The increasing energy demand has prompted engineers to explore deeper wells where rich oil and gas reserves exist. However, the high-temperature and high-salt conditions have impeded the further application of traditional water-based fracturing fluids in such reservoirs. Therefore, it is urgent to develop fracturing fluids that are suitable for such geographic characteristics. In this study, for the first time, a novel synthetic polymer, poly-(acrylamide-co-acrylic acid-co-2-acrylamido-2-methyl-1-propanesulfonic acid) (P3A), was investigated as a rheological modifier for water-based fracturing fluids in high-temperature and high-salt conditions and compared with a guar gum system. Results showed that the apparent viscosity increased with increasing P3A and guar gum concentrations, and the thickening ability of P3A was much better than that of guar gum. Despite the better shear and temperature resistance and proppant suspension ability of guar gum fluids in high-temperature and saturated salt conditions, plentiful solid residues after gel-breaking have prevented their progress in the petroleum industry. P3A fluids have no residues, but the unsatisfying proppant suspension capability and high dosage encourage us to promote their rheological performance via interaction with an organic zirconium crosslinker. Infrared spectroscopy and scanning electron microscopy were applied to guarantee the successful reaction of P3A with the crosslinker. The subsequent investigation indicated that the transformed fracturing fluid exhibited remarkably improved thickening capability and satisfying rheological performance in terms of temperature and shear resistance and proppant-carrying ability as well as gel-breaking results in a high-temperature and saturated salt environment. All of the above results suggest the potential application of crosslinked P3A in hydraulic fracturing for the reservoirs with hostile conditions, and this article also provides a new orientation for synthetic polymers utilized in the oil and gas industry.

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We report for the first time nonlinear frequency conversion—specifically optical parametric oscillation—in OP-GaP layers grown by hydride vapor-phase epitaxy on 3-inch OP-GaAs templates. Continuous tuning with wavelength coverage from 3.9–12 µm was achieved by using stepped and fan-out gratings having periods from 18.0–35.2 µm, which propagated 150 µm of a 1.2-mm-thick layer before overgrowth. Anti-reflection-coated OP-GaP crystals were pumped at 1040 nm with an ultrafast Yb-fiber laser, yielding idler output powers up to 150 mW (60 mW) in spectra centered at a wavelength of 5.6 µm (10.7 µm).

We report a 976 nm diode-pump passively Q-switched Er3+-doped ZBLAN fiber laser based on a semiconductor saturable absorber mirror (SESAM). The maximum average output power of 3.01 W was obtained at a slope efficient of 17%. Stable passively Q-switched pulses with a pulse energy of 10.82 µJ and a pulse duration of 0.45 µs, corresponding to a peak power of 24.45 W, were obtained at a repetition rate of 278.5 kHz and a center wavelength of 2798.8 nm. To the best of our knowledge, this is the highest current average output power from a passively Q-switched fiber laser at 2.8 µm based on a SESAM.

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