Abstract: A method for contamination monitoring includes measuring water based mud filtrate density and resistivity at downhole conditions, logging properties of a downhole fluid to find at least a resistivity and a density of a fluid sample at the downhole conditions, establishing a linear relationship between a water based mud filtrate conductivity at downhole conditions and the water based mud filtrate density at the downhole conditions, determining a density and a resistivity for native formation water, estimating a density for water based mud filtrate using the linear relationship between conductivity and density, and estimating a water based mud filtrate contamination.

Abstract: A method includes operating a downhole acquisition tool including a guard probe and a sample probe in a wellbore that contains a fluid that includes a native reservoir fluid and a contaminant. The method also includes receiving a first portion of fluid into the guard probe and a second portion of fluid into the sample probe, estimating a contamination level of the first or second portions based on a fluid property of the respective first and second portions, determining an initial guard flow rate of the first portion, determining an initial sample flow rate of the second portion, using a processor to adjust a guard flow rate of the second portion over pump time after the contamination level of the first portion is at or below a contamination level threshold, and adjust a sample flow rate of the first portion based on the adjusted guard flow rate and total flowrate.

Abstract: Methods and apparatus for operating a downhole tool within a wellbore adjacent a subterranean formation to pump contaminated fluid from the formation into the downhole tool while measuring first and second fluid properties of the contaminated fluid. The contaminated fluid comprises native fluid from the formation and a contaminant. The downhole tool is in communication with surface equipment located at surface. The downhole tool and/or surface equipment is operated to estimate a formation volume factor of the contaminated fluid based on at least one of the first and second fluid properties of the contaminated fluid. A linear relationship is then estimated between the first fluid property and a function that relates the first fluid property to the second fluid property and the estimated formation volume factor of the contaminated fluid. A fluid property of the contaminant is then estimated based on the estimated linear relationship.

Abstract: First piston position data of a piston in a displacement unit is obtained based on an output signal from a sensor associated with the displacement unit, the output signal being dependent upon a physical position of the piston in the displacement unit. Second piston position data of the piston in the displacement unit is obtained based on data indicative of a number of revolutions of a hydraulic motor in a hydraulic system, the hydraulic system being operable to drive the piston of the displacement unit. Based on the second piston position data, a flow rate of a fluid pumped by the displacement unit is estimated. A system correction factor is generated based on the first piston position data and the second piston position data. The estimated flow rate is adjusted based on the system correction factor.

Abstract: Systems and methods for obtaining in-situ measurements of mixed formation fluids are provided. A downhole acquisition tool may move to a first station in a wellbore in a geological formation to collect a sample of first formation fluid from the first station. The downhole acquisition tool may move to a second station in the wellbore and a sample of second formation fluid may be collected. A proportion of the first formation fluid and the second formation fluid may be mixed within the downhole acquisition tool in-situ while the downhole acquisition tool is within the wellbore to obtain a formation fluid mixture. The formation fluid mixture may be passed into a fluid testing component of the downhole acquisition tool while the downhole acquisition tool is in the wellbore to measure fluid properties of the formation fluid mixture in-situ.

Abstract: This disclosure relates to a downhole acquisition tool having a formation testing module. The formation testing module includes a fluid chamber comprising a piston and configured to store a fluid and to receive a flowback fluid from a geological formation, wherein the fluid is substantially free of solids. Additionally, the formation testing tool has a first conduit fluidly coupled to the fluid chamber and extending from a flowback conduit and a first outlet of the formation testing module, wherein the flowback conduit is configured fluidly coupled to the geological formation and configured to receive the flowback fluid from the geological formation, and wherein the first conduit is configured to receive the flowback fluid from the flowback conduit. Further, the formation testing module has a first flow control device positioned downstream from the fluid chamber, wherein the first flow control device is configured to control a flow of the fluid exiting the fluid chamber.

