Skeletonization and impermeability characterization of discontinuity interface for reservoir with sandstone compartment

Abstract

In the process of fluvial sedimentary evolution, mudstone interlayer is frequently developed in the interval of sandstone deposition, forming a reservoir of sandstone compartment. Some generally nonpermeable or semipermeable interlayers become discontinuity interfaces of a reservoir, which is one of the causes for the complexity in the distribution of remaining oil. The degree of the impermeability of the discontinuity interface on fluid flow is critical to the development of hydrocarbons. The discontinuity interface, a small-scale reservoir discontinuity comparing with the fault, is generally below the seismic vertical resolution ([Formula: see text]). The key to the study of the discontinuity interface is to characterize the variation of plane characteristics of sediments between isochronous seismic horizons. Therefore, we can extract seismic attributes between isochronous seismic horizons to analyze the subtle changes of seismic data, which reflect the distribution of the discontinuity interfaces. In the experiment of gradient vector to detect discontinuity interface in seismic attribute, the authors find that the width of the discontinuity interface is caused by the “lens” shape of the sandstone itself. This phenomenon is an indicator of the impermeability of the discontinuity interface. Here, we have developed a two-step method. First, we use the erosion operator of mathematical morphology to locate the skeleton of the discontinuity interface with the steering of the gradient direction. Second, we measured the width of the discontinuity interface to indicate its impermeability. The application to a field data set demonstrates that the results of this proposed method are consistent with the production data of the wells. The proposed method characterizes the reservoir heterogeneity refined from sandstone sets to a single sandstone bed, which improves the resolution of seismic geologic interpretation.