Using Uncontrolled Acoustic Energy in Combination with Controlled Seismic Source Energy to Retrieve Information About a Subsurface

In a technological process of the kind in which one or more images of subsurface geological features are generated based on recorded seismic data acquired by sensors while a vessel towed one or more controlled seismic sources in a body of water and while one or more uncontrolled acoustic sources were present in the body of water, the specific improvement comprising:

• isolating controlled source components from the recorded seismic data, wherein the controlled source components correspond to acoustic energy emitted by activations of the one or more controlled seismic sources;
• isolating uncontrolled source components from the recorded seismic data, wherein the uncontrolled source components correspond to acoustic energy emitted by the vessel, and wherein the uncontrolled source components include at least one of the following attributes:
• signal content present at lower frequencies than signal content present in the controlled source components, and signal content present at longer offsets than signal content present in the controlled source components;
• and
• applying the isolated controlled source components as an input to an imaging process, and applying the isolated uncontrolled source components as an input to the or another imaging process, to generate one or more images of the subsurface, thereby utilizing, in at least one of the images, at least one attribute present in the uncontrolled source components that is not present in the controlled source components.

One or more non-transitory computer-readable media containing instructions that, when executed by one or more processors, cause the one or more processors to perform a method of imaging a subsurface disposed beneath a water bottom, wherein the method comprises:

• accessing a current recorded dataset from continuously recorded marine seismic data, wherein the current recorded dataset includes signals associated with one or more uncontrolled acoustic sources and also signals associated with one or more controlled seismic sources;
• performing one or more iterations of a separation procedure on the current recorded dataset to accumulate isolated controlled source components and isolated uncontrolled source components therefrom, wherein the separation procedure comprises:
• determining a controlled source component of the current recorded dataset and adding the controlled source component to the isolated controlled source components, wherein the controlled source component corresponds to signals in the current recorded dataset that are associated with at least one of the controlled seismic sources;
• subtracting the controlled source component from the current recorded dataset to generate a reduced recorded dataset;
• determining an uncontrolled source component of the reduced recorded dataset and adding the uncontrolled source component to the isolated uncontrolled source components, wherein the uncontrolled source component corresponds to signals in the reduced recorded dataset that are associated with at least one of the uncontrolled acoustic sources;
• subtracting the uncontrolled source component from the reduced recorded dataset to generate a residual recorded dataset;
• and
• determining if signal energy in the residual recorded dataset differs by at least a threshold amount from signal energy in at least one of the current recorded dataset and the reduced recorded dataset, and, if so, replacing the current recorded data set with the residual recorded dataset and performing another iteration of the separation procedure;
• and
• applying the isolated controlled source components as an input to an imaging process, and applying the isolated uncontrolled source components as an input to the or another imaging process, to generate one or more images of the subsurface.