Research On Signal Detection And Processing Of Drilling Mud Pulse

With the increasing construction works for cluster well, obstacle bypassing well, multilaterial well, and connected well, as well as increasing depth of reservoir,equipments are required to provide more and more formation informations. During drilling operation, MWD(measurement while drilling) technology is generally used to ensure accurate measurement of well track and geologic parameter and to improve the accuracy of well track control. Well track and geological information around the downhole can be obtained by using MWD technology without breaking the normal drilling operation. Informations can be realtime transmitted to surface in some way. Then the surface decoding equipment will complete the analysis and process of the signal.With the development of new technology, downhole information transmission way has changed from cable way to wireless way, and data transmission speed changed from low to high. there are two mainly wireless transmission ways:mud pulse way( negative or positive ) and electromagetic pulse way. Currently, most of MWD uses the mud pulse way. In this way, downhole information transmits to surface system by mud pulse, and surface decoding system will do some necessary preprocess of the signal.At last, the decoding system will restore the mud pulse into the raw information, and realtime display these information on PC.In this document, first of all, it introduces the wireless signal generation, transmission principle and signal processing technology, and provides the surface decoding system design, then describe detail analog filtering and digital filtering techniques, achieves from the stand pipe pressure sensor to surface decoding system signal transmission channels design; In Signal Processing, using the FIR digital filter to filte the mud pulses signal; gets the effective signal decoding means after researched the pulse encoding rulse.and program the WDM drives, pulse detection and data management software in Windows operation system.The surface decoding system has reached the same level of the Similar foreign equipment, and some high speed digital filter is better than others. At last, Accuracy and reliability of the surface decoding system has improved by updated the digital filter and decoding technology based on the field test results.From the field test results, Mud pulses decoding system has reached the design target and achieved the design function.But at the same time, this decoding system has some disadvantages, and designer has pointed out the aspect to need further improvement, and the designer has provided some advice for improvement the decoding system also.