MULTIPLE REFLECTION PROBLEMS IN WESTERN CANADA

Abstract

The purpose of this paper is to stimulate interest in the problems of sedimentary multiple reflections in Canada and to show examples of some of the existing types. The types considered are: Second White Specks to the Paleozoic surface, the Blairmore to the Paleozoic surface, the suspected Ireton or base of the Nisku to the Paleozoic surface, the Devonian to the Paleozoic surface, and the base‐of‐weathering to the Paleozoic surface. Record examples were contributed by oil companies in Calgary to illustrate the Cretaceous‐to‐Paleozoic surface and the base‐of‐weathering‐to‐Paleozoic‐surface types. Records showing the other types are classified as confidential and unavailable. The base‐of‐weathering‐to‐Paleozoic‐surface multiple is shown with supporting cross‐sections and record‐sections as well as the simple field procedure, based on known data, that can be used by the field interpretation staff to help confirm this type of multiple. The problem of correctly interpreting seismic records where multiple reflections are present is discussed, and the criteria for distinguishing between multiple anomalies and true structures (particularly reef structure) presented. The conclusions drawn from the discussion are that for most types of multiple reflection interference accurate interpretations can be made. However, multiple reflections in certain areas can make definite interpretive results impossible.