A Reservoir Characterization Case Study Based on the Structural and Depositional Isochronous Framework

Ling, Yun; Guo, Xiangyu; Song, Qianggong; Xia, Zhu

This case study is from northwest of Zhungar Basin in west China. The depth of the reservoirs is 2000m with average thickness 218m, and the lower two sedimentation cycle among total three consisted of twenty sand set with average thickness 2~5m. Production started in 1982 with well spacing of 375m for sand sets in lower part of reservoir, and the production of upper part started in 1999. High density 3-D seismic was acquires in 2009 hopefully for better reservoir study, and relative reservoir information preserved PSTM and PSDM processing was implemented.

Reservoir characterization is used to be implemented by interpolation of well data in this area, but its reliability is inevitably reduced due to the structural and depositional complexity of the delta front and delta plain facies. To overcome the ambiguity in reservoir modeling, reservoir characterization based on the structural and depositional isochronous framework was thus applied.

Reservoir structural isochronous framework refers to the isochronic interface which corresponding to the continuous seismic event and can be tracked during seismic data interpretation. The top and bottom of the reservoir is the two such frameworks in this study. Reservoir depositional isochronous framework here refers to the discontinuous seismic event generated by the physical property difference (impedance interface) inside the sedimentation cycle. Under the control of the structural isochronous framework, 3-D sequence stratigraphy interpretation helps in picking up two such depositional isochronic interface inside the reservoir.

Under the constraint of the structural and depositional isochronous framework, and with the interval of the structural framework being subdivide into the grid which appropriate for the well log, reservoir model are built from spatial interpolation of well data finally.

Integrated interpretation with development information proved that this reservoir characterization result is more reliable, and the spatial heterogeneity of the reservoir is better described.

AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013