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 method for transmitting data from a downhole tool is provided. In one embodiment, the method includes acquiring data for a formation fluid through downhole fluid analysis with a downhole tool in a well. The acquired data can include optical spectrum data measured with a spectrometer and other data. The method also includes generating time blocks of the acquired data and transmitting the time blocks from the downhole tool. More particularly, generating the time blocks may include compressing at least some of the optical spectrum data according to a first compression technique and compressing at least some of the other data according to one or more additional compression techniques. The compressed data can be packaged into the time blocks such that at least some of the time blocks include both compressed optical spectrum data and compressed other data for the formation fluid. Additional methods, systems, and devices are also disclosed.

Abstract: A method for sampling a downhole formation fluid includes pumping formation fluid into the flowline of a downhole sampling tool, measuring a saturation pressure of the formation fluid in the flowline while pumping, and adjusting the pumping rate such that the fluid pressure in the flowline remains within a predetermined threshold above the measured saturation pressure.

Abstract: A method for sampling a downhole formation fluid includes pumping formation fluid into the flowline of a downhole sampling tool, measuring a saturation pressure of the formation fluid in the flowline while pumping, and adjusting the pumping rate such that the fluid pressure in the flowline remains within a predetermined threshold above the measured saturation pressure.

Abstract: Various methods for detecting and accounting for the effects of half-stroking by a pump are provided. In one embodiment, a method includes operating a pump of a downhole tool to pump fluid from a formation through the downhole tool and determining pressure differentials between a formation pressure and pressure of the fluid within the downhole tool. The pressure differentials for each of a forward stroke and reverse stroke of the pump can be summed and then compared to enable identification of onset of half-stroking by the pump. Additional systems, devices, and methods are also disclosed.

Abstract: A method includes operating a downhole acquisition tool in a wellbore in a geological formation. The wellbore or the geological formation, or both, contain a reservoir fluid. The method also includes receiving a portion of the reservoir fluid into the downhole acquisition tool and performing downhole fluid analysis using the downhole acquisition tool in the wellbore to determine at least one measurement associated with the portion of the reservoir fluid. The at least one measurement includes fluid density, optical density, or both. The method also includes using a processor of the downhole acquisition tool to obtain compressibility of the reservoir fluid based at least in part on the fluid density, the optical density, or both and determining a composition of the reservoir fluid based at least in part on the compressibility.

Abstract: A downhole fluid testing system includes a downhole acquisition tool housing configured to be moved into a wellbore, where the wellbore contains fluid that comprises a native reservoir fluid of a geological formation and a contaminant. The system includes a pump to pump fluid through the downhole acquisition tool, a sensor configured to analyze portions of the fluid and obtain a fluid property the fluid from an optical spectrometer, including an optical density, and a controller coupled to the housing to receive a first plurality of measurements over time from the sensor, estimate a future saturation pressure of the fluid at specific time increments via a processor based in part on the first plurality of measurements and a saturation pressure model, and control a flow rate of the pump that causes the flow line pressure to remain above the estimated future saturation pressure plus a value of the associated uncertainty.

Abstract: A method includes positioning a downhole acquisition tool in a well-logging device in a wellbore in a geological formation, where the wellbore or the geological formation, or both contain a reservoir fluid. The method includes performing downhole fluid analysis using a downhole acquisition tool in the wellbore to determine a plurality of fluid properties associated with the reservoir fluid. The method includes generating a nonlinear predictive control model representative of the plurality of fluid properties based at least in part on the downhole fluid analysis. The method includes adjusting the nonlinear predictive control model based at least in part on an output representative of a pump flow control sequence at a first time interval and the plurality of fluid properties.

Abstract: A method for transmitting data from a downhole tool is provided. In one embodiment, the method includes acquiring data for a formation fluid through downhole fluid analysis with a downhole tool in a well. The acquired data can include optical spectrum data measured with a spectrometer and other data. The method also includes generating time blocks of the acquired data and transmitting the time blocks from the downhole tool. More particularly, generating the time blocks may include compressing at least some of the optical spectrum data according to a first compression technique and compressing at least some of the other data according to one or more additional compression techniques. The compressed data can be packaged into the time blocks such that at least some of the time blocks include both compressed optical spectrum data and compressed other data for the formation fluid. Additional methods, systems, and devices are also disclosed.

