The placing on production of low-quality pay zones at giant Pinedale gas-condensate field in northwest Wyoming could increase the original gas in place estimate, said Ultra Petroleum Corp., Houston. “The significance of continually evaluating the low-quality pay is to provide necessary data to increase the OOIP estimate of Pinedale field and over time, increase Ultra Petroleum’s natural gas reserves and production,” the company said Aug. 5.
The company has completed 45 wells in low-quality pay with 178 frac stages, or about four fracs per well across about 450 ft of completed Cretaceous Lance/Mesaverde section for just the cost of perforating and the added frac stages.
“The results indicate that the low-quality pay is from uncontacted sand lenses near the wellbore that are beyond the detection range of logging tools,” the company said.
Ultra, with plans to have drilled 155 operated wells in Pinedale in 2008, is to have drilled 38 delineation wells this year compared with 13 in 2007. Reserves attributed to all delineation wells drilled so far averaged 120% of predrill reserve estimates.
Ultra drilled and cased 74 wells in the 6 months ended June 30, compared with 87 in all of 2007. Spud to TD averaged 22 days in the most recent quarter, down from 35 days in all of 2007, reducing well costs in spite of large steel price increases.
Further efficiency is expected from a Bureau of Land Management final supplemental environmental impact statement record of decision to be issued shortly that is to allow year-round drilling and completion in concentrated development areas.
Along with a large increase in the number of wells drilled, the full-year access is expected to enable operators to optimize development and limit environmental degradation (OGJ, June 16, 2008, p. 19).