“These were serious incidents that resulted in environmental degradation and the evacuation of citizens from their homes,” DEP Director of District Oil and Gas Operations John Ryder said. “The department has been working closely with Carrizo during the past year to ensure the company implements changes that will greatly minimize a recurrence of these incidents.”
The well control incident in Washington Township began in the early evening of March 13, 2013, during the hydraulic fracturing of the Yarasavage 1H well. Carrizo reported that production fluid was escaping uncontrolled from the gas well at a rate of 800 to 1,100 barrels per hour and was escaping containment.
Carrizo initially responded to the incident by implementing temporary containment, removing escaped fluid with vacuum trucks, and contacting a well control specialist company for assistance.
In anticipation that natural gas would be released from the well, an evacuation notice was delivered later that evening to four residences, and three families were evacuated.
The well was successfully shut in by noon on March 14 with about 5,400 barrels of production fluid recovered and secured in tanks.
DEP’s Oil and Gas program issued Carrizo a notice of violation letter on March 18 for violations of the Clean Streams Law, Solid Waste Management Act and Chapter 78 oil and gas regulations. The letter also requested a comprehensive list of detailed technical information be submitted, including proposed corrective actions and changes to the company’s completion and well control procedures.
In its response, Carrizo stated that the root cause of the release was a leak in the frack tree flange, potentially caused by a torque relaxation of the flange bolts. An analysis was also conducted to determine any defects in the material.
In response to the Yarasavage well control incident, Carrizo committed to evaluating several issues and implementing improvements where appropriate. Improvements were made to site security and safety programs, including employee training and contractor verification. Carrizo also implemented several technical changes to its hydraulic fracturing operations. Some of those key improvements are:
- Changes to the frack tree configuration, including removal of the spacer spool from the frack tree rig-up
- Assignment of a line boss to monitor for leaks during hydraulic fracturing
- Implementing staggered use of solid bridge plugs in fracking interval isolation, which allows the operator to torque check critical connections with the frack tree in a relaxed condition
- Performance of tree re-torqueing and maintenance during hydraulic fracturing operations at the determined optimum timing interval
The department plans to share Carrizo’s improvements with other operators so these operators may evaluate their operations and consider implementing similar changes where applicable.
In a second incident, Carrizo reported a spill of about 9,240 gallons at its Mazzara well pad in Washington Township to DEP on April 30, 2013. The fluid was production water from a Carrizo well pad in Susquehanna County as well as a bentonite clay and freshwater mix from a pipeline boring operation.
The spill occurred when a hose transferring the fluid from a truck to a tank slipped out of the tank’s ventilation port and fell out of containment, releasing fluid off the well pad.
The fluid migrated through the field stone foundation of a nearby private residence and discharged from a seep in the basement garage. It also traveled across the road to a pasture where livestock were raised requiring their temporary re-location.
DEP’s Oil and Gas Program staff requested Carrizo to sample potentially impacted residential and agricultural water supplies, and provide potable drinking water to them, which Carrizo did. The company also implemented a number of remediation measures in a timely manner.
The department issued a notice of violation letter to Carrizo on May 7, 2013 for violations of the Clean Streams Law, Solid Waste Management Act, and Chapter 78 oil and gas regulations. The letter also required that a sampling plan, engineering study and fluid handling analysis be submitted.
Carrizo’s response indicated that personnel conducting the fluid transfer operation failed to follow proper procedure.
DEP’s Environmental Cleanup and Brownfields program is overseeing the remediation at both well pads. Contaminated soil has been excavated and properly disposed, while periodic groundwater sampling by Carrizo continues.
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