Unformatted text preview: etic seismogram depends on well log quality, seismic data processing quality, and the ability to extract a representative wavelet from seismic data The acoustic log is generally calibrated with check-shot or vertical seismic profile (VSP) before combining with the density log to produce acoustic impedance. Synthetic seismigram indicates also if the target horizon is peak or trough in seismic sections. 46 Geology & Geophysics in Oil Exploration Mahmoud Sroor Geology & Geophysics in Oil Exploration Interpretation steps:
1-Loading the data: • Seismic sections: (poststack data). • Available Wells data: Well logs & formation tops • Velocity Data of wells: from Check-shot survey or Vertical Seismic Profiling. 2-Well Tie: We create a Synthetic Seismogram to know the accurate location of the formation tops of intersested horizonthen tie it with the seismic section. Synthetic indicates also that if the horizon response is peak or trough. From the well, we know the depth of the event (Formation tops). From plotting values of depths & times which came from the check-shot survey, we can extract the time value for certain depth ( to mark that depth on seismic section). We repeat these steps with all wells to get the true depth of the horizon. NOTES: • We must know the datum of survey (datum survey in seismic called Seismic refrence datum). • If the Check-shot time is one way time, we must convert it to two way time. • We must know the type of well depth (TVD, MD, or TVDsubsea). 3-Picking intersted Horizon: Picking is a reflection on a seismic section. It involves deciding what wiggles from trace to trace are from the same reflection a-Arbitrarly Line: it is a seismic line contains the data of the available wells (called also Key line in 2-D interpretation) This line contain the most accurate data because it contains a real data about the depth of intersted horizon became from already drilled wells. This arbitary line is determines from a map view of data then flatterned as one seism...
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This note was uploaded on 01/05/2011 for the course GEOL 1 taught by Professor Jenniferalford during the Spring '10 term at Indian Institute of Technology, Roorkee.
- Spring '10