08-16-02-14W2 SPILL 20141005.Pdf
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Project No.12633.01 RELEASE REMEDIATION OUNGRE 8-16-2-14 W2M SWD WELL HEAD RELEASE October 5, 2014 Prepared for Gibson Energy Partnership 617 Railway Avenue Weyburn, Saskatchewan S4H 0A9 December 12, 2014 Buffalo Head Projects: 12633.01 1 INTRODUCTION In response to a well head failure which resulted in the release of a mixture of oilfield waste water and production fluid from the Gibson Energy Partnership (Gibson) Oungre 8-16-2-14 W2M (8-16) salt water disposal (SWD) site, Gibsons contracted Buffalo Head Environmental Ltd. (Buffalo Head) to assess the release and direct remedial work required. This report outlines the initial release response and remediation work completed. 1.1 Background and Scope of Work On October 5, 2014, a leak occurred when a section of the 8-16 SWD well head corroded allowing a mixture of oilfield waste water and production fluid to be released. The fluid, which originated from the Gibson 1-16-2-14 W2M (1-16) waste processing facility (WPF), pooled within the disposal building before running out onto the gravelled access road. Fluid was temporarily retained by clay berms surrounding the well site but eventually was able to migrate north away from the well site and east out into an area of agricultural land. Fluid then ran approximately 95 meters east across the agricultural land before reaching the ditch bordering the west edge of Highway 35 (Figure 1). The leak was discovered by Gibson personnel a few hours after it had occurred and a vacuum truck was retained immediately to recover standing fluid from the surface of the spill area. Gibson personnel contacted Buffalo Head on the afternoon of October 5, 2014, to respond to the release and implement containment, recovery and remediation activities and ensure final remediation efforts met with the expectations of the Saskatchewan Ministry of the Economy, Petroleum Development Branch (ECON, PDB) and Gibson. From October 6 through October 8, 2014, Buffalo Head directed remedial efforts including a remedial excavation of impacted soils as well as collection of confirmatory soil samples. Fluid recovery during the initial response as well as reclamation of the remedial excavation was completed in-house by Gibson personnel. 2 SITE DESCRIPTION The 8-16 SWD is located 2.4 kilometres (km) south and 0.25 km west of Oungre, SK, within the Rural Municipality of Souris Valley, number 7, on agriculturally zoned lands currently used for agricultural cropping. As referenced in the Acton et al. (1995), The Ecoregions of Saskatchewan, the 8-16 SWD is located in the Lake Alma Upland within the Mixed Grassland Ecoregion of the Prairie Ecozone of Saskatchewan. The Lake Alma Upland is a hilly hummocky morainal area, representing the Missouri Coteau. It extends from Ceylon to the United States border. There is some drainage to Long Creek in The Gap and from several coulees along the escarpment; otherwise, surface drainage is limited to flow to local small lakes. Native mixed-grass prairie is limited to hummocky morainal landscapes, where it is interspersed with cropland. A more continuous grassland cover occurs in steeply sloping areas and coulees on the Missouri Coteau escarpment. A variety of grasses are common on the uplands, with shrubs limited to more moist depressional areas. Dark brown loam soils formed in glacial till deposits are common on all of these landscapes. Most of the Lake Alma upland is cropland. Cereals are the major crop. Pasture and rangelands are associated with local areas of hilly land. 110 Perkins Street Estevan, SK S4A 2L7 P: (306)634-5750 F: (306)634-5751 The regional soils information for the project area was referenced from the Weyburn and Saskatchewan Portion of the Virden Map Area. The spill area spans two separate local soil descriptions, Am2 and AmBk1. Amulet (Am) soils are dominantly dark brown soils formed in clay loam textured moderately calcareous glacial till. Brooking (Bk) soils are dominantly dark brown solonetzic soils formed in loam to clay loam textured, moderately calcareous glacial till. Am2 soils are mainly orthic Amulet soils with eroded and calcareous Amulet soils on knolls, and poorly drained soils in depressions. AmBk1 soils are mainly orthic Amulet soils with calcareous Amulet soils on knolls, and solonetzic Brooking soils in lower areas. Strong solonetzic soils are not common. The project area also spans two distinct soil salinity designations, 1MP and 2MP as derived from the Soil Salinity Map of the Weyburn-Virden Area, Saskatchewan. The 1MP designation is defined as soil where a few salt crystals are usually visible and under native conditions salt tolerant plants are present; 0-3% of the area is affected by salinity; average electrical conductivity (EC) of the 0-60 cm depth is 4-8 deciSiemmens per metre (dS/m); Saline soils occur on the edges of depression, sloughs or runways. All soils in the bottoms of the depressions are leached and non-saline. These areas generally occur on relatively level or very gentle regional slopes. The 2MP designation is defined as soil where a few salt crystals are usually visible and under native conditions salt tolerant plants are present; 3-10% of the area is affected by salinity; average EC of the 0-60 cm depth is 4-8 dS/m; Saline soils occur on the edges of depression, sloughs or runways. All soils in the bottoms of the depressions are leached and non-saline. These areas generally occur on relatively level or very gentle regional slopes. 