Lorie K. Bear

Integrated velocity model estimation for improved positioning with anisotropic PSDM

There are many geologic settings where anisotropic migration is necessary to obtain accurate seismic images. While this is well known, stable anisotropic parameter estimation has posed a serious challenge. Seismic data, though extensive in coverage, cannot constrain the anisotropy parameters alone (Tsvankin and Thomsen, 1995). The set of parameters is better constrained by integrating the seismic information with certain types of well data. However, the well data are generally sparse, so the parameters are only constrained at a few locations. Nonuniqueness is obviously a fundamental issue in our estimation problem.

A robust and accurate seismic attenuation tomography algorithm

Summary We developed a seismic-attenuation-tomography algorithm for improving image amplitude fidelity and other geophysical applications. This algorithm is based upon the centroid-frequency-shift method. However, compared with the conventional centroid-frequency-shift method, our algorithm has been significantly improved through the

Integrated Velocity Model Estimation For Accurate Imaging

Surface seismic reflections, surface seismic direct arrivals, well data and prior geologic information can be used to constrain a subsurface velocity model.

Incorporating non‐seismic information for improved positioning with anisotropic PSDM

Theoretical and numerical studies have shown that surface seismic data alone do not adequately constrain VTI anisotropy parameter estimation (Tsvankin and Thomsen, 1995). The integration of sonic log, vertical checkshot, offset checkshot (OCS), and horizon-based constraints into our migration velocity analysis procedure allows us to develop models for the VTI parameters V0, e, and δ (Thompson, 1985) that are consistent with geology, measured traveltimes, and moveout of the seismic data. We show anisotropic PSDM (APSDM) examples from three marine areas, each of which exhibits marked P-wave anisotropy. Our velocity analysis procedure leads to models that are physically reasonable, and in each case we observe improved positioning accuracy compared to isotropic PSDM.

Integrated velocity model estimation for accurate imaging

Surface seismic reflections, surface seismic direct arrivals, well data and prior geologic information can be used to constrain a subsurface velocity model. These various sources of subsurface velocity information have different strengths and weaknesses. Integrating all available velocity information into a velocity model increases the accuracy of the model by offsetting the weakness of one data type with the strengths of another. We call the process of building a model that integrates all data integrated velocity model estimation.