Nitro-Lift System in the Barnett Shale
Vernon Daniels
Nitro-Lift Systems
Abstract
Operators in the Barnett Shale and other unconventional gas plays have the inherit problem of dealing with frac water both before and after the frac. Because of the massiveamounts of water it takes to open theshale fractures some wells do not flow-back as expected. The conventional ways to de-water the wells are the old reliables we all know swabbing, pump units, submersibles, foam units, etc. Nitro-Lift Technologies L.L.C. has developed a patent pending process which can be used by operators to de-water wells by making nitrogen on location then boosting the pressure and pumping the nitrogen down the annuluseither through valves or right around the end of the tubing.Although, complicated the process is working very well for operators in the Barnett and Woodford Shales.
The Nitro-Lift equipment separates atmosphere on locationby using hollow-fiber membrane technology. A typical job would go something like this, after arriving on a Barnett Shale location the Nitro-Lift trailer is spotted approximately 50 ft. from the well-head.
A hose is then connected to a standard API-2" fitting on the casing. The unit is started and prepared for nitrogen generation. A rotary screw compressor takes in air and sends it to a series of filters for pre-conditioning. Once conditioned, the air goes through the membranesto a Nitro-Lift designed booster compressor capable of 500MCF/Day @ 4000 PSI. The Nitrogen is then pumped down the annulus until full. At this point the Nitrogen starts to compress and push the annular water column down the hole until it reaches the end of the tubing, the wellwill then u-tube. In some cases the well continues to flow or Nitro-Lift continues to pump, whichever the case, until the well flows naturally. Average working pressures and rates for the Barnett Shaleare as follows:
Well Depth of 6000' approx. 2500PSI and 300MCF/D
Average recovery rate of 30to 150 BW/Hr.
Average completion 1.5-2.5 MMCF/D
Largest completed producer over 5MMCF/D
Largest amount water jetted back 3200 BP/D
Nitro-Lift has used the units for plunger-lifting, gas-flooding, fluid-jetting, fluid lifting through conventional gas-lift valves. Nitro-Lift has built units from 35 HP to 550 HP. Nitro-Lift currently has 4-units working in theBarnett Shalefield.