Evaluation of selected seismic attributes and structural interpretation of Miano area using limited 2D seismic data (T-1458) (MFN 3328)

Abstract

Miano gas field located in Lower Indus Basin, Pakistan, is chosen to perform attribute analysis and check its effectiveness. Before performing attribute analysis, both manual and digital interpretation was done for the study area. Five horizons namely, Sui Main Limestone, Parh Limestone, Lower Goru Shale interval, B Sand Interval and Chiltan Limestone were marked. Contour maps were generated both in time and depth domains. Negative flower structures have been interpreted which are conforming to transtensional tectonic regime in the area. B Sand Interval is acting as reservoir for this field. At the level of productive sands, no structural closure is recognized in the study area indicating subtle trap. Attributes including variance, instantaneous amplitude, instantaneous frequency, cosine of phase, isochron thickness and maximum amplitude have been tested and their effectiveness verified. Apart from these attributes, several other attributes were also run. But, only those attributes are selected that gave unique and concluding results on the data provided for the study. There were certain restrictions of availability with respect to seismic and well data, therefore implementation of