Abstract: Vibrating wire viscometers are described. Some example vibrating wire viscometer housings include a flowline through the housing to expose a first wire to a downhole fluid, a cavity in the housing to hold a magnet and to conduct one or more additional wires from the flowline to a signal generator, first and second electrically conductive posts mechanically coupled to the housing to hold the first wire in tension within the flowline, and a seal mechanically coupled to the housing to prevent access to the magnet by the downhole fluid.

Abstract: Vibrating wire viscometers are disclosed. An example vibrating wire viscometer includes first and second electrically conductive tubes, where the first tube is at least partially inserted into the second tube, and where the first and second tubes are coupled via an electrically insulating bonding agent. The example viscometer further includes first and second electrically conductive pins inserted into respective ones of the first and second tubes, and an electrically conductive wire fastened to the first and second pins to vibrate in a downhole fluid to determine a viscosity of the downhole fluid.

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: Methods and apparatus to determine a concentration of nitrogen in a downhole fluid are described. An example apparatus to determine a concentration of nitrogen in a downhole fluid includes a fluid measurement unit to measure a first fluid composition and a density of at least a hydrocarbon and carbon dioxide in a sample of the downhole fluid. Additionally, the example apparatus includes one or more sensors to measure at least a pressure and a temperature of the sample. Further, the example apparatus includes a processing unit to determine a first theoretical density based on at least the first fluid composition, the temperature, and the pressure the sample. Further still, the example apparatus includes an analyzer to determine a first difference between the density of at least the hydrocarbon and the carbon dioxide in the sample and the first theoretical density. The first difference is associated with a concentration of nitrogen in the sample.

Abstract: Methods of calibrating a fluid analyzer for use in a wellbore are described. An example method of generating calibration data for a fluid analyzer for use in a downhole tool involves lowering a downhole tool including a fluid analyzer to a location in a wellbore, measuring, via the fluid analyzer, a characteristic value of a calibration fluid or a vacuum while the fluid analyzer is at the location, obtaining an expected characteristic value for the calibration fluid or the vacuum at the location, and comparing the measured characteristic value to the expected characteristic value to generate a calibration value for the fluid.

Abstract: A method and a tool that implements a method which includes measuring the viscosity and flow rates of formation fluids and obtaining the ratio of relative permeabilities of the formation fluids and wettability of the formation using the same.

Abstract: Vibrating wire viscometers are disclosed. An example vibrating wire viscometer includes first and second electrically conductive tubes, where the first tube is at least partially inserted into the second tube, and where the first and second tubes are coupled via an electrically insulating bonding agent. The example viscometer further includes first and second electrically conductive pins inserted into respective ones of the first and second tubes, and an electrically conductive wire fastened to the first and second pins to vibrate in a downhole fluid to determine a viscosity of the downhole fluid.

Abstract: Vibrating wire viscometers are described. Some example vibrating wire viscometer housings include a flowline through the housing to expose a first wire to a downhole fluid, a cavity in the housing to hold a magnet and to conduct one or more additional wires from the flowline to a signal generator, first and second electrically conductive posts mechanically coupled to the housing to hold the first wire in tension within the flowline, and a seal mechanically coupled to the housing to prevent access to the magnet by the downhole fluid.

Abstract: A method and a tool that implements a method which includes measuring the viscosity and flow rates of formation fluids and obtaining the ratio of relative permeabilities of the formation fluids and wettability of the formation using the same.

Abstract: Methods and apparatus to use multiple sensors to measure downhole fluid properties are described. An example method of measuring a property of a downhole fluid involves obtaining a plurality of measurements for each of a plurality of sensors. Each of the measurements corresponds to a same property of the downhole fluid, and each of the sensors is differently configured to measure the property. Additionally, the example method involves obtaining a plurality of weighting values, each of which corresponds to one of the sensors. The example method also involves applying the weighting values to the respective measurements obtained by each of the corresponding sensors to generate a weight-corrected measurement for each of the sensors. Further still, the example method involves generating a value representative of a measurement of the property of the downhole fluid based on the weight-corrected measurements and outputting the value representative of the measurement of the property.

Abstract: Example methods and apparatus to perform downhole x-ray fluorescence to detect sulfur in formation fluids are disclosed. A disclosed example downhole x-ray fluorescence apparatus comprises a flowline comprising a flowline wall, an x-ray source, a boron carbide crystal window in the flowline wall to allow x-rays emitted by the x-ray source to pass into a formation fluid in the flowline, and a detector to measure a value representative of a fluorescence of the formation fluid in response to the emitted x-rays.

