Schlumberger Technology Corporation

Ian Traboulay

Edward Harrigan

Douglas W Grant

Oliver Clinton Mullins

Andrew L Kurkjian

Robin McGowan

Thomas Distefano

A formation testing tool and method for providing pressure controlled sampling is provided. A flow line delivers formation fluid to a sample chamber in the testing tool. A first valve controls the flow of formation fluid from the flow line to the sample chamber. A piston is slidably disposed in the sample chamber to define a sample cavity and a actuation cavity having variable volumes determined by movement of the piston. An actuator is also provided to move the piston in a first direction to increase the volume of the sample cavity and a second direction to decrease the volume of the sample cavity whereby formation fluid may be drawn into the sample cavity and pressurized therein using the actuator and the first valve.

Apparatus and method for controlling the pressure of fluid within a sample chamber

The compressibility of a formation hydrocarbon sample is determined downhole by using a borehole tool to obtain the sample downhole, and, at two different pressures, subjecting the sample to near infrared illumination and conducting spectral absorption measurement of peaks at and/or around about 6,000 cm and/or at and/or about 5,800 cm (the absorption peaks of methane and crude oil respectively). The compressibility of the sample is determined from the change in the peak areas, the change in pressure, and the measured peak area itself. According to a preferred embodiment of the invention, the pressure is changed at least 2000 pounds per square inch (psi), and preferably 4000 or more psi between measurements.

Methods and apparatus for optically measuring fluid compressibility downhole

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Sugar Land, TX, United States of America

Ian Traboulay