2012-03-14_REVISION - P2010026 (4)

Home Browse Search

The project comprises 21 wells for leaching, heating and observation (Figure 24) plus an array of downgradient ground water monitoring wells. Plans call for all wells to be drilled prior to the leaching phase. Wells will be drilled with directional control, with a design deviation from vertical of —4 ft at 2,000 ft depth ( -8 ft diameter). Total depth of the deepest well is projected to be <2,350 ft. The deepest will be the leach well; others will be drilled to —2,255 ft, and some may be drilled up to 20 ft deeper than their functional depths to accommodate electrical logging tools. Domestic use water will be transported to the site from outside sources for use in all drilling. This follows Shell's standard drilling methods for drilling in the Piceance Basin. Drilling water typically is supplied from the Meeker public water supply. Cuttings and drilling fluids will be routed to an unlined pit for disposal. Wells will be drilled with air mist and common water well drilling lubricants. The leaching and heating zone will include leach, heater, hydrocarbon producer, and observer wells. Some wells will contain pressure or temperature sensors. Each will comprise a conductor casing cemented into shallow bedrock and an intermediate casing set at the top of the leaching and pyrolysis zone and cemented in place. The heater wells form two hexagonal patterns with maximum diameter of 18.5 ft (Figure 25, Figure 30). Two producer wells flank the central heater (leach) well, and six observation wells will monitor temperature during the heating and pyrolysis phases — three inside the heater pattern and three outside. Geological conditions at the East RDD are very well informed by the recent drilling of Shell appraisal well 135 -4 -298 (SAW -1 well) and 5 hydrology wells on the 138 -4 -298 Pad, which is approximately 500 ft northeast of SAW -1. Ground water is expected at about 250 ft depth, based on the water level in well 135 -4 -298 (SAW -1 well). Wells drilled by Shell in the Piceance Basin in the past 10 years generally encountered small amounts of gas, particularly in the deeper formations. The gases contain mostly N and CH with lesser volumes of O and CO (Schatzel et al, 1987 [14]). Hydrogen and ammonia may be present. Samples collected in closed containers for up to 125 days contained up to 0.195 cm /g of gas. A sulfur odor often is detected in drilling of Uinta and some of the shallow Parachute Creek wells. Although TEL (lower explosive limit) measurements are checked at all wells during drilling, and even though methane and sulfur gas occur typically, LELs have never been exceeded. When unusual gas levels are encountered, drilling is shut down and the well is allowed to vent. Notice of Intent 36 Shell Frontier Oil & Gas Inc. December 2010