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: Apparatus and methods for filling a pressure compensated fluid container with a liquid. An example method includes restraining movement of a piston slidably disposed within the fluid container in a first piston position, wherein the piston divides the fluid container into first and second portions. The method further includes pumping the liquid into the first portion to compress gas located within the first portion, stopping the pumping of the liquid into the first portion, and stopping the restraining of movement of the piston to permit the piston to move to a second piston position due to expansion of the gas compressed within the first portion.

Abstract: Apparatus and methods for filling a pressure compensated fluid container with a liquid. An example method includes restraining movement of a piston slidably disposed within the fluid container in a first piston position, wherein the piston divides the fluid container into first and second portions. The method further includes pumping the liquid into the first portion to compress gas located within the first portion, stopping the pumping of the liquid into the first portion, and stopping the restraining of movement of the piston to permit the piston to move to a second piston position due to expansion of the gas compressed within the first portion.

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: A technique facilitates controlling flow in a wellbore with a simplified valve. The design of the valve also enables reduction in the overall length of the valve to improve spatial considerations. The valve comprises a valve component, e.g. a flapper, movable between a closed position and an open position. A flow tube is designed to selectively open the valve component with reduced travel, thus enabling a shortened flow tube. The short flow tube enables use of valve housings, springs, and other valve components having a reduced length.