Coiled Tubing & Fluid Pumping PDF Print E-mail
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Wednesday, 23 January 2013 13:26

Coiled Tubing and pumpingOMEL Coiled tubing (CT) cleanouts are used to clean debris and/or particulates from boreholes. Water- or oil-based fluids can be used, mixed with nitrogen if required. Most cleanouts are done with a simple BHA consisting of a connector, a double check valve, and a wash nozzle. Wash nozzles are offered in many different configurations, depending on the particular job and preference.

Other options for cleanout tools include:

  • mandrel bypass tools when gas lift mandrels are included in the well completion
  • packer jumpers when difficulties are encountered in passing through restrictions
  • positive displacement motors and bits.

Reverse circulation

In large casings with a restriction in the wellbore above, CT can be used for reverse circulation. A special surface rig-up is used which allows the direction of flow to be switched simply by operating a few valves. A safety pop-off valve is included to control the annulus pressure. This technique can be applied very effectively and safely in the right circumstances.

Stimulation

CT is also used for acid stimulation. It can be placed across the perforated interval and reciprocated while the acid is pumped, placing the unspent and undiluted acid directly across the interval in question. The acid is not contaminated with borehole debris when it is placed though CT. Furthermore, live acid does not contact the wellbore, thereby protecting the production tubing and hardware. The well can be put back on production immediately after the stimulation operation by jetting it with nitrogen pumped through the CT. This reduces the chance of any by-products precipitating as the acid is spent.

Last Updated on Wednesday, 23 January 2013 14:49