Mud Pulse Telemetry systems in drilling operations have enabled the industry to gather valuable directional and formation data while drilling the well, and to optimize the drilling process. This makes drilling operations more cost efficient and allows the drilling of complex wells. In recent years, new LWD technologies have dramatically increased the amount of information collected downhole. This increasing demand for realtime bandwidth is a major challenge for conventional Mud Pulse Telemetry, which has data rates that are normally below 3 bits per second. This paper describes a system for downhole-to-surface Mud Pulse Telemetry that uses baseband or carrier modulated pressure signals generated by a novel mud pulser design and a surface data acquisition unit with advanced signal processing capabilities. The new system is able of handling the complex and continuously varying properties of the transmission channel (the pipe bore filled with flowing drilling mud) by optimizing the transmission signal and the surface processing algorithms in realtime. Under a given scenario, higher data rates can be achieved that, from a log-quality standpoint, result in high log-densities for improved realtime decision making. Surface processing algorithms include active pump noise cancellation, dual pressure transducer processing, signal filtering and signal decoding. In addition, the system contains an automated calibration routine that after turning pumps-on measures the characteristics of the transmission channel. This novel feature assures that the latest knowledge about the transmission channel is available in the processing algorithms. The new system has been successfully run in field-trials in the United States, North Sea, South America and the Middle East. During these deployments, data rates could be substantially increased compared to previous offset runs. The focus in this paper will be on a description of the system and its impact on both MWD and LWD realtime services. Introduction Mud Pulse Telemetry (MPT) has been the global standard for real time data delivery from Measurement While Drilling (MWD)/Logging While Drilling (LWD) systems for the past thirty years. This is largely due to the robustness of the downhole system, the simple concept of a single down hole transmitter and a single surface receiver, proven performance under various conditions and the possibility to adjust various down hole Bottom Hole Assembly (BHA) parameters while drilling the well. With the introduction of more complex MWD/LWD tools and services, most of which produce large amounts of real-time data, it has become crucial to use the available mud channel more efficiently to ensure that there is sufficient information to make informed decisions whilst drilling. This is a complex task given the uncertainty and continuous fluctuations of the various system properties in the mud channel, most of which are outside the control of the MWD/LWD service company, these include:mud pumpspulsation dampenerssurface pipingpressure transducer locationsdrill string componentsmud propertieswell depth In addition, MWD/LWD companies have to deal with a limited amount of down hole power which adds to the restrictions in optimizing the entire system. This paper introduces a new telemetry system, including a novel, advanced, mud pulser design which has been in development since 2001 and a new surface data acquisition unit with improved signal processing capabilities. The overall system is able to automatically adjust its decoding parameters during data transmission. Since measurements are made continuously, fluctuations of channel properties are captured and accounted for. Field-trials have been carried out that proved the new concept. Data rates of up to 20 bits per second (bps) have been achieved in commercial drilling situations. Compared to earlier offset runs this is an increase of more than 200%. Those optimized, high data rates are essential to support present and enable future MWD/LWD services.
Mud Pulse Telemetry (MPT) systems enable the MWD/LWD companies to transmit to surface valuable directional and formation data during the drilling process. This data is used to optimize the drilling process, making drilling operations more cost efficient and allowing the drilling of more complex wells. The major factors limiting MPT data rates include maximum downhole signal strength, signal attenuation, surface induced noise and surface piping induced signal reflections. Most of these are not predictable, not arbitrarily adjustable and potentially change their properties during the course of data transmission. To achieve maximum possible data rates under those challenges, telemetry systems must be highly flexible, both downhole and at the surface receiver. Downhole, the transmission tool should be able to support different signal types and different signal frequencies to optimally use the transmission channel (the mud filled pipe bore).These signaling parameters should be changeable during operation. On surface, sophisticated noise processing should be employed to increase the overall system Signal-to-Noise Ratio (SNR). This paper describes a new system for mud pulse telemetry that supports two signaling types, different signal modulations and various signal frequencies. The new system comprises a novel mud pulser and a digitally controlled, automatically adjusted surface system. With the downhole mud pulser in the borehole, the new system allows the optimization of the mud pulse telemetry process for maximum MWD/LWD information at surface while drilling the well. This paper introduces the system and gives details on how the achieved high speed data rates of the new telemetry system have helped to deliver real time answers while drilling. Introduction Mud Pulse Telemetry (MPT) systems share a common communication principle (Figure 1). Downhole, drilling fluid passes a moving valve that in some fashion restricts flow and in turn generates pressure waves which travel to surface at varying speeds depending on the drilling fluid properties. The mud channel (the pipe bore filled with flowing drilling mud) causes the transmitted signal to be attenuated and further distorted. Depending on the severity of the channel conditions, signal reception can be a difficult task. Major components affecting signal properties include mud pumps, pulsation dampeners, surface piping, pressure transducer locations, drill string components, mud properties, well depth and others. Due to the complexity of the involved parameters and their often varying properties, reliable high speed telemetry requires a system that adapts its downhole and surface settings during drilling. In this paper we discuss a new telemetry system comprising a novel, advanced and reliable mud pulser design and a new surface data acquisition unit with enhanced signal processing capabilities. The system can automatically adjust its decoding parameters during data transmission by making continuous measurements of the transmission channel conditions during drilling. This assures high speed mud pulse telemetry even under highly varying mud channel conditions. The entire system has been extensively tested and improved since 2001 and data rates of up to 20 bits per second (bps) have been achieved in commercial drilling situations. Using this data rate increase of more than 200% compared to previous offset runs, higher quality decision making was attained in various applications. Those optimized, high data rates are essential to support present services and to enable future MWD/LWD services, including reservoir navigation service (RNS), wellbore stability and drilling optimization. In the next sections we introduce the downhole mud pulser and the new surface system with a focus on how to optimize the quality of the signal received at surface. We explain the implemented features and highlight a case that showed higher data rates to be the enabling technology for efficient Reservoir Navigation Service (RNS) operations.
