LWD/MWD Demodulation

LWD/MWD Demodulation using ASDH Universal Pressure Strap Case Study installed two pressure straps on the lower end of the standpipe, 5″ carbon steel. Used lube, Installation Box, 30 reps, Loctite on set screw. Did not interfere with ongoing drilling. We let them thermally synchronize for two hours.

The stand pipe was rated 5000psi. The pressure was 1600 PSI so we set the straps at 2.3v with the installation box.Later we checked and pressure was close to 1250, so the strap read 2v. ASD pressure strap was up and running without interfering with the ongoing drilling. We did not need to stop to penetrate the pipe. We were able to make a voltage calculation to preset the correct PSI with use of our installation box. There was no down time on the rig.

After hooking up the cable we were able to track to pressure from the doghouse. We ran the test on two separate parallel setups on two independent computers.

Client set up does not allow for a 2 point calibration. So we set the max pressure to 5000 to match the API of the pipe. Pressure was changing with the tool pulses Later a better cable was run to the sensor and also the pumpstroke signal was added for better noise cancellation. The signal was decoded and could keep up with the standard pressure sensor.