DEPARTMENT OF NATURAL RESOURCES Bill Ritter, Jr., Governor

Lisa Bracken Complaint 200277433 October 19, 2010

October 19, 2010

Certified Mail Return Receipt Requested #7010 0290 0002 2752 5635 Ms. Lisa Bracken 6548 CR 331 Silt, Colorado 81652 RE: Complaint 200277433 West Divide Creek Gas Sample Analysis

6548 CR 331 Silt, Colorado 81652

NWNW 12 7S 92W, Garfield County, Colorado Dear Ms. Bracken: As you know, the Colorado Oil and Gas Conservation Commission (COGCC) conducted a field trip to your property on August 17, 2010 to install flagging in areas of concern for a soil gas survey Encana was preparing to conduct on your property. During that site visit, you showed me a stretch of West Divide Creek where a sizeable volume of gas bubbled out of the creek bed when you walked on it. I entered your observation as a complaint into our database system so there is a means of tracking this observation. The complaint number associated with this observation is 200277433. Due to our scheduling conflicts, the earliest that I could conduct a second field visit to your property with equipment to collect a sample of the gas which bubbled out of the creek bed was on September 1, 2010. One sample was collected on September 1, 2010 for gas composition, isotopic and carbon 14 (C14) analysis. The sample was received by Isotech Laboratories Inc. (Isotech) in Champagne, Illinois on September 7, 2010. This letter summarizes the results of the chemical analyses of that sample and provides some reference documents for your use.

FIELD SAMPLING

As previously stated, I visited your property on September 1, 2010 with Ken Walter, an environmental consultant working on behalf of the COGCC. This was also the day that Vista Geosciences (Vista), on behalf of Encana, was conducting a walking soil gas survey on your property in the same vicinity. You, Ken, and I went to the northern portion of your property, near the location where West Divide Creek intersects your eastern fence line. I did not observe effervescence or bubbles in the creek water as we walked beside the stream. The water was clear and I did not notice any odor of hydrogen sulfide (rotten eggs) from the water (Attachment 1, Photo 1). Ken took photos and a video of the sample collection process. When you walked over the creek bed in the area of concern, vigorous bubbling commenced around your feet, although at a slightly slower rate than it did when we were out there on August 17, 2010. I collected a sample of the bubbles by first filling a 1-liter plastic container with water from West Divide Creek, then placing the full bottle over a funnel under water, and then placing the funnel-bottle sampling apparatus over the bubbles coming

DEPARTMENT OF NATURAL RESOURCES Bill Ritter, Jr., Governor

707 Wapiti Court. Suite 204 Rifle, CO 81650

Phone: (970) 625-2497 FAX: (970) 625-5682

www.colorado.gov/cogcc


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up around your feet (Photo 2).The sample was collected by letting the bubbles of gas displace the water in the plastic bottle, filling the 1-liter bottle three quarters full of gas. Some creek water remained in the bottle at the time when the bottle was capped under water. A pink biocide capsule was attached by the laboratory to the lid of the bottle with silicone, so that the biocide dissolved in the water, killing any bacteria in the water, and turning the water pink (Photo 4). Removing living bacteria in the sample container allowed for retention of the gas sample in the same condition in which it was collected, so that no further alteration of the gas sample by biologic processes occurred during shipment to the laboratory. Vista Geoscience personnel conducted their soil gas survey in the same portion of West Divide Creek immediately after I collected the stream bed gas sample (Photo 3). Vista personnel observed the same occurrence of gas bubbling out of the creek bed when it was stepped upon, and they collected a separate sample of the gas. Results of Vista’s gas sample will be included in the soil gas survey report Encana prepares. The sample I collected with you was labeled with the name “NLB-WDC-StBedGas”, a shorthand notation for “Northern Lisa Bracken [property,] West Divide Creek, Stream Bed Gas”. The sample container was transported after sample collection in an inverted position at all times, so that the gas was trapped in the bottom of the container (which pointed upward) (Photo 4), and the container’s lid with the water above it was below the gas. In this manner, the gas has no chance of escaping from the bottle, and a leak of the stream water could be noticed before the gas sample was compromised. No leakage of water from the bottle occurred during transport.

