English to Russian Tech/Engineering Petroleum Eng/Sci logging

EMI - CAST after Mini Frac

The Electrical Micro Imaging tool (EMI) produces images of the borehole wall based on 150 micro-resistivity measurements distributed over 6 pads that contact the borehole wall.

The Circumferential Acoustic Scanning tool provides borehole images based on the reflections of an ultrasonic beam at the borehole wall.

In the present example, both imaging tools where run before and after a mini frac operation in a wellbore. The log shows the entire recorded EMI image in track one, an expanded EMI image in track two and the CAST image on the same scale in track 3. Please note that the entire interval of the expanded images is only 24 ft.

Both images clearly show the fracture created during the mini frac test. Both tools provide oriented images, hence the direction of the fracture can be measured. Fractures are created in the direction of the maximum principal stress, or parallel to the minimum principal horizontal stress and therefore the orientation of the stress field is known based on these images.