Oil well logging

Oil well logging


Wireline and MWD/LWD

Oil or gas reservoirs lay deep underground, and geological survey is conducted in order to obtain physical properties along with the depth or detailed locations around the drilling tool. There are basically two oil well logging technique called Wireline logging and LWD (logging while drilling) / MWD (measurement while drilling) logging. They require measurement in deep underground.

In Wireline, a sensor is inserted with a cable (or wire) in the drilled well, physical property along the well (or cased well) are logged while the sensor position is scanned.

In the case of LWD/MWD, the detecting probe is attached closely with a drill bit and the measurement is taken real time while drilling, then logged and formation is evaluated. PMTs are used to measure radioactivity information from the formation combined with a scintillator, either natural gamma, scattered gamma or neutrons depending on the information to obtain.

The temperature around the detector could be very high (up to 90°C, 150°C, 175°C or 200°C ), in addition, especially for LWD/MWD, strong vibration or shock is applied during the measurement. Therefore, good performance and very good reliability during harsh condition are required.

Figure 1:  Wireline

Figure 1: Wireline

Figure 2: LWD-MWD

Figure 2: LWD/MWD

Ruggedized photomultiplier tubes

Oil well logging

For oil well logging, Hamamatsu offers dozens of different ruggedized photomultiplier tubes. These PMTs feature a special bialkali photocathode that is highly temperature resistant, allowing the detector to be used with downhole tools at deeper drilling depths. This high-temperature photocathode also offers stable operation and long life at temperatures up to 90℃, 175 ℃, or 200℃. (For example, Hamamatsu’s newest high-temp photocathode can operate for more than 1000 hours at up to 200℃.) Furthermore, Hamamatsu’s ruggedized PMTs are designed with highly shock/vibration -resistant electrode structures that ensure reliable operation under harsh conditions.

Our ruggedized photomultiplier tubes come in sizes from 13mm (1/2") to 51mm (2") diameter.


Please note that if you do not find a PMT on this website that meets your needs, Hamamatsu would be happy to discuss with you a customized product (tube or assembly) for your unique requirements.