Abstract: A method and system are provided for detecting the wax appearance temperature (WAT) of a hydrocarbon fluid sample. The hydrocarbon fluid sample is run through a microfluidic channel at controlled temperatures while sensing the pressure drop across the channel. The WAT is determined by finding a temperature at which the pressure (drop) across the microfluidic channel caused by a temperature reduction of the hydrocarbon fluid sample does not stabilize over a given time interval, thereby establishing the WAT as being at that temperature or between that temperature and a previous higher temperature where the pressure (drop) stabilized over time.

Abstract: A system for measuring asphaltene content of crude oil, includes a microfluidic chip, the microfluidic chip having a crude oil sample inlet port, a solvent port, a mixer and reactor section in fluid communication with the crude oil sample inlet port and the solvent port, and a filter in fluid communication with the mixer and reactor section, the filter having an inlet side and an outlet side, a waste port in fluid communication with the inlet side of the filter, and a product port in fluid communication with the outlet side of the filter. The system further includes an optical cell in fluid communication with the product port.

Abstract: A technique facilitates detection and analysis of constituents, e.g. chemicals, which may be found in formation fluids and/or other types of fluids. The technique comprises intermittently introducing a first fluid and a second fluid into a channel in a manner which forms slugs of the first fluid separated by the second fluid. The intermittent fluids are flowed through the channel to create a mixing action which mixes the fluid in the slugs. The mixing increases the exchange, e.g. transfer, of the chemical constituent between the second fluid and the first fluid. The exchange aids in sensing an amount of the chemical or chemicals for analysis. In many applications, the intermittent introduction, mixing, and measuring can be performed in a subterranean environment.

Abstract: A method and apparatus for analyzing solubility of asphaltenes of a hydrocarbon fluid sample involves a sequence of operations including: i) performing microfluidic mixing operations that form a mixture that includes the hydrocarbon fluid sample, a solvent that dissolves asphaltenes and a precipitant that precipitates asphaltenes; ii) using microfluidic processes that result in precipitation of asphaltenes from the mixture resulting from i); iii) performing microfluidic filtering operations that remove precipitated asphaltenes resulting from ii) and passes permeate; and iv) performing optical spectroscopy on the permeate resulting from iii). The operations of i)-iv) can be repeated over iterations that vary the amount of solvent relative to the precipitant in the mixture. These iterations can cause varying fractional precipitation of asphaltenes in each given iteration.

Abstract: A system for measuring asphaltene content of crude oil, includes a microfluidic chip, the microfluidic chip having a crude oil sample inlet port, a solvent port, a mixer and reactor section in fluid communication with the crude oil sample inlet port and the solvent port, and a filter in fluid communication with the mixer and reactor section, the filter having an inlet side and an outlet side, a waste port in fluid communication with the inlet side of the filter, and a product port in fluid communication with the outlet side of the filter. The system further includes an optical cell in fluid communication with the product port.

Abstract: An apparatus and a method including exposing a first fluid to a pre-filter, observing the first fluid, introducing a second fluid to the first fluid, exposing the first and second fluids to a filter, and observing the first and second fluids wherein the observing the first fluid and observing the first and second fluids comprise optical measurements and the first fluid comprises material from a subterranean formation. Some embodiments may compare the optical measurements of the first fluid and the first and second fluids and/or estimate the first fluid's likelihood of forming precipitants with other fluids and/or the first fluid's asphaltene content.

Abstract: A system for measuring asphaltene content of crude oil, includes a microfluidic chip, the microfluidic chip having a crude oil sample inlet port, a solvent port, a mixer and reactor section in fluid communication with the crude oil sample inlet port and the solvent port, and a filter in fluid communication with the mixer and reactor section, the filter having an inlet side and an outlet side, a waste port in fluid communication with the inlet side of the filter, and a product port in fluid communication with the outlet side of the filter. The system further includes an optical cell in fluid communication with the product port.

Abstract: A system for measuring asphaltene content of crude oil, includes a microfluidic chip, the microfluidic chip having a crude oil sample inlet port, a solvent port, a mixer and reactor section in fluid communication with the crude oil sample inlet port and the solvent port, and a filter in fluid communication with the mixer and reactor section, the filter having an inlet side and an outlet side, a waste port in fluid communication with the inlet side of the filter, and a product port in fluid communication with the outlet side of the filter. The system further includes an optical cell in fluid communication with the product port.

Abstract: A method for determining an asphaltene yield curve and an asphaltene flocculation point includes obtaining a crude oil sample and measuring an optical spectrum of the crude oil sample. A titrant is then mixed with the crude oil sample at different concentrations. At each concentration, precipitated asphaltenes are filtered from the mixture and the optical spectrum of the filtrate is measured. The optical spectrum of the filtrate is then subtracted from the optical spectrum of the crude oil sample. A fractional asphaltene precipitation is determined for each concentration of titrant. A flocculation point is determined corresponding to an inflection point in the fractional asphaltene precipitation for each concentration of titrant.

