As well completions and operating objectives grow more complex, it is reassuring that certain physical parameters can be measured and predicted with extremely high precision. Precision during operational execution using real-time measurements from a customized bottomhole assembly (BHA) is a benefit offered by coiled tubing (CT) fiber-optic technology. Today marks an important milestone and basis for a new era with the development of a real-time hybrid CT service that integrates fiber-optic and electric communication and power. This paper discusses an efficient milling operation using real-time fiber optics with continuous power from the surface, referenced as the first operation performed globally.
The following three potential risks are typically associated with milling operations:
CT failure attributed to cyclic fatigue loading under extreme conditions and/or exceeding the torque capacity as a consequence of the transmission of the rotational force of the motor.
Premature damage to the components of the motor while exceeding the torque capabilities of the motor because of the lack of parameters at surface while milling.
Motor stall that can converge into a bit-stuck scenario, or misinterpreting torque output through the motor when pumping fluid commingled with an incompressible gas.
The sum of all these conditions generated a challenging scenario. These conditions were also ideal to validate the accuracy and reliability of this technology wherein, because of downhole sensors (torque, load, and differential pressure), it was possible to monitor the milling process in real time, even when there was no detected variation in these operational parameters at the surface.
The real-time fiber-optic integrated system enables efficient, reliable execution during CT milling operations. Additional downhole insight is available with the new generation of hybrid technology for CT services, which combines fiber-optic and electric downhole powering communication. This system was designed with an open architecture to accommodate virtually any wireline or mechanical tool in the industry to address operator challenges, such as a milling operations, allowing the operator to monitor the weight on the bit, torque, and differential pressure through the bit. With the ability to constantly monitor bottomhole conditions, it was possible for the engineer to make decisions in real time, even when there was no evidence of any milling constraint at surface. Because the variables did not vary during operation, efficiency increased because of adequate optimization of the motor capabilities.
This paper explores one of the many possibilities operators have with hybrid technology for CT services, radically increasing reliability on location. This technology allowed the operator to significantly diminish operational time during milling in a single run without limitations to power or operational duration.