TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractWellbore cleanouts represent the main application of coiled-tubing (CT) services. Despite a long history of utilizing CT to remove sand and other fill material from oil and gas wells, advancement in the technology, and a growing body of experience, many wells are still not cleaned adequately, some wells cannot be cleaned at all, and a downhole stuck CT or other serious problems are encountered too often. Based on gathered experience and extensive research and development of new tools and techniques, a new, highly engineered and integrated system for wellbore cleanouts was developed. This paper presents the new integrated system approach, which can eliminate wellbore fill-removal problems and provide effective wellbore cleanouts under virtually any wellbore conditions. Case studies are included that show the performance of the new system in difficult field environments.

For more than 50 years, coiled tubing (CT) has been an intervention technology primarily used 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, increasing certainty, improving safety and efficiency, and reducing time and cost. In this paper, a review of a CT telemetry system with 2 ⅛-in. tube wire, including the technology development and field application, 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, etc. The CT telemetry system described in this paper consists of the surface hardware and software, a 2 ⅛-in. tube wire inside the CT connecting the surface equipment and the downhole tools and sensors, and a versatile bottomhole assembly, designed in three sizes (i.e., 2 ⅛-, 2 ⅞-, and 3 ½-in.). The 2 ⅛-in. tube wire has the dual purpose to power up the downhole sensors and to transfer the real-time downhole data to surface. The sensors available are a casing collar locator (CCL), two pressure and temperature transducers (capable to measure downhole data inside and outside of the tool), 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 only changing parts of the bottomhole assembly, significantly reducing the operational time and cost and increasing safety. Another advantage stems from the downhole data certainty in real time, as the CT field crew can promptly intervene based on dynamic downhole events. A state-of-the-technology review of the 2 ⅛-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 as logging, zonal isolation, collapsed casing identification, scale removal, cleanout and perforation, milling, confirmation of jar activation during fishing jobs, etc., are also summarized. 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 paper summarizes the results stemming from 10 years of global experience with the 2 ⅛-in. tube wire CT telemetry system. A new case history involving the 2 ⅛-in. tube wire CT telemetry system and a vibratory tool is presented for the first time. As currently there is a strong inertia to automate the drilling operations, all details presented in this paper show that the CT telemetry systems are poised to become standard technologies for all CT operations in the not-so-distant future.

Summary 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.