SAMPLE SHIPMENT

The gas sample was collected late in the day on September 1, 2010. It was placed on ice for storage the next day, prior to packing for shipment to the laboratory (Photos 5 and 6). An error on the Federal Express air bill precluded my being able get the sample shipped before the end of the day on September 2, 2010. I spoke with the Isotech laboratory manager Steve Pelphrey regarding my concerns about holding time for this gas sample. Steve reported to me that if biocide is present in the water in the sample container, then the sample will hold, without alteration of the gas chemistry, for up to a month. The sample could not be shipped on September 3, 2010 for delivery on September 4, 2010, because Isotech was not open on Saturday for sample receipt. The following Monday, September 6, 2010 was a national holiday and Isotech was not open that day either. For these reasons, I held the sample, on ice, over the holiday weekend prior to shipping it on ice, via Federal Express (air bill 8722-9432-7586) on Tuesday, September 7, 2010. Isotech received the sample on September 8, 2010. SAMPLE ANALYTICAL RESULTS

The laboratory data report from Isotech Laboratory, Inc. is included as Attachment 2.

Gas Composition Analysis

The gas produced from the oil and gas wells around your property is “thermogenic” and it is produced from the Williams Fork Formation of the Mesa Verde Group. Thermogenic gas from the Williams Fork Formation was formed by the thermal breakdown of organic material which was placed in rocks over 65 million years ago. High temperatures created by deep burial over geologic time break down organic material and forms “thermogenic” gas. In this area thermogenic gas typically contains methane (C1), ethane (C2), propane (C3), iso-butane (iC4), normal butane (nC4), iso-pentane (iC5), normal pentane (nC5), and hexane (C6). Biogenic methane gas occurs in most near-surface environments and is a principal product of the decomposition of buried organic material by bacteria. Naturally occurring biogenic gas contains mostly methane (C1), but may contain a small amount of ethane (C2).


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Laboratory results from the creek bed gas sample indicated that only a very small amount of methane (C1) was present (1.41%). No hydrocarbon gases heavier than methane were detected. The absence of propane (C3), iso-butane (iC4), normal butane (nC4), iso-pentane (iC5), normal pentane (nC5), and hexane (C6) would indicate that the gas is from a biogenic source not a thermogenic source and, therefore, not related to oil and gas wells in the vicinity of your property. The air we breathe consists mostly of nitrogen (78%), oxygen (20%), argon (1%), and carbon dioxide (CO2, 0.03%). The results from this sample show that most of the gas in the sample is a mixture of gases at concentrations similar to the concentrations of those gases in the air (except for the methane and CO2, which are elevated relative to air).

Analyte Air concentration (percentage)

NLB-WDC-StBedGas Sample concentration (percentage)

N2 (nitrogen) 78.1%

76.87%

O2 (oxygen) 20.9%

20.59%

Argon 0.93%

0.919%

CO2 (carbon dioxide) 0.03%

0.21%

CH4 (methane) 0.00015%

1.41%

The volumes of these gases in the creek bed sample are similar to common air, with minor amounts of methane and CO2. The source of the air in the creek bed is unknown, but may be attributed to air flushed out of the soil and rock by percolation of irrigation water up gradient or uphill of the creek.

Isotopic Analysis of Methane

• The deuterium/hydrogen isotope ratio for the methane in the creek bed gas sample is –377.7 parts per mil (‰).

• The carbon-13/carbon-12 isotope ratio for the methane in the creek bed gas sample is -60.56 ‰. I have included a cross-plot of the stable methane isotopes for the creek bed gas sample to help discuss the sample results in Attachment 3. On the cross-plot you will notice the area near the top right corner labeled as “Thermogenic Gas”. This is the area of the cross-plot where the methane produced by the gas wells in this area would plot. The creek bed gas plots in the area below that defined as “Near Surface Microbial Gas” which is methane gas of a biogenic origin. The results of this sample are similar to the results of five previous samples collected by the COGCC in 2004 and 2007.


