Abstract: A method for identifying the type of a sampled formation fluid, such as a hydrocarbon, is provided. In one embodiment, the method includes measuring absorbance by a sample of a formation fluid at multiple wavelengths of electromagnetic radiation with a spectrometer. The method also includes distinguishing between multiple fluid types to identify a fluid type of the sample most likely to match an actual fluid type of the sample based on the measured absorbance at two or more wavelengths of the multiple wavelengths. Additional systems, devices, and methods are also disclosed.

Abstract: Methods and related systems are described for real-time wellsite production allocation analysis. Spectroscopic in-situ measurements are made in the vicinity of a wellsite of a produced fluid from one or more boreholes. The produced fluid includes in a co-mingled state, at least a first fluid component from a first production zone and a second fluid component from a second production zone. An allocation is estimated in real-time for at least the first fluid component in the produced fluid based at least in part on the spectroscopic in-situ measurements. The in-situ measurements can be several types, for example: (1) absorption of electromagnetic radiation having wavelengths in the range of ultraviolet, visible and/or infrared light, (2) X-ray fluorescence spectroscopy measurements, (3) electromagnetic scattering spectroscopic measurements such as Raman spectroscopy measurements, (4) NMR spectroscopy measurements, and (5) terahertz time-domain spectroscopy measurements.

Abstract: A method for measuring asphaltene content of a crude oil is provided. In one embodiment, the method includes measuring an optical density of a live crude oil within a well and calculating a formation volume factor of the live crude oil based on the measured optical density. The method also includes determining asphaltene content of the live crude oil based on the measured optical density and the calculated formation volume factor of the live crude oil. Additional methods, systems, and devices are also disclosed.

Abstract: A method includes pumping fluid from outside of a downhole tool through a flowline of the downhole tool with a pump and taking first measurements, using at least one sensor, within the flowline during a first stage of pumping the fluid. The method further includes estimating a saturation pressure of the fluid, via a processor, based on the first measurements and a saturation pressure model generated based on second measurements taken using the at least one sensor during a second stage of pumping the fluid, and operating the pump to maintain a fluid pressure in the flowline greater than the estimated saturation pressure.

Abstract: A system includes a downhole formation fluid sampling tool. The system also includes an optical spectrometer of the downhole formation fluid sampling tool and a processor. The optical spectrometer is able to measure an optical characteristic of a formation fluid flowing through the downhole formation fluid sampling tool over a plurality of wavelengths. The optical spectrometer is designed to generate optical spectra data indicative of the optical characteristic. The processor is able to receive the optical spectra data generated by the optical spectrometer, to predict a parameter corresponding to one component of multiple components of the formation fluid based on the optical spectra data, and to calculate an uncertainty in the predicted parameter based on the optical spectra data.

Abstract: A system includes a downhole formation fluid sampling tool and a processor. An optical spectrometer of the downhole formation fluid sampling tool is able to measure an optical characteristic of a formation fluid flowing through the downhole formation fluid sampling tool over a plurality of wavelengths. The optical spectrometer generates optical spectra data indicative of this optical characteristic. The processor is designed to receive the optical spectra data generated by the optical spectrometer and to estimate a formation volume factor of the formation fluid based on the optical spectra data.

Abstract: A gas separation and detection tool for performing in situ analysis of borehole fluid is described. The tool comprises a sampling chamber for a downhole fluid. The sample chamber comprises a detector cell with an opening. The tool also comprises a gas separation module for taking a gas from the downhole fluid. The gas separation module comprises a membrane located in the opening, a support for holding the membrane, and a sealant applied between the housing and the membrane or support. Moreover, the tool comprises a gas detector for sensing the gas.

Abstract: An optical spectrometer includes a near black body light source, a reference detector in a first optical path and a single measurement detector in a second optical path. A sample cell including a fluid flow line may be positioned in the second optical path upstream of the measurement detector. Optical energy ma be emitted at a plurality of filament temperatures and first and second sets of optical intensities measured at the reference and measurement detectors. The first and second sets of optical intensities may be processed to compute a substantially continuous transmittance spectrum of a fluid sample in the fluid flow line by inverting the acquired optical intensity measurements.

Abstract: Methods and systems to characterize a fluid in a reservoir to determine if the fluid is in one of equilibrium or non-equilibrium in terms of one of gravity, solvency power, entropy effect or some combination thereof. The method includes acquiring tool data at each depth for each fluid sample of at least two fluid samples wherein each fluid sample is at a different depth and communicating the tool data to a processor. Determining formation properties of each fluid sample to obtain formation property data and determining fluid properties for each fluid sample to obtain fluid property data. Selecting a mathematical model based on one of gravity, solvency power or entropy, in view of a fluid property, using one of tool data, formation property data, fluid property data, known fluid reservoir data or some combination thereof, to predict if the fluid is in an equilibrium distribution or a non-equilibrium distribution.

Abstract: A technique facilitates estimation of the viscosity of heavy oil. The method comprises evaluating a sample of oil by using an infrared spectrum sensor to obtain a reference temperature based on infrared absorbance. The reference temperature can then be used to determine viscosity data on the sample at a given temperature or temperatures.

