Denbury fined $662,500 for Mississippi blowout of CO2 injected in high pressure enhanced oil recovery, So much carbon dioxide came out that it settled in hollows, suffocating deer and other animals by the Newstar.com, July 26, 2013
Denbury Resources promises to bring new life to old oilfields by pumping in carbon dioxide to force additional oil to the surface. But the company’s oilfields have seen a series of uncontrolled carbon dioxide blowouts that may bring up oil and drilling fluids with them, including one last month near Delhi. One of the biggest such incidents has resulted in Denbury agreeing to pay a $662,500 fine to the Mississippi Department of Environmental Quality over a 2011 oil well blowout in Yazoo County. It’s one of the largest environmental fines Mississippi has assessed in the last 10 years. And questions linger about whether Denbury and other companies pumping carbon dioxide underground are doing enough to ensure long-abandoned oil wells are safely capped and can stand up to the pressure that forces up the oil.
Denbury has had at least two other Mississippi blowouts since 2007. It has been fighting the release near Delhi since June 13, where carbon dioxide and drilling fluids broke through the ground’s surface. Denbury, based in Plano, Texas, said the technique is decades old and it operates safely. “Prior to commencing injections of carbon dioxide into an oilfield, Denbury creates a development plan that includes an analysis of previously drilled well records,” spokesman Ernesto Alegria wrote in an email this week. “Denbury’s primary objective in creating the plan is to develop these fields in the safest and most efficient manner.” In 2007, the company saw carbon dioxide releases in Mississippi’s Lincoln and Amite counties. In December 2007, a few Amite County homes were evacuated after a well Denbury was working on blew out. By that time, some in southwest Mississippi had warned that the pressure of the carbon dioxide could cause wells that had been capped decades earlier to rupture.
Environmental regulators said that’s what happened at an abandoned well south of Yazoo City. The well’s metal pipe had been stripped and the 2,000-foot-deep hole vented carbon dioxide, oil and drilling mud for 37 days starting Aug. 9, 2011. So much carbon dioxide came out that it settled in some hollows, suffocating deer and other animals, Mississippi officials said. The company ultimately drilled a new well to plug the old one, and removed 27,000 tons of drilling mud and contaminated soil and 32,000 barrels of liquids from the site. “It had serious impacts in the immediate vicinity,” said Richard Harrell of the Mississippi DEQ. Monitoring wells show no contamination in underground water supplies. That’s a threat because the well crosses an aquifer used for drinking water in the Jackson area. Deeper down, it also crosses the Sparta aquifer, a significant drinking water source across the entire lower Mississippi Valley.
“Denbury has worked with government and local officials and agencies to thoroughly remediate any isolated and unrelated releases of well fluids in our operated fields,” Alegria said. Harrell said Mississippi fined the company because officials believe Denbury should have more closely inspected abandoned wells before it began injecting carbon dioxide. Instead, the company may have relied too much on paper records of old wells at the Mississippi Oil and Gas Board. More serious is what some people have termed an “underground blowout” near Delhi in another old oil field that Denbury is reviving. … It was detected in Franklin Parish when a monitor showed unsafe concentrations of methane in the air. At first, authorities suspected a natural gas pipeline, but Louisiana Department of Natural Resources spokesman Patrick Courreges said it now appears two or more plugged wells gave way underground. Methane, carbon dioxide, oil, water, brine and sands pushed up through the earth in a sparsely populated, marshy area. Concentrations of carbon dioxide were so high initially that Courreges said responders wore breathing apparatus to keep from suffocating. Courreges said Denbury has stabilized the situation by pumping in “kill fluid” — water with lots of calcium chloride that forms a barrier keeping carbon dioxide from surfacing. He said hundreds of Denbury employees and contractors continue working in the area. … When the company injects the carbon dioxide into the shale, it increases the pressure beneath the earth’s surface from a natural 1,400 to 1,500 pounds per square inch to about 1,800. Franklin Parish Sheriff Kevin Cobb has said he considers the leak “a big deal and a major concern,” and Richland Parish Sheriff Lee Harrell has expressed similar concerns. Harrell said Denbury officials “have told us it could take as long as eight months” to resolve. Courreges said this is the first time Louisiana regulators are aware carbon dioxide has vented to the surface in such large quantities. He said a cleanup will be needed, but because the investigation is still going on, he couldn’t speculate about whether the state would fine Denbury. … Denbury is using the same technique in Texas, Wyoming and Montana. Alegria said Denbury “works to apply the information gained from operating these floods to further improve their safety and efficiency.” [Emphasis added]
Pfffft Goes Promise of Pumping C02 Underground by Andrew Nikiforuk, January 12, 2011, The Tyee.ca
At the time EnCana Corporation (now Cenovus Energy) had started to flood the aging crude field with gallons of salt water and tonnes of CO2 piped from a North Dakota coal gasification plant nearly 320 miles away. … Around the same time Cameron and Jane Kerr, who own nine quarters of land in the midst of the project, started to notice some leaks.
For the record, the couple have 16 abandoned, producing or injecting wells within 1.6 kilometres of their land. Scientists have long noted that nearly 1,000 production and injection well sites on top of the project could act like wicks and draw up CO2 into the atmosphere. In 2003 the Kerrs dug a gravel pit to service EnCana’s oil roads. After the pit promptly filled with water, the Kerrs observed strange doings including foaming, discolouration and hissing bubbles. They also discovered the carcasses of dead ducks, a rabbit and a goat by the pit. When several gaseous explosions rocked the pond in 2007, the couple moved to Regina. “We have a problem and no [one] wants to properly investigate it,” Jane Kerr told Canadian Business at the time.
Although the Saskatchewan government promised to do a year-long study on the farm’s air, water and soil, the Kerrs say it never happened. What they got instead were a few ad hoc day-long tests and nothing more. … Unlike so-called government and industry experts intent on declaring the safety of carbon cemeteries before the evidence is in, Lafleur found lots of CO2. Using tried and true carbon sensors designed to detect oil deposits, Lafleur discovered dangerously high concentrations of the gas on the Kerr’s property. … In one location alone Lafleur detected concentrations as high as 110,607 parts per million (ppm), twice the amount needed to asphyxiate a person. Near the Kerr’s home he also recorded concentrations of 17,000 ppm, a level “that far exceed the threshold level for health concerns.”
As a consequence “CO2 could enter the home in dangerous concentrations through the crawl space due to negative pressures caused by a natural gas heating furnace.” Given that Cenovus’s closest injection well lies a mile away from the Kerr home, Lafleur concluded that the CO2 was probably seeping through open fractures and faults that intersect the Weyburn field. In other words, there were cracks in the cemetery. In addition a Saskatchewan lab confirmed that the CO2 found at Kerr’s place clearly originated from “the CO2 injected into the Weyburn reservoir.”
When the Kerrs and Ecojustice presented this information to the government and Cenovus nearly four months ago, they got a lot of silence. [Emphasis added]
[Refer also to:
A Case History of Tracking Water Movement Through Fracture Systems in the Barnett by P. Handren, March 2011, Shale EPA Workshop
“As well density increases it becomes increasingly probable that wells will communicate either through previously created fractures or through adjacent wellbores and then into previously created fractures.” [Emphasis added]