Image logs

image logs were introduced by schlumberger in 1980.
these logs are advanced and most widely use in industry.
 Image logs can provide detailed picture of the wellbore that represent the geological and petro physical properties of the section being logged.

1. Image Log

2. Image Log image logs were introduced by schlumberger in 1980. these logs are advanced and most widely use in industry.  Image logs can provide detailed picture of the wellbore that represent the geological and petro physical properties of the section being logged.

3. Types formation micro imager log (fmi). ultrasonic bore hole image log (ubi). optical image log

4. FMI WHAT DOES FMI MEASURES:   Image logs are resistivity or acoustic devices that measure certain physical properties of the rock at or near the well that can be displayed as images of the wellbore, which can then be interpreted on a computer.  rock properties depends on following factors: composition diagenesis grain size grain orientation FMI images provide critical information if the rock structure and sedimentary features are significant determinants of formation productivity.

5. WORKING PRINCIPLE FMI logs, carry an array of electrodes on pads used to produce an electrical image of the formations seen on the borehole wall it gives 80% coverage of borehole .  The FMI yields a continuous, high-resolution electrical image of a borehole . other companies have since developed similar high-resolution electrical borehole imaging tools.

6. During the measurement, high frequency current is emitted from each buttons which creates an equipotential surface parallel to the borehole wall. The tool focuses the current a short distance into the formation Differences of potential are measured between each buttons and the upper tool cartridge housing (tool upper electrode)

7. Device FMI tool

8. Core and FMI If the FMI-derived image is of sufficient quality and calibrated against the core, it can provide a continuous survey of the formation in places where core is not cut, there was no core recovery, or when a core has been damaged through handling, transportation, or plugging.   

9. Benefits interpret formations accurately Improve reservoir descriptions Make decisions on site Get data in difficult environments, including deviated and horizontal wells Save time and money with complete interpretations in one image pass

10. UBI Other Common Names to this log: 1. CBIL (pronounced Cybill) stands for Continuous Borehole Image Log  2. Borehole tele viewer

11. WORKING Acoustic image logs, also called tele viewer or CBIL logs, use a rotating transducer to measure acoustic images over the entire borehole . The rotating transducer incorporated in the UBI sonde is both a transmitter and a receiver. The UBI ultrasonic borehole imager lets you analyze fractures and the stress regime and conduct borehole stability studies using images with 100% borehole coverage.

12. The rotating transducer incorporated in the UBI sonde is both a transmitter and a receiver.  The transducer subassembly is available in a variety of sizes for logging the complete range of normal open hole sizes.  For open hole applications, the UBI tool is logged with the transducer operating at either 250 or 500 kHz.

13. Advanced borehole imaging independent of mud type the UBI* Ultrasonic Borehole Imager enables the analysis of fractures, stress and borehole stability studies, and enables structural interpretations that are uninfluenced by mud type.  borehole stability and breakout information can be derived from the accurate borehole cross section as measured by the UBI tool.

14. Applications High-resolution geological interpretation Borehole stability Stress analysis analysis of fractures.

15. Device ubi tool

16. OBI The Optical Borehole Imager (OBI) sonde operated by EGS provides an orientated digital visual image of the borehole wall at a variety of operator-configured horizontal and vertical resolutions By means of a high-resolution video camera mounted in the optical sensor head  captures a series of circular images of the borehole wall .

17. Specifications the Optical Televiewer can be run in both air filled and (clear) water filled holes. Further processing allows for the computation and display of standard information on fractures and other geological features Image resolution : 360 to 1440 pixel 360° oriented optical Image

18. Applications of image log Core orientation Reconstruction of missing core Fracture identification and evaluation (both natural and induced Identification and characterization of depositional features Reservoir architecture Identification of well bore failures (breakouts)