21
Prevedel Bernhard, Askew Warren, Eddison Alan: Directional drilling methods and apparatus.. Anadrill Int, Schlumberger Services Petrol, August 5, 1992: EP0497420-A1 (21 worldwide citation)

In accordance with illustrative embodiments of the present invention, more accurate directional drilling is carried out by providing a downhole adjustable bent housing that is selectively operated to produce a bend angle in the drill string between a downhole motor and the drill bit, providing a nea ...


22
Auzerais Francois, Dussan Elizabeth: Determining horizontal and/or vertical permeability of an earth formation.. Schlumberger, Schlumberger Services Petrol, Schlumberger Technology, Schlumberger Holdings, December 30, 1992: EP0520903-A2 (21 worldwide citation)

Fluid flow measurements are made in situ using a repeat formation tester with a modified probe aperture, or on rock samples using a mini-permeameter with a modified probe aperture. The modified probe aperture has an elongate cross-section, such as elliptic or rectangular. A first flow measurement is ...


23
Orban Jacques, Richardson Neil W: Method of and apparatus for making near-bit measurements while drilling.. Anadrill Int, Schlumberger Services Petrol, August 4, 1993: EP0553908-A2 (21 worldwide citation)

In accordance with illustrative embodiments of the present invention, a measuring-while-drilling system includes a sensor sub (22) positioned at the lower end of a downhole motor assembly (14) so that the sub is located near the drill bit (13). The sub houses instrumentalities that measure various d ...


24
Orban Jacques, Squire Roy: Sonic vibration telemetering system.. Anadrill Int, Schlumberger Services Petrol, July 28, 1993: EP0552833-A1 (21 worldwide citation)

In accordance with illustrative embodiments of the present invention, a sonic vibration transmitter that is used, for example, in telemetering measurements made while drilling includes a body that mounts a stack of ceramic crystals which generate bursts of sonic vibrations when excited by encoded el ...


25
Kleinberg Robert L, Fukuhara Masafumi, Griffin Douglas D, Sezginer Abdurrahman, Chew Weng C, Day Peter I, Kenyon William E, Lipsicas Max: Borehole measurement of nmr characteristics of earth formations and interpretations thereof.. Schlumberger, Schlumberger Services Petrol, Schlumberger Technology, Schlumberger Holdings, April 19, 1995: EP0649035-A1 (21 worldwide citation)

Borehole NMR logging apparatus and methods, and methods for the interpretation thereof. A logging tool is provided which produces a strong, static and homogeneous magnetic field B0 in a Volume of an adjacent formation on one side of the tool to measure nuclear magnetic resonance characteristics ther ...


26
Chaudoreille Francois, Permuy Alfred, Donzier Eric: A density and viscosity sensor. Schlumberger Services Petrol, Schlumberger Technology, Schlumberger Holdings, Prad Res & Dev, July 4, 2007: EP1804048-A1 (21 worldwide citation)

A density and viscosity sensor 1 for measuring density and viscosity of fluid F, the sensor 1 comprising: - a resonating element 3, 3A, 3B, 3C, 3D, 3E, 3F, 3G arranged to be immersed in the fluid F, - an actuating/detecting element 4, 4A, 4B coupled to the resonating element, - a connector 7 for cou ...


27
Hache Jean Michel D, Moulin Pierre A, Phillips Wayne J: Motion compensation apparatus and method for determining heading of a borehole.. Anadrill Int, Schlumberger Services Petrol, April 5, 1995: EP0646696-A1 (21 worldwide citation)

A method and apparatus is disclosed for measuring motion signals of gyroscopes in downhole instruments used to determine the heading of a borehole. An illustrative embodiment of the invention includes a measuring-while-drilling system which may experience motion even while the drill string is suspen ...


28
Ciglenec Reinhart, Dorel Alain P: Formation pressure measurement while drilling utilizing a non-rotating sleeve. Schlumberger Holdings, Schlumberger Services Petrol, February 9, 2000: EP0978630-A2 (21 worldwide citation)

A downhole tool and method are provided for collecting data from a subsurface formation during drilling operations. The tool includes a tubular mandrel (302) adapted for axial connection in a drill string positioned in a wellbore penetrating the subsurface formation and a stabilizer element or sleev ...


29
Detournay Emmanuel: Method of determining the drilling conditions associated with the drilling of a formation with a drag bit.. Anadrill Int, Schlumberger Services Petrol, January 15, 1992: EP0466255-A2 (20 worldwide citation)

This invention is based on a new model describing the drilling process of a drag bit and concerns a method of determining the drilling conditions associated with the drilling of a borehole through subterranean formations, each one corresponding to a particular lithology, the borehole being drilled w ...


30
Orban Jacques, Mayes James: Ultrasonic measurement apparatus and method for boreholes.. Schlumberger, Schlumberger Services Petrol, Schlumberger Technology, Schlumberger Holdings, September 13, 1995: EP0671547-A1 (19 worldwide citation)

Pulse-echo apparatus and methods are disclosed for measuring characteristics of a borehole while it is being drilled. A component of a bottomhole assembly, preferably a drill collar, is provided with one or more ultra-sonic transceivers. A pulse-echo sensor of the transceiver is preferably placed in ...