This letter reports the measurement of single living cell's refractive index ͑RI͒ using the optical grating resonant cavity with buffer modulation on a biochip. The cell's RI is a significant cell biophysical property which has potential in cancer and disease diagnoses. The single cell is trapped optically within the cavity, and the transmission spectra shift due to the change of surrounding buffer, without/with cell, are used to determine the cell's effective RI and effective thickness. The measurement shows that Madin-Darby canine kidney cell has an effective RI of 1.383± 0.001. Moreover, the optical trapping technique eliminates uncertainty and avoids cell damage.

A largely tunable chirped fiber Bragg grating (CFBG)-based dispersion compensator with fixed center wavelength is demonstrated. Tunable dispersion ranging from 178 to 2126 ps/nm, corresponding to a large range of 3-db bandwidth from 0.42 to 5.04 nm, is realized by using a 10 cm-long CFBG with an original bandwidth of 1.61 nm. The variation in center wavelength is less than 0.2 nm.

This literature review summarizes the theory and application of chelating agents in scale removal. The objective of this work is to give the reader a better understanding of scale removal methods by chelating agents in oil field applications. This paper reviews results that were obtained through various laboratory tests, which aid in understanding chelating agent interactions with formation rock and formation fluids. Results were obtained through a variety of tests including compatibility, dissolution, Inductively Coupled Plasma (ICP), Environmental Scanning Electron Microscope (ESEM) and X-Ray Diffraction (XRD). At high temperatures, conventional acids such as hydrochloric acid (HCl) show severe corrosion, lack of penetration and sludging characteristics. Several organic acids were proposed to solve these issues. However, even organic acids result in solubility and incompatibility issues. Based on these shortcomings, chelating agents are often used and show good dissolving power, low corrosion, low sludging tendencies, excellent iron control, and some are highly degradable and environmentally friendly. In addition, chelating agents are commonly used to dissolve most oil field scales that are both insoluble in HCl and detrimental to production. This work summarizes the applications of chelating agents in the stimulation sector, including the latest developments and field applications of chelating agents. Readers can easily expand on this paper to further explore the wide range of applications chelating agents can offer the oil and gas industry.

Summary Typically, water-based fracturing treatments consume a large volume of fresh water. Providing consistent freshwater sources is difficult and sometimes not feasible, especially in remote areas and offshore operations. Therefore, several seawater-based fracturing fluids have been developed in an effort to preserve freshwater resources. However, none of these fluids minimizes fracture-face skin and proppant-conductivity impairment, which can be critical for unconventional well treatments. Several experiments and design iterations were conducted to tailor raw-seawater-based fracturing fluids. These fluids were designed to have rheological properties that can transport proppant under dynamic and static conditions. The optimized seawater-based fracturing-fluid formulas were developed such that no scale forms when additives are mixed in or when the fracturing-fluid filtrate is mixed with different formation brines. The tests were conducted using a high-pressure/high-temperature (HP/HT) rheometer, coreflood, and by aging cells at 250 to 300°F. The developed seawater-based fracturing fluids were optimized with an apparent viscosity greater than 100 cp at a shear rate of 100 seconds–1 and a temperature of 300°F for more than 1 hour. The use of polymeric- and phosphonate-based scale inhibitors (SIs) prevented the formation of severe calcium sulfate (CaSO4) scale in mixtures of seawater and formation brines at 300°F. Controlling the pH of fracturing fluids prevented magnesium and calcium hydroxide precipitation that occurs at a pH value of greater than 9.5. Most importantly, SIs had a negative effect on the viscosity of seawater fracturing fluid during testing because of their negative interaction with metallic crosslinkers. The developed seawater-based fracturing fluids were applied for the first time in an unconventional and a conventional carbonate well and showed very promising results; details of field treatments are discussed in this paper.