| dc.description.abstract | The ever-increasing demand for energy resources has led to drilling more complex and challenging wells. The information required to navigate through these complex geologies is provided by highly sophisticated sensors embedded in logging-while-drilling and measurements-while-drilling downhole tools. These combined with rotary steerable systems have made it possible to drill highly deviated, extended reach, and multilateral wells with high precision.
Drilling operations can be considered high-risk operations due to the large number of sources that can lead to undesirable outcomes. Therefore, data transmission from downhole sensors and communication with downhole tools is vital to drill safely and successfully a well.
Mud-pulse telemetry is the most used telemetry method to transmit the data from downhole tools to the surface. However, advancements in sensor technology and the development of new tools have resulted in higher amounts of data needed to be transmitted to the surface to take advantage of the resolution they now provide fully. The reliance on mud-pulse telemetry, which offers relatively low data transmission speed and broadband, has been the limiting factor, often sacrificing higher drilling rates to obtain the required data quality.
The introduction of wired drill pipe, capable of delivering bi-directional telemetry at speeds up to 10.000 times faster than traditional mud-pulse, has removed the reliance on mud-pulse, making it possible to obtain memory-mode quality real-time data. Wired drill pipe also enables the use of along string measurements. These measurement tools are placed along the string and gather pressure, temperature, and drilling dynamics data. Thus, it is now possible to understand the downhole environment along the wellbore and not just a few meters behind the bit. This makes it possible to timely identify well control and well stability events, thereby making risk-informed decisions to mitigate the risk of hazardous events and additionally optimizing drilling operations.
The objective of this thesis is to provide a description of the drilling process and the tools that have made it possible to drill the wells that nowadays are drilled. Further, it describes different telemetry methods but focuses on mud-pulse telemetry and its limitations. Then, the wired drill pipe system is extensively described, and it is presented the way it allows the integration of measurement tools along the string. Furthermore, it is shown how these tools enable making risk-informed decisions to reduce the risk during drilling operations. The result is safer drilling operations to be achieved while also saving time by reducing the telemetry time, preventing tool failures, and avoiding resource-demanding well remediation operations. Finally, it is discussed how the availability of real-time high-quality data and full bi-directional instantaneous communication with downhole tools has enabled a step towards more automated drilling operations. The combination of high-speed data transfer with machine learning and artificial intelligence has made it possible to develop autonomous drilling services capable of optimizing the well path and reducing well times. | |
