ABSTRACT

Historically, in dipmeter analysis, depositional patterns are delineated for environmental, structural, and stratigraphic interpretations. The proposed method is a more fundamental approach, which uses raw data measurements from the dipmeter sonde to aid the geologist or log analyst in describing subsurface structures on a stratigraphic scale. Raw data are available at the well site, require only a basic understanding of sedimentary features and facies, and can be combined with computed results. A case study illustrates the reconstruction of sedimentary features from a raw data log recorded by a six-arm dipmeter.

The dipmeter is a wireline tool with a series of evenly spaced focused electrodes applied to the circumference of the borehole wall. The raw data are presented as curves representing the electrode response and tool orientation. In outcrop, the geologist can often see an entire sedimentary feature in 3 dimensions relative to its depositional environment. Therefore, a large range of features can be resolved. However, in the borehole environment the perspective is reduced to the borehole diameter, thus reducing the range of recognizable features. In this study, a table was assembled that identifies the features distinguished by the proposed method as a function of borehole diameter.

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