Also, topographic relief can cause the vertical stress to be skewed off vertical. Either of these conditions could result in a misinterpretation of breakout azimuth and, thus, hydraulic fracture azimuth. Research is presently focusing on qualitative and potentially quantitative stress interpretation using borehole breakouts. Numerous commercially- available logging tools can be used to detect and measure breakouts. These tools give a nearly continuous caliper around the well that significantly enhances breakout recognition and measurement when compared with oriented calipers and borehole cameras.
Oriented calipers can also provide the necessary data for breakout analyses.
There are several criteria that can be used to distinguish true breakouts from other types of borehole enlargements. Examples of the these types of tools include the Formation MicroScanner and Formation MicroImager. In addition, old wells with dipmeter or other oriented caliper logs can be analyzed for breakouts. An additional method for acquiring breakout data is the use of an oriented borehole video imager. Borehole cameras may provide an acceptable choice for air- filled boreholes since electrical or acoustic tools cannot be used in this medium.