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Carbon 14 Analysis of Gas

Hydrocarbons, including methane, are composed of carbon and hydrogen atoms. Carbon dioxide is composed of carbon and oxygen atoms. The Carbon 14 (14C) analysis age dates the carbon atoms present in a sample, regardless of which molecule (methane or carbon dioxide) the carbon is associated with. Thus, 14C analysis can provide an estimate of age of the organic material that was the source of the methane or carbon dioxide. This age date can in turn help determine the source of the gas in a sample. An excellent reference paper regarding the geochemical fingerprinting for gas identification is included as Attachment 4 for your reference. It provides a discussion of 14C presence in the environment and its use in gas identification, from which the following is a quote:

All living things contain 14C, which is formed in the upper atmosphere. When plant material decomposes to methane, the methane will contain approximately the same concentration of 14C as the organic material from which it was formed. The half-life of 14C is 5,730 years. Using sensitive analytical equipment, one can measure the concentration of 14C in organic materials that are less than about 50,000 years old…. Because the atmospheric testing of nuclear devices in the 1950s and 1960s produced substantial amounts of 14C enriched carbon dioxide and because all plants and animals attain their carbon either directly or indirectly form the atmosphere, all plant or animal material that has grown since approximately 1960 has 14C concentrations above the natural levels. This elevated 14C concentration can be utilized as a tracer…14C concentrations are expressed as percent modern carbon (pMC) where 100 pMC is defined as the “natural” (pre-bomb) 14C concentration of atmospheric dioxide…Because thermogenic gases are generally formed from organic materials that are millions or hundreds of millions of years old, thermogenic methane does not contain any detectable 14C. Because of this, 14C analysis provides an easy way of unequivocally differentiating thermogenic methane from that formed by the bacterial decomposition of more recent organic materials….And because the 14C fingerprint is not affected by secondary alteration, it can be used to unequivocally identify methane from sources such as landfills and marshes.

The 14Cconcentration in the gas sample collected from the creek bed was 107.3 (+/- 0.4) % modern carbon (pMC), and is included in the Isotech report in Attachment 2. The reason that the percentage is greater than 100% is that the carbon is sourced from organic matter that formed when the 14C concentrations of atmospheric carbon dioxide were elevated as a result of above ground nuclear testing conducted worldwide (since about 1955). If the gas sample from the creek bed originated from thermogenic gas, regardless of the amount of modification by bacteria, no 14C could have been detected.

CONCLUSIONS

Based on the analytical results of this sample, it does not appear that the creek bed has been impacted as a result of nearby oil and gas operations. The results of the 14C analysis support the conclusions drawn from both the compositional and stable isotopic results for the sample. The conclusion drawn from all three analyses indicate that the gas sample we collected is predominantly air, with small amounts of methane and carbon dioxide. The methane and carbon dioxide were created by bacteria decomposing recent organic materials and are thus biogenic in origin.


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Attachment 1- Photo Log of Sample Collection


Photo 1 Location in West Divide Creek where gas sample

was collected

Photo 2 NLB-WDC-StBedGas Sample collection

Photo 3 Vista Geosciences personnel conducting soil

gas survey in same area

Photo 4 Inverted sample container,

biocide biocide turned water pink


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Photo 5 Preparing sample for shipment, container inverted

Photo 6 Sample ready for shipment, packed with ice and bubble wrap


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Attachment 2 –

Isotech Laboratory Gas Sample Data Report


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Attachment 3 – Isotopic Gas Plot


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Attachment 4 - Publication: Advances in the Use of Geochemical Fingerprinting for Gas Identification

Documents

DEPARTMENT OF NATURAL RESOURCES Bill Ritter, Jr., Governor