Numerous lessons have been learned from the use of a wide selection of technological elements in the construction of wireline tractors and mechanical services tools. It is well-known that downhole tool design is challenging and requires the use of the latest developments in physics, material science, electronics, mechanical engineering, and software because the tools operate in very harsh environments characterized by extreme pressures, high temperatures, and corrosive fluids. Wireline tractor and mechanical services tools face not only all of these difficulties but also some unique challenges. For example, the tools operate at much higher power levels compared with other wireline tools. The efficient delivery and use of power downhole is an active area of technology development. Another challenge is that the tools interact intensively with the borehole walls or elements of the well completion by exerting very large mechanical forces to tractor along the well, exercise completion elements, mill or cut tubing, remove and collect debris, set or pull plugs, and fish stuck tools. They are also subjected to high shock levels from explosive devices. All of these lead to heavily stressed components.A comparative study has been conducted of a broad range of technologies, from the evaluation of single components such as electric motors to entire systems such as the selection of a drive mechanism, power delivery scheme, or traction control system. The study discusses single-and three-phase AC and DC motors, AC and DC power delivery schemes, reciprocation versus continuous drive mechanisms, power efficiency of downhole systems, downhole electronics challenges, traction control mechanisms, and the impact of technology selection on functional performance and reliability. The choice of components and technologies is not purely a technical decision, and difficulties and best practices related to selection are discussed. Selection criteria also include rigorous qualification testing.The advantages and disadvantages of a broad selection of technological elements have been identified. The value of instrumentation, real-time data acquisition, control, and automation is emphasized. Additionally, the importance of proper job planning is discussed and recommendations made for types of simulations that must be included in job planner software.

A new high-strength electrical release device has been developed that supersedes the typical weakpoint and achieves the same strength as the tool tension rating. A stronger release device facilitates running heavier tools on wireline, along with the ability to run significantly longer gun strings, which increases operational efficiency. The release device was subjected to a rigorous qualification program conducted to ensure the highest safety and reliability of this device under demanding conditions. This technology uses a motorized release that holds two sections together via retractable dogs. The release device operates using new telemetry protocols that are combinable and segregated from other communication schemes. An optional battery with a preset timer provides redundant control if electrical communication is lost during operations. After the electrical release signal is sent, the motor activates the release mechanism, enabling the device to separate, even with significant residual tension on the toolstring. Completion of rigorous qualification testing was necessary to confirm performance for the heavy load requirements and high shock levels characteristic of long perforating toolstrings. The new electrical release device has delivered flawless performance in seemingly impossible well programs. In field cases, the device was the optimal answer in providing a secondary release device that is high functioning in the harsh perforating environment. One case presents the completion of a project that involved the collaboration of six product lines. The release device was used with coiled tubing deployment of extremely long gun strings in a reservoir containing high H2S and CO2 content. The device enabled a significant reduction in the number of coiled tubing runs, which resulted in a significant increase in operational efficiency. Another application enabled the conveyance of large gun strings using wireline, which reduced the number of descents required and saved valuable time for the operator. These well programs were successfully completed because of the extreme engineering qualification achieved. For example, surface integration testing involved a maximum allowable gun string of more than 120 ft in a well to model downhole exposure. If this trend continues, it is possible that this device will change the future of wireline perforating operations. The new controllable electrical release device with exceptional strength enables the deployment of heavy tools and long guns on both coiled tubing and wireline. This will lead to efficiencies in well design as well as optimization and a higher standard in wireline perforating operations.

This paper presents the design features and the results from field trials of a new wireline tractor developed specifically for through-tubing intervention into producing horizontal wells with barefoot completions. Many Middle East horizontal wells have barefoot completions in which the producing zone is left without tubulars. The vertical section is cased and production tubing put in place. Intervention for production logging or remedial work is challenging due to the need to pass through tubing and then operate in open hole. Intervention is conducted on coiled tubing or wireline tractors. Coiled tubing has limited reach in open hole due to higher friction, and it chokes flow through the tubing, resulting in inaccurate production logs. Conventional wheeled tractors apply stress that can destroy some formations at the wheel contact point. This leads to heavy slippage and extremely slow progress. Several technical innovations were implemented in the new tractor to overcome these challenges. A reciprocating mechanism drives a pair of linked grips with independent opening diameters to conform to variations in borehole geometry while providing a large contact area with the formation. The radial force is hydraulically amplified from the tractor load, enabling it to grip with as much force as required. Results from field trials show little to no slippage in conditions where previous tractors have struggled. The tractor features dual floating hubs that let it close in the uphole direction when tractoring to improve restriction navigation or close in the downhole direction while pulling out of hole to prevent self-locking. The combination of the dual floating hubs and a constant-force opening mechanism enables automatic navigation of restrictions and expansions where previous technologies would have required a manual open/close sequence. These innovations were successfully tested in several tractor operations. One case study is presented in which these features were instrumental in successfully getting to the bottom of the well and back to surface. In one case, the same well was logged using coiled tubing, a prior-generation tractor, and the new tractor. A comparison of these intervention methods is shown. The integration of a reciprocating tractor drive mechanism with novel technical solutions for linked grips, pad pressure regulation, constant force expansion, dual floating hubs mechanism, and automatic navigation has resulted in more reliable and efficient tractor operation in wells with barefoot completions.

