Presentation on theme: "High Resolution Carbonate Reef Interpretation Using Cross Well Data"— Presentation transcript:
1High Resolution Carbonate Reef Interpretation Using Cross Well Data Thomas Morgan, Ph.D., SchlumbergerMike Raines*, Whiting Petroleum*formerly with Sandridge EnergyPresented to the Permian Basin Geophysical Society in Midland, TX, 15 October, 2009.
7Tomographic Velocity Inversion Picked Direct Arrivals3D Thin Layer Model3D Ray TracingModel Interfaces and Layer Parameters Described by Chebyshev Polynomials
8Tomographic velocity inversion result Tomographic velocity inversion result. Red track is Vp, Green over-lay on Vp is Tomographic Vp.
9Imaging Kirchhoff Integral Prestack Reflection Imaging Depth Dip Oriented and Aperture LimitedRay Trace Travel Times from Tomographic VelocitiesAngle Gather Output
10Processed cross well profile Processed cross well profile. Green log is Vp, blue is gamma, red is neutron porosity. Note 100 foot horizontal guide lines. Recovered at least 800 Hz after imaging.
1130 degrees 45 degrees 70 degrees Profile display is nearly true 1:1. Incidence angles from 30 to 70 degrees were used during imaging. Upgoing reflections.
12Interpretation Approach Profile is in DepthExact depth tie at the wells– no time to depth conversion neededResolution at the outcrop level – human scale geologyGeological Interpretation versus Geophysical InterpretationGeologically guided interp, but still have to pay attention to geop – just at a smaller scale.
13Composite model of Michigan Basin Pinnacle Reef. From Huh et. al Composite model of Michigan Basin Pinnacle Reef. From Huh et. al., Depositional Environments of Pinnacle Reefs, Niagara and Salina Groups, Northern Shelf, Michigan Basin.
14Evaporites Reef Zone Grey Niagaran Burnt Bluff Carbonate Well log only starting point, three wells and major formation tops. Vp and porosity logs shown.Burnt Bluff Carbonate
21Organic Reef Bioherm Tidal Flats Supratidal Island Final tidal flats phase.
22Repeat of Northern Michigan Silurian reef model with depositional environments for reference to interpretation.
23West Texas Permian Reef Multiple profilesMore complicated structureBetter well controlSurface seismic availableSecond study area.
24RightMiddleWest Texas profile loop. We will look at the three profiles label “left”, “middle” and “right” from the direction indicated by the arrow. Can now process with a 3D model and honor gross dip trend.Left
25Top of reef interpretation from surface seismic overlain on cross well profiles.
26Detailed cross well interpretation. Top of reef has been re-interpreted. Internal reef structures have been interpreted.~ Reef TopMarker Near OWC
27Stacked Mounds Inter-Mound CO3 Debris Shaley Lag Deposit~ Reef Top (Erosional)On LapEnlargement of left profile. Note how the wells are honored much more closely on the cross well interpretation.Inter-Mound CO3 DebrisMarker Near OWC
29Shaley Lag Deposit~ Reef TopEnlargement of right profile.
30Conclusions Depth profiles provide unambiguous well ties Resolution allows a truer look at the geologyGeophysical effects pushed down to smaller scaleReservoir level geologic Interpretation is possibleSecond study area.
31High Resolution Interpretation of a Permian Reef Michael A. Raines, Sandridge Tertiary, LLC,Thomas R. Morgan*, Ph.D., SchlumbergerPoster PDC P2, Station D1Tuesday, October 27 at 11:40 a.m.Shameless promotion!
32Acknowledgments:We would like to thank Sandridge Energy and Michigan Technological University for the use of the data.References:Bube, K., and R. Langan, 1999, On a continuation approach to regularization for crosswell tomography: 69th Annual International Meeting, SEG, Expanded Abstracts,Liao, Q., and G. A. McMechan, 1997, Tomographic imaging of velocity and Q, with application to crosswell seismic data from the Gypsy Pilot Site, Oklahoma: Geophysics, 62,Quan, Y., and J.M. Harris, 1997, Seismic attenuation tomography using the frequency shift method: Geophysics, 62,Huh, M.H., L.I. Briggs, and D. Gill, 1977, Depositional Environments of Pinnacle Reefs, Niagaran and Salina Groups, Northern Shelf, Michigan Basin, in: Studies in Geology No. 5, Reefs and Evaporites – Concepts and Depositional Models, AAPG, J.H. Fisher ed.