Textural characteristics of volcanic strata and its constraint to impedance inversion
Volcanic strata have pseudostratified, stratified and massive textures which are more complex than sedimentary rocks. Thus, it should not simply be simulated with stratified models,and it results in a difficulty in volcanic reservoir prediction with seismic data. A primary key point for volcanic reservoir exploration and development is to build up proper volcanostratigraphic models. Both pseudostratified and stratified models are built up based on typical volcanostratigraphic textures of outcrops of Jiutai and Datun area in the southeastern Songliao Basin. The internal beds of pseudostratified strata show great changes in dipping direction and angles, and contact obliquely with the top and bottom strata. The dip angle of volcanic rock bed decreases from central to distal parts along a given edifice's limb, and the exact stratigraphic textural model is built up by interpolation following the top and/or bottom surface trends. A borehole named as Well YS2 is selected to perform impedance inversion constrained by stratified and pseudostratified models respectively. As a result, both the dimension and thickness of low-impedance show significant differences between the stratified model and the pseudostratified model. Therefore, the stratigraphic texture of volcanic edifice should be precisely characterized before impedance inversion, and then the stratigraphic textural model is built up with internal interpolation to ensure the inversion reliability. This study offers a theoretical basis for effective exploration of volcanic petroleum reservoirs.
NETL
NSTL
万方数据
维普
