摘要:
Methods and apparatuses for analyzing a downhole fluid are disclosed. An example method may involve the steps of admitting the downhole fluid in a test volume, controllably inducing a pressure change in the test volume based on at least one prescribed rate, measuring pressures in the test volume at a plurality of times, using the pressures measured at the plurality of times to determine a time at which an actual rate of the pressure change in the test volume deviates from the at least one prescribed rate, and detecting an occurrence of phase transition of the downhole fluid based on the determined time.
摘要:
Methods and apparatuses for analyzing a downhole fluid are disclosed. An example method may involve the steps of admitting the downhole fluid in a test volume, controllably inducing a pressure change in the test volume based on at least one prescribed rate, measuring pressures in the test volume at a plurality of times, using the pressures measured at the plurality of times to determine a time at which an actual rate of the pressure change in the test volume deviates from the at least one prescribed rate, and detecting an occurrence of phase transition of the downhole fluid based on the determined time.
摘要:
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.
摘要:
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.
摘要:
A method (and corresponding apparatus) for downhole fluid analysis of petroleum formation fluids. The method includes capturing in a chamber of a downhole tool at least two immiscible formation fluids in a generally segregated state (the fluids including petroleum), activating a fluid mixing means to mix the fluids in the chamber to create an emulsion therefrom, and allowing the emulsified fluids to segregate while measuring light transmittance through the segregating fluids in order to calculate a transition time period based on the light transmittance through the fluids in the chamber. The transition time period is preferably bounded by the time required for the light transmittance values measured by the light detector to reach a baseline light transmittance. The transition time period characterizes the stability of an emulsion formed by the captured fluids. The methods and apparatus can also be used for other fluid testing applications beyond downhole formation fluid testing.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.