2012-12-12_REVISION - P2010026 (3)

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Casing in all other sections including a potential contingency casing string, will be cemented by displacement. With the displacement method, the casing is installed to the section TD then lifted a few feet off bottom to create a fluid pathway between the interior and exterior of the casing. Cement is next applied inside the casing and capped with a wiper plug. Water is then added to the column above the plug, providing weight that drives the cement down the casing and up the annulus until cement returns are observed at the surface. All wells — horizontal heaters and observer /producer — will be cemented with Premium Plus cement and additives (as recommended by laboratory tests and simulations) which may include but are not limited to dispersant agents, antifoam material, fluid loss agents, silica flour and extender or retardant additives with a 9.5 to 11.5 lbs /gallon (ppg) lead, and a 13.5 to 15.8 ppg tail. Once cement returns are observed at the surface, the cement will be allowed to set for the prescribed setting time (usually 8 hours). Cement recipe and slurry weight may change depending on laboratory tests and simulations, however all efforts will be made and best practices applied to ensure proper zonal isolation on each interval. A cement bond log and /or isolation scanner log will be run in each well after cementing. The cement bond log is an acoustic geophysical measurement that indicates the presence of cement as a measure of the degree of bonding in the annulus between casing and the drilled hole. 5.43 Conductor Casings Conductor casing will be installed at all wells. Conductors for both horizontal heaters and producer / observer wells will be in the range between 13 -3/8 in to 20 in with casing shoe placed from a depth of 60 ft to 200 ft and penetrating 3 ft minimum into bedrock. Possible conductor casings specifications are: • 13 -3/8 in O.D. (48 lbs /ft, H -40 Grade steel, STC or equivalent) • 20 in O.D. (94.01bs /ft, H -40 Grade steel, STC or equivalent). Casing will be cemented from T.D. to surface with type I /II neat cement, placed in the annulus via tremmie pipe or through stab -in cementation using a cement stinger and a float shoe. 5.4.4 Heater Wells The main function of the horizontal heater wells is to test the tendency for hotspots to form along the heater in three subsurface environments. For this purpose, two horizontal heater wells will be drilled in the Nahcolitic Oil Shale and one horizontal heater well in the Illitic Oil Shale. All horizontal drilling will occur below the dissolution surface. The minimum horizontal section requirement for active heating in each horizontal well is 1,000 ft with an additional pocket of 150 ft to compensate for the expansion of the canister during the heating process. As presented in table 6.1, horizontal heater well design (Figure 7) will consist of a 13 -3/8 in to 20 in conductor set into the bedrock and cemented to surface, followed by a 12 -1/4 in hole drilled to the end of the build -up section (i.e. 90° inclination) to run and cement to surface a 9 -5/8 in casing containing pressure transducers and bubbler tube ported to the casing ID. An 8.5 in open hole section will then be drilled along the heated interval to run a 4.5 in sealed canister from surface to 10