The FMI fullbore formation microimager gives you microresistivity formation images and dip data in water-base mud, differentiating the structures and. UltraTRAC all-terrain wireline tractor conveys FMI microimager ft in carbonate reservoir lateral in only 7 h, New Mexico. The FMI-HD high-definition formation micro-imager employs the well-proven microresistivity imaging approach of the industry-standard FMI fullbore formation .
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Electrical echlumberger tools have proved superior to the ultrasonic televiewers in the identification of sedimentary characteristics and some structural features such as natural fractures in sedimentary rocks. Borehole televiewers work best where the borehole walls are smooth and the contrast in acoustic impedance is high. These are conventional four-arm dipmeters for which the four microelectrodes are replaced by microinduction sensors.
The first borehole televiewer, operating at a relatively high ultrasonic frequency of 1. Schlumbergr number of electrodes was limited by tool-transmission electronics. The principal application of downhole video has been in air-filled holes in which acoustic and contact electrical images cannot be obtained.
Optical imaging Acoustic imaging Electrical imaging Methods that draw on both acoustic and electrical imaging techniques using the same logging tool Prensky  has provided an excellent review of this important subject. The principal drawback is that they require a transparent fluid in liquid-filled holes. The televiewer has superseded multiarm dipmeter calipers for these applications.
Moreover, the reflected signal is degraded in elliptical and oval wellbores because of non-normal incidence. Use this section for citation of items referenced in the text to show your sources. The resolution of electrical microimaging tools is governed by the size of the buttons, usually a fraction of an inch.
However, the image probably relates to a depth of investigation of no more than 0. The microelectrodes respond to current density, which is related to localized formation resistivity.
The pads and flaps contain an array of button electrodes at constant potential Fig. However, in this downhole case, the aperture of the sensor gives an intrinsic spatial resolution of 0. The combination of FMI images and dip data clearly differentiates the eolian and interdune schlumbrrger in this 8.
Brochure: FMI-HD High-Definition Formation Microimager
Schlumbberger UBI measures reflection amplitude and radial distance using a direct measurement of mud velocity. The size of the subassembly is selected on the basis of the diameter of the hole that is to be logged. Prensky  has provided an excellent review of this important subject. Specific applications are fracture identification, analysis of small-scale sedimentological features, evaluation of net pay sxhlumberger thinly bedded formations, and the identification of breakouts irregularities in the borehole wall that are aligned with the minimum horizontal schlumberher and appear where stresses around the wellbore exceed the compressive strength of the rock.
Modern tools contain a magnetometer to provide azimuthal information. Current is focused into the formation, where a depth of investigation schlukberger several tens of centimeters is claimed. The measurement principle of the microresistivity imaging devices is straightforward. These travel through the drilling mud and undergo partial reflection at the borehole wall.
The tool, therefore, has a high-resolution capability in measuring variations from button to button. Downhole cameras were the first borehole-imaging devices.
The high-resolution image is normalized with respect to the low-resolution part of the signal or to another resistivity logging tool.
Microresistivity schlumbergwr are able to detect pay in places where conventional log analysis might overlook it. Rather than have to change out the mud specifically for a microresistivity imaging survey, two other approaches have been pursued.
They are especially useful for net-sand definition in thinly laminated fluvial and turbidite depositional environments. Data are presented as orientated, juxtaposed pad outputs whereby the cylindrical surface of the borehole wall is flattened out. The tool can also be used for investigating the geometry of the inner surface of casing where it is not desired to measure resonant ringing as an indicator of cement integrity.
The FMI tool is able to detect laminations as thin as 0. The tools can be run as dipmeters. The other major historic limitation, the need to wait until the camera is recovered before the images can be seen, has fallen away with the introduction of digital systems.
Brochure: FMI Fullbore Formation MicroImager Brochure | Schlumberger
Breakouts are indicated by the low acoustic amplitude of the reflected signal, shown here as darker areas. Ultrasonic measurements can be made using the same tool in all types of drilling mud, and this can facilitate interwell comparisons. The travel time for the acoustic pulse depends on the distance between the transducer and the borehole wall, as well as the mud velocity. If it is smaller, it might still be detected.
The term “borehole imaging” refers to those logging and data-processing methods that are used to produce centimeter-scale images of the borehole wall and the rocks that make it up. Borehole imaging has been one of the most rapidly advancing technologies in wireline well logging. Examples of these irregularities are fractures, vugs, and breakouts. The resistivity of the interval between the button-electrode array and the return electrode gives rise to a low-resolution capability in the form of a background signal.
It can operate in all downhole environments other than gas-filled holes. However, drilling with oil-based or synthetic muds has increased because of the improved drilling efficiency and greater borehole stability relative to water-based muds. The third factor is the scattering or absorption of acoustic energy by particles in the drilling mud.
Both of these tools predated the UBI. Thus, the borehole televiewer also operates as an acoustic caliper log.
The context is, therefore, that of open hole, but some of the tools are closely related to their cased-hole equivalents. Note schoumberger more complete description of borehole geometry afforded by the X and Y calipers in Track 1.
This requirement has limited the application of downhole cameras. In contrast, note the undiagnostic smoothed form of the conventional array induction logs around depth XX30 ft in Track 2.
Unless transparent fluid can be injected ahead of the lens, the method fails. Acoustic borehole-imaging devices are known as “borehole televiewers.