Abstract: A gas separation and detection tool for performing in situ analysis of borehole fluid is described. A separation system such as a membrane is employed to separate one or more target gasses from the borehole fluid. The separated gas may be detected by reaction with another material or spectroscopy. When spectroscopy is employed, a test chamber defined by a housing is used to hold the gas undergoing test. Various techniques may be employed to protect the gas separation system from damage due to pressure differential. For example, a separation membrane may be integrated with layers that provide strength and rigidity. The integrated membrane separation may include one or more of a water impermeable layer, gas selective layer, inorganic base layer and metal support layer. The gas selective layer itself can also function as a water impermeable layer. The metal support layer enhances resistance to differential pressure. Alternatively, the chamber may be filled with a liquid or solid material.

Abstract: A method and a tool that implements a method which includes measuring the viscosity and flow rates of formation fluids and obtaining the ratio of relative permeabilities of the formation fluids and wettability of the formation using the same.

Abstract: Methods and apparatus to determine a concentration of nitrogen in a downhole fluid are described. An example apparatus to determine a concentration of nitrogen in a downhole fluid includes a fluid measurement unit to measure a first fluid composition and a density of at least a hydrocarbon and carbon dioxide in a sample of the downhole fluid. Additionally, the example apparatus includes one or more sensors to measure at least a pressure and a temperature of the sample. Further, the example apparatus includes a processing unit to determine a first theoretical density based on at least the first fluid composition, the temperature, and the pressure the sample. Further still, the example apparatus includes an analyzer to determine a first difference between the density of at least the hydrocarbon and the carbon dioxide in the sample and the first theoretical density. The first difference is associated with a concentration of nitrogen in the sample.

Abstract: A wireline-conveyed side-wall core coring tool for acquiring side-wall core from a geological formation for performing in-situ side-wall core analysis. The coring tool has a core analysis unit operable to measure geophysical properties of an acquired side-wall core. The measured geophysical properties may be used to determine the success of the acquisition of side-wall cores by the coring tool. The core analysis unit is operable of performing an in-situ interpretation of measured geophysical property of the side-wall core and transmitting in near real-time the measurements or the interpretation results to surface data acquisition and processing apparatus.

Abstract: A method for determining properties of a formation fluid is provided and includes: obtaining fluid data related to Carbon-Hydrogen molecular bonds in C6+ from a fluid analyzer; and considering the fluid data to calculate mass fractions of hydrocarbon flowing through the fluid analyzer. The method further includes computing gas-oil-ratio of hydrocarbon based on the mass fractions of hydrocarbon. Another method for determining a gas-oil-ratio of a formation fluid includes: obtaining fluid data related to Carbon-Hydrogen molecular bonds in C6+ from a fluid analyzer; considering the fluid data to derive mass fractions of gas and oil; and computing gas-oil-ratio of hydrocarbon based on the derived mass fractions.

Abstract: A downhole fluid analysis system comprises an input light signal that is directed through a fluid sample housed in a sample cell. The input light signal may originate from a plurality of light sources. A light signal output from the sample cell is then routed to two or more spectrometers for measurement of the represented wavelengths in the output light signal. The output of the spectrometers is then compared to known values for hydrocarbons typically encountered downhole. This provides insight into the composition of the sample fluid. Additionally, the input light can be routed directly to the two or more spectrometers to be used in calibration of the system in the high temperature and noise environment downhole.

Abstract: Methods and systems are provided for downhole analysis of formation fluids by deriving fluid properties and associated uncertainty in the predicted fluid properties based on downhole data, and generating answer products of interest based on differences in the fluid properties. Measured data are used to compute levels of contamination in downhole fluids using an oil-base mud contamination monitoring (OCM) algorithm. Fluid properties are predicted for the fluids and uncertainties in predicted fluid properties are derived. A statistical framework is provided for comparing the fluids to generate, in real-time, robust answer products relating to the formation fluids and reservoirs thereof. Systematic errors in measured data are reduced or eliminated by preferred sampling procedures.

Abstract: A downhole fluid analysis system comprises an input light signal that is directed through a fluid sample housed in a sample cell. The input light signal may originate from a plurality of light sources. A light signal output from the sample cell is then routed to two or more spectrometers for measurement of the represented wavelengths in the output light signal. The output of the spectrometers is then compared to known values for hydrocarbons typically encountered downhole. This provides insight into the composition of the sample fluid. Additionally, the input light can be routed directly to the two or more spectrometers to be used in calibration of the system in the high temperature and noise environment downhole.

Abstract: A wireline-conveyed side-wall core coring tool for acquiring side-wall core from a geological formation for performing in-situ side-wall core analysis. The coring tool has a core analysis unit operable to measure geophysical properties of an acquired side-wall core. The measured geophysical properties may be used to determine the success of the acquisition of side-wall cores by the coring tool. The core analysis unit is operable of performing an in-situ interpretation of measured geophysical property of the side-wall core and transmitting in near real-time the measurements or the interpretation results to surface data acquisition and processing apparatus.