Westerngeco L.l.p.

Colin Thomson

Philip Kitchenside

Robin Fletcher

James Rickett

Christopher H Chapman

Rodrigo Fuck

Processing data representing a wavefield propagating through a medium by defining, based on one or more properties of a region of the medium and of the wavefield therein, a desired timestep and a desired spatial step for a discrete operator. Discrete seed operators having an initial timestep and an initial spatial step less than the desired timestep and the desired spatial step are then defined, and these seed operators are compounded to obtain an operator having a greater timestep and upscaled to obtain an operator having a greater spatial step. The compounding and upscaling are repeated until an operator having the desired timestep and the desired spatial step is obtained. The operator having the desired timestep and the desired spatial step may be applied to the data representing the wavefield propagating through a medium to propagate the data backwards in time to recreate the wavefield at earlier times.

Processing wavefield data incorporating large timesteps and upscaled medium properties

Systems and methods for compensating for spatial and slowness or angle blurring of plane-wave reflection coefficients in imaging. A wave field may be determined at a reference depth proximate to a reflector for a shot record. A receiver-side blurring function may be determined at the reference depth. An aggregate blurring function may be constructed based at least partially on the source wave field and the receiver-side blurring function. A plane-wave reflection coefficients may be determined based at least partially on the aggregate blurring function.

Compensating for space and slowness/angle blurring of reflectivity

Forward modeling is performed to compute a response of a target structure, the forward modeling accounting for distortion of a reflected signal from a reflector in the target structure. Waveform inversion is performed using the response of the forward modeling.

Waveform inversion using a response of forward modeling

Method for velocity model building and analysis using wavefield-coordinates reflection operators in wave-equation migration or reverse-time migration.

Method for velocity model building and analysis

There is provided a method of direct waveform inversion of turning waves () to determine parameters characterizing properties of the earth or sub-sections of the earth, particularly of parts of the earth which are capable of trapping hydrocarbons with the inversion yielding from the wavefield of turning waves information representing or being equivalent to velocities or slownesses and/or the gradient of velocities or slownesses, particularly by evaluating wavefield data in the vicinity of turning points (). The method can be applied sequentially as a survey sinking method.

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Cambridge, United Kingdom

Colin Thomson