The promise of drilling systems automation is to increase well construction efficiency, delivering quality wells in a safe, reliable and predictable manner. This promise is achieved in part by creating a digital infrastructure that extends vertically from the drill bit to the remote enterprise, and horizontally from exploration to production. Critical to the success of automation is the unimpeded flow of quality data through this infrastructure. This paper focuses on studying only drilling systems automation, but the lessons learned can be applied to other disciplines such as completions and production. Due to the disconnected nature of the well construction business with multiple disciplines and companies involved, data silos and restrictions are numerous. This paper describes the development of a wellsite-based automation system consisting of an open data aggregator, with networked surface and downhole sensors and real-time applications for process monitoring, advice and control. The data aggregator is designed to allow all relevant parties to access and share data in a high-velocity deterministic environment. This access and sharing permits easy implementation of comprehensive drilling system automation, be it monitoring, advising or control, in a controlled, productive and safe manner. The paper also describes the implementation of automation applications using data from the aggregator, covering real-time drilling optimization and hydraulics. Operation of the data aggregator at the wellsite with connection to rig systems and remote operating centers is described. The data aggregator uses protocols that are international standards, and it is designed to be open and not proprietary. From an implementation standpoint, this allows easy interface of the aggregator to measurement and control systems, and access to copious third-party communication products, reducing development time and increasing reliability. Observations are that many rig instrumentation and control systems use either customized or proprietary protocols; common data information standards are lacking in the oilfield. In addition, data ownership and governance must be addressed at an industry level, as well as secure bi-directional flow of data between wellsite and town. While these topics are, to some extent, being addressed in industry road-mapping and guidance groups, progress is slow and this hinders the adoption of technology. The paper describes the development and implementation of an open data aggregator for the wellsite. The aggregator allows third-party real-time applications to use and share data, and to collaborate on industry standards. It further describes the development of automation applications riding on the data aggregator, and their use in drilling systems automation. This case study illustrates and examines issues that must be addressed at the company and industry level to move universal drilling systems automation closer to reality.
Regardless of whether you look at consumer or industrial applications, whenever a technical breakthrough in available communication bandwidth is achieved, the affected en vironment and feasible applications change significantly. One recent example was the introduction of the digital subscriber line (DSL) to replace modems for Internet access.With high-speed telemetry systems becoming economically viable in an increasing number of drilling applications, our industry is in a situation similar to that seen at the introduction of DSL. Following the parallel of Internet access via DSL vs. modem, the relevant questions are: How has high-speed telemetry changed the drilling process, and what further changes will we see in the near future?This article first intends to explain why oilfield service companies continually strive for higher telemetry data rates. It then identifies and exemplifies fields of application for both available technologies-high-speed mud-pulse telemetry and wired drillstring telemetry-with two case histories. The conclusion provides an outlook on possible future opportunities and technological developments.
Directional drilling today is a manual process characterized by monitoring drilling parameters and trends, predicting the future wellbore trajectory and adjusting steering parameters as required. When drilling with a rotary steerable system (RSS) in the bottom-hole assembly (BHA), the trajectory control system is distributed between surface and downhole. The surface control makes use of downhole measurements and capabilities of the rotary steerable BHA, and in turn is used to control the downhole components, forming a ‘directional drilling control loop’ and allowing the efficient drilling of a quality wellbore. Traditionally, the directional driller assumes the surface control, whereas downhole control was executed by the RSS-BHA allowing to drill certain parts of a section automatically. With the advent of automation, the surface control can be executed by a control system. This paper introduces a new automated trajectory drilling service for a rotary steerable system. The system is capable of predicting the wellbore trajectory, deriving steering proposals to follow the planned trajectory closely or steer back to plan, and submitting those steering downlinks automatically to the downhole RSS with the directional driller observing the system. The paper explains the underlying control methodology and the automation system architecture. Furthermore, operational considerations such as handling of formation disturbances are discussed. The concept of embedding the driller and directional driller in the decision-making workflow is outlined. Finally, the performance of the automated trajectory drilling system is assessed and field test results from two case studies are presented, where up to 98 % of a single wellbore has been drilled automatically. To date, a total of 3,926 m have been drilled automatically with the automated drilling system.
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