Monthly Archives: November 2012

8:25 p.m. Bayou Corne Field Update

Office of Conservation
Bayou Corne Field Update
Nov. 27, 2012 Activities

Texas Brine Facility

Oxy 3-A Cavern Well –
Injecting brine/removing oil and flaring natural gas

Vent Well to Top of Aquifer –
Flaring gas at 46.9 mcf/day

Vent Well to Top of Cap Rock –
Shut in pending plug and abandon evaluation

Sinkhole Site –
Settling/shifting of material underlying sinkhole created disturbance of water in sinkhole in morning roughly coinciding with USGS report of observance of seismic activity – crude oil emulsion and woody debris from sinkhole bottom observed rising to surface, water from nearby swamp seen flowing into sinkhole. Surface activity observed for several minutes before water calmed again.

Conservation/Shaw Operations

Observation/Vent Well #1 –
Flaring gas at 32 mcf/day

Observation/Vent Well #2 –
Flaring gas at 30 mcf/day

Observation/Vent Well #3 –
Removing water to improve flaring efficiency

Observation/Vent Well #4 –
Flaring gas at 12 mcf/day

Bayou Corne Community
Participating in ongoing in-home monitoring effort with DEQ
Oversight of installation of first Office of Conservation-directed Texas Brine geoprobe monitoring well in Bayou Corne community, additional geoprobes to be installed

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2:55 p.m. Sinkhole Event

An event occurred at the sinkhole around 11:30 pm today which is being considered as a “burp”.  Vegetative debris and hydrocarbons came up from below the sinkhole.  A few trees in the southwest corner did fall in however most of the debris came from below the sinkhole.  Texas Brine removed all crews from the sinkhole and is checking the boom surrounding the area to make sure everything is in tact.

A video from the sinkhole, post-event is posted at:

http://www.youtube.com/user/assumptionla

3:20 p.m. Office of Conservation Field Update

Office of Conservation
Bayou Corne Field Update
Nov. 25, 2012 Activities

Texas Brine Facility

Oxy 3-A Cavern Well –

· Shut in to build pressure

Vent Well to Top of Aquifer –

· Shut in, awaiting adjustment to improve flaring efficiency

Vent Well to Top of Cap Rock –

· Shut in pending plug and abandon operations

Sinkhole Site –

· No cleanup operations today

Conservation/Shaw Operations

Observation/Vent Well #1 –

· Casing perforated in preparation for flaring operations – monitoring pressures to determine impacts of nearby flaring of Observation/Vent Well #2

Observation/Vent Well #2 –

· Flaring gas at 42 mcf/day

Observation/Vent Well #3 –

· Preparing well to begin flaring operations

Observation/Vent Well #4 –

· Shut in, making adjustments to improve flaring efficiency

Bayou Corne Community

· Participating in ongoing in-home monitoring effort with DEQ

1:50 p.m. Recent Seismic Monitoring

Analysis from Itasca Group on recent seismic monitoring that can be posted to Assumption blog to give information to public on latest evaluation —

Dr. Will Pettitt, Principal Geophysicist at Itasca Consulting Group, has reviewed the seismic data recorded overnight on November 20/21. Long-period seismic tremors and micro-earthquakes have been observed, similar to those defined previously by Dr. Steve Horton of CERI/USGS, and recorded mainly on station LA08 closest to the sinkhole. The long-period seismic tremors are postulated to be caused by gas and/or fluid movements through the rock collapse zone below the sinkhole on the edge of the salt dome. Micro-earthquakes of this nature are typically associated with small-scale rock movements, and again are believed to be occurring in the collapse zone. The source of both of these event types continues to be investigated by experts.

7:50 a.m. Status of Hydrogen Sulfide in Bayou Corne AreaPrepared by Gary R. Hecox, Ph.D.

Status of Hydrogen Sulfide in Bayou Corne Area

Prepared by Gary R. Hecox, Ph.D., Shaw Environmental & Infrastructure, Inc.

Shaw Environmental & Infrastructure, Inc. (Shaw) has reviewed existing data and is currently collecting new data to evaluate the conditions related to the hydrogen sulfide observed in the Texas Brine Relief Well #2 completed in the cap rock. At all times, protection of local residents and project staff is and will remain the top priority when making decisions and recommendations for response activities related to site conditions.

Currently there are five vent wells completed in the alluvial aquifer and one, Relief Well #2, completed in the cap rock. Four of the vent wells have positive wellhead pressure indicating gas accumulation; the fifth well has no wellhead pressure.

Acting out of an abundance of caution to the potentially changing conditions when notified about the detection of hydrogen sulfide gas on Tuesday November 20, 2012, Shaw shut down flaring operations on the two ORW vent wells currently being flared. This was done to allow for collection of quantitative hydrogen sulfide data and develop the appropriate plan and monitoring measures to safely go forward with flaring operations. ORW-2 has since resumed flaring and Texas Brine Relief Well #1 remained flaring. Flaring operations are being monitored for hydrogen sulfide by the local ambient air monitors and site personnel.

DNR and Shaw have discussed with Texas Brine what occurred at the Relief Well #2. The geophysical log on Relief Well #2 showed gas accumulation from 142 to 150 feet in the alluvial aquifer immediately below the base of the overlying clay and from 424 to 432 feet in the cap rock on top of the salt of the Napoleonville dome. On November 15, 2012 this well was perforated in the cap rock at depths of 424 to 427 feet and 455 to 457 feet. The gas accumulation zone in the alluvial aquifer was not perforated. On Monday November 19, 2012, Texas Brine set up the flare on this well and started flaring gas from the cap rock. Venting and flaring continued until late in the day when water started to be produced from the well. Texas Brine set up a gas/water separator and restarted flaring operations. After a very short period of flaring, site personnel noticed hydrogen sulfide odors from the water being discharged from the separator. At this time, one of the AreaRae monitors was used to check for hydrogen sulfide gas. When hydrogen sulfide was confirmed, Texas Brine stopped flaring operations, shut-in and locked the wells, and set a safety perimeter. The well currently remains shut-in and locked.

Shaw has checked the ORW vent wells for hydrogen sulfide. In the two wells being flared, no detectable hydrogen sulfide concentrations were measured in the gas. Low concentrations of hydrogen sulfide, consistent with a swamp environment, were measured in the two ORW wells that have not been flared. Shaw is checked all 18 of the shallow Geoprobe wells for hydrogen sulfide. All of these shallow wells were nondetect for hydrogen sulfide.

At this point in time, it appears that the hydrogen sulfide produced by Relief Well #2 was only from the cap rock and not the alluvial aquifer vent wells. While low concentrations of hydrogen sulfide have been detected at some of the bubble sites, the concentrations are well below those that would pose a human health risk. Other than Relief Well #2, all hydrogen sulfide concentrations measured are consistent with the production of hydrogen sulfide caused by decay of trees and other vegetation in a swamp environment.