Abstract: Formation fluid sample container apparatus are described. An example apparatus includes a downhole tool having a body including an opening and a cavity extending into the body from the opening. The sample container includes an elongated container for holding a formation fluid sample and a sheath coupled to an outer surface of the elongated container and at least partially surrounding the elongated container. The sample container is fixed in the cavity and the sheath is to increase the mechanical integrity of the elongated container in a downhole environment.

Abstract: A system includes a downhole formation fluid sampling tool and a processor. An optical spectrometer of the downhole formation fluid sampling tool is able to measure an optical characteristic of a formation fluid flowing through the downhole formation fluid sampling tool over a plurality of wavelengths. The optical spectrometer generates optical spectra data indicative of this optical characteristic. The processor is designed to receive the optical spectra data generated by the optical spectrometer and to estimate a formation volume factor of the formation fluid based on the optical spectra data.

Abstract: A drilling system includes a first section of a drilling tool having a collar configured to hold internal components of the first section. The drilling system also includes a second section of the drilling tool configured to be coupled with the first section in a specific orientation relative to the first section. The second section is interchangeable with at least one different section.

Abstract: A method for identifying the type of a sampled formation fluid, such as a hydrocarbon, is provided. In one embodiment, the method includes measuring absorbance by a sample of a formation fluid at multiple wavelengths of electromagnetic radiation with a spectrometer. The method also includes distinguishing between multiple fluid types to identify a fluid type of the sample most likely to match an actual fluid type of the sample based on the measured absorbance at two or more wavelengths of the multiple wavelengths. Additional systems, devices, and methods are also disclosed.

Abstract: A tool to be used within a wellbore including a wall, the wellbore extending through a formation including formation fluid, includes a first packer and a second packer. The first packer includes a packer port to enable formation fluid flow through the first packer, with the second packer spaced from the first packer. The first packer and the second packer are expandable to abut the wellbore wall to form an interval within the wellbore between the first packer and the second packer, in which the tool further includes an interval port in fluid communication with the interval.

Abstract: A system includes a downhole formation fluid sampling tool. The system also includes an optical spectrometer of the downhole formation fluid sampling tool and a processor. The optical spectrometer is able to measure an optical characteristic of a formation fluid flowing through the downhole formation fluid sampling tool over a plurality of wavelengths. The optical spectrometer is designed to generate optical spectra data indicative of the optical characteristic. The processor is able to receive the optical spectra data generated by the optical spectrometer, to predict a parameter corresponding to one component of multiple components of the formation fluid based on the optical spectra data, and to calculate an uncertainty in the predicted parameter based on the optical spectra data.

Abstract: A method includes pumping fluid from outside of a downhole tool through a flowline of the downhole tool with a pump and taking first measurements, using at least one sensor, within the flowline during a first stage of pumping the fluid. The method further includes estimating a saturation pressure of the fluid, via a processor, based on the first measurements and a saturation pressure model generated based on second measurements taken using the at least one sensor during a second stage of pumping the fluid, and operating the pump to maintain a fluid pressure in the flowline greater than the estimated saturation pressure.

Abstract: 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.

Abstract: A downhole compressible fluid sampling tool includes a primary fluid flow line deployed between a fluid inlet probe and a fluid outlet line. A fluid analysis module and a fluid pumping module are deployed in the primary fluid flow line. The fluid pumping module includes a pump in parallel with a bypass flow line having a bypass valve. A compressible fluid sampling vessel is deployed in parallel with and in fluid communication with the primary flow line. A method for obtaining a sample of a compressible downhole fluid includes turning off the pump and opening the bypass valve to enable the downhole fluid to flow into the fluid sampling vessel. The pump may then be optionally turned back on to pressurize the sample.

Abstract: A method and/or a system determines mechanical properties of a fluid-bearing formation. One or more packers may be used to measure and/or collect data regarding mechanical properties of a formation. The formation characteristics may be, for example, the stability of the formation, design parameters for frac-pack/gravel-pack operations, and sand production. The packer may expand within a wellbore of a formation until enough pressure is applied to fracture a wall of the wellbore. Before, during and/or after the fracturing of the wall, multiple measurements may be taken by the packer. After fractures are initiated, fluid may be pumped into and/or drawn from the formation using drains disposed on the packer. Additional packers may be used above and/or below the packer for isolating intervals of the wellbore.