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Wednesday, July 18, 2012

Explosion Occurred at Residential Site: Initial Investigation was Ignition of Methane Gas






















BEFORE THE OIL AND GAS CONSERVATION COMMISSION
OF THE STATE OF COLORADO

IN THE MATTER OF EXPENDITURES FROM THE OIL AND GAS                            )                    CAUSE NO. 1E
CONSERVATION AND ENVIRONMENTAL RESPONSE FUND FOR                        )
THE COLORADO OIL AND GAS CONSERVATION COMMISSION                           )                    ORDER NO. 1E-5

REPORT OF THE COMMISSION

This cause came on for an emergency hearing before the Commission on April 26, 2007, in Suite 801, 1120 Lincoln Street, Denver, Colorado for an order to allow the expenditure of additional funds from the Oil and Gas Conservation and Environmental Response Fund.  The Commission held this emergency hearing pursuant to its authority under §34-60-108(3), C.R.S. (2004).

 

FINDINGS


1.  An explosion occurred on April 17, 2007 in Las Animas County at a building site where a residential structure was under construction.  The initial investigation by the Stonewall Fire Protection District indicated that the cause of the explosion was the ignition of methane gas.  Since the explosion the Colorado Oil and Gas Conservation Commission (COGCC) staff has worked diligently to ensure that the health, safety and welfare of the public in the vicinity of the explosion site has been protected while they are conducting investigations to determine the source of the gas that caused the explosion and while they develop a strategy for mitigating and, if possible, remediating the source of the gas and lingering impacts.  The residential structure is owned by Mr. Stephen and Mrs. Audrey Bouvier and is located in the NW¼ NW¼ of Section 32, Township 33 South, Range 66 West, 6th P.M., Las Animas County, Colorado. 

                        2.  COGCC staff is working cooperatively with Mr. and Mrs. Bouvier, the Bouvier’s insurance company (Farmers Insurance Company), the Farmers Insurance Company’s investigators (TDI Investigations), Las Animas County, the City of Trinidad, Gustavson Associates, Cornerstone Construction, Cornerstone Construction’s insurance company (Safeco Insurance Company), the Stonewall Fire Protection District, Primero School District, Pioneer Natural Resources USA, Inc., and other interested parties.  The results of the soil gas surveys have been shared with these entities and they will be provided with the subsequent reports.

                        3.  On April 18 and 19, 2007 the COGCC’s contractor, LT Environmental, Inc. (LTE), conducted soil gas surveys to determine the aerial extent of the high methane concentration in the soil in the vicinity of the Bouvier residence and associated water well; in the vicinity of two (2) other residential structures and the water well associated with these, which are located approximately 300 feet southeast of the explosion site; and in the vicinity of the Primero School, the associated bus garage and residential structures, which are located approximately one (1) mile east of the explosion site. 

4.  The soil gas survey conducted in the vicinity of the explosion site delineated the aerial extent of the high concentrations of methane in the soil.  In this area high concentrations of methane occur in a relatively small area adjacent to and underneath the Bouvier residence and the associated water well.  Methane was not detected in or around the two (2) other residential structures and the water well associated with these.  Methane was detected in the vicinity of, but not inside, the bus barn associated with the Primero School.  The aerial extent and concentrations of the methane were similar to those detected in previous surveys conducted by LTE on behalf of the COGCC.   Methane was not detected in the vicinity of or inside the school building or any of the associated residential structures.

5.  The COGCC and its contractor are investigating  potential sources of the methane gas that caused the explosion, including the Trinidad MGP #1 Well (API 05-071-06045), the Trinidad MGP #2 Well (API 05-071-06070), and the Trinidad MGP #3 Well (API 05-071-06048) (these three wells are located in the NW¼ NW¼ of Section 32, Township 33 South, Range 66 West, 6th P.M., and were plugged and abandoned in 1984 by Gustavson Associates and the City of Trinidad) coal seams that crop out in the vicinity of the house; the water well associated with the Bouvier residence; and two (2) producing gas wells, and the Melbourne #21-32 Well (API 05-071-07728) and the Melbourne #21-32 TR Well (API 05-071-07510), which are located approximately 850 feet northeast of the explosion site.

6.  Based upon information contained in the COGCC database and well files, it appears that the Trinidad MGP #1 Well (API 05-071-06045) is located immediately adjacent to or perhaps underneath the explosion site.  The remains of the residential structure, foundation, and debris make it impossible to identify any surface indication of this well, so COGCC intends to excavate the area and uncover the well head; however this cannot be accomplished until the insurance company’s investigation of this incident is complete. 

7.  COGCC staff and its contractors have developed a multi-phased plan to determine the source of the methane that caused the explosion and to ensure that public health, safety, welfare and the environment are protected during the investigation and until mitigation of the methane seepage is achieved.  The total estimated cost for this work is Seventy Four Thousand Nine Hundred Fifty dollars ($74,950.00).  The individual components of this work are described below in Finding 8 through Finding 21. 

