2012-03-15_REVISION - M1977300 - Laserfiche WebLink

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Whetstone Associates PLASTIC TUBING AIR LINE r 6// PRESSURE REGULATOR STUFFING CYLINDER BOX / NI / TI CORE DRILL ROD WIRELINE INJECTION PRESSURE GAUGE TOTALVJNG FLOW METER GROUND SURFACE BOREHOLE Technical Memorandum GLOBE VALVE VERFLOW TO TANK GLOBE BYPASS VALVE NONSURGING PUMP Figure 2. Example Above - Ground Assembly for Packer Permeability Tests The packer will be inflated using nitrogen gas from a high pressure cylinder connected to the down - hole assembly via a regulator and airline. There must be enough slack in the airline to allow full movement of the sliding ends of the packers without creating tensional stress on the fittings. A full inspection of the packer assembly and a trial inflation to 300 psi will be performed before deployment to look for nitrogen leaks. Short sections of steel pipe with approximate diameter of the borehole will be used to cover each packer during the trial inflation and soapy water will be used to inspect connections for gas leaks.. The airline will be zip -tied to the standpipe at ten- to 20 -foot intervals to prevent excessive slack which could snag on the walls of the borehole. Packer inflation pressure will be determined for each interval based on submergence so that the pressure is sufficient to compensate for the hydrostatic head on the section, the seating requirements of the packer, and the maximum differential pressure that will be created between the test zone and the overlying water column. The potential maximum hydrostatic head on the section will be about 750 feet (320 psi). The maximum differential injection pressure will be about 150 psi. The potential maximum inflation pressure for the packer assembly will be about 500 psi. After the packers are seated, it is necessary to wait for water levels to stabilize in the packed interval before beginning the injection permeability tests. Typical wait times are 10 minutes to more than one hour, depending on the formation permeability. Permeability tests for each interval will be performed in three to five steps of about three to five minutes duration each. Water will be injected into the formation during each step at constant pressure until the flow stabilizes. The flow will then be recorded for a three minute interval. Stable flow is an important condition of the test prior to recording the data, and in some cases, the procedure may require additional time to meet the stability criterion. Each section will be tested at three to five pressure steps starting at about 15 psi on the surface gauge and stepping up to a maximum of about 60 to 80 psi before stepping back down to the initial injection pressure. The total differential pressure on the section will be equal to the pump head (gauge pressure) + elevation head (pressure caused by the weight of the water column above the shut -in static water level) — frictional 4109C.120309 6