Sensor Ball: An Autonomous Untethered Logging Platform

Abstract

Downhole conditions of oil and gas reservoirs change with time. Monitoring this change is critical to enhance hydrocarbon recovery from the reservoir. Conventionally, downhole measurements of physical and chemical properties of downhole formation fluids are taken using wireline logging or using permanent downhole sensors. Wireline logging is a complex operation that requires several miles of wireline cable, a winch, a crane and a specialized crew that knows how to operate this equipment [1]. In addition, a blowout preventer, a lubricator and a specialized crew to install and operate are needed. The complexity and cost of wireline operations makes it difficult to acquire reservoir data frequently. The other alternative for gathering downhole data more frequently is installing permanent sensors or optical fibers in the well [2-3]. However, due to the harsh downhole conditions, these sensors need to be extremely reliable and continuously maintained. Moreover, surface data acquisition systems for these sensors increase their cost significantly and reduces their applicability to every well. Both methods have their own limitations and there is a need for more practical and less expensive oil field instruments for well logging. Engineering small, inexpensive and robust logging instruments has its own challenges. Solving these challenges has been the main focus area of Sensors Development Team at Aramco Research Center in Houston. This paper describes one of the concept ideas that was successfully engineered and tested in our facility and successfully deployed and retrieved in the field in Saudi Arabia in collaboration with our EXPEC ARC and Northern Area Production Engineering and Well Services Divisions in Saudi Arabia.

An Autonomous Environmental Logging Microsystem (ELM) for Harsh Environments

“…The ELM achieved similar temperature range and slightly lower pressure range compared with other systems. Compared to the work in [6] and in [9][10], the ELM achieved a much smaller size. Compared with the work in [7][8], the ELM is implemented with commercial electronics, which leads to better prototyping yield and faster upgrading time.…”

“…Table II compares critical parameters of the ELM with similar downhole sensing systems in literature [6][7][8][9][10]12]. The ELM achieved similar temperature range and slightly lower pressure range compared with other systems.…”

“…Yu et al and Shi et al have reported research prototypes for temperature and pressure measurement that used customized electronics within Φ7.5 mm polymer spheres and provided deployment lifetimes of 8 hours at 100°C [7][8]. Erjola et al and Huseyin et al reported an untethered sensor platform with a cylindrical shape of Φ60.4 mm×66.0 mm, with a buoyance control unit permitting the sensor to float back to the surface at a programmed depth [9][10]. At the University of Michigan, we are developing an environmental logging microsystem (ELM) platform that combines customized sensors with a low power commercial microcontroller [11].…”