8. Initial Soil Gas Surveys - A soil gas survey will be conducted in the vicinity of the explosion site and the Primero School.  Prior to initiating the field work, the Utility Notification Center of Colorado (UNCC) will be contacted to identify any buried facilities in the survey area.  The shallow subsurface soil, approximately three feet below ground surface (bgs), will be investigated using a slide-hammer, tubing, and gas meter to measure the concentration of combustible gas.  The four gases to be measured include oxygen, methane, carbon monoxide, and hydrogen sulfide.  The survey will begin around the perimeter of the Bouvier residence and extend outward into the surrounding area; radiating in all directions to identify the presence or absence of combustible gas and to attempt to delineate the horizontal extent of methane seepage.  The soil gas survey at the Primero School will focus on the structures present including the school, bus garage, and the houses located west of the bus garage.  Each subsurface gas concentration measurement will be located using a global positioning system (GPS) accurate to within one meter.  LTE will also map the location of the residence, water supply wells, buried utilities, pertinent roads, and other pertinent features using the GPS.  The estimated cost for this work is Three Thousand dollars ($3,000.00).

9.  Water Well Investigation - One water well was identified at the Bouvier residence, one water well was identified at the residence located approximately 300 feet to the southeast, and one water well was identified at the Primero School.  Soil gas surveys will be conducted around the exterior of the water wells and the well caps will be opened and the atmosphere within the well will be tested for the presence of methane.   Water samples will be collected from each well for laboratory analysis.  The wells will be purged and sampled using the protocols established in the COGCC's Raton Basin Phase II Seep Investigation project.  The analyses will include major cations and anions and dissolved methane.  If free methane gas is present inside the well casing, then the gas will be sampled and analyzed for composition and stable isotopes.  Water and gas samples will be submitted to laboratories for analysis under a rush turn-around-time.  The estimated cost for this work is Two Thousand Nine Hundred dollars ($2,900.00).

10.  Surface Geology Reconnaissance - The surface geology in the vicinity of the Bouvier residence will be investigated to understand potential migration pathways and source areas for methane seepage.  This task includes: identification of coal seams that crop out in the area; measuring strike and dip of bedding planes; evaluating stratigraphy based on field observations, water well logs, and production well logs for the site; identifying evidence of faulting; developing a geologic conceptual model; and preparing cross-sectional diagrams.  The estimated cost for this work is One Thousand Three Hundred dollars ($1,300.00).

11.  Soil Gas Sampling – A soil gas sample from the Bouvier residence seep area will be collected and analyzed for composition and stable isotopes.  The sample will be collected using a hand-pump and a mylar bag and submitted to Isotech Laboratory in Champaign, Illinois for analysis under a rush turn-around-time.  The estimated cost for this work is  Eight Hundred dollars ($800.00).

12.  Soil Gas Survey at Nearby Abandoned Production Wells - A licensed surveyor will be used to locate the three (3) abandoned well sites (the Trinidad MGP #1 Well (API 05-071-06045), the Trinidad MGP #2 Well (API 05-071-06070), and the Trinidad MGP #3 Well (API 05-071-06048)),  based on existing plat maps and other data in the COGCC well files.  Once the well locations are identified, soil gas surveys will be conducted.  Soil gas surveys at the abandoned well sites will use a 300-feet by 300-feet survey grid with a 100-feet grid spacing and additional survey points adjacent to the well marker, if one is found.  The estimated cost for this work is Two Thousand Eight Hundred dollars ($2,800.00).

13.  Inspection of Residence East of Primero School Bus Garage – A soil gas survey around the perimeter of the residential structures located 300 feet east of the Primero School bus garage will be conducted.   The interiors of the buildings will be monitored to determine whether methane is present.  Given the close proximity of these residential structures to the seep area at the bus garage, it is prudent to determine if the occupants of these structures are threatened by the potential accumulation of explosive vapors in confined spaces.   The horizontal extent of seepage at this property will be mapped.  The estimated cost for this work is Eight Hundred dollars ($800.00).

14.  Soil Gas Survey at Mine Corehole in Section 32, Township 33 South, Range 66 West – An attempt will be made to find the mine corehole (M39) which is located in Section 32, Township 33 South, Range 66 West, approximately 2,400 feet east of the Bouvier residence.  If the corehole is found and if access to the property is obtained from the land owner, then a soil gas survey will be performed to determine whether methane is seeping from the corehole.  The estimated cost for this work is Eight Hundred dollars ($800.00).


15.  Indoor Air Quality Testing - Indoor air quality testing of the Primero School bus garage will be conducted under the direction of a Certified Industrial Hygienist (CIH).  The testing will include sampling for methane concentration within the building, particularly during periods of time when the building is not in use (evenings and weekends).   Two (2) samples from five (5) locations over 8-hour and 48-hour periods will be collected and analyzed.  The estimated cost for this work is Seven Thousand Five Hundred dollars ($7,500.00).

