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The pressure gradient (from ground level) represented by <br /> 2,367.4 psig at the casing shoe = 2,367.4 psi/3,660 ft = 0.65 psi/ft. <br /> Based on other leakoff test data in the Nortonville, the maximum test gradient of <br /> 0.65 psi/ft fell short of formation breakdown, and a wellhead pressure limitation higher than 779 <br /> psig is justifiable. The Victor Fine Foods wastewater disposal well at Lodi (VFF Deep Injection <br /> Well No. 1) was tested to incipient breakdown at a 0.73 psi/ft gradient in the Nortonville. <br /> Applying this value as a reasonable estimate of the incipient breakdown gradient at the NCPA <br /> Lodi STIG #1 site, the corresponding water injection wellhead pressure would be calculated as <br /> follows: <br /> (0.730 - 0.434)psi/ft * 3,660 ft = 1,083 psig <br /> To arrive at a reasonably conservative injection pressure limitation for the NCPA well, this <br /> calculated pressure is reduced by 10 percent. <br /> Recommended injection pressure limitation = 0.9 * 1,083 psig = 975 psig <br /> This pressure is equivalent to a gradient of 0.70 psi/ft at the shoe of the 7-in. casing. <br /> In reality, a limitation of 975 psig is slightly more conservative than indicated by the <br /> above calculations. This is because NCPA Lodi STIG #1 has a cemented liner, and pressure <br /> in the Domengine will be confined at the base of the Nortonville (3,747 ft KB) which is 87 ft <br /> deeper than the shoe of the 7-in. casing. <br /> Mesquite Group, Inc. -35 <br />