Time-lapse seismic interpretation in t-p space using pre-stack data
He, Y.-X., Angus, D.A., Yuan, S.-Y., Blanchard, T.D., Clark, R.A. and Hildyard, M.W., 2015. Time-lapse seismic interpretation in 7-p space using pre-stack data. Journal of Seismic Exploration, 24: 475-496. We present a new algorithm to measure time-lapse vertical traveltime shifts in seismic pre-stack shot and CMP gathers by tracking traces having constant horizontal slowness in 7-p space. Unlike other methods for measuring these attributes from stacked volumes, our use of pre-stack data avoids errors and uncertainties inevitably introduced in conventional time-lapse processing, such as choosing a suitable migration velocity model and cross-correlation time-window size. Results are localised to a given interval and thus free from overburden effects. This approach is used to estimate layer vertical traveltime shifts, a reservoir compaction-dilation coefficient, and hence calculate both velocity and thickness changes within a reservoir and the overburden. We demonstrate the method using synthetic reflection data generated using both a ray-based and a finite-difference full-waveform algorithms on two suites of models: a simple four-layer reservoir model; and a hydro-mechanical simulation model. We compare our estimates of layer interval vertical time-lapse traveltime shifts and velocity and thickness changes with those of the input model. The results indicate that the new T-p time-lapse method produces sufficiently accurate results compared to conventional methods.
- Alkhalifah, T., 1998. Acoustic approximations for processing in transversely isotropic media.Geophysics, 63: 623-631.
- Alkhalifah, T. and Tsvankin, I. 1995. Velocity analysis for transversely isotropic media.Geophysics, 60: 1550-1566.
- Angus, D.A., Verdon, J.P., Fisher, Q.J., Kendall, J.-M., Segura, J.M., Kristiansen, T.G., Crook,
- A.J.L., Skachkov, S., Yu, J. and Dutko, M., 2011. Integrated fluid-flow, geomechanic andseismic modelling for reservoir characterization. Recorder, Can. SEG, 36: 27-36.
- Chapman, C.H., 1981. Generalized Randon transforms and slant stacks. Geophys. J. Roy.Astronom. Soc., 66: 445-453.
- Cox, B. and Hatchell, P., 2008. Straightening out lateral shifts in time-lapse seismic. First Break,26: 93-98.
- Diebold, J.B. and Stoffa, P.L., 1981. The traveltime equation, tau-p mapping, and inversion ofcommon midpoint data. Geophysics, 46: 238-254.
- Fuck, R.F., Bakulin, A. and Tsvankin, I., 2009. Theory of traveltime shifts around compactingreservoir: 3D solution for heterogeneous anisotropic media. Geophysics, 74: D25-D36.
- Ghaderi, A. and Landro, M., 2009. Estimation of thickness and velocity changes of injected carbondioxide layers from prestack time-lapse seismic data. Geophysics, 74(2): 017-028.
- Guest, W.S. and Kendall, J.-M., 1993. Modelling seismic waveforms in anisotropic inhomogeneousmedia using ray and Maslov asymptotic theory: Applications to exploration seismology. Can.J. Expl. Geophys., 29: 78-92.
- Hatchell, P. and Bourne, S., 2005. Rocks under strain: Strain-induced time-lapse time-shifts areobserved for depleting reservoirs. The Leading Edge, 12: 1222-1225.
- He, Y.-X. and Angus, D.A., 2014. Pre-stack time-lapse seismic attributes analysis in tau-p domain.
- Extended Abstr., 76th EAGE Conf., Amsterdam: We-P06-01.
- He, Y.-X., Angus, D.A., Clark, R.A. and Hildyard, M.W., 2015(a). Analysis of time-lapsetravel-time and amplitude changes to assess reservoir compartmentalization. Geophys.Prosp., doi: 10.1111/1365-2478.12250.
- He, Y.-X., Angus, D.A., Blanchard, T.D., Wang, G.-L., Yuan, S.-Y., and Garcia, A., 2015(b).
- Time-lapse seismic waveform modelling and analysis using hydro-mechanical models for adeep reservoir undergoing depletion. Submitted to Geophys. J. Internat.
- Herwanger, J.V. and Koutsabeloulis, N., 2011. Seismic Geomechanics: How to Build and Calibrate
- Geomechanical Models using 3D and 4D Seismic Data. EAGE, Houten.
- Kappus, M.E., Harding, A.J. and Orcutt, J.A., 1990. A comparison of tau-p transform methods.Geophysics, 55: 1202-1215.
- Landro, M. and Stammeijer, J., 2004. Quantitative estimation of compaction and velocity changesusing 4D impedance and traveltime changes. Geophysics, 69: 949-957.
- Larsen, S., Wiley, R., Roberts, P. and House, L., 2001. Next-generation numerical modelling:incorporating elasticity, anisotropy and attenuation. Expanded Abstr., 71st Ann. Internat.SEG Mtg., San Antonio: 1218-1221.496 HE, ANGUS, YUAN, BLANCHARD, CLARK & HILDYARD
- Reine, C., Clark, R. and van der Baan, M., 2012. Robust prestack Q-determination using surfaceseismic data: Part 1 - Method and synthetic examples. Geophysics, 77: R45-R56.
- Reste, T., Stovas, A. and Landrg, M., 2005. Estimation of layer thickness and velocity changeusing 4D prestack seismic data. Extended Abstr., 67th EAGE Conf., Madrid: C010.
- Reste, T., Stovas, A. and Landre, M., 2006. Estimation of layer thickness and velocity changesusing 4D prestack seismic data. Geophysics, 71(6): 9-S234.
- Selwood, C., 2010. Researching the Optimum Bandwidth to Extract 4D Time Shifts. M.Sc. Thesis,University of Leeds, Leeds.
- Shapiro, S.A., 2003. Elastic piezosensitivity of porous and fractured rocks. Geophysics, 68:1954-1966.
- Smith, S.S. and Tsvankin, I., 2012. Modelling and analysis of compaction-induced traveltime shiftsfor multicomponent seismic data. Geophysics, 77(6): T221-T237.
- Stoffa, P.L., Buhl, P., Diebold, J. and Wenzel, F., 1981. Direct mapping of seismic data to thedomain of intercept time and ray parameter - A plane wave decomposition. Geophysics, 46:255-267.
- Thomsen, L., 1986. Weak elastic anisotropy. Geophysics, 51: 1954-1966.van der Baan, M. and Kendall, J.-M., 2002. Estimating anisotropy parameters and traveltimes inthe tau-p domain. Geophysics, 67:1076-1086.van der Baan, M. and Kendall, J.-M., 2003. Traveltime and conversion-point computations andparameter estimation in layered, anisotropic media by 7-p transform. Geophysics, 68:210-224.
