Schlumberger Technology Corporation

Emmanuel Desroques

Kai Hsu

Satoru Umemoto

Hiroshi Inoue

Tsutomu Yamate

Christopher Harrison

Kentaro Indo

Toru Terabayashi

Anthony Robert Holmes Goodwin

Noriyuki Matsumoto

Jiro Takeda

Sophie Nazik Godefroy

Anthony Smits

Yukio Sudo

Hidenori Tsuboi

Vibrating wire viscometers are disclosed. An example apparatus to determine the viscosity of a downhole fluid is described, the apparatus including a wire to be immersed in a downhole fluid, to vibrate when an alternating current is applied to the wire within a magnetic field, and to generate an electromotive force when vibrating within the magnetic field, the wire comprising a first resistance. The apparatus further includes a nulling circuit coupled to the wire, wherein the nulling circuit comprises a second resistance that is selectable to be substantially equal to the first resistance, and an analyzer coupled to the wire and the nulling circuit to determine the first resistance, the second resistance, and a viscosity of the downhole fluid based on the first and second resistances, at least one characteristic of the wire, and the electromotive force.

Vibrating wire viscometers

Methods and apparatus to evaluate subterranean formations are described. An example method of evaluating a subterranean formation includes, obtaining a first sample from a first wellbore location. Additionally, the example method includes obtaining a second sample from a second wellbore location different than the first wellbore location. Further, the example method includes mixing the first sample with the second sample in a flowline to obtain a substantially homogenous mixture. Further still, the example method includes measuring a parameter of the mixture to evaluate the subterranean formation.

Methods and apparatus to evaluate subterranean formations

Methods and apparatuses for analyzing a downhole fluid are disclosed. An example method may involve the steps of admitting the downhole fluid in a test volume, controllably inducing a pressure change in the test volume based on at least one prescribed rate, measuring pressures in the test volume at a plurality of times, using the pressures measured at the plurality of times to determine a time at which an actual rate of the pressure change in the test volume deviates from the at least one prescribed rate, and detecting an occurrence of phase transition of the downhole fluid based on the determined time.

Methods and apparatus for analyzing a downhole fluid

A downhole tool, configured to be suspended in a borehole traversing an earth formation, includes a downhole data acquisition system placed in the tool body and electrically connected to an electric power generator at the formation surface. The downhole data acquisition system includes a sensor for detecting local conditions in the borehole, and a transducer for transducing the voltage of an input signal from high to low or low to high. The transducer having a gallium nitride or silicon carbide based discrete semiconductor device.

Downhole tool

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Paris, France

Emmanuel Desroques