Schlumberger Technology Corporation

Albert H Wignall

David C Hoyle

Jeffrey B Aron

James J Walulik

Anthony K Booer

A tool for conducting gravimetry survey downhole in an earth formation includes a pressure vessel which houses a gravity sensor that is supported by a gimbal. The gravity sensor is aligned with vertical before taking gravity measurements by a first stepper motor and a second stepper motor. The first stepper motor incrementally rotates the gimbal about the pivot axis of the gimbal while the second stepper motor incrementally rotates the gimbal about the longitudinal axis of the pressure vessel. The stepper motors are controlled by an electronic processor that responds to signals from an accelerometer assembly that measures the inclination of the pressure vessel with respect to vertical. An elevator mechanism translates the gravity sensor from one station to the next inside the pressure vessel to make gravity measurements and an optical encoder monitors the position of the gravity sensor inside the pressure vessel.

Downhole gravity tool

A monopole transmitter for a sonic well tool includes an axial tube, a piezoceramic cylinder surrounding the axial tube, an endcap disposed at each end of and firmly contacting the cylinder, and an apparatus for holding the endcaps firmly against the axial tube. The endcaps firmly contact the axial tube without simultaneously contacting an upper bulkhead. The apparatus may include spring washers disposed between the bulkhead and at least one endcap, or it may include a spring disposed between a nodal mount and each endcap. A nodal mounting tube may be disposed around the axial tube, a ring being disposed at each end of the nodal mounting tube, each ring being disposed outside of the cylinder, the apparatus including a spring disposed between each ring and an endcap outside of the cylinder for biasing the endcaps in tension against a ring thereby holding each endcap firmly in contact against the axial tube.

Monopole transmitter for a sonic well tool

A sonic well tool includes a transmitter array, including at least one monopole transmitter and at least one dipole transmitter, and a receiver array for receiving sonic pressure wave signals from a surrounding borehole formation. A first attenuation and delay apparatus is positioned above the receiver array and a second attenuation and delay apparatus is positioned below the receiver array in the sonic well tool. The first attenuation and delay apparatus includes an attenuation member comprising a plurality of interleaved rubber and metal like washers for attenuating compressional and flexural waves propagating along a metal, center support rod to the receiver array and an inner housing comprising a bellows section having a corrugated shape and a thin transverse dimension for delaying the propagation of compressional and flexural waves along the inner housing to the receiver array. The second attenuation and delay apparatus includes a plurality of mass loading rings surrounding the outer housing of the sonic well tool for attenuating the flexural waves propagating up the outer housing from a sonic transmitter and a further inner housing including a further bellows section having a corrugated shape and a thin transverse dimension for delaying the propagation of compressional and flexural waves up the tool, along the inner housing, to the receiver array. The sonic well tool also includes a differential volume compensator for changing the quantity of oil encapsulated in the sonic well tool in accordance with changes in oil volume and changes in borehole temperature and pressure. The receiver array includes a plurality of hydrophone sets, each hydrophone set including at least one pair and preferably at least two pair of hydrophones disposed in a cross section of the tool, one hydrophone of a pair being disposed opposite the other hydrophone of the pair in the cross section.

Sonic well tool transmitter receiver array including an attenuation and

A sonic isolation joint (SIJ) of a sonic well logging tool is disposed between a sonic transmitter section and a sonic receiver section of the tool and attenuates compressional and flexural waves which propagate longitudinally along an axis of the tool when the sonic transmitter transmits a pressure wave into a formation of a borehole. The SIJ comprises a first outer housing, a second outer housing, an inner housing disposed within the first and second outer housings, a first attenuation member disposed between the first outer housing and the inner housing and a second attenuation member disposed between the second outer housing and the inner housing, each of the attenuation members including a plurality of rubber isolating washers, and a plurality of steel washers interleaved with the plurality of rubber isolating washers. The attenuation members are each fit between a flange of the outer housing and a flange of the inner housing and are compressed when the sonic dipole tool string is lowered into the borehole.

Sonic well logging tool longitudinal wave attenuator

A transmitter for a sonic wall logging tool contains a piston, the plane of the piston being disposed along the longitudinal axis of the tool. The piston moves, in its entirety, transversely with respect to the tool when an alternating current flows in two coils disposed in magnetic fields created by two mangets. Sonic positive pressure waves are created on one side of the piston, and sonic negative pressure waves are created on the other side of the piston. Shear waves are created in the formation, a positive shear wave being created in the formation on one side of the tool, and a negative shear wave being created in the formation on the other side of the tool.

Growing community of inventors

Friendswood, TX, United States of America

Albert H Wignall