Wells in the oil-and-gas industry continue to be drilled to deeper depths. These wells present complex challenges for completion and intervention operations because operators demand the same level of performance achieved on shallower wells while providing a cost-effective and safe solution.

The size of coiled tubing (CT) deployed in deep-reach wells is maximized to achieve a greater level of performance and operational efficiency, while reducing the pressure requirements of equipment. However, weight restrictions, reel capacity, depth, and trajectory of the well can limit the size of CT that can be used.

Using a new cationic polymer friction reducer allowed CT operations to achieve higher rates and velocities while maintaining hydrostatic pressure and lowering surface-treating pressures. The friction reducer has the following attributes:

  • It is salt tolerant, which enables a wider scope of use.

  • Effective at low concentrations.

  • Easily mixed on-the-fly.

  • Compatible with nonionic additives.

  • Can be used up to 200°F.

  • Compatible with shale formations.

  • Extremely rapid hydration.

  • Created for use with water-based fracturing fluids in unconventional shale formations.

  • Gives the customer the ability to reuse flowback and produced water without damage to the formation or addition of fresh water.

This paper describes the new friction reducer and the benefits of using it in unconventional shale formations. Also included is a case history to demonstrate the success of the system in CT drillouts. These field trials provided data to confirm the following benefits.

  • A 25% treating-pressure reduction was achieved; 20% was predicted using an existing friction reducer.

  • Using a friction reducer lowers pumping pressure and hydraulic-horsepower requirements.

  • The system enables increased pumping rates, lowered surface-treating pressure, and higher velocities.

  • Cost savings were achieved and and value was added to the operator.

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