Abstract: The present disclosure relates to systems and methods for determining an integrity of a sample chamber. In certain embodiments, formation fluid is collected from a subterranean formation within a sample chamber disposed in a downhole tool, the downhole tool is withdrawn from a wellbore, an estimated surface pressure of the collected formation fluid is determined, the estimated surface pressure of the collected formation fluid is compared with an actual surface pressure of the sample chamber, and the integrity of the sample chamber is determined based on the comparison of the estimated surface pressure and the actual surface pressure.

Abstract: Methods are provided for reservoir analysis. In some embodiments, a reservoir may be analyzed by obtaining abundance ratios at a first measurement station and a second measurement station and determining an abundance ratio trend. Abundance ratios at a third measurement station may be obtained and plotted versus depth with the previously obtained abundance ratios. A change in the abundance ratio trend may be identified and result in further investigation of the reservoir. If the abundance ratio is unchanged, additional abundance ratios may be obtained and plotted versus depth to further evaluate the abundance ratio trend. Methods for reservoir analysis using fluid predictions with and without offset well information are also provided.

Abstract: Apparatus and methods for obtaining initial settings of station-specific parameters descriptive of wellbore/formation properties specific to downhole pressure test stations, and obtaining initial settings of station-shared parameters descriptive of petrophysical properties of petrophysically unique formation zones. A pressure transient model of the zones is obtained by regression utilizing the pressure data of each station and the initial settings of the station-specific and station-shared parameters. The regression analytically determines a model value of at least one of the station-specific parameters and the station-shared parameters.

Abstract: A method includes positioning a downhole acquisition tool in a wellbore in a geological formation. The method includes operating a pump module to gather information for a fluid outside of the downhole acquisition tool that enters the downhole acquisition tool from a first flowline, a second flowline, or both while the downhole acquisition tool is within the wellbore. Operating the pump module includes controlling a valve assembly to a first valve configuration that enables the fluid to flow into the downhole tool via the first flowline fluidly coupled to a first pump module.

Abstract: A downhole tool designed to be disposed in a borehole of a subterranean formation is provided. The downhole tool includes a probe used to interface with the subterranean formation in order to sample fluid from or to inject fluid into the subterranean formation. The downhole tool also includes a sample flowline fluidly coupled to the probe and used to direct fluid through the downhole tool. The downhole tool further includes at least two volume chambers. These volume chambers each include a first side fluidly coupled to the sample flowline, a second side fluidly coupled to the guard flowline, and a piston separating the first side from the second side. The downhole tool is able to control a flow of fluid from a high pressure environment to a low pressure environment via the at least two volume chambers, the sample flowline, and the guard flowline.

Abstract: A method including positioning a downhole acquisition tool in a wellbore in a geological formation; performing a pretest sequence to gather at least one of pressure or mobility information based on downhole acquisition from a sample line, a guard line, or both while the downhole acquisition tool is within the wellbore. The pretest sequence includes controlling a valve assembly to a first valve configuration that may allow the fluid to flow into the downhole tool via one or more flowlines toward a pretest system. The one or more flowlines include the sample line only, the guard line only, or both the sample line and the guard line; and drawing in the fluid through the one or more flowlines. The method also includes controlling the valve assembly to a second valve configuration. The second valve configuration is different from the first valve configuration and may block the one or more flowlines from drawing in the fluid.

Abstract: First piston position data of a piston in a displacement unit is obtained based on an output signal from a sensor associated with the displacement unit, the output signal being dependent upon a physical position of the piston in the displacement unit. Second piston position data of the piston in the displacement unit is obtained based on data indicative of a number of revolutions of a hydraulic motor in a hydraulic system, the hydraulic system being operable to drive the piston of the displacement unit. Based on the second piston position data, a flow rate of a fluid pumped by the displacement unit is estimated. A system correction factor is generated based on the first piston position data and the second piston position data. The estimated flow rate is adjusted based on the system correction factor.

