High density source spacing using continuous composite relatively adjusted pulse

Abstract

The invention relates to continuously or near continuously acquiring seismic data where at least one pulse-type source is fired in a distinctive sequence to create a series of pulses and to create a continuous or near continuous rumble. In a preferred embodiment, a number of pulse-type seismic sources are arranged in an array and are fired in a distinctive loop of composite pulses where the returning wavefield is source separable based on the distinctive composite pulses. Firing the pulse-type sources creates an identifiable loop of identifiable composite pulses so that two or more marine seismic acquisition systems with pulse-type seismic sources can acquire seismic data concurrently, continuously or near continuously and the peak energy delivered into the water will be less, which will reduce the irritation of seismic data acquisition to marine life.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a non-provisional application which claims benefit under 35 USC §119(e) to U.S. Provisional Application Ser. No. 61 / 365,631, filed Jul. 19, 2010 entitled “Unique Composite Relatively Adjusted Pulse” and U.S. Provisional Patent Application Ser. No. 61 / 365,663, filed Jul. 19, 2010 entitled “Continuous Composite Relatively Adjusted Pulse” and U.S. Provisional Patent Application Ser. No. 61 / 494,952, filed Jun. 9, 2011 entitled “High Density Source Spacing Using Continuous Composite Relatively Adjusted Pulse”, which are all incorporated herein in their entirety.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT[0002]None.FIELD OF THE INVENTION[0003]This invention relates to emitting seismic energy into a marine environment that is able to travel into the seafloor and reflect from and refract through geological structures and be received and recorded by hydrophones.BACKGROUND OF THE INVENTION[0004]It is very exp...

AI Technical Summary

Benefits of technology

The invention is about a process for getting seismic data and information about geological structures in the earth. A plurality of seismic receivers are placed to receive seismic energy, and a pulse-type seismic source is used to emit pulses of seismic energy into the earth. These pulses create a seismic energy wavefield response from the geological structures in the earth. The seismic energy is recorded by the receivers and processed to identify the distinctive pulses and data segments that overlap with them. This helps to gather more data about the geological structures and create a more complete picture of the earth's structure.

Problems solved by technology

It is very expensive to acquire seismic data in marine environments.

Thus, once the survey is started, there is a lot of pressure to acquire data twenty-four hours a day, seven days a week.

A problem arises when another survey crew is collecting data in the same general area at the same time.

The two operations may contaminate one another and be forced to work out a time sharing arrangement where only one crew acquires data for a period of time and then waits while the other crew takes a turn.

A second concern in the collection of seismic data in marine environments is harm, injury or irritation of whales and other marine life due to the intensity of the energy coming off the seismic sources.

The power of these pulses in the water is presumed to be at least annoying to sea animals that use echo location like whales, dolphins and others.

Seismic surveying techniques may cause these animals to leave the area and some believe that it may be harmful to sea life.

This is particularly bad in a wide azimuth shooting where multiple vessels are towing guns and all guns are fired in a round-robin fashion.

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