3 METHODOLOGY 3.1 Initial Spill Response and Remediation Gibson personnel shut in the 1-16 WPF, which feeds the 8-16 SWD, upon discovery of the leak on October 5, 2014, and contracted Brady Oilfield Services (Brady) of Halbrite, SK, to supply a vacuum truck to recover standing fluid from the surface of the spill area. A total of 3.0 cubic meters (m3) of fluid was recovered as part of the initial response and transported to the Gibson Midale WPF near Midale, SK, for disposal. Gibson personnel then initiated emergency response by completing notifications to Buffalo Head and the Saskatchewan Ministry of the Economy, Petroleum Development Branch in Estevan, SK. Buffalo Head responded to the release on October 6, 2014. Upon inspection it was determined the release had occurred due to a corroded section of the well head which allowed an unknown volume of oilfield waste water and production fluid to be released from the well head. Fluid pooled within the disposal building before running out onto the gravelled access road (Photos 1 & 2). Fluid was temporarily retained by clay berms surrounding the well site but eventually was able to flow north away from the well site and east out into an area of agricultural land (Photos 3-5). Fluid then migrated approximately 95 meters east across the agricultural land before reaching the ditch bordering the west edge of Highway 35 (Figure 1). Preliminary field screening was completed using an EC soil probe with conductivities regularly exceeding field screen detection limits of 20 dS/m through the centerline of the spill; background conductivities varied between 1.6 and 2.2 dS/m. A water sample was taken from a small volume of fluid (<1 litre) which had collected in a low depressional pocket in the west ditch bordering Highway 35. The sample was field screened for EC and chloride concentration with results exceeding detection Limits of 20 dS/m and 6,627 mg/L respectively. An emergency request was placed with Sask1stCall and Quest Line Locating (Quest) of Estevan, SK, was contracted to locate any buried facilities and to perform a three way sweep of the spill area in preparation for remedial excavation. A flowline and power cable running Page 2 of 7 from the 1-16 WPF to the 8-16 SWD as well as a cathodic system was located and staked in addition to a Saskpower cable running north-south through the spill area east of the 8-16 SWD. Tristen Hydrovac (Tristen), of Regina, SK, was retained to complete daylighting of the power cables, flowline and cathodic lines within the proposed remedial excavation area (Photo 6). On October 7, 2014, Buffalo Head arranged to have Torrent Energy Services (Torrent) of Weyburn, SK, supply a trackhoe and end dump trucks to excavate impacted soil from the spill area and haul to the Gibson Heward Landfill, near Heward, SK, for disposal (Photos 7-10). An EC soil probe was used to field screen and guide the excavation. A total of 198.9 metric tonnes of soil was loaded and hauled to the treatment pad at the Gibson Heward Landfill. On October 8, 2014, Buffalo Head arranged to have Torrent supply a trackhoe and end dump trucks to recover any remaining impacted soil and haul to the Gibson Heward landfill for disposal (Photos 11-14). An additional 144.2 metric tonnes was recovered for a total of 343.1 metric tonnes hauled to date. The excavation area was measured using differentially corrected GPS and revealed a total surface area of 1,159 m2. The area in the vicinity of the well head which was not scraped measured approximately 50 m2. Residual field measured conductivities ranged from 1.5 to 3.4 dS/m across the remedial excavation. Following impacted soil removal, Buffalo Head recovered soil samples from the spill area which were then relinquished to AGAT Laboratories (AGAT), in Calgary, AB, for analysis. On October 23, 2014, Gibson personnel completed reclamation of the remedial excavation which, as reported by Gibson, required the importing and placement of approximately 40 m3 of clay and 230 m3 of topsoil. Following the placement of the material using a rubber-tired backhoe, a grader was retained to re-contour the surface of the reclamation area (Photos 15 & 16).