BISCHKE, R. E., W. FINLEY and D. J. TEARPOCK*, Subsurface Consultants and Associate, LLC, Lafayette, LA; Rozel Energy, Lafayette, LA

Abstract: Growth Analysis (dd/d): Case Histories of the Resolution of Correlation Problems as Encountered while Mapping around Salt

We present the dd/d Growth Plot Analysis, and show examples of how the technique can solve mapping or correlation problems around salt, where you lack confidence in correlating the well logs or 3-D seismic. The quantitative growth history of a structure is employed to resolve correlation problems. Growth structures form as sediments are deposited near active faults, mobile salt or in subsiding basins. The law of superposition requires that the growth sediments be deposited in a systematic manner. We demonstrate that growth sediments obey nonrandom processes, and that growth sediments record the history of deposition along with the dynamic processes that affect the deposition of sediments. Accordingly, correlations obtained from the growth sediments record the progressive histories of structures. In order to study the growth history using Dd/d, the correlations are usually presented in the form of a graph. Surprisingly, on the plots of Dd/d the correlations often plot along monotonic or linear curves. Although growth plots confirm that sediments are deposited systematically, growth typically changes abruptly across sequence boundaries, disconformities, and active faults. Abrupt changes in growth on the plots indicate abrupt tectonic or stratigraphic changes. Correlation data points that deviate from the general linear trends may represent stratigraphic miscorrelations. The Dd/d Growth Plot Analysis is a powerful technique. The high-resolution Dd/d technique graphically displays the growth history of an area in a manner that is readily interpreted.