Abstract: A downhole tool designed to be disposed in a borehole of a subterranean formation is provided. The downhole tool includes a probe used to interface with the subterranean formation in order to sample fluid from or to inject fluid into the subterranean formation. The downhole tool also includes a sample flowline fluidly coupled to the probe and used to direct fluid through the downhole tool. The downhole tool further includes at least two volume chambers. These volume chambers each include a first side fluidly coupled to the sample flowline, a second side fluidly coupled to the guard flowline, and a piston separating the first side from the second side. The downhole tool is able to control a flow of fluid from a high pressure environment to a low pressure environment via the at least two volume chambers, the sample flowline, and the guard flowline.

Abstract: A method for using an optical spectrum of mud filtrate for analysis of fluid drawn from a formation is provided. The method includes performing downhole fluid analysis of formation fluid drawn at a wellbore measurement station and determining an optical spectrum of mud filtrate in the formation fluid drawn at the wellbore measurement station. The method also includes performing downhole fluid analysis of formation fluid drawn at an additional wellbore measurement station, and performing the downhole fluid analysis of formation fluid drawn at the additional wellbore measurement station includes using the determined optical spectrum of the mud filtrate in the formation fluid previously drawn at the wellbore measurement station. Additional methods, systems, and devices are also disclosed.

Abstract: A method including positioning a formation testing tool within a wellbore formed within a subsurface reservoir, wherein the tool has a focused opening to enable fluid communication with the reservoir, and the tool has a horizontally-displaced observation probe configured to obtain pressure data; determining one of horizontal permeability and horizontal mobility of the reservoir based on measuring a flow response of the subsurface reservoir one of at and adjacent to the observation probe; and determining orthogonal components of one of the horizontal permeability and horizontal mobility based on the measured flow response.

Abstract: Methods are provided for reservoir analysis. In some embodiments, a reservoir may be analyzed by obtaining abundance ratios at a first measurement station and a second measurement station and determining an abundance ratio trend. Abundance ratios at a third measurement station may be obtained and plotted versus depth with the previously obtained abundance ratios. A change in the abundance ratio trend may be identified and result in further investigation of the reservoir. If the abundance ratio is unchanged, additional abundance ratios may be obtained and plotted versus depth to further evaluate the abundance ratio trend. Methods for reservoir analysis using fluid predictions with and without offset well information are also provided.

Abstract: A downhole tool having multiple packers and a controller operable to operate the packers to establish upper, middle, and lower intervals. The controller then establishes the upper and lower intervals at formation pressure, and establishes the middle interval at hydrostatic pressure. The controller then creates a pressure signal in one of the upper and lower intervals and then records a resulting pressure transient in both of the upper and lower intervals. The controller is also operable to establish the middle interval at formation pressure and establish the upper and lower intervals at below hydrostatic pressure but above formation pressure, and then create the pressure signal in the middle interval and subsequently record a resulting pressure transient in the middle interval.

Abstract: Systems and methods for obtaining in-situ measurements of mixed formation fluids are provided. A downhole acquisition tool may move to a first station in a wellbore in a geological formation to collect a sample of first formation fluid from the first station. The downhole acquisition tool may move to a second station in the wellbore and a sample of second formation fluid may be collected. A proportion of the first formation fluid and the second formation fluid may be mixed within the downhole acquisition tool in-situ while the downhole acquisition tool is within the wellbore to obtain a formation fluid mixture. The formation fluid mixture may be passed into a fluid testing component of the downhole acquisition tool while the downhole acquisition tool is in the wellbore to measure fluid properties of the formation fluid mixture in-situ.

Abstract: A method and an apparatus for characterizing a fluid provide for flowing a sample fluid through a microfluidic flow line and subsequently flushing the flowline with flushing fluid alone or together with heating and/or exposure to a pulsating electromagnetic field. A tracer fluid is injected and tracked in a microfluidic line based on known properties of the tracer fluid.