ABSTRACT

The Fracture Identification Log uses the four resistivity correlation curves recorded by the High Resolution Dipmeter for the location of mud-filled, vertical fractures. The tool generally tends to rotate as it is pulled up the hole, and when one of the dipmeter pads crosses such a fracture in a resistive carbonate or sandstone formation, the fracture is indicated as a conductive anomaly on the corresponding dipmeter curve.

Results using this FIL (FOOTNOTE *) technique in the Cretaceous of North Louisiana and Mississippi are reported. Experience to date indicates that the fractured chalk of the Pendleton-Many Field and Monroe Gas Field, both of North Louisiana and the fractured chalks of Mississippi exhibit the same dipmeter-curve responses as had been seen earlier in the Austin Chalk of South Texas. In the Waveland Field, Hancock County, Mississippi, where gas is produced from a fractured Mooringsport Limestone section, Fracture Identification Logs run on several wells indicated more fracturing than had previously been recognized. In North Louisiana the FIL technique has defined fracture systems in the Sligo and Smackover carbonates, and in the low-porosity Cotton Valley sandstones.

Results to date indicate that the FIL technique can be very helpful in the location and definition of natural-fracture systems.