Frowns and smiles

Passage of horizontal, or near horizontal wells through a succession often results in the observation of bedding planes as chevrons on a borehole image.  These chevrons can face up or down the well path.  If these images are plotted with reference to low-side then a simple visual mnemonic allows you to determine if you are going up or down a given stratigraphical succession.  With non-inverted successions U shaped chevrons “smiles” indicate that the well path is going up the stratigraphical column; whereas ∩ shaped chevrons “frowns” imply the well is passing down the column.  This allows younging directions to be determined and folds to be classified into synclines and anticlines.  Remember, frown for down, smile for up.



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