Interferometric reservoir monitoring with a single passive source

Changes in the subsurface can be imaged by subtracting seismic reflection data at two different states, one serving as the initial survey or base, and the second as the monitor survey. Conventionally, the reflection data are acquired by placing active seismic sources at the acquisition surface. Alternatively, these data can be acquired from...

Interferometric redatuming of autofocused primaries and internal multiples

Recently, an iterative scheme has been introduced to retrieve the down- and upgoing Green's functions at an arbitrary level ?F inside an acoustic medium as if there were a source at the surface. This scheme requires as input the reflection response acquired at the surface and the direct arrival of the transmission response from the surface to...

Acoustic wavefield separation using horizontal receiver arrays deployed at multiple depths on land

We present a novel inversion scheme for decomposing upgoing and downgoing wavefields from vertical particle velocity recordings in downhole arrays at multiple depth levels. Our method requires no knowledge of the subsurface medium parameters as the required operators are obtained directly from the data by direct-wave interferometry. As we...

Downhole interferometric illumination diagnosis and balancing

With seismic interferometry or the virtual source method, controlled sources can be redatumed from the Earth’s surface to generate so-called virtual sources at downhole receiver locations. Generally this is done by crosscorrelation of the recorded down-hole data and stacking over source locations. By studying the retrieved data at zero time lag,...

Interferometric redatuming by multidimensional deconvolution

Seismic reflection imaging is a popular method to image, characterize and monitor the Earth's subsurface. In this method, seismic signals are sent into the subsurface and their reflections are collected. Strong heterogeneities in upper sections of the subsurface often pose a problem for imaging deeper sections. To overcome these problems, it has...

Controlled-source interferometric redatuming by crosscorrelation and multidimensional deconvolution in elastic media

Various researchers have shown that accurate redatuming of controlled seismic sources to downhole receiver locations can be achieved without requiring a velocity model. By placing receivers in a horizontal or deviated well and turning them into virtual sources, accurate images can be obtained even below a complex near-subsurface. Examples...

Methodology for dense spatial sampling of multicomponent recording of converted waves in shallow marine environments

A widespread use of converted waves for shallow marine applications is hampered by spatial aliasing and field efficiency. Their short wavelengths require dense spatial sampling which often needs to be achieved by receivers deployed on the seabed. We adopted a new methodology where the dense spatial sampling is achieved in the common-receiver...

Estimating and correcting the amplitude radiation pattern of a virtual source

In the virtual source (VS) method we crosscorrelate seismic recordings at two receivers to create a new data set as if one of these receivers were a virtual source and the other a receiver. We focus on the amplitudes and kinematics of VS data, generated by an array of active sources at the surface and recorded by an array of receivers in a...