![]() ![]() Thanks to their ability to withstand such adverse or challenging environments, sensors that employ fiber optic cables are in high demand for such use. Often, geofluid systems need dynamic acoustic, strain, temperature and pressure monitoring that can take place in extreme environments like those found at a great depth, pressure or temperature. Thanks to the fact that fiber optic cable is durable and can be installed in harsh environments for long periods of time, the technology offers the opportunity for those seeking to implement environmental monitoring in sensitive geologic operations. During this process, the distributed sensing system can measure at all points along the fiber, which occur at a pre-determined clock-time interval over periods of well operational time. Surface instruments termed interrogator units (IU) are used to send a series of laser light pulses into the fiber and additionally to record the return of the naturally occurring back-scattered light signal, as a function of time. The sensing element is optical fiber, without any additional transducers in the optical path. Distributed sensing does not rely upon manufactured, discrete sensors, unlike conventional sensor systems that rely on discrete sensors measuring at pre-determined points, but instead uses the optical fiber itself as a sensing device as well as a two-way transmitter of the signal (light). The fiber in the subsurface fiber optic cable offers thousands of detection points.Ĭontinuous, real-time measurements are facilitated by DFOS technology, which takes place along the entire length of a fiber optic cable at minimal spatial intervals. DAS senses changes in small physical acoustic vibrations along a glass fiber optic strand encased in a cable to measure vibrations. Currently, there is no other method that obtains the same quality and level of detail about physical conditions in a wellbore when compared to fiber optics.Ĭhiefly, distributed acoustic sensing (DAS) is used to listen to hydraulic fracturing related signals, fluid and gas flow signals, along with sensing seismic source response, such as that which takes place in a vertical seismic profile (VSP). This informed decision naturally leads to well production performance enhancement along with safety at the well site, and ultimately works towards optimizing production from oil and gas wells. The engineer and scientist onsite can make decisions that support operational optimization using critical data from the downhole well environment from distributed fiber optic sensing (DFOS). There is a new generation of fiber optic sensing systems, which can be employed to great utility in the monitoring of well conditions within the oil and gas industry, resulting in improved performance. Molecular weights of br-PMVBS (M n = 1500-3300 g/mol M w = 3800-7400 g/mol) and their polydispersity (M w/M n = 2.0-2.5) were determined by a size exclusion chromatography (SEC).Sponsored by Minus K Technology May 28 2021 They contained linkages: Si-O-Si, Si-O-B, vinyl(methyl)siloxane functional groups (CH 2=CH)MeSiO (Dvi), dimethylsiloxane mers (CH 3) 2SiO (D), and non-reactive trimethylsiloxy terminal groups (CH 3) 3SiO 0.5 (M), but they did not have: hydroxyl functional groups: Si-OH and B-OH, and sensitive to water B-O-B linkages. The prepared br-PMVBS had in their structures: triple branching borosiloxane units: BO 1.5 and in some cases methylsiloxane moiety CH 3SiO 1.5 (T). On the basis of analysis of their 29Si-NMR spectra the microstructure of polysiloxane chains was proposed. Chemical structures of br-PMVBS were confirmed by elemental analysis and spectroscopic methods (FTIR, emission atomic spectroscopy ICP-AES, and NMR: 1H, 29Si and 11B). The solvent was distilled off from filtrates and low molecular weight siloxane oligomers were removed by a vacuum distillation at 130-150 C. HCl was filtered off and washed with a dry ether.In order to fully react (“to block”) trace silanol groups, reactions of intermediate PMVBS with additional batches of Me 3SiCl were carried out in the third step, C 5H 5N In the second step of synthesis ether solution of B(OSiMe 2Cl) 3 was added to a mixture of appropriate organic chlorosilanes (Me 2SiCl 2, MeViSiCl 2, MeSiCl 3, and Me 3SiCl) and all reagents were reacted with stoichiometric amounts of water, in the presence of pyridine (as an acceptor of HCl), in dry ether, at low temperature (usually at -10 to 0 C). By reacting boric acid with an excess of dimethyldichlorosilane (Me 2SiCl 2) in dry ether a “borosiloxane precursor”: tris(chlorodimethylsilyl) borate B(OSiMe 2Cl) 3 was prepared. New liquid branched poly(methylvinylborosiloxanes) (br-PMVBS) of random structure were synthesized in three steps. ![]()
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