A 200°C, 35,000-psi HP/HT MWD Tool: Development Program, Architecture, Mission Profile, and Prototype Testing Results to Date

Abstract

Military electronics and sensors with hermetic packages specified to 125°C have been the mainstay of the industry for many years. Oilfield service companies have long designed these components into downhole tools that operate in environments up to 175°C, but for significantly reduced periods of time. However, new development of hermetic military electronics has all but ceased, forced from the marketplace by less demanding, lower temperature consumer applications such as cell phones, portable computers, and personal data assistants (PDAs). Unfortunately, downhole tools designed with consumer electronics face substantially reduced life at higher temperatures. Therefore, oilfield service companies must employ innovative solutions and rigorous environmental qualification to ensure maximum reliability. At the same time the desire for additional services in ever more extreme environments is growing. This paper describes the development program, tool architecture, mission profile, and prototype testing results to date of a retrievable, reseatable measurement-while-drilling (MWD) tool specifically designed to operate at temperatures up to 200°C and pressures up to 35,000 psi. Summary This paper describes the development of a retrievable, reseatable, high -pressure/high-temperature (HP/HT) MWD tool specifically designed to operate at temperatures up to 200°C and pressures up to 35,000 psi. This project began in 2003 and is partially funded by the United States Department of Energy's National Energy Technology Laboratory (DOE/NETL) as part of the DeepTrek Program. DOE/NETL is active in promoting research into new oilfield technologies. To date, the DOE/NETL DeepTrek Program has provided greater than $24 million for research projects in the following four key technology areas: Background The DeepTrek program is aimed at expanding America's economically recoverable deep (>20,000 ft) gas resource. This program targets technologies that will allow greater efficiency in drilling operation at temperatures in excess of 200°C, pressures of between 20,000 to 30,000 psi, and achievement of reduced overall drilling costs in deep natural gas and oil wells. The development of a reliable HP/HT MWD tool is an important element in this overall program. MWD technology incorporating advancements in tool design, electronics, sensors, and power supply is expected to allow real-time assessment and analysis of direction and inclination, subsurface temperature, annular and internal pressure, formation identification via gamma ray, and other drilling parameters in this hostile environment. Historically service companies have provided MWD solutions to operate in bottomhole temperatures of up to 175°C. As client markets expand there is an increasing need for tools that will survive much higher temperatures. Wireline tools, owing to shorter run durations and their ability to be run with flasks, have long been able to evaluate these higher temperature wellbores, but directional drilling (DD) has been constrained partially due to lack of real-time surveying equipment that can survive for the time required downhole. The >175°C MWD market is small but growing. This true 200°C direction and inclination (D&I) tool is designed and built not just to "survive" at very high wellbore temperatures and pressures, but to perform reliably for a specified minimum amount of time. The pressure rating of 35,000 psi is considered in anticipation of the new frontiers in deepwater drilling. Because many HP/HT environments are particularly challenging from a drilling mechanics standpoint, annular and internal pressure measurements are included as well.