Schlumberger

Coiled Tubing & Fluid Pumping

CT applications for operations involving pumping a fluid into the well

Use CT to clean out boreholes and perform acid stimulation, reverse circulation, cementing, pressure control, and a variety of other operations that involve pumping a fluid—water- or oil-based—into the well.

Cleanouts

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.

Cementing

When wells are abandoned or recompleted, CT can place very small volumes of cement inside the well very accurately. The cement is placed as a balanced plug at an exact spot in the well. Perforations can be squeezed and fluids can be pumped to dress off the top of a plug or to clean out any excess cement inside the well. Consequently, less preparatory work is required to recomplete the well.

Applications

  • Cleanouts—fluid-based, foam-based, energized fluid–based
  • Reverse circulation
  • Fluid swab-out
  • Well killing
  • Pressure control
  • Pressure testing
  • Stimulation
  • Cementing

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Coil Tubing Services, A Schlumberger Company

Use CT for Fluid Pumping Operations

Coiled Tubing and Fluid Pumping
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