A method of determining a concentration of hydrogen sulfide in a fluid comprises exposing a sensor to the fluid, the sensor comprising a pair of electrodes defining a gap therebetween and a sensing material bridging the gap between the electrodes, measuring a value of an electrical parameter of the sensor at an applied frequency of greater than about 10 kHz and a voltage of less than about 1.0 volt when the sensor is exposed to the fluid, and determining the concentration of hydrogen sulfide in the fluid based at least in part on the measured value of the electrical parameter. Related apparatuses and methods are also disclosed.

A method and system for diagnosing a condition of an air-breathing aircraft engine are described. The method comprises obtaining a sample of lubricating fluid from the engine, filtering the sample to obtain a plurality of particles from the lubricating fluid, obtaining chemical composition data for the plurality of particles, determining a quantity of volcanic ash in the lubricating fluid by considering each one of the particles as composed partially of volcanic ash and partially of at least one other material and determining a first percentage of surface area of the particles covered by the volcanic ash and a second percentage of the surface area of the particles covered by the at least one other material, the volcanic ash having associated thereto a predetermined chemical composition, and diagnosing a condition of the engine based on the quantity of volcanic ash found in the lubricating fluid.

Quantifying an amount of sulfur in a petroleum sample includes sequential extraction and quantification of inorganic and organic sulfur species. An exemplary process includes extracting inorganic sulfur components from the sample to yield extracted inorganic sulfur components and a residual sample, and reducing the sulfur in the extracted inorganic sulfur components to yield a first quantity of hydrogen sulfide. The organic sulfur components are extracted from the residual sample to yield extracted organic sulfur components, and the sulfur in the extracted organic sulfur components is reduced to yield a second quantity of hydrogen sulfide. The amount of sulfur in the first quantity of hydrogen sulfide and the amount of sulfur in the second quantity of hydrogen sulfide are combined to yield a total amount of sulfur in the sample.

A method of determining sulfur content in an aqueous fluid containing spent hydrogen sulfide scavenger from a scrubber or contactor tower is described as is a method of optimizing the hydrogen sulfide scavenger treatment rate in a scrubber or contactor tower. The method includes the steps of providing a sample of an aqueous fluid from the scrubbing tower where the aqueous fluid contains spent hydrogen sulfide scavenger; and using x-ray fluorescence to determine the amount of total sulfur in the sample. The method may also use the total sulfur content in the sample to determine the spent hydrogen sulfide scavenger in the sample and/or determine scavenger uptake. The method may also include the step of adjusting the amount of scavenger introduced into the aqueous fluid in the tower in response to the scavenger uptake, to optimize the scavenger treatment in the scrubber or contactor tower.

A contrast device for analysis of a wellbore fluid includes: a substrate; and a contrast agent adhered to the substrate, wherein the contrast agent is configured to respond to an analyte within the wellbore fluid thereby altering a measurable characteristic of the contrast agent. A system including the contrast device may further include an energy source and a detector to facilitate measuring the characteristic of the contrast agent.

Systems and methods are disclosed for providing virtual assays of an oil sample such as crude oil based on near infrared (NIR) spectroscopy carried out on the oil sample, and the density of the oil sample. The virtual assay provides a full range of information about fractions of the oil sample including naphtha, gas oil, vacuum gas oil, vacuum residue, and other information about the properties of the oil sample. Using the system and method herein, the virtual assay data pertaining to these several fractions of the oil sample and the oil sample itself are obtained without the need to fractionate the oil sample into the several components.

Systems and methods are disclosed for providing virtual assays of an oil sample such as crude oil based on Fourier transform ion cyclotron resonance (FT-ICR) mass spectroscopy carried out on the oil sample, and the density of the oil sample. The virtual assay provides a full range of information about fractions of the oil sample including naphtha, gas oil, vacuum gas oil, vacuum residue, and other information about the properties of the oil sample. Using the system and method herein, the virtual assay data pertaining to these several fractions of the oil sample and the oil sample itself are obtained without fractionation of the oil sample into the several components.

Systems and methods are disclosed for providing virtual assays of an oil sample such as crude oil based on nuclear magnetic resonance (NMR) spectroscopy carried out on the oil sample, and the density of the oil sample. The virtual assay provides a full range of information about fractions of the oil sample including naphtha, gas oil, vacuum gas oil, vacuum residue, and other information about the properties of the oil sample. Using the system and method herein, the virtual assay data pertaining to these several fractions of the oil sample and the oil sample itself are obtained without fractionation of the oil sample into the several components.

Robust methods for quantitating the amount of elemental sulfur in a fluid whereby a caustic solution is mixed with the fluid, and the elemental sulfur present in the fluid reacts to form a colored solution that can be compared to a series of standards. The methods can be performed in a laboratory or the field and allow for real time feedback. Once the concentration of the elemental sulfur is known, appropriate methods of treatment can proceed. Test kits for performing the methods in the field are also described.

To measure an internal state of an engine, for example, the engine oil consumption conveniently and correctly, an inspection apparatus of the present invention for inspecting the internal state of the engine by using an exhaust gas of the engine including engine oil includes a data storage unit that stores content information about a plurality of elements contained in the engine oil, a data acceptance unit that accepts analysis information about a plurality of elements contained in the exhaust gas, and an inspection unit that compares the content information about the engine oil with the analysis information to inspect the internal state of the engine.