Composite strain sensing with a combined interferometric and polarimetric fiber-optic strain gauge

Author(s):  
N. Furstenau
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Cheng-Cheng Zhang ◽  
Bin Shi ◽  
Song Zhang ◽  
Kai Gu ◽  
Su-Ping Liu ◽  
...  

AbstractVertical deformation profiles of subterranean geological formations are conventionally measured by borehole extensometry. Distributed strain sensing (DSS) paired with fiber-optic cables installed in the ground opens up possibilities for acquiring high-resolution static and quasistatic strain profiles of deforming strata, but it is currently limited by reduced data quality due to complicated patterns of interaction between the buried cables and their surroundings, especially in upper soil layers under low confining pressures. Extending recent DSS studies, we present an improved approach using microanchored fiber-optic cables—designed to optimize ground-to-cable coupling at the near surface—for strain determination along entire lengths of vertical boreholes. We proposed a novel criterion for soil–cable coupling evaluation based on the geotechnical bearing capacity theory. We applied this enhanced methodology to monitor groundwater-related vertical motions in both laboratory and field experiments. Corroborating extensometer recordings, acquired simultaneously, validated fiber optically determined displacements, suggesting microanchored DSS as an improved means for detecting and monitoring shallow subsurface strain profiles.


2021 ◽  
Author(s):  
Chet Hopp ◽  
Yves Guglielmi ◽  
Antonio Pio Rinaldi ◽  
Florian Soom ◽  
Quinn Wenning ◽  
...  

2021 ◽  
Author(s):  
Pradeep Lall ◽  
Jinesh Narangaparambil ◽  
Tony Thomas ◽  
Kyle Schulze

Abstract Printed electronics has found new applications in wearable electronics owing to the opportunities for integration, and the ability of sustaining folding, flexing and twisting. Continuous monitoring necessitates the production of sensors, which include temperature, humidity, sweat, and strain sensors. In this paper, a process study was performed on the FR4 board while taking into account multiple printing parameters for the direct-write system. The process parameters include ink pressure, print speed, and stand-off height, as well as their effect on the trace profile and print consistency using white light interferometry analysis. The printed traces have also been studied for different sintering conditions while keeping the FR4 board’s temperature limit in mind. The paper also discusses the effect of sintering conditions on mechanical and electrical properties, specifically shear load to failure and resistivity. The data from this was then used to print strain gauges and compared them to commercially available strain gauges. By reporting the gauge factor, the printed strain gauge has been standardized. The conductive ink’s strain sensing capabilities will be studied under tensile cyclic loading (3-point bending) at various strain rates and maximum strains. Long-term performance testing will be carried out using cyclic tensile loads.


Sensors ◽  
2017 ◽  
Vol 17 (4) ◽  
pp. 667 ◽  
Author(s):  
Monssef Drissi-Habti ◽  
Venkadesh Raman ◽  
Aghiad Khadour ◽  
Safiullah Timorian

SPE Journal ◽  
2021 ◽  
pp. 1-10
Author(s):  
Ge Jin ◽  
Gustavo Ugueto ◽  
Magdalena Wojtaszek ◽  
Artur Guzik ◽  
Dana Jurick ◽  
...  

Summary The characteristics of hydraulic fractures in the near-wellbore region contain critical information related to the production performance of unconventional wells. We demonstrate a novel application of a fiber-optic-based distributed strain sensing (DSS) technology to measure and characterize near-wellbore fractures and perforation cluster efficiency during production. Distributed fiber-optic-based strain measurements are made based on the frequency shift of the Rayleigh scatter spectrum, which is linearly dependent on strain and temperature changes of the sensing fiber. Strain changes along the wellbore are continuously measured during the shut-in and reopening operations of a well. After removing temperature effects, extensional strain changes can be observed at locations around the perforation cluster during a shut-in period. We interpret that the observed strain changes are caused by near-wellbore fracture aperture changes caused by pressure increases within the near-wellbore fracture network. The depth locations of the measured strain changes correlate well with distributed acoustic sensing (DAS) acoustic intensity measurements that were measured during the stimulation of the well. The shape and magnitude of the strain changes differ significantly between two completion designs in the same well. Different dependencies between strain and borehole pressure can be observed at most of the perforation clusters between the shut-in and reopening periods. We assess that this new type of distributed fiber-optic measurement method can significantly improve understanding of near-wellbore hydraulic fracture characteristics and the relationships between stimulation and production from unconventional oil and gas wells.


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