摘要:
Methods of analyzing formation fluids in an oilfield environment are near-infrared absorption spectroscopy. Indications of near-infrared absorptions are analyzed to determine the concentration of compounds in a formation fluid sample.
摘要:
Methods of detecting carbon dioxide in downhole environments are provided. Near-infrared light is transmitted through a gas downhole. Indications of near-infrared absorptions are detected from the gas and used to determine the presence of carbon dioxide.
摘要:
A method and apparatus detects dew precipitation and determines dew precipitation onset pressure in a sample of formation fluid located downhole in an oilfield reservoir. In a preferred embodiment, the method includes (a) isolating a sample of formation fluid downhole; (b) illuminating the sample downhole with fluorescence excitation light; (c) measuring at least one characteristic of fluorescence short from the sample; (d) reducing pressure on the sample; (e) repeating steps (b) to (d); (f) detecting dew precipitation when a change is detected in a parameter that is a function of the at least one characteristic of fluorescence emission; and (g) setting dew precipitation onset pressure equal to pressure on the sample when the change in the parameter is detected. The parameter preferably is a function of fluorescence intensity and fluorescence red shift, and the change is an increase in fluorescence intensity and detection of fluorescence red shift. Also, the function includes a ratio of a measured intensity at a first wavelength to a reference intensity, and the reference intensity is a function of a measured intensity at a second wavelength.
摘要:
A method for determining properties of a formation fluid including obtaining data related to an optical density at a methane peak and an optical density at an oil peak for a fluid sample at a plurality of times, calculating an apparent gas-oil-ratio of the sample fluid from the optical density of the fluid sample at the methane peak to the optical density of the fluid sample at the oil peak at each of the plurality of times based on the data, selecting a power function of a sampling parameter for a buildup of the apparent gas-oil-ratio, calculating an exponential constant of the power function based on the data, and determining at least one selected from the group consisting of a contamination free gas-oil-ratio and a percent contamination.
摘要:
A downhole characterization apparatus for formation fluids is provided. The apparatus comprises a downhole tool including a flowline for flowing the formation fluids capable of isolating a quantity of the formation fluids in a portion thereof; and a pump unit for depressurizing the isolated formation fluids; and a measurement controller which controls the downhole tool. The measurement controller includes a rough value estimation unit which estimates a rough value of the bubble point pressure of the formation fluids; and a speed controller which controls the depressurizing speed of the pump unit such that the isolated formation fluids are depressurized at a first speed to a certain pressure which is a predetermined value higher than said estimated rough value, and the isolated fluids are depressurized at a second speed which is slower than said first speed in order to measure a precise value of the bubble point pressure.
摘要:
A method of downhole characterization of formation fluids is provided. The method includes: estimating a rough value of the bubble point pressure of the formation fluids; depressurizing the formation fluids at a first speed to a certain pressure which is a predetermined value higher than the estimated rough value while the formation fluids are isolated in a portion of the flowline; and depressurizing the isolated fluids at a second speed which is slower than the first speed in order to measure a precise value of the bubble point pressure.
摘要:
A downhole characterization apparatus for formation fluids is provided. The apparatus comprises a downhole tool including a flowline for flowing the formation fluids capable of isolating a quantity of the formation fluids in a portion thereof; and a pump unit for depressurizing the isolated formation fluids; and a measurement controller which controls the downhole tool. The measurement controller includes a rough value estimation unit which estimates a rough value of the bubble point pressure of the formation fluids; and a speed controller which controls the depressurizing speed of the pump unit such that the isolated formation fluids are depressurized at a first speed to a certain pressure which is a predetermined value higher than said estimated rough value, and the isolated fluids are depressurized at a second speed which is slower than said first speed in order to measure a precise value of the bubble point pressure.
摘要:
Some principles described herein contemplate implementation of downhole imaging for the characterization of formation fluid samples in situ, as well as during flow through production tubing, including subsea flow lines, for short term investigation, permanent, and/or long term installations. Various methods and apparatus described herein may facilitate downhole testing. For example, some embodiments facilitate multi-dimensional fluorescence spectrum measurement testing downhole.
摘要:
Some principles described herein contemplate implementation of downhole imaging for the characterization of formation fluid samples in situ, as well as during flow through production tubing, including subsea flow lines, for short term investigation, permanent, and/or long term installations. Various methods and apparatus described herein may facilitate downhole testing. For example, some embodiments facilitate multi-dimensional fluorescence spectrum measurement testing downhole and correlating the fluorescence with other oil properties.
摘要:
A method of determining GOR comprising subjecting a fluid to spectroscopic analysis at a first wavelength sensitive to gas and a second wavelength sensitive to oil, determining a response matrix for the contribution of gas at the first and second wavelengths and the contribution of oil at the first and second wavelengths, determining a signal response vector and the two wavelengths, calculating a mass fraction vector from the response matrix and the signal response vector and using the mass fraction vector to determine GOR.