UBIT is a kind of ultrasonic logging tool. It can be used in the well full of liquid, but it is cannot be used in the mud full of gas (The data will weaken seriously). It has two kinds of logging services: IMAGED MODE andCASED HOLE MODE. IMAGED MODE is used for the imaging in the open hole, cased hole and the formation crack investigation. The CASED HOLE MODE is used to evaluate the cement sonic impedance outside case and check the corrosion of case.

UBIT tool is composed of the electric circuit, directional sub and rotating sonde. The electric circuit is composed of RTU board, V40 processor board, DSP signal processing board, transmitting control and preamplifier board and motor control board and slow A/D board. The RTU address is 2C0 0.The surface logging system communicates with CAST by D4TG to get the useful downhole information.

UBIT includes two ultrasonic transducers, each of which can act as either transmitter or receiver. The imaging transducer is mounted on the rotating scanner head. When the ultrasonic transducer of 360 degree rotation transmits the sonic wave beam to side wall, the sonic energy is transmitted by the side wall, and return to the transducer. Recode the returned sonic energy (amplitude) and transmitting time through the transducer. The returned sonic energy is mainly related with the sonic resistance of side wall and the geometry shape of borehole. In the well wall without the crack, the greater the sonic resistance of well wall is, the bigger the returned energy is, Wise versa, In the well wall of the crack hole, the returned sonic energy is in proportional  to the area of out zone of the hole. In addition, the smoothness of well wall influences the returned sonic energy. If the well wall is not flat, it will scatter to the sonic, and the returned the sonic energy will become small. The other transducer is the mud transducer (Mud -Cell Transducer). It is used to measure the sonic velocity of borehole fluid. The mud transducer is opposed to the fix reflector, because the distance of reflector and transducer is known, so by recording the transmitting time of transducer, slowness of borehole fluid can be confirmed.

The main influence factors of ultrasonic imaging: Shape of transducer, work frequency, distance to the formation, the mud density in the well, borehole and the centered condition of the tool. The smaller of transducer’s shape is, the higher work frequency is, it is more near to the formation, the mud density is small, and the facula is small, then the attenuation of sonic wave is small. While the more small of the transducer is, the power is small;  the work frequency is higher, the sonic attenuation is big; the mud density is bigger, the sonic attenuation is bigger. If decrease the work frequency, it influences the space resolution. If the well is not regular or the centralizing of tool is not good, the image appears the vertical stripe to cover the character. 

Max. Temperature:      175℃

Max. Pressure:             140Mpa

O.D:                               92mm

Length:                        5450mm

AC power supply:       120Vac±10v,50~60HZ

DC power :             150VDC,1.5A

Caliper Measuring range:

5.5’’~13.375’’（cased hole）

4.5’’~12.5’’ （Open hole）

     Parameter Comparison of Imaging Mode and Casing Mode