and	well	completion	op erations.		Based	on	the	results, a	Class	I	area	AQRV	analysis	is required	for	the	project	because	t he	Q/d	ratio	for	the	proposed source	is	greater	th an	10.		A	copy	of the	Q/d	analysis	is	pr ovided	in	Appendix	F.



### 2.3. MODELED PARAMETERS

As	mentioned	previously,	Anadarko is	requesting	the	flexibility to	drill	and	complete	one	or	more wells	in	any	of	the	lease	blocks within	the	“wedge”	while	compl ying	with	any	operational	and emission	limitations	prescribed	i n	the	air	permit s	that	will	be issued.		Therefore,	the	Class	I	area modeling	analysis	was	performed for	each	Class	I	area	with	the drillship	assumed	to	be	located	at the	closest	point	within	the	“we dge”	of	the	project	(worst‐case location)	to	the	Class	I	areas.

For	Breton‐NWR,	the	NW corner	of	the	Desoto	Canyon	lease	block 141	was	determined	to	be	the worst‐case	drillship	location.		For	St.	Marks	NWR	and	Bradwell Bay	Wilderness,	the	NE	corner	of	the

11 U.S. Forest Service – Air Quality Program, National Park Service – Air Resources Division, U.S. Fish and Wildlife Service – Air Quality Branch , Phase I Report of the Federal Land Managers’ Air Quality Related Values Workgroup (FLAG)--Revised, 2010.