Normal Rocky Mountain operating procedures have been modified to conform with special conditions found in the non-marine Tertiary section. Hard abrasive rocks, fracturing, numerous hydrocarbon shows, intermediate gas and water sands, and high pour point oil have governed the choice of methods. Low penetration rates, extensive coring, and testing to adequately evaluate productivity and distinguish the contents of potentially productive zones result in high drilling costs. Recurring loss of circulation below the top of the Green River sands and siltstones have contributed to high drilling fluid costs. Penetration rate has been increased considerably by increasing drilling weight above 25,000 lbs. Loss of circulation has ben reduced by maintaining mud weight at a practical m nimum and pretreating with fine fibrous and granular material before drilling into the Green River. Usual completion practice is to cement 7" casing through the pay zone, gun perforate, run tubing, and swab. Except for oil squeezing of sandstone and acidizing of calcite-lined fractures, stimulation methods have not been helpful so far. Increased productivity of one well resulted from setting pipe on top of the pay and coring with oil indicates that this procedure may be desirable where conditions permit.

Rods for rod pumps are equipped with paraffin scrapers and downhole hydraulic pumps are operated with heated power oil to prevent wax accumulation in the tubing. After the oil reaches the surface, it is kept fluid by heating until mixed with less viscous oil on its way to the refinery.

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