Abstract: A method includes operating a downhole acquisition tool in a wellbore in a geological formation and performing formation testing using the downhole acquisition tool in the wellbore to determine at least one measurement associated within the geological formation, the wellbore, or both. The downhole acquisition tool includes one or more sensors that may detect the at least one measurement and the at least one measurement includes formation pressure, wellbore pressure, or both. The method also includes using a processor of the downhole acquisition tool to obtain a response characteristic associated with the formation, the wellbore, or both based on oscillations in the at least one measurement and determining at least one petrophysical property of the geological formation, the wellbore, or both, based on the response characteristic. The petrophysical property includes permeability, mud filter cake permeability, or both.

Abstract: A method includes operating a downhole acquisition tool in a wellbore in a geological formation and performing formation testing to determine at least one measurement associated within the formation, the wellbore, or both. The tool may include sensors to detect measurements including, for example, formation pressure and/or wellbore pressure. The tool may also include a processor to obtain at least one spectral characteristic associated with the measurement, which may include frequencies of oscillation. The processor may also determine one or more parameters, associated with an oscillation suppression process, based on the spectral characteristic and remove oscillations, including noise associated with fluctuations of a fluid level in the wellbore, in the measurement based on the parameters. Petrophysical parameters may be estimated based on the modified measurement.

Abstract: A method of investigating an earth formation. A tool having a pressure sensor is used in a borehole to collect formation fluid pressure data over time. A pressure derivative curve is generated from the formation fluid pressure data by conducting a piecewise linear regression of the data having optimal window length values L determined by calculating a derivative with respect to L of a pressure derivative value (DD), and selecting values of L where DD has a transition that departs from oscillatory behavior to gradual change. The pressure derivative is calculated with piecewise linear regression with the optimal window length values 2L. Different L values are generated for different groups of data points obtained over time. The pressure derivative is then used for flow regime determination.

Abstract: Methods are provided for tracking carbon dioxide (CO2) migration in a hydrocarbon-bearing reservoir located under a cap rock in a formation. In one embodiment, at least one seismic source and a plurality of receivers are located in spaced boreholes in the formation with the sources and receivers located near or at the reservoir so that direct paths from the sources to the receivers extend through the reservoir. CO2 is injected from the borehole containing the seismic sources into the reservoir, and the sources are activated multiple times over days and seismic signals are detected at the receivers. From the detected signals, time-lapse travel delay of direct arrivals of the signals are found and are used to track CO2 in the reservoir as a function of time. In another embodiment, the sources and receivers are located above the reservoir, and reflected waves are utilized to track the CO2.

Abstract: A method of investigating an earth formation. A tool having a pressure sensor is used in a borehole to collect formation fluid pressure data over time. A pressure derivative curve is generated from the formation fluid pressure data by conducting a piecewise linear regression of the data having optimal window length values L determined by calculating a derivative with respect to L of a pressure derivative value (DD), and selecting values of L where DD has a transition that departs from oscillatory behavior to gradual change. The pressure derivative is calculated with piecewise linear regression with the optimal window length values 2L. Different L values are generated for different groups of data points obtained over time. The pressure derivative is then used for flow regime determination.

Abstract: A method includes operating a downhole acquisition tool in a wellbore in a geological formation and performing formation testing to determine at least one measurement associated within the formation, the wellbore, or both. The tool may include sensors to detect measurements including, for example, formation pressure and/or wellbore pressure. The tool may also include a processor to obtain at least one spectral characteristic associated with the measurement, which may include frequencies of oscillation. The processor may also determine one or more parameters, associated with an oscillation suppression process, based on the spectral characteristic and remove oscillations, including noise associated with fluctuations of a fluid level in the wellbore, in the measurement based on the parameters. Petrophysical parameters may be estimated based on the modified measurement.

Abstract: A method includes operating a downhole acquisition tool in a wellbore in a geological formation and performing formation testing using the downhole acquisition tool in the wellbore to determine at least one measurement associated within the geological formation, the wellbore, or both. The downhole acquisition tool includes one or more sensors that may detect the at least one measurement and the at least one measurement includes formation pressure, wellbore pressure, or both. The method also includes using a processor of the downhole acquisition tool to obtain a response characteristic associated with the formation, the wellbore, or both based on oscillations in the at least one measurement and determining at least one petrophysical property of the geological formation, the wellbore, or both, based on the response characteristic. The petrophysical property includes permeability, mud filter cake permeability, or both.

Abstract: Methods are provided for tracking carbon dioxide (CO2) migration in a hydrocarbon-bearing reservoir located under a cap rock in a formation. In one embodiment, at least one seismic source and a plurality of receivers are located in spaced boreholes in the formation with the sources and receivers located near or at the reservoir so that direct paths from the sources to the receivers extend through the reservoir. CO2 is injected from the borehole containing the seismic sources into the reservoir, and the sources are activated multiple times over days and seismic signals are detected at the receivers. From the detected signals, time-lapse travel delay of direct arrivals of the signals are found and are used to track CO2 in the reservoir as a function of time. In another embodiment, the sources and receivers are located above the reservoir, and reflected waves are utilized to track the CO2.