We study a data-driven approach to multi-mode interval velocity analysis in laterally inhomogeneous and anisotropic media. We obtain a simple model-independent description of long-spread reflection moveout versus offset for both symmetric and asymmetric wave modes. It resolves a trade-off between anisotropy and lateral heterogeneity. This is done using offset-dependent arrivalangle and wavefron...

We present a simple method for computing angle-domain Common Image Gathers (CIGs) using prestack reverse time migration. The proposed method is an extension of the method proposed by Rickett and Sava (2001) to compute CIGs by downward-continuation shot-profile migration. We demonstrate with a synthetic example the use of the CIG gathers for migration velocity updating. A challenge for imaging b...

A transversely isotropic (TI) model in which the tilt is constrained to be normal to the dip (DTI model) allows for simplifications in the imaging and velocity model building efforts as compared to a general TI (TTI) model. Although this model cannot be represented physically in all situations, for example, in the case of conflicting dips, it handles arbitrary reflector orientations under the a...

Reflections and refractions from wide-angle, densely sampled, multi channel streamer data are transformed automatically to the slowness-depth domain using a downward continuation algorithm. The method may be used to rapidly obtain velocity functions for use in pre-stack depth migration processes. Incorporation of the reflection data has the potential to produce velocity images in complex geolog...

Prestack depth migration of shot profiles by downward continuation is a practical imaging algorithm that is especially cost-effective for sparse-shot wide-azimuth geometries. The interpretation of offset as the displacement between the downward-propagating (shot) wavefield and upward-propagating (receiver) wavefield enables us to extract offset-domain common imagepoint (CIP) gathers during shot...

The problem of bottom hole effusion is an important reason for the reduction and even shutdown natural gas wells. Downward velocity string drainage recovery process, which can improve flow rate discharge more liquid from wellhead. However, depth timing a technical that has been difficult to solve by field engineers. To this problem, paper designs method select in case highly deviated wells appl...

We analyze the amplitude variation as a function of reflection angle (AVA) for angle-domain common image gathers (ADCIG) produced via wave-equation migration. Straightforward implementations of the two main ADCIG methods lead to contradictory, thus inaccurate, amplitude responses. The amplitude inaccuracy is related to the fact that downward-continuation migration is the adjoint of upward-conti...