Application of Seismic Data and Sequence Stratigraphy for Constraining a Stochastic Model of Calcite Cementation

Abstract

Copyr!ghl 1996 Souety 01 Petroleum Englneets Tfus papr was prepared Ior presentatum at the EuroPan 3-D Resewo(r Modellmg Conference held tinSIavanger Noruay, 16-17 F.@ 19S6 Th!s paper was selected for presentatwn by the SPE Prcgram Commrttes following rwvlew o! Information conlamed m an abstrOct submlfted by the author(s) Conlenls of the paper as presented, have not been rWBWd by the Society of PekOleum Engineers and are sublect to correc!aon by the author(s) The mater,al, aspresented, doss not necesswfy rellect any pos{fton O( the .SOCtaty01 Petroleum Engineers or Its membas Papsrs plesenmd .91SPE mstxmgs ale subject to publlcellon rewew by Edllortal Comm!ltee of the Sccmty of Petroleum Engmeem Permlssm 10 copy IS restricted to an abslract of not more than 300 words. Illustrations may not be copIsd The ab$tracf should cwtam COOWNCUOUS acknowlsdgmenl of where and by wtmrn the parer was presented Write Llbrarlan, SPE, P O 6333636, Richardson, TX 75063 .3S36 USA, lax 01.214-952-9435 AbstractCalcite cemented sandstone layers are common heterogeneities in shallow marine reservoirs where they cause significant flow barriers. Field analogue studies indicate that the most laterally persistent cemented layers are associated with sequence stratigraphic bounding surfaces where the cementation forms a complex network of beds concentrated around both maximum flooding surfaces and sequence boundaries Although individual calcite cemented beds are thin, they arc associated with very high acoustic impedances and concentration of these thin, high impedance beds around bounding surfaces produces a significant seismic response which can be used to provide information on the spatial distribution of flow barriers. This information along with a sequence stratigraphic interpretation of the reservoir and geometrical data extracted from field analogues provides the input for an integrated reservoir description of calcite cemented barriers using a stochastic modelling approach.The stochastic model is a non-stationary' indicator field \vith an external trend in the indicator proportions, Vanograms are used to control the geometry of individual cemented beds. Sequence stratigraphy and seismic data are used to define spatial trends in the proportion of cemented beds; sequence stratigraphy provides the vertical constraints, and seismic data provide lateral constraints.The modelling approach has been tested using data from the TOGI area of the Troll gas field in the Norwegian North Sea. A controlled (verifiable) test has been carried out using synthetic seismic data based on a realistic, heterogeneous, 3D acoustic model of TOGI, These data have been inverted using a constrained sparse-spike seismic inversion technique. The test demonstrated that the prototype modelling procedure functioned satisfactorily. The integration of data from several sources contributed to the generation of realistic heterogeneity models constrained by a maximum amount of information.A test using real seismic data from TOGI has been initiated. The results of the sparse...

Closed-Loop Feedback Control for Production Optimization of Intelligent Wells Under Uncertainty

“…The calcite cemented layers can be identified in cores, wireline logs and analogous outcrops (Lien et al 1992;Evensen et al 1993;Gibbons et al 1993), and are interpreted to vary in lateral extent from discontinuous nodules to laterally extensive stratified layers that can be correlated between wells (see, for example, Figure 11 in Gibbons et al 1993). In addition, dipping reflectors of low to high amplitude are observed in seismic crosssections and time slices across the Sognefjord Formation, which are interpreted as clinoform surfaces associated with calcite-cemented concretions (Bakke et al 1996;Dreyer et al 2005;Holgate et al in review). Calcite cementation is therefore interpreted to occur preferentially along the flooding surfaces that bound the parasequences, and along clinoform surfaces within each parasequence.…”