Schlumberger Technology Corporation

Aaron Jacobson

Kuo-Chiang Chen

Murat Ocalan

Nathaniel Wicks

Jagdish H Shah

Michael G Supp

Brindesh Dhruva

Elizabeth B Dussan, V

Fredrick A Jenet

Stephane Pierre

Jennifer Trittschuh

Stéphane Briquet

A mechanism for moving elements in a fluid filled housing using a pump with the element to be moved attached rigidly to the pump or to a port assembly connected to the pump. The pump assembly or port assembly moves as a result of differential pressure created between a first and a second chamber separated from each other by the pump assembly or port assembly. Movement of the fluid in one direction increases or decreases pressure, the pressure change resulting in a net force in one direction or the other.

Mechanical system for movement along a housing axis

A formation tester for determining the formation pressure of a subsurface formation traversed by a wellbore comprises of:&#x2014;an elongate tester body;&#x2014;a support plate () that is extendible outwardly from the surface of the formation tester body, said support plate carrying probe means () to establish a passageway between the inside of said formation tester body and said formation, and a sealing pad () connected to said probe means to isolate said passage way between the inside of said formation tester body and said formation;&#x2014;anchoring means () to settle said tester body at a level within the wellbore. The elongate tester body comprises an eccentric portion () wherein said support plate is mounted such that a determined standoff is maintained between said elongate tester body and the wall of the wellbore when said tester body is settled at a level in the wellbore.

Permanently eccentered formation tester

A method for determining formation fluid pressure in earth formation surrounding a borehole wall uses a downhole probe coupled to a variable-volume cavity. The probe is driven into contact with formation at the borehole wall. The method includes expanding the volume of the cavity during a first period of time to establish fluid communication between tool fluid and formation fluid, by withdrawing a minimal amount of fluid from the formation. During a second period of time the tool pressure is allowed to equilibrate to formation pressure. When pressure equilibrium is established, formation fluid pressure is set equal to tool pressure. A preferred embodiment includes terminating expanding the volume of the cavity on detecting a break in the mud cake seal. An associated formation pressure tester tool includes an elongated body; a probe defining a formation fluid inflow aperture, an electromechanical assembly defining a variable-volume cavity, a pretest flow line coupling the aperture to the cavity, a pressure sensor coupled to the cavity; and downhole electronic means for controlling the expansion of the volume of the cavity.

Determining the pressure of formation fluid in earth formations surrounding a borehole

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Paris, France

Aaron Jacobson