Public Briefing 2014 03 11 Rev4 - State of LouisianaA World of SolutionsTM 3 Sinkhole—February...

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Public BriefingEvacuation Order in Effect

585 days—1 year, 7 months, 8 days

March 11, 2014

A World of SolutionsTM 2

Sinkhole and south berm Cavern conditions Seismic events Gas Conditions and Venting

Agenda

Sinkhole—February 2014

‐2’‐2’

‐10’‐10’

‐2’‐2’

‐10’‐10’Primary subsidence areaPrimary subsidence area

SinkholeSinkhole

Between ‐2 and ‐10‐foot contour: Primary Sinkhole Subsidence Area

Deeper than ‐10 feet: Sinkhole

‐205’(‐260’ March

Aug‐12

Oct‐12

Dec‐12

Feb‐13

Apr‐13

Jun‐13

Aug‐13

Oct‐13

Dec‐13

Feb‐14

(Acres)

Sinkhole Area Subsidence Area

Sinkhole & Subsidence Area Volume and Area

Aug‐12

Oct‐12

Dec‐12

Feb‐13

Apr‐13

Jun‐13

Aug‐13

Oct‐13

Dec‐13

Feb‐14

Volume (Cub

ic yards)Millions

Volume

Total Subsidence VolumeSinkhole Volume

Sinkhole and New South Berm Alignment

Oxy 3 Cavern Tag Data—Vertical Depth

Solids interface near top of cavern

Sinkhole Volume Compared to Oxy 3 Cavern Volume

Note: Final Oxy 3 cavern volume when mining ended in 2009 was estimated from the 2007 total cavern volume (sonar volume + bottom sludge) and the historical measured rate of cavern growth.

Oxy 3A Casing and Tubing Pressure

Tubing pressure declining—that is

Pressure difference caused by oil and gas in casing

Well work‐over

MEQ Event Histogram

Sinkhole Appears

Active Sites

MRAA Gas Area

Bubble Site Intensity Changes ( Oct 2012 to Jan 2014)

Gas Classification

New bubble site

4.9 32.7

Total Volume Vented (mmcf) Daily Vent Rate (mcfd)

Gas Volum

In CommunityOutside Community

Status of Gas Venting

Data date: 3/6/2014

TBC Community Venting Program

Well DateFlow Rate (mcfd)

Cum. Flow (mcf) FWHP (psig)

ORW‐36 3/6/2014 10.4 2,353 47.5ORW‐37 3/6/2014 0.0 249 0.0ORW‐46 3/6/2014 1.5 525 45.0ORW‐49 3/6/2014 2.7 408 46.0ORW‐50 3/6/2014 7.8 923 44.0ORW‐52 3/6/2014 1.0 208 48.0ORW‐53 3/6/2014 0.2 79 37.0ORW‐55 3/6/2014 8.3 139 48.0ORW‐56 3/6/2014 0.5 23 46.5ORW‐58 3/6/2014 0.2 5 12.0Total 32.7 4,911 ‐‐

Average 3.3 491 37.4

mcfd Thousands cubic feet per daymcf Thousands cubic feetFWHP Flowing wellhead pressurepsig Pounds per square inch gauge

Pressure Monitoring Well Data

PMW‐18S

PMW‐16S

PMW‐19S

BC‐2

TBC‐3

No Pressure at PMW‐08S

Pressure Monitoring Shut‐in Wellhead Pressures

9/3/2013 10/3/2013 11/2/2013 12/2/2013 1/1/2014 1/31/2014 3/2/2014

Wellhead Pressure (p

BC 2 PMW 16s PMW 18s PMW 19s TBC 3

PMW‐18S ~50’ from ORW‐52PMW‐19S ~50’ from ORW‐54

Well seal issues @ BC‐2

TBC‐03 No Pressure

ORW Operations—Start of Venting

Aquitard

GasGas

Gas to Flare

ORW Operations—During Venting

Aquitard

GasGas

Gas to Flare

Radius of Influence

Option 1—No dewatering– Have to mitigate gas using only the excess gas pressure (3‐5 psig)– Keep wellhead pressure high to avoid “watering” out of well

• Initially gas pressure high enough to avoid “water” out• As gas is removed, in the immediate vicinity of the vent well, the gas pressure can

drop to MRAA water pressure and well fills with water

– ROI (radius of gas removal) will be relatively small– Need more, closer‐spaced vent wells– Longer time to mitigate gas

Option 2—With Dewatering– Gas mitigation using 40 to 50 psig pressure drops– Water controlled in well with dewatering pumps– ROI relatively larger – Fewer vent wells– Shorter gas mitigation time

MRAA Gas Mitigation—Options

Concerns raised about subsidence because of vent well dewatering Community Dewatering Tests including Subsidence Monitoring– ORW‐38 test

• 10 psi pressure drop• Pumping for one week

– ORW‐21 test being• Water pressure drop of 40‐50 psi• Extensive monitoring for subsidence in vicinity of well

Subsidence (Consolidation ) Issue

Thank You

Bayou Corne Community

Sinkhole

Grand Bayou

Public Briefing 2014 03 11 Rev4 - State of LouisianaA World of SolutionsTM 3 Sinkhole—February...

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