Ten Years of Continuous Technology Development and Field Application of a Coiled-Tubing Tube-Wire Telemetry System: Past, Present, and Future
Authors: Livescu Silviu , Watkins Tom , Najafov Jeyhun 
Published: October 2018

For more than 50 years, coiled tubing (CT) has been an intervention technology used primarily to maintain or increase production. In the last 10 years, CT telemetry systems have been used for such applications as milling, stimulation, well cleanouts, gas lifting, camera services, logging, and perforating. These systems have resulted in increased certainty, improved safety and efficiency, and reduced time and cost. In this article, a review of a CT telemetry system with 0.125–in. tube wire, including the technology development and field applications, is presented for the first time.

Unlike conventional CT for which surface–measured parameters, such as CT weight and length and pumping pressure, are the only parameters available to monitor the operation's progress, CT telemetry systems provide real–time monitoring of downhole data such as pressure, temperature, depth, and others. The CT telemetry system described in this article consists of the surface hardware and software, a 0.125–in. tube wire inside the CT connecting the surface equipment and the downhole tools and sensors, and a versatile bottomhole assembly (BHA), designed in three sizes (i.e., 2.125–, 2.875–, and 3.5–in.). The 0.125–in. tube wire has the dual purpose of powering the downhole sensors and transferring the real–time downhole data to the surface. The sensors available are a casing–collar locator (CCL), two pressure and temperature transducers (capable of measuring downhole data inside and outside the BHA), and tension, compression, and torque gauges. In addition, cameras with front and lateral views and flow–through capabilities could be used. One of the advantages of this CT telemetry system is its versatility: Switching between applications is as simple as changing parts of the BHA, significantly reducing the operational time and cost, and increasing safety. Another advantage stems from the acquisition of real–time downhole data, enabling the CT field crew to intervene promptly on the basis of dynamic downhole events.

A state–of–the–technology review of the 0.125–in. tube–wire CT telemetry system is presented for the first time. The many benefits of the real–time monitoring of the downhole parameters during such CT applications are summarized. These applications include logging, zonal isolation, collapsed–casing identification, scale removal, cleanout and perforation, milling, confirmation of jar activation during fishing jobs, and others. Many of these applications were performed together, and the real–time monitoring of downhole data increased the job efficiency, control, and safety, and reduced the operational costs by simplifying the operational procedures and equipment.

The article summarizes the results stemming from 10 years of global experience with the 0.125–in. tube–wire CT telemetry system. A new case history involving the 0.125–in. tube–wire CT telemetry system and a vibratory tool is also presented for the first time. With the current trends to automate drilling operations, the details presented in this article show that the CT telemetry systems are poised to become standard technologies for all CT operations in the not–so–distant future.