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.

Water hammer tools (WHTs) are used in coiled tubing (CT) operations for postponing a potential helical lock-up and running deeper into the hole. By rapidly opening and closing a valve in the tool, pressure pulses are created and the axial vibrating force is overcoming the friction between the CT and the wellbore. The pressure pulses depend on the CT parameters (size and material), WHT parameters (size and valve frequency), pumping rate, and downhole pressure. Although the effect of the water hammer pulses on the axial and radial vibrations has been investigated before, the coupling between water hammer pulses and the axial and radial vibrations for CT operations is not currently understood. Radial vibrations may be important as they may reduce the normal and thus the frictional forces between the CT and the wellbore and increase the reach in long horizontal wells. In this paper the effect of the water hammer pulses on the radial vibrations is investigated. A numerical model was developed to simulate the water hammer pulses and vibrations of the CT and WHT assembly. The model was validated against lab data for the case of a single WHT located at the end of a CT. Then the model was used to investigate the optimal performance of the WHT. Several scenarios, such as a WHT located between two CTs and two WHTs working in tandem, were also investigated. It is concluded that the radial vibrations which appear due to the water hammer pulses when two WHTs are used in tandem may be beneficial in reducing the friction forces between the CT and the wellbore. When two WHTs are used, a relationship between the additional pumping pressure and the distance between the two tools is also proposed.

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.

Well intervention operations in extended-reach wells with sand, proppant, or other fill or in openhole wells are becoming important especially in the Middle East, where many exiting long openhole laterals need to be stimulated to maintain existing production. New laboratory and field results with a lubricant and a 2 ⅛-in. fluid hammer tool are shown to significantly increase the coiled tubing (CT) reach in laterals with sand. These results can be extended to openhole wells, as the coefficients of friction (CoF) between CT and metal casing completely covered with sand or an openhole are similar. While theoretically increasing the CT diameter could extend the CT reach, in practice, this may not be always possible due to completion size limitations or logistical challenges with onshore road transport or offshore crane lifting/deck loading limitations. Hydraulic technologies such as fluid hammer tools and downhole tractors have extended the CT reach significantly in cased wells, but their successful application in long openhole laterals has not been reported in literature. In addition, metal-on-metal lubricants are used in cased wells with laterals longer than 10,000 ft, but their application in similarly long sand-screen-completed or long openhole laterals is much more limited due to the higher friction. In this paper, laboratory and field results with a lubricant and a new 2 ⅛-in. fluid hammer tool are presented for sand-screen-completed wells. The lubricant was initially tested in laboratory for compatibility with representative formation rock samples. Given the fact that the lubricant itself contains a clay stabilizer component, it performs better than other commercial lubricants tested in low-, medium-, and high-permeability rock samples. The fluid pumped through the CT and 2 ⅛-in. fluid hammer tool creates pressure pulses with frequency of 8 Hz by opening and closing a valve inside the tool. These pressure pulses generate axial and radial forces that act simultaneously on counteracting the friction force between the CT and the formation: the axial force increases the bottom hole assembly (BHA) tensile load; and the radial force reduces the normal contact force, and thus the friction force. Combining the effects of the lubricant and the new 2 ⅛-in. fluid hammer tool in a pre-job CT modeling software results in CoFs reduced by 50-60%, from a default value of 0.36 without any friction reduction technology to 0.15-0.18 when both the lubricant and the tool are used. Laboratory testing with the lubricant alone showed that CoF between CT and a surface completely covered by sand decreases by 40-50%, from the default value of 0.36 to 0.18-0.22, for temperatures between 20 and 98°C. These CoFs were validated against field data from a sand-screen-completed well in the North Sea. Friction reduction of this magnitude is expected to significantly extend the CT reach in long openhole laterals. In this paper, the lubricant and the new 2 ⅛-in. fluid hammer tool are briefly described and the data acquired during the laboratory testing and field operation is discussed. These results improve the current industry understanding of the CT friction in sand-filled cased wells and openhole wells and show great benefits in using the extended-reach CT technology consisting of the lubricant, the 2 ⅛-in. fluid hammer tool, and the CT modeling software for extending the CT reach in sand-filled cased and openhole laterals.