Abstract: A downhole sampling tool is operated to obtain formation fluid from a subterranean formation, which then flows through a flowline of the downhole sampling tool. Real-time density and optical density sensors of the downhole sampling tool are co-located proximate the flowline. Contamination of the formation fluid in the flowline is then determined based, at least in part, on the real-time density and optical density measurements obtained utilizing the co-located sensors.

Abstract: Obtaining in-situ, at a first time, first optical spectral data associated with a formation fluid flowing through a downhole formation fluid sampling apparatus, and then obtaining in-situ, at a second time after the first time, second optical spectral data associated with the formation fluid flowing through the downhole formation fluid sampling apparatus. A wavelength-independent scattering intensity within the formation fluid flowing through the downhole formation fluid sampling apparatus is then determined based on the first and second optical spectral data, and a wavelength-dependent scattering intensity within the formation fluid flowing through the downhole formation fluid sampling apparatus is determined based on the first and second optical spectral data.

Abstract: Obtaining in-situ optical spectral data associated with a formation fluid flowing through a downhole formation fluid sampling apparatus, and predicting a parameter of the formation fluid flowing through the downhole formation fluid sampling apparatus based on projection of the obtained spectral data onto a matrix that corresponds to a predominant fluid type of the formation fluid.

Abstract: A system and method for determining at least one fluid characteristic of a downhole fluid sample using a downhole tool are provided. In one example, the method includes performing a calibration process that correlates optical and density sensor measurements of a fluid sample in a downhole tool at a plurality of pressures. The calibration process is performed while the fluid sample is not being agitated. At least one unknown value of a density calculation is determined based on the correlated optical sensor measurements and density sensor measurements. A second optical sensor measurement of the fluid sample is obtained while the fluid sample is being agitated. A density of the fluid sample is calculated based on the second optical sensor measurement and the at least one unknown value.

Abstract: A system and method for obtaining a clean fluid sample for analysis in a downhole tool are provided. In one example, the method includes directing fluid from a main flowline of the downhole tool to a secondary flowline of the downhole tool. While the fluid is being directed into the secondary flowline, sensor responses corresponding to the fluid in the secondary flowline are monitored to determine when the sensor responses stabilize. The secondary flowline is isolated from the main flowline after the sensor responses have stabilized. A quality control procedure is performed on the fluid in the secondary flowline to determine whether the captured fluid is the same as the fluid in the main flowline. Additional fluid from the main flowline is allowed into the secondary flowline if the captured fluid is not the same.

Abstract: A system and method for determining at least one fluid characteristic of a downhole fluid sample using a downhole tool are provided. In one example, the method includes performing a calibration process that correlates optical and density sensor measurements of a fluid sample in a downhole tool at a plurality of pressures. The calibration process is performed while the fluid sample is not being agitated. At least one unknown value of a density calculation is determined based on the correlated optical sensor measurements and density sensor measurements. A second optical sensor measurement of the fluid sample is obtained while the fluid sample is being agitated. A density of the fluid sample is calculated based on the second optical sensor measurement and the at least one unknown value.

Abstract: Variable volume systems and methods of use thereof described herein are capable of making calibrated determinations of fluid properties and phase behavior of a fluid sample. The determinations can be calibrated based on one or more calibration functions, such as system volume corrected for pressure and temperature variations. Cross-checking the results of measurements can be used to determine accuracy of the calibration or monitor for leaks or other anomalies of the variable volume systems. The variable volume systems can be implemented in a well logging tool and are capable of being calibrated downhole.

Abstract: A method and system that characterizes hydrogen sulfide in petroleum fluid employs a tool that includes a fluid analyzer for performing fluid analysis (including optical density (OD) for measuring carbon dioxide concentration) of a live oil sample, and a storage chamber for an analytical reagent fluidly coupled to a measurement chamber. An emulsion from fluid of the sample and the reagent is produced into the measurement chamber. The reagent changes color due to pH changes arising from chemical reactions between components of the sample and the reagent in the measurement chamber. The tool includes an optical sensor system that measures OD of a water phase of the emulsion at one or more determined wavelengths. The pH of the water phase is derived from such OD measurements. The pH of the water phase and the carbon dioxide concentration in the sample is used to calculate hydrogen sulfide concentration in the sample.

Abstract: Example methods and apparatus to determine phase-change pressures are disclosed. A disclosed example method includes capturing a fluid in a chamber, pressurizing the fluid at a plurality of pressures, measuring a plurality of transmittances of a signal through the fluid at respective ones of the plurality of pressures, computing a first magnitude of a first subset of the plurality of transmittances, computing a second magnitude of a second subset of the plurality of transmittances, comparing the first and second magnitudes to determine a phase-change pressure for the fluid.

Abstract: A system for determining the asphaltene content of crude oil includes a first optical flow cell, a first spectrometer operably associated with the first optical flow cell, and a mixer in fluid communication with the first optical flow cell. The system further includes a crude oil injection/metering device configured to receive the crude oil, the crude oil injection/metering device being in fluid communication with the first optical flow cell; a titrant injection/metering device in fluid communication with the mixer, the titrant injection/metering device configured to receive a titrant; and a filtration unit in fluid communication with the mixer. The system further includes a second optical flow cell in fluid communication with the filtration unit, and a second spectrometer operably associated with the second optical flow cell.