Exxonmobil Upstream Research Company

Philip J Summerfield

Dennis E Willen

Xinyou Lu

Brian J Fielding

Tom C Phillips

Ruben Quintanilla

Anne K Rutledge

Larry S Gale

Apparatus and method for estimating the 3D orientation angles for remotely deployed devices with flexible arms such as dipole antennas of receivers used in marine controlled-source electromagnetic surveys to explore for hydrocarbons. Acoustic transponders or transducers, or other positioning sensors such as attitude sensors or strain-sensitive fiber optic cables are placed on each electrode arm of the receiver. Acoustic sensors () on the receiver frame () work in conjunction with the positioning sensor(s) () on the electrode arms () to provide accurate 3D spatial position of the receiver electrodes () relative to the receiver frame. Alternatively, sonar transducers mounted on the frame are used to image the electrode arms, which image can be enhanced by fixing reflectors to the arms. An attitude sensor is mounted on the receiver frame, enabling conversion of the relative electrode positions to an earth reference frame.

Determining orientation for seafloor electromagnetic receivers

Method for real time monitoring of the waveform transmitted by an electromagnetic survey source, using a near-source monitoring receiver to measure electromagnetic field and transmitting the measured signal in real time to a control location.

Source monitoring for electromagnetic surveying

Apparatus and method for a steerable horizontal electric dipole source system for underwater deployment as a moving source in electromagnetic surveying of subsurface regions for hydrocarbons. Position locating sensors () are placed near each electrode (), and means () are provided for correcting the electrodes to be at the same elevation with azimuth aligned with the source tow line () and the electrode mid-point positioned over the source tow line, based on instantaneous location information from the sensors. The streamer () connecting the electrodes may also be monitored for shape by sensors, with corrections made by lateral and vertical control means disclosed herein. The invention can be applied to any marine streamer used in geophysical surveys, including a towed streamer () of electromagnetic or seismic receivers ().

Method to maintain towed dipole source orientation

Method for separating responses of multiple transmitters m a controlled source electromagnetic survey by using mutually orthogonal transmitter waveforms and transforming the combined response to the frequency domain () The mutual orthogonality can be based disjoint frequency spectra or on phase encoding of a common waveform element ().

Growing community of inventors

Katy, TX, United States of America

Philip J Summerfield