Hampson Russell Tutorial 〈FRESH〉

The tutorial is honest about the limitations here—specifically the ill-posed nature of the inverse problem (where multiple Earth models fit the same seismic data). It introduces and sparse-spike inversion as regularization techniques to stabilize the solution. The final output, such as the Lambda-Rho (incompressibility) versus Mu-Rho (rigidity) crossplot, provides the ultimate lithology-fluid discriminant. Gas sands show low Lambda-Rho (compressible) but moderate Mu-Rho, whereas shales show high values for both.

The pedagogical climax of the tutorial is the (B vs. A). Instead of interpreting raw amplitudes, the user learns to interpret clusters on a crossplot. The tutorial explains that water sands, shales, and gas sands occupy distinct quadrants of the A-B plane. It introduces the concept of the Shuey background trend —the line defining "wet" sediments. Deviations from this line (specifically, decreasing gradient and decreasing intercept) indicate potential hydrocarbons. This transforms interpretation from a qualitative art ("is it bright?") into a quantitative science ("does it plot in the gas sand quadrant?"). hampson russell tutorial

A hallmark of the tutorial’s effectiveness is its visual interactivity. It allows users to input real well-log data (P-wave velocity, S-wave velocity, and density) and instantly observe the calculated reflectivity series. By toggling between the exact Zoeppritz solution and the Aki-Richards approximation, the user develops an intuitive understanding of when the approximations are valid (i.e., at small angles of incidence) and when they fail. This "visual mathematics" transforms abstract equations into a tangible, physical phenomenon, demonstrating that a gas sand will exhibit a characteristic increase in amplitude with offset (Class III AVO), while a hard overpressure shale might show a decrease. Gas sands show low Lambda-Rho (compressible) but moderate

The tutorial transitions from theory to application by addressing real-world seismic noise. It instructs users on how to generate (stacking multiple Common Depth Points to increase signal-to-noise ratio) and how to perform angle stacks (near, mid, and far). The key technical innovation taught here is the weighted stacking process to solve for intercept (A) and gradient (B). Instead of interpreting raw amplitudes, the user learns

The Hampson–Russell Tutorial: A Paradigm for Bridging Theory and Practice in AVO Analysis