Occurrence of BTEX from Oil- and Gas-Related Incidents in ... · 49th US Rock Mechanics | GWPC | Underground Injection Conference | February 23Geomechanics Symposium | June 28 -25,

49th US Rock Mechanics | Geomechanics Symposium | June 28 – July 1, 2015GWPC | Underground Injection Conference | February 23-25, 2016

Occurrence of BTEX from Oil- and Gas-Related Incidents in Groundwater above the Denver-Julesburg BasinKatherine J. Armstrong, Jessica D. Rogers, Troy L. Burke, and Joseph N. Ryan

University of Colorado, Boulder

49th US Rock Mechanics | Geomechanics Symposium | June 28 – July 1, 2015GWPC | Underground Injection Conference | February 23-25, 2016

Objectives

Understanding spills and releases

Frequency

Groundwater contamination potential

Causes

Facility types

Materials released

Future exposure assessments of organic contaminants in groundwater

49th US Rock Mechanics | Geomechanics Symposium | June 28 – July 1, 2015GWPC | Underground Injection Conference | February 23-25, 2016

BTEX in groundwater

What are the BTEX compounds?

Present in:

hydraulic fracturing fluids

flowback and produced waters

petroleum products

Frequently tested in Colorado Oil and Gas Conservation Commission (COGCC) database

Proxy for other organic compounds of concern

49th US Rock Mechanics | Geomechanics Symposium | June 28 – July 1, 2015GWPC | Underground Injection Conference | February 23-25, 2016

Colorado Oil and Gas Information System (COGIS)

Spill files

https://data.airwatergas.org/cogcc/query

Laboratory data, consultant reports

49th US Rock Mechanics | Geomechanics Symposium | June 28 – July 1, 2015GWPC | Underground Injection Conference | February 23-25, 2016

Colorado Oil and Gas Information System (COGIS)

Remediation files

https://data.airwatergas.org/cogcc/query

Laboratory data, consultant reports

49th US Rock Mechanics | Geomechanics Symposium | June 28 – July 1, 2015GWPC | Underground Injection Conference | February 23-25, 2016

Incidents considered

2010 and 2012 (planned: 2010-2014) Incident date > Form 19 submit date > Form 27 submit date

Township-range box

COGCC GIS Online

49th US Rock Mechanics | Geomechanics Symposium | June 28 – July 1, 2015GWPC | Underground Injection Conference | February 23-25, 2016

Identifying potential groundwater impact

Operator-reported field

Spill reports

Remediation reports

Manual review of spill and remediation files with identified/possible groundwater impact

49th US Rock Mechanics | Geomechanics Symposium | June 28 – July 1, 2015GWPC | Underground Injection Conference | February 23-25, 2016

Number of distinct incidents

Year All incidents*Groundwater

impact

2010 222 102

2012 249 86

Total 471 188

*Predicted

49th US Rock Mechanics | Geomechanics Symposium | June 28 – July 1, 2015GWPC | Underground Injection Conference | February 23-25, 2016

Facility types (groundwater impact)

153

27

2 2 11 1 1

1

tank battery

flow line

gas compressor station

gathering line

liquid containment pond

gas pipeline

pit

well pad

unknown

incidentstank battery

incidents

flow line

49th US Rock Mechanics | Geomechanics Symposium | June 28 – July 1, 2015GWPC | Underground Injection Conference | February 23-25, 2016

Incident causes (groundwater impact)

11239

15

154

2 1

equipment failure

historical (undefined)

historical (equipment failure)

vandalism

human error

unknown

line repair

equipment failure

incidents

historical (undefined)

historical (equipment failure)

49th US Rock Mechanics | Geomechanics Symposium | June 28 – July 1, 2015GWPC | Underground Injection Conference | February 23-25, 2016

Materials released (groundwater impact)

99

86

66

10

1 1 1

produced water

condensate

oil

unknown

natural gas

brine

calcium-chloride enriched water

produced water

incidents

condensate

incidents

oil

incidents

49th US Rock Mechanics | Geomechanics Symposium | June 28 – July 1, 2015GWPC | Underground Injection Conference | February 23-25, 2016

Rates of spills/releases (producing wells)

YearProducing

wellsAll incidents*

Groundwater impact

Groundwater impact (BTEX)

2010 17,855 1.24% 0.57% 0.52%

2012 20,775 1.20% 0.41% 0.35%

*Predicted

49th US Rock Mechanics | Geomechanics Symposium | June 28 – July 1, 2015GWPC | Underground Injection Conference | February 23-25, 2016

Rates of spills/releases (producing wells)

Gross et al. (2013)

Surface spills affecting groundwater associated with <0.5% of active wells (July 1, 2010 – July 1, 2011)

49th US Rock Mechanics | Geomechanics Symposium | June 28 – July 1, 2015GWPC | Underground Injection Conference | February 23-25, 2016

Rates of spills/releases (production volumes)

0

1

2

3

4

5

6

7

8

9

10

2010 2012

Ove

rall

inci

de

nts

pe

r m

illio

n

bar

rels

pro

du

ced

0

1

2

3

4

5

6

7

8

9

10

2010 2012O

vera

ll in

cid

en

ts p

er

mill

ion

b

arre

ls p

rod

uce

d

OIL PRODUCED WATER

25 million bbl 41 million bbl 41 million bbl 60 million bbl

49th US Rock Mechanics | Geomechanics Symposium | June 28 – July 1, 2015GWPC | Underground Injection Conference | February 23-25, 2016

Challenges and uncertainties

Manual file review

Locating basic information

Lab data availability

Actual spill/remediation overlap

Historical releases

49th US Rock Mechanics | Geomechanics Symposium | June 28 – July 1, 2015GWPC | Underground Injection Conference | February 23-25, 2016

Conclusions

Characteristics of groundwater-impacting spills

Facilities: tank batteries, flow lines

Causes: equipment failure, historical releases

Materials: produced water, condensate, oil

Frequency, extent of groundwater impacts

All spills: ~1.2% of number of producing wells

Groundwater impact: ~40% of spills

BTEX groundwater impact: ~90% of groundwater-impacting spills