Saudi Arabian Oil Company

King Fahd University of Petroleum and Minerals

Abdulrahman Alshuhail

Hussain Alzaher

Alaa El-Din Hussein

Abdullatif Al-Shuhail

Constantinos Tsingas

Ali Abdulhameed Aldawood

Emad Abdo Mohammed Al-Hemyari

A system for a first digitally controlled grounded inductor simulation circuit may include an OP-AMP, a digitally controlled current amplifier (DCCA), a voltage buffer, two resistors, and a capacitor. The first digitally controlled grounded inductor simulation circuit allows adjustment of an equivalent inductance value (CRR/A) through programming a digitally controlled current gain (A) of the DCCA. A system for a second digitally controlled grounded inductor simulation circuit includes an OP-AMP, a digitally controlled current amplifier (DCCA), a dual output current follower (CF), an active current division network (CDN), two resistors, and a capacitor. The second digitally controlled grounded inductor simulation circuit allows adjustment of an equivalent inductance value (CRR/αA) via programming the active CDN and the DCCA.

Digitally controlled ground inductor simulation circuits

An autonomous underwater seismic wave generation system includes a housing, and an autonomous navigation system, a propulsion system and a seismic wave generator, each connected to the housing. The autonomous navigation system can navigate the autonomous underwater seismic wave generation system to subsea locations including a location on a seabed. The propulsion system can drive the autonomous underwater seismic wave generation system to the location on the seabed. The seismic wave generator can couple to the location on the seabed to generate seismic waves at the location on the seabed.

Autonomous underwater vehicle to generate seismic waves

A digitally controlled grounded capacitor multiplier includes: a single capacitor directly connected at one end to an input voltage and at another end to a negative input of an operational amplifier; the operational amplifier including a negative feedback loop; and a digitally controlled current amplifier (DCCA) connected to an output of the operational amplifier. The DCCA digitally controls the digitally controlled grounded capacitor multiplier. The digitally controlled grounded capacitor multiplier comprises only two active devices consisting of the operational amplifier and the DCCA.

Digitally controlled ground capacitor multiplier

A computer-implemented method includes the following. A frequency sweep using sweep parameters is emitted from a vibratory seismic source into geological layers. The sweep parameters include frequencies and modulation parameters for seismic waves. Signals are received from one or more sensors. The signals include seismic data acquisition information, including values identifying energy reflected back from boundaries where rock properties change. A determination is made regarding which of the reflected seismic waves are attenuated. The determination uses an integral transform and a thresholding algorithm for image segmentation. Optimum sweep parameters are determined based on the reflected seismic values that are attenuated and updated to compensate for local geology effects. The emitting, receiving, determining attenuation, determining optimum parameters, and updating are repeated until the received signals are determined to be satisfactory.

Spatially adaptive vibrator sweep parameter selection during seismic data acquisition

A current-mode Schmitt Trigger includes a plurality of current output stages connected to a common supply voltage that powers the current-mode Schmitt Trigger, a main input on one of the current output stages that receives an input current, and a non-inverting output on a different one of the current output stages that is shorted to the main input to establish a positive closed-loop feedback and supplies a non-inverting output current as the input current. The current-mode Schmitt Trigger includes only active components.

Current-mode Schmitt trigger using current output stages

A square wave oscillator includes a Schmitt Trigger with a first output that outputs a first output current, a capacitor connected to the first output of the Schmitt Trigger, and a resistor that connects the capacitor to an input of the Schmitt Trigger to form a closed-loop negative feedback. The closed-loop negative feedback sustains an oscillation of the square wave oscillator and causes a frequency and an amplitude of the oscillation to be independent of a supply voltage of the Schmitt Trigger.

Current-mode square wave oscillator

A digitally controlled grounded capacitance multiplier circuit system and method is disclosed. The capacitance multiplier (CM) circuit comprises an op-amp, a digitally controlled current amplifier and two resistors in addition to a reference capacitor. The CM circuit is designed using complementary metal-oxide-semiconductor (CMOS) technology. The value of the equivalent capacitance can be adjusted through digitally programming the gain of the current amplifier. The CM circuit provides a significant multiplication factor while using two active devices.

Digitally controlled grounded capacitance multiplier

Embodiments of super-virtual borehole sonic interferometry include machines, systems, and methods that can increase the signal-to-noise ratio of sonic log waveforms. Embodiments include performing a common shot gather and recording traces with a sonic tool, repositioning the tool and performing another common-shot gather; cross-correlating each trace with neighboring corresponding traces for each common shot gather, which leads to creating the virtual trace response due to a redatumed virtual source; stacking the common virtual traces with common ray paths for different common shot gathers; convolving the virtual traces with an actual trace that travels from the source through the virtual source to a receiver on the tool; and stacking the traces having common ray paths. The resulting waveforms can have a signal-to-noise ratio significantly greater than the signal-to-noise ratio of the original waveforms, due to the two stacking operations following each redatuming step.

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Dhahran, Saudi Arabia

Abdulrahman Alshuhail