Abstract: A system for characterizing crude oil fractions includes a maltenes sample reservoir, a first solvent reservoir, a second solvent reservoir, and a third solvent reservoir. The system further includes a valve in fluid communication with the first solvent reservoir, the second solvent reservoir, and the third solvent reservoir and a pump in fluid communication with the valve. The system further includes a packed bed in fluid communication with the maltenes sample reservoir and the pump, a flowthrough cell in fluid communication with the packed bed, a spectrometer operably associated with the flowthrough cell, and a computer operably associated with the spectrometer. A method for characterizing crude oil fractions includes providing a maltene sample, eluting saturates, aromatics, and resins of the maltene sample, determining an optical density of each, and determining a concentration of each of the saturates, aromatics, and resins based upon optical densities over time for each.

Abstract: A method for determining an asphaltene yield curve and an asphaltene flocculation point includes obtaining a crude oil sample and measuring an optical spectrum of the crude oil sample. A titrant is then mixed with the crude oil sample at different concentrations. At each concentration, precipitated asphaltenes are filtered from the mixture and the optical spectrum of the filtrate is measured. The optical spectrum of the filtrate is then subtracted from the optical spectrum of the crude oil sample. A fractional asphaltene precipitation is determined for each concentration of titrant. A flocculation point is determined corresponding to an inflection point in the fractional asphaltene precipitation for each concentration of titrant.

Abstract: A system for measuring asphaltene content of crude oil, includes a microfluidic chip, the microfluidic chip having a crude oil sample inlet port, a solvent port, a mixer and reactor section in fluid communication with the crude oil sample inlet port and the solvent port, and a filter in fluid communication with the mixer and reactor section, the filter having an inlet side and an outlet side, a waste port in fluid communication with the inlet side of the filter, and a product port in fluid communication with the outlet side of the filter. The system further includes an optical cell in fluid communication with the product port.

Abstract: An apparatus for measuring phase behavior of a reservoir fluid comprises a first sample container and a second sample container in fluid communication with a microfluidic device defining a microchannel. A first pump and a second pump are operably associated with the sample containers and the microfluidic device to fill the microchannel with a reservoir fluid and to maintain a predetermined pressure of reservoir fluid within the microchannel.

Abstract: A system for performing a flash separation of a reservoir fluid includes a sample chamber configured to hold the reservoir fluid and a flash apparatus in fluid communication with the sample chamber. The flash apparatus includes a microfluidic device configured to flash the reservoir fluid in fluid communication with the sample chamber, and a separation chamber configured to separate the flashed reservoir fluid into a liquid phase and a gaseous phase in fluid communication with the microfluidic device. The system further includes a gas receptacle configured to store the gaseous phase. A method for performing a flash separation of a reservoir fluid includes providing a reservoir fluid to a microfluidic device, urging the reservoir fluid through the microfluidic device such that the reservoir fluid is lashed within the microfluidic device, and separating a liquid phase and a gaseous phase from the flashed reservoir fluid.

Abstract: A method for measuring saturate, aromatic, and resin fractions of a hydrocarbon fluid includes separating maltenes from the hydrocarbon fluid and separating saturate, aromatic, and resin fractions from the maltenes. The method further includes determining an optical density of each of the saturate, aromatic, and resin fractions at a predetermined wavelength and correlating the optical density of each of the saturate, aromatic, and resin fractions to predetermined data to determine each of the saturate, aromatic, and resin fractions.

Abstract: An apparatus and a method including exposing a first fluid to a pre-filter, observing the first fluid, introducing a second fluid to the first fluid, exposing the first and second fluids to a filter, and observing the first and second fluids wherein the observing the first fluid and observing the first and second fluids comprise optical measurements and the first fluid comprises material from a subterranean formation. Some embodiments may compare the optical measurements of the first fluid and the first and second fluids and/or estimate the first fluid's likelihood of forming precipitants with other fluids and/or the first fluid's asphaltene content.

Abstract: A method of measuring thermo-physical properties of a reservoir fluid includes introducing the fluid under pressure into a microchannel, establishing a stabilized flow of the fluid through the microchannel, inducing bubble formation in the fluid disposed in the microchannel, and determining the thermo-physical properties of the fluid based upon the bubbles formed as the fluid flows through the microchannel.

Abstract: A system for determining the phase envelope of a gas condensate includes a microfluidic device defining an entrance passageway, an exit passageway, and a microchannel in fluid communication with the passageways. The system includes an input sample bottle in fluid communication with the entrance passageway and a first pump associated with the input sample bottle for urging the gas condensate, in the input sample bottle, into the entrance passageway. The system further includes an output sample bottle in fluid communication with the exit passageway and a second pump associated with the output sample bottle for pressurizing the gas condensate, in the output sample bottle, into the exit passageway in opposition to the first pump. The system includes a temperature control device for controlling the temperature of the gas condensate in the microchannel. The first pump and the second pump operate to provide a desired pressure drop across the microchannel.

Abstract: Methods and related systems are described for analyzing phase properties in a microfluidic device. A fluid is introduced under pressure into microchannel, and phase states of the fluid are optically detected at a number of locations along the microchannel. Gas and liquid phases of the fluid are distinguished based on a plurality of digital images of the fluid in the microchannel. Bi-level images can be generated based on the digital images, and the fraction of liquid or gas in the fluid can be estimated versus pressure based on the bi-level images. Properties such as bubble point values and/or a phase volume distribution ratio versus pressure for the fluid are can be estimated based on the detected phase states of 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.