Changes

Given computation approaches tailored for structural applications, structural dip can then be defined by looking for a consistent trend on the arrow plot. The most repetitive dip should be the structural dip.

Given computation approaches tailored for structural applications, structural dip can then be defined by looking for a consistent trend on the arrow plot. The most repetitive dip should be the structural dip.

The interpretation of structural anomalies is best accomplished by comparison to a set of models—the simpler the model, the better. A simple model, such as the one shown in Figure 5 for a normal fault with drag, is adequate to describe the geometry of such a fault. Figure 6 shows a more complicated arrow plot of low angle dips, reducing to a minimum then increasing to a high angle with the azimuth changing continuously with the dip angle. This is the signature of a tilted plunging anticline. A cross-sectional sketch of the anticline can be produced using the rule of interchangability of perspectives in which the horizontal geometry is interpretable from the vertical pattern of dip. (The application of dipmeter data to solving structural problems is covered in the chapter on “[[Evaluating structurally complex reservoirs]]” in Part 6.)

The interpretation of structural anomalies is best accomplished by comparison to a set of models—the simpler the model, the better. A simple model, such as the one shown in Figure 5 for a normal fault with drag, is adequate to describe the geometry of such a fault. Figure 6 shows a more complicated arrow plot of low angle dips, reducing to a minimum then increasing to a high angle with the azimuth changing continuously with the dip angle. This is the signature of a tilted plunging anticline. A cross-sectional sketch of the anticline can be produced using the rule of interchangability of perspectives in which the horizontal geometry is interpretable from the vertical pattern of dip. (The application of dipmeter data to solving structural problems is covered in “[[Evaluating structurally complex reservoirs]]”.)

[[file:dipmeters_fig5.png|thumb|{{figure number|5}}Simple dip model for the description of a normal fault with drag.]]

[[file:dipmeters_fig5.png|thumb|{{figure number|5}}Simple dip model for the description of a normal fault with drag.]]