Input/output, Inc.

Texas Instruments Corporation

Geospace Technologies Corporation

Other

Gtc Corporation

Paul E Carroll

Charles Geoffrey Rice

Robbin Barnet Adams

James Michael Hallaman

Roy W James, Iii

Jesus Eduardo Prado

Bhasker Vajapeyam

Glenn D Fisseler

Kent A Byerly

Michael L Abrams

Ralph A Harris

Karl J Schuler

William C Voigt

Thomas Glen Ragan

Charles K Bowen

Gillan C Smith

Eugene David Bednar

Roy Wilson James, Iii

Roy Wilson James Iii

Warren Moore, Jr

Robbin B Adams

A recording system and method for conducting seismic surveys including cordless battery-operated digital recorders, each employing an integral global positioning system receiver that is only periodically enabled for the purpose of establishing synchronized acquisition clock signals among all the recorders. The satellite receiver adjustment cycle is varied depending on past acquisition clock accuracy and temperature changes. A time stamp is recorded with the digitized seismic data in non-volatile memory. The memory is sized to allow extended periods of operation. Each recorder preferably includes a low-power system timer that may be used as a timer to remotely turn on and off the recorders according to a pre-programmed schedule to conserve power when the system is not in use. Electronic components are idled or de-energized when not needed.

Low-power satellite-timed seismic data acquisition system

A method and an apparatus are provided for matching the response of hydrophones,to the response of geophones,and significantly reducing response variations between hydrophones caused by inherent characteristics. The method includes the steps of determining a capacitance,for each of the hydrophones,in an operating environment, configuring a filter,based on the capacitance,, and modifying a response of a channel of the hydrophone,using the filter,. The apparatus includes an acquisition unit,having a geophone,and a hydrophone,, a recording unit,, a processing unit,and a filter,for correcting for variation between hydrophones,and changing a first order low frequency response of the hydrophone,to appear like a second order response like that of the geophone

Apparatus and method for correcting for capacitance variations in hydrophones

A seismic ocean bottom positioning device include a series of seismic stations spaced apart at a predetermined interval along a cable. Each station includes a hydrophone, a motion sensing device such as a geophone and an acoustic positioning circuit. A preamplifier is coupled to a seismic channel. The hydrophone is also coupled to the seismic channel. An acoustic channel is also coupled to the preamplifier and coupled to the hydrophone.

Acoustic positioning of seismic ocean bottom cable

An improved bottom cable for a seismic marine data acquisition system 10. The bottom cable 30 includes a cable section 30b having a bus 48. The cable, along with the cable section and bus, are used to electrically connect a master control unit 40 to first and second modules 32b and 32c, respectively. The bus 48 includes first and second switches 48b and 48c, respectively, located near opposite ends of the bus. In this way, if a leak R1 occurs in the bus, the first and second switches can be opened, thereby electrically isolating the bus and stopping the leak.

Power switching method for marine seismic acquisition systems

A lightning protection system is disclosed for a seismic data acquisition system having single or multiple geophones positioned at predetermined ground locations over a large area. A surge suppressor is placed across the leads to which the geophones strings are connected. Such surge suppressor preferably comprises a gas discharge arc tube. The base or spike of each geophone is implanted in the ground, A ground lead is connected to the surge suppressor. Electrical energy from a lightning strike affecting the geophones, cables, data acquisition boxes, etc. is dissipated by the surge suppressors through the multiple spikes to the earth thereby to minimize damage resulting from lightning.

Lightning protection for seismic data acquisition system

A method for a seismic data acquisition system (FIG. 1) for determining whether a geophone circuit break is in a seismic cable conductor pair (22) or in a takeout conductor pair (26). A resistor (32, 32A) is positioned across the takeout conductor pair (26) for a geophone group (20). An impedance measuring device (30) determines if the break is in the seismic cable conductor pair (22) by measuring infinity for an open circuit, or by measuring the impedance of the resistor (32, 32A) if the break is in the takeout conductor pair (26).

Method for detecting breaks in geophone cables for seismic data

A low-cut filter is provided which has a frequency response with its low frequency end attenuation limited. The low-cut filter has the effect of increasing effective channel bandwidth while simultaneously allowing low frequency signals from deep within the earth to be included in the output signal. Effective channel bandwidth is increased because low frequency seismic signals are attenuated, automatically allowing channel gain to be increased by a gain ranging amplifier. Increased channel gain automatically amplified the low-amplitude high-frequency end of the spectrum resulting in increased effective bandwidth. A high frequency boost filter is provided whereby the high frequency signal components of the seismic signals may be further relatively amplified thereby enhancing the channel effective bandwidth. The boost filter is provided in the system's input stage in order to keep its effect on system input noise to a minimum.

Bandwidth enhancing seismic acquisition system and method

The system for suppressing an ambient noise signal which comtaminates a desired signal includes a noise pickup detector for detecting the ambient noise signal. A noise discriminator processes the detected noise signal into noise data. A reference noise generator converts the noise data into a reference noise signal. The noise generator automatically adjusts the reference noise signal to correspond with changes in the noise signal as it is being detected. A filter filters the reference noise signal into an error signal which is adapted to remove the noise signal from the contaminated signal. A cross-correlator cross-correlates the contaminated signal with the reference noise signal and adjusts the filter to produce the required error signal.

Noise suppression during seismic exploration

A geophysical data acquisition system is disclosed having a dynamic range larger than that achievable with typical existing systems. The range of input signals that can be accommodated by a system are limited on the lower end by the noise level of the system and at the upper end by saturation levels of the system. High amplitude input signals can be accommodated by the system if certain unneeded frequency components are filtered off at a sufficiently early point in the signal flow path. In the present invention this desirable filtering is accomplished while maintaining a high gain level in the signal flow path ahead of those components which introduce high noise levels. As a result, the system has an expanded dynamic range and the needed capability to faithfully acquire low amplitude signals.

Method and apparatus for increasing the dynamic range of a data

In a long line data acquisition system, an input network is provided for coupling the lines to a data acquisition unit. The network includes the cascade combination of a first filter presenting a low pass frequency response to common mode voltage and a second filter presenting a low pass frequency response to difference mode voltage. The output of the second filter is coupled to an amplifier having high common mode rejection. The network substantially reduces, at the amplifier input, both common mode and difference mode noise picked up by the lines.

Growing community of inventors

Houston, TX, United States of America

Paul E Carroll