Problems/Comments

Petroleum hydrocarbons released during drilling support operations and maintenance. The site consists of a gravel pad, a reserve pit, an inactive well, and three potential flare pits. There are two wells at the site: Kuparuk State 24-11-12, Well API # 50-029-20068-00, Kuparuk State 22-11-12, Well API # 50-029-20192-00. The Kuparuk 24-11-12 site assessment found three locations within the gravel pad which exceed potential cleanup levels for petroleum hydrocarbons GRO (gasoline-range organics), and DRO (diesel-range organics). Petroleum-contaminated gravel at Kuparuk 24-11-12 is categorized as both RCRA E&P exempt and non-exempt depending upon its location and origin. There is petroleum contaminated soil at two former flare pit areas that is recommended for removal based on a cleanup level of 500mg/Kg DRO. BPXA has scheduled the reserve pit and gravel pad for abandonment during winter 2005-2006. The gravel pad will be removed in its entirety regardless of contaminated levels to promote rehabilitation of the tundra. The Kuparuk 24-11-12 site is located approximately 22 miles west of the Prudhoe Bay Operating Center (PBOC) on the North Slope of Alaska. The gravel pad at the site is well compacted and it is approximately 850 feet in length, varying in width from approximately 100 feet on the eastern portion to 200 feet on the western portion. The maximum height of the gravel pad was approximately 5 feet, relative to the surrounding topography. The Kuparuk 24-11-12 site was used as an exploration pad for two wells. The current status of the Kuparuk 22-11-12 well is suspended and its location is marked by a wellhead tree. The Kuparuk 24-11-2-12 well has been plugged and abandoned and its location is marked by the well casing, extending approximately eight feet above tundra grade. The gravel pad is comprised of gray, fine to coarse gravel with a significant amount of sand and silt. Gravel size ranges from a quarter of an inch to approximately 3 inches in diameter. The pad is underlain by peat, silty sand, and native gravelly sand which is more fine grained and angular then that of the gravel pad. Large concentrations of gravel were observed overlying the tundra at three locations east and one location west of the site access road. The gravel west of the access road appeared to be mixed with a tar/crude oil material. The gravel east of the access road appeared to show minor amounts of salt damage and prevalent iron staining was observed in adjacent surface water bodies. A thin layer of gravel was also present on the tundra north of the gravel pad, and on both sides of the site access road prism. The thin layer of gravel extended 300 feet north of the gravel pad, and perhaps even further. The thin layer of gravel was poorly defined due to tundra reclamation. Three dark gray to black surface stains were observed on the gravel pad surface. The largest surface stain measured approximately 7 feet by 4 feet. Several areas of concern were noted along the gravel pad margin. Sheen tests produced moderate hydrocarbon sheen in a thermokarst trough extending into the tundra from the east pad margin. Strong hydrocarbon odors and iron staining were noted in the thermokarst trough. A small tundra pond located adjacent to the north pad margin was surrounded by iron stained and black stained gravel. Sheen tests produced moderated hydrocarbon sheen on the tundra pond. Sheen test also produced hydrocarbon sheen in localized areas along the south and west gravel pad margins. Approximately one-third of the pad surface is believed to contain CO2 soil gas at concentrations greater than 0.3%. URS submitted a letter describing the 2001 Site Assessment that the gravel pad areas are showing elevated CO2 concentrations (greater than 0.3%) should be evaluated in more detail. Additional information regarding the concentration and vertical distribution of suspected hydrocarbon contamination in these identified areas is recommended to determine future actions at the site.

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Requirements

No associated sites were found.