Text of Borehole Seismic Introduction. Seismic Signals in the borehole Borehole Environment Borehole survey...
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Borehole Seismic Introduction
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Seismic Signals in the borehole Borehole Environment Borehole survey types Borehole seismic deployment Overview
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A VSP or Vertical Seismic Profile is the process of recording seismic data in a wellbore environment. The geophones are vertical in the earth versus horizontal along it as in surface seismic. What is a VSP?
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Checkshot Vertical Incidence Walkaway 3D-VSP DBSeis Offset VSP Salt Proximity Zero Offset LWD Tool SeismicMWD Integrated Seismic Surveys GECO LONGVA OSLO Pressure & Temperature Flow & Phase 4C Sensors Borehole Seismic Surveys
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Introduction Seismic Signals in the borehole Borehole Environment Borehole survey types Borehole seismic deployment
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Depth Time Downgoing direct arrival Downgoing multiple Reflected upgoing primary Reflected upgoing multiple Seismic Signal in the Borehole
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Depth Time Time-Depth Seismic Reflections Vertical Seismic Profile
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Depth Time Surface Seismic VSP Transit Time (TT) TT Reflection Time (OWT) OWT TT TWT = OWT + TT Reflection TWT One-Way Time vs. Two Way Time
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Borehole Multiples Upgoing Multiples
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Borehole Multiples Downgoing Multiple
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Borehole Multiples All Multiples
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Tube waves are generated when surface waves from the source come in contact with the borehole fluid and become a guided wave traveling up and down the borehole. As the tube wave travels vertically in the borehole it pushes the wall horizontally. When the geophones are properly clamped to the borehole wall most of the tube wave energy will be seen in the horizontal geophones. At changes in the borehole dimensions some of the tube wave energy will be reflected back to the surface. This will also occur when the energy reaches the bottom of the hole. Tube Wave Energy Source
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Tube Waves Raw Data One-Way Time Depth Horizontal Channel Vertical Channel Tube wave Y X HODOGM Y X
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Surface Seismic Comparison Depth Offset Two-Way Time One-Way Time VSP Data Surface Seismic
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Introduction Seismic Signals in the borehole Borehole Environment Borehole survey types Borehole seismic deployment
AVO Walkaway True Seismic Amplitude With Changing Offset True Seismic Amplitude With Changing Offset P-P and P-SV Analysis Reflector Source Positions P-Wave S-Wave AVO WALKAWAY Anisotropy velocity model Q factor analysis
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Salt Proximity Survey Provides Accurate Salt Face Image 2D, 2.5D and 3D Imaging Solutions
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3D VSP Very High Sub- Surface Imaging Resolution Exploration and Development Applications Detailed Preplanning and 3D Modeling Required 3-D VSP Well 1Well 2 Well 1Well 2 3D-VSP Depth Migration Surface seismic 3D PSDM 3D VSP
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Introduction Seismic Signals in the borehole Borehole Environment Borehole survey types Borehole seismic deployment
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Borehole seismic on Wireline Applications All seismic applications Operations - Max deviation dependant of well liquid type & well geometry (example: so far, ASI ran in 77 deg deviation, in Brine) Downhole Geophones Source Reference Sensors Recording Unit Downgoing Wavefront Pit
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Pipe Conveyed Acquisition Applications All seismic applications Operations Max deviation: no limit (113 o exp) Ex : 3 * CSI / MDT / Pex / DSI Extendable CSI sub isolates geophones from tool body & pipes Wet connect CSI Pressure sampling Sonic Neutron Gamma density Tension sub Resistivity Gamma spectroscopy Compression sub
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Through Drill Seismic TDS Applications All seismic applications, & particularly... Position of the drill bit: on the surface seismic from the target... Imaging beside the well... Prediction ahead of the bit Operations Data acquisition... Tool Pumped down Reciprocate between levels No circulation Acquisition 10 min max Min deviation so far = 7 deg Max deviation so far = 90 deg Saving rig time Taking effective and fast decisions Conventional VSP source GAC sensor Drill bit TDS Thru-Drill Seis
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Logging While Drilling Applications Real Time checkshots... Position of the drill bit: on the surface seismic from the target Along with ISONIC: Calibration of ISONIC data & RT Synthetic seismogram Operations Saving rig time Taking effective and fast decisions seismic reflector LWD Tool sea floor MWD telemetry SeismicMWD seismic reflector Drill Bit Sensors Weights Sensor sea floor Source Drill Bit Seismics Surface System
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Through Tubing Seismic Applications All seismic applications, & particularly...... Imaging beside the well (coil tubing drilling, well redevelopment, etc) Operations Data acquisition - Stop production VSP source Geophones (GAC)
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Simultaneous Acquisition Applications All seismic applications, & particularly... Acquiring borehole seismic data before surface processing starts: Velocity anisotropy, Q attenuation, AVO, VSP-guided processing, shear model Operation Tool stays stationary in the well Platform Joint acquisitions with GP