Wireline electromechanical release devices are critical and imperative for wireline operations. New-technology intervention and tractor tools cannot be deployed in oil wells without a reliable release device. For the intrinsic challenges of high temperature and longer horizontal wells, the reliability of these electromechanical release devices in the event a toolstring gets stuck downhole becomes even more important. The ability to operate an electromechanical release device on battery at high temperature reduces the overall risk of the intervention because it provides a secondary release option in case there is a damage to the wireline cable or toolstring that prevents communication with the release device downhole. A battery-operated release device activates on the expiration of a programmed timer, even in the absence of wireline power or the presence of a short circuit. The programmed timer can be updated only if communication with the toolstring is feasible, otherwise it reliably releases as originally programmed. Battery-operated electromechanical release devices for 175°C-rated tools, require the battery and associated control and power management electronics to function reliably at 175°C. Due to the chemical composition of this high-temperature battery, its capacity at low temperature is a small fraction of its capacity at high temperature. This presents a challenge in deploying these batteries, because some are installed and activated at surface ambient temperature of –10°C, for deployment in 175°C wells. Now the solution exists as a result of the combination of the development of a high-temperature battery and sophisticated battery management to maximize battery capacity for high-temperature operations. Through thorough qualification, this high-temperature battery was developed and validated. Test results show that the battery works optimally above 120°C. Below 120°C, the battery depletes exponentially, as the temperature decreases. The release device has been designed to intelligently manage battery capacity by switching to wireline power when it is present. The reliable low-bandwidth telemetry makes it possible to update the timer as desired during the wireline operation. The passivation prevention circuit helps prevent battery chemical passivation, maintaining its maximum capacity during the operation. All these technology components combined enable reliable and repeatable battery activation of the electromechanical release device at 175°C.

New electromechanical anchoring and shifting mechanisms for a 2 1/8-in. wireline shifting tool employ innovative linkage designs to enable passage through 2.2-in.-diameter restrictions and deployment in casings up to 5.0-in. inner diameter. The anchoring system delivers 60,000-lbf force through the entire opening range, and the tool provides more than 16,000 lbf of linear actuation force to the pressure- activated shifter. Using wireline shifting tools for sliding sleeves, pulling plugs, fishing, and other operations requiring high axial forces is becoming more common because the tools generate forces comparable with surface- controlled pipe-conveyed devices while offering excellent operational control and real-time feedback downhole. Because operations may include going through a small-diameter restriction before shifting in a larger borehole, tools must open to a large diameter, a property known as the expansion ratio. However, as the expansion ratio increases, the ability of conventional tools for generating large linear forces diminishes. New anchor and shifting designs feature large expansion ratios while preserving the ability to deliver large linear loads. Solutions are presented to the numerous challenges of the design for a wireline toolstring typically including an anchor, linear actuator, and shifting tool. The anchoring system has the capability to apply constant radial force that is independent of the borehole size. As with all intervention tools, it cannot stick to the tubular and must be fail-safe and fully retractable within the tool outside diameter (OD) in case of a power loss, even in high-debris environments. Integrity of the tubular where the anchor is set must be maintained. The anchoring force must not be influenced by the axial push/pull force of the linear actuator. Self-centralization of the anchoring system is needed to eliminate the large bending forces that would otherwise occur from the linear actuator action. Both the anchor and shifting tool must have features that enable pulling them out of hole reliably, even through a restriction. Force and opening displacement sensors are important in giving real-time feedback of the state of the system. In combination with integrated firmware, this enables the system to react to events in the hundred-milliseconds range for effective, high-accuracy operations. Examples are presented for tool usage for specific applications. The novel designs presented in this paper expand the operating envelope of mechanical services on wireline to operations in wells that were previously not serviceable by such tools. Wider application of wireline tools will lead to reduced operational time and bring an increased success rate and intervention reliability on a lower cost conveyance platform.