Masdar Institute, the Petroleum Institute and MIT are working on a smart sensor technology for the oil & gas industry, dubbed Smart Mud.
This nano-sensor technology is made up of active sensor cubes of three to four millimeters in diameter that are designed to be injected, thousands at a time, into wells, or pipelines, to wirelessly send data on transient phenomena to engineers monitoring the well or pipeline.
These phenomena include stress, acidity and other real-time factors.
“These sensors will collect and transmit the data collected from the well or pipeline, which can then be stored, retrieved and monitored. The sensor tells the engineer, as a function of time and location, the environment in which that sensor was moving,” said Dr Irfan A. Saadat, PhD, professor Microsystems Engineering Coordinator, General Education Programme, Masdar Institute.
There are many applications Smart Mud can be used for in oil & gas; to monitor pressure, stress, temperature, to monitor the transient behaviour of certain oil & gas processes and to look for stressors inside rock formations. With Smart Mud technology, Dr Saadat hopes that companies will now have access to that data.
“The reason the sensor technology was not previously available is because of the hostile environment in the oil wells or pipelines. Also, a self-contained integrated sensor was just not available to use,” said Dr Saadat.
Oil & gas is a particularly challenging environment for sensor technology, due to the highly corrosive nature of the environments these sensors must operate in, the extremely high temperatures downhole, and the need to power these mini computers.
Temperatures in a well can be anywhere from 150 degrees centigrade upwards. In the past when researchers tried to develop sensors for use downhole, they faced a maximum temperature threshold of 130 degrees with silicon-based technologies.
However, there is a new semi-conductor technology that has been developed using gallium nitride, a binary III/V direct bandgap semiconductor, which has been commonly used in bright light-emitting diodes.
The compound is a very hard material that has a Wurtzite crystal structure. Its wide band gap of 3.4 eV affords it special properties for applications in optoelectronic, high-power and high-frequency devices. For example, GaN is the substrate which makes violet (405 nm) laser diodes possible, without use of nonlinear optical frequency-doubling.
“GaN can withstand temperatures up to 1000 degrees centigrade and function as electronics, so now the problems of electronics able to withstand high temperatures have been answered, the question about form factor has been answered,” said Dr Saadat.
There has also been developments in sensor technology that can withstand high temperatures. Graphene, a two-dimensional, crystalline allotrope of carbon, is able to sense different environments and pressures and at the same time is very inert, meaning it is stable to 700 degrees.
“You put graphene in a corrosive hostile environment where other metals and sensors may not function and it can function,” said Dr Saadat.
The last critical factor that needed to be in place for Smart Mud to be developed is a way to energise the smart mud sensors themselves.
“When you put the sensor into a tiny 3-4mm cube, the energy harvesting from your environment means your whole circuitry, the transmission, your recording, needs to function on that minimum energy requirement and the minimum energy circuits have just started to be developed,” said Dr Saadat.
Downhole vibrations can be used to power sensor technology, in the same way that kinetic watches are powered. These energy harvesting capabilities in development can generate milliwatts of power in a tiny system.
With the three necessary components now in place; energy, temperature resistant components and corrosion resistant components, Smart Mud is ready to be developed.
“I think we are sitting at a nexus with all of these things converging. Therefore the smart mud concept is ready to be created,” said Dr Saadat.
MIT, along with its Abu Dhabi partners the Masdar Institute and the Petroleum Institute hope to complete a prototype of the Smart Mud nano sensor in the next two to three years and are seeking an oil service company to sponsor their research, said Dr Saadat.
Saadat did not put a cost to the budget required to bring the technology to prototype, but said six to seven researchers would be needed.
