Abstract: Expanding Field of Seislog Applications

A. V. Street

The Seislog process represents one of the powerful new techniques for extracting geologic information from reflection seismic data. The first applications were in petroleum exploration and have greatly enhanced the interpretations of porosity developments and stratigraphic traps. Some plays, developed from Seislog studies now have been drilled and some of the prognoses were successful.

The most obvious extension of the method is into the very near surface. New high-resolution amplifiers now make it possible to record the high frequencies necessary to resolve the first 1,000 ft (300 m) or so below the surface in sufficient detail to be used for civil engineering applications. Mineable coal deposits also may be mapped with appropriate modifications to the field and processing techniques. A Seislog study often can provide a fairly reliable prognosis of drilling conditions for the engineer as well as useful information for designing a cementing program, if and when casing must be set.

Although the prime interest of the explorationist is generally in the low-velocity features, with the possible implication of porosity, the drilling engineer has an interest in the entire section.The low-velocity incompetent formations may drill easily but can cause circulation problems. The high-velocity beds may be much slower to drill. Also, if a casing problem is anticipated, it can be very useful to know, in advance of the drill, which formations are most likely to provide good anchor points for the cementing program.

AAPG Search and Discovery Article #90961©1978 AAPG Annual Convention and Exhibition, Oklahoma City, Oklahoma