16. Methane Detection Systems - Methane detection systems will be installed in the residential structures located southeast of the Bouvier residence, the bus garage at the Primero School, the residential structures west of the bus garage (especially those located within 40 feet of the seepage) and if possible the residential structures east of the bus garage.  Three detectors will be installed in the residence near the Bouvier residence, two detectors in each of the three houses closest to the bus garage, two detectors in the house east of the bus garage, and three detectors in the bus garage for a total of at least 14 detectors.  The detectors will be solid-state, will not require calibration and contractor maintenance, and will be designed for residential use.  The sensors will be hard-wired into the existing electrical system.  If required, additional monitoring equipment will be installed in other structures.   The estimated cost for this work is Eighteen Thousand Five Hundred Fifty dollars ($18,550.00).

17.  Subsequent Soil Gas Surveys – At least one additional soil gas survey at the Bouvier residence and Primero School will be conducted.  The survey event will be performed in a manner similar to the previous soil gas surveys.  The follow up survey will be useful in evaluating changes over time and may assist in the identification of the source of the seeping gas.  The estimated cost for this work is Five Thousand dollars ($5,000.00).

18.  Well head Detection - Once the debris from the Bouvier residence is removed from the site, a metal detector will be used to attempt to locate the Trinidad MGP #1 Well (API 05-071-06045).   A backhoe will be used to excavate the area and uncover the well head for inspection.  The estimated cost for this work is Two Thousand Five Hundred dollars ($2,500.00).

19.  Meetings/Presentations – The contractor will attend meetings and prepare presentations regarding the results of this investigation at the request of the COGCC.  This includes meetings with COGCC staff and Commissioners, county officials, and other interested parties.  The estimated cost for this work is Three Thousand dollars ($3,000.00).

20.   Reporting - All field activities will be summarized in letter reports.  The reports will include maps illustrating the location of soil gas survey probes and the concentration measured at each location.   Pertinent photographs of the areas will be included in the reports.  Other pertinent tables, figures, and supporting documentation will be presented, as necessary.  The first report will include the findings of the initial soil gas surveys, water well investigation, surface geology reconnaissance, soil gas sampling, and soil gas surveys at abandoned well locations.  Indoor air quality testing work plan and results, subsequent soil gas survey, and well head detection activities will be summarized in separate reports.  The estimated cost for this work is Sixteen Thousand dollars ($16,000.00).

21.  Project Management and Technical Assistance - This task includes the costs for labor and expenses required for project management and for providing technical assistance to the COGCC staff in investigating the methane seep at the Bouvier residence and Primero School such as conducting research, providing recommendations for additional assessment and/or mitigation, or additional data evaluation.  The estimated cost for this work is Ten Thousand dollars ($10,000.00).

22.  The facts set forth in the foregoing paragraphs Finding No. 1 through Finding No. 21 are the reasons that the Commission finds the immediate issuance of this emergency order is imperative for the preservation of public health and safety and that observance of the requirements for notice and hearing pursuant to §§24-4-105 or 34-60-108(2), C.R.S. (2004) would be contrary to the public interest.

23.  The COGCC was appropriated Three Hundred Twelve Thousand Thirty Three Dollars ($312,033) in fiscal year 2006-07 for the Environmental Assistance and Complaint Resolution line item.  These funds are regularly expended throughout the fiscal year, July 1 through June 30, on environmental projects to investigate, prevent, monitor, or mitigate conditions that threaten to cause, or that actually cause, a significant adverse environmental impact on any air, water, soil, or biological resource and to investigate alleged violations of any provision of Title 34 Article 60 C.R.S., any rule, or order of the Commission, or any permit where the alleged violation threatens to cause or actually causes a significant adverse environmental impact.  As a result, most of these funds are already committed for fiscal year 2006-07, leaving an insufficient balance to fund the anticipated activities associated with the investigation of the significant adverse impacts to public health, safety, and welfare associated with the explosion at the Bouvier residence.  A more appropriate source of funding is the Emergency Response line item, which was established by the legislature for the first time in fiscal year 2006-07.  This line item gives the COGCC access to One Million Five Hundred Thousand dollars ($1,500,000) from the Oil and Gas Conservation and Environmental Response fund for the investigation, prevention, monitoring, and mitigation of circumstances which are caused by or are alleged to be associated with oil and gas activities and which call for immediate action by the Oil and Gas Conservation Commission.  An emergency creates a threat to public health, safety, or welfare or to the environment as proclaimed by the Oil and Gas Conservation Commission Director and approved by order of the Oil and Gas Conservation Commission. 

24.  The total estimated cost for all of the different aspects of this complicated investigation project is Seventy Four Thousand Nine Hundred Fifty dollars ($74,950.00).  In accordance with §34-60-124(7), C.R.S., the Commission should authorize the expenditure of  Seventy Four Thousand Nine Hundred Fifty dollars ($74,950.00) from the One Million Five Hundred Thousand dollars ($1,500,000) Emergency Response line item for the investigation of the cause of the explosion at the Bouvier’s residence and lingering impacts associated with methane seepage in the area.

25.  If the source of the flammable gas causing this emergency situation is found to be related to oil and gas operations and if a responsible party is identified, then in accordance with §34-60-124(7), C.R.S., attempts to recover expenditures from the Oil and Gas Conservation and Environmental Response from the responsible party(ies) will be made.



















































Data compiled by: Shane Davis
Source: COGCC







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