1
Pralay K Das: Apparatus and method for measuring differential pressure while drilling. Anadrill, Stephen L Borst, Dave Gordon, February 21, 1989: US04805449 (49 worldwide citation)

An apparatus and method for measuring differential pressure of mud internal a drill string and mud in a borehole annulus is disclosed. The apparatus typically comprises: a drill collar having a pressure balancing piston in hydraulic contact with the borehole annulus mud; a shaped cylinder in contact ...


2
Pralay K Das: Methods and apparatus for controlled directional drilling of boreholes. Anadrill Incorporated, April 26, 1988: US04739841 (44 worldwide citation)

In the representative embodiments of the present invention described herein, new and improved methods and apparatus are disclosed for measuring various forces acting on an intermediate body between the lower end of a drill string and the earth-boring apparatus coupled thereto whereby the magnitudes ...


3
Pralay K Das, Haoshi Song: Load cells for sensing weight and torque on a drill bit while drilling a well bore. Schlumberger Technology Corporation, David P Gordon, Wayne I Kanak, February 7, 1995: US05386724 (43 worldwide citation)

A load cell for sensing weight and torque on a drill bit during a drilling operation includes a cylindrical load cell made from a material with minimum residual stress. A plurality of strain gages are arranged symmetrically on each load cell and electrically coupled to form two Wheatstone bridges. T ...


4
Pralay K Das, Joe Marzouk: Replaceable electrical device for a downhole tool and method thereof. Baker Hughes Incorporated, Madan Mossman & Sriram P C, March 16, 2004: US06705406 (13 worldwide citation)

A downhole tool for use in a wellbore, comprises a tubular member, such as a drill collar housing, in a drill string. The tubular member has at least one cavity formed on an external surface. At least one housing is adapted to be insertable and extractable in the cavity without further tool disassem ...


5
Pralay K Das, Eric Joseph Deutsch, Charles Haynes: Integrated, single collar measurement while drilling tool. Baker Hughes Incorporated, Madan Mossman & Sriram P C, January 4, 2005: US06839000 (11 worldwide citation)

An integrated, single collar measurement while-while-drilling tool is presented that comprises formation sensors, directional sensors, pressure sensors, a mud pulse telemetry device, and a turbine-generator power device configured in a single collar housing that is no longer than a standard drill co ...


6
Pralay K Das, Eric Joseph Deutsch, Charles Haynes: Integrated, single collar measurement while drilling tool. Baker Hughes Incorporated, Paul S Madan, Madan Mossman & Sriram PC, May 1, 2003: US20030080743-A1

An integrated, single collar measurement while-while-drilling tool is presented that comprises formation sensors, directional sensors, pressure sensors, a mud pulse telemetry device, and a turbine-generator power device configured in a single collar housing that is no longer than a standard drill co ...


7
Pralay K Das, Joe Marzouk: Replaceable electrical device for drilling tool. Baker Hughes Incorporated, Paul S Madan, Madan Mossman & Sriram PC, October 2, 2003: US20030183384-A1

A downhole tool for use in a wellbore, comprises a tubular member, such as a drill collar housing, in a drill string. The tubular member has at least one cavity formed on an external surface. At least one housing is adapted to be insertable and extractable in the cavity without further tool disassem ...