Terahertz channel modeling of underground sensor networks in oil reservoirs

Abstract

Abstract-Future enhanced oil recovery technology requires wireless sensor networks to effectively operate in underground oil reservoirs. In this case, the millimeter scale sensor nodes with the antennas at the same scale have to be deployed in the confined underground oil reservoir fractures. This necessitates the sensor nodes to be operating in the THz frequency range. In this paper, the propagation based on electromagnetic (EM) waves in the Terahertz band (0.1-120.0 THz) through a crude oil/water mixture and soil medium is analyzed in order to explore its applicability in underground oil reservoir assessments. The developed model evaluates the total path loss and the absorption loss that an EM wave experiences when propagating through the crude oil/water mixture and soil medium. Our results show that sensors can communicate successfully for distances up to 1 centimeter and we have determined the existence of two transmission bands, in which the path loss is below 100 dB. Among those, the frequency window, which provides best performance, determined as 70 to 85 THz. Different path and absorption loss schemes considered, which suggests that the 70 to 85 THz band is suitable for sensor communications in a medium of crude oil/water mixture and soil.

Terahertz channel modelling of wireless ultra‐compact sensor networks using electromagnetic waves

“…Absorption spectrum of water at various temperatures in the whole infrared (IR) region (0 < wave number ṽ< 4000 cm −1 ) can be obtained from attenuated total reflection spectra recorded in the mid-infrared region is combined with absorption spectra measured in the far-infrared region. Then, the absorption spectrum L water (in dB) of the EM waves in a sample of pure water within distance d can be calculated according to the Beer-Lambert law as in (8) [15,27,30]. In (8) medium is changed into the water, where d is the transmission distance; k water ( f ) is the absorption coefficient, which is a function of the operating frequency and is influenced by the liquid temperature.…”

“…As the height of the fracture is <3 cm in oil reservoirs and 0.5 cm in hydraulic fracturing, the size of the sensor nodes should be in the millimetre magnitude. Furthermore, the millimetre scale sensor nodes necessitate antennas at the same scale which implies that the operating frequency has to be in the gigahertz or THz range [15,16]. These millimetre scale sensor nodes can also be used in underground water environment which has narrow height as in the oil recovery process and hydraulic fracturing.…”

Toward the Internet of Underground Things: A Systematic Survey

“…The authors in [46] also compared the theoretical and measured results for UGWSNs where the above analytical model fits well within 3.45 dBm of the measured data. In [19] EM waves in Terahertz band (0.1-120 THz) were investigated for oil reservoirs. The path loss (in dB) for EM signals in the Terahertz band is given in [19] as follows…”

A Survey on Subsurface Signal Propagation

“…The channel model in Equation 10is used by the [37] to create a testbed for UGWSNs and [174] compares the theoretical and actual measured values in testbed. In [32,175], authors give the path loss formula in Terahertz band (0.1-120 THz) as follow:…”