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 techniques 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 : Wireline

Figure : LWD / MWD


Figure : Figure : LWD / MWD

Figure : Wireline



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