1
Stoller Christian, Wijeyesekera Nihal, Dasgupta Urmi, Wraight Peter, Philip Olivier: Method for determining formation density and formation photo-electric factor with a multi-detector-gamma-ray tool. Schlumberger, Schlumberger Technology, Schlumberger Holdings, September 16, 1998: EP0864884-A2 (28 worldwide citation)

This invention is an advanced method for determining formation density in an array-detector density tool (11). The use of three or more detectors (12,13,14) yields an improved accuracy and precision of the formation density measurement even in the presence of a large standoff between the tool and th ...


2
Wraight Peter, Marienbach Edouard, Hache Jean Michel, Rhein Knudsen Erik, Evans Michael: Apparatus for subsurface formation evaluation.. Schlumberger, Schlumberger Prospection, July 12, 1989: EP0323773-A2 (14 worldwide citation)

A measurement while drilling nuclear tool adapted to be coupled in the drill string to make formation evaluations and methods of using are described. A neutron source (58) is positioned on the cylindrical axis of the tool while a connected gamma ray source (47) is eccentered against an interior side ...


3
Wraight Peter: Methods and apparatus for evaluating formation characteristics while drilling a borehole through earth formations.. Schlumberger, Schlumberger Services Petrol, Schlumberger Technology, Schlumberger Holdings, March 13, 1991: EP0417001-A2 (9 worldwide citation)

The MWD methods and MWD apparatus disclosed herein include methods and apparatus for rotating a directionally-responsive radiation sensor having an outwardly-directed response axis in a borehole. These MWD methods and MWD apparatus further includes methods and apparatus for obtaining a series of suc ...


4
Wraight Peter, Marienbach Edouard, Hache Jean Michel, Evans Mike, Rhein Knudsen Erik: Methods and apparatus for safely measuring downhole conditions and formation characteristics while drilling a borehole.. Schlumberger, Schlumberger Prospection, September 14, 1988: EP0282402-A2 (6 worldwide citation)

In the practice of the present invention, new and improved MWD apparatus is cooperatively arranged to be coupled to a MWD tool arranged to be suspended in a borehole from a drill string and adapted for measuring at least one downhole condition not requiring irradiation by a radioactive source and at ...


5
Edwards John, Stoller Christian, Renoux Nicolas, Wraight Peter David, Griffiths Roger: Fluid marker and detector for use during underbalanced drilling. Schlumberger Holdings, September 8, 2004: GB2399111-A (6 worldwide citation)

Fluid flowing from a formation into a borehole drilling environment is marked by an activation device 6 such as a pulse neutron generator and subsequently detected by a device 7 such as a gamma ray detector, located a distance d away from the activation device. Preferably, the devices are mounted on ...


6
Stoller Christian, Wijeyesekera Nihal, Dasgupta Urmi, Mckeon Donald, Wraight Peter: Method and apparatus for measuring formation density and the formation photo-electric factor with a multi-detector gamma-gamma tool. Schlumberger, Schlumberger Technology, Schlumberger Holdings, August 26, 1998: EP0860715-A1 (4 worldwide citation)

The present invention is an improved method and tool for determining formation density by using an array of gamma-ray detectors. This invention can correct for large standoffs encountered in abnormally shaped boreholes and in particular for the increased standoffs typically encountered by mandrel to ...


7
Stoller Christian, Wraight Peter David, Adolph Robert A: Sigma/porosity formation logging tool with neutron monitor. Schlumberger Holdings, December 13, 2006: GB2427024-A (4 worldwide citation)

A tool 30 for formation logging includes a support configured for movement in a borehole; a neutron source 31 disposed on the support; a neutron monitor 32 disposed on the support and configured to monitor an output of the neutron source; a gamma-ray detector 34 disposed on the support and spaced ap ...


8
Wraight Peter D: Monitoring formation fractures surrounding borehole. Schlumberger, September 6, 1995: GB2287093-A (4 worldwide citation)

A method of monitoring formation fractures in real-time is performed in which a fluid containing a radio-active tracer element is pumped at a high pressure down a wellbore into a formation. As the fluid creates fractures and moves through the formation gamma-rays are emitted from the radio-active tr ...


9
Wraight Peter, Griffiths Roger, Stephenson Kenneth E: Measuring mud flow velocity using pulsed neutrons. Schlumberger Services Petrol, July 7, 2004: EP1435430-A1 (3 worldwide citation)

The invention relates to methods and apparatus for determining downhole mud flow rates and other downhole parameters. A method for determining a downhole parameter includes operating a pulsed neutron generator (6), pulsing the pulsed neutron generator (6) off, detecting a substantially unactivated d ...


10
Wraight Peter: Methods and apparatus for safely handling radioactive sources in measuring-while-drilling tools.. Schlumberger, Schlumberger Prospection, May 31, 1989: EP0318343-A2 (2 worldwide citation)

A logging apparatus for investigating properties of earth formations while a borehole is being drilled is proposed to comprise a tubular drill collar (14) adapted to be coupled to a drill string and adapted to permit the flow of drilling fluid lengthwise through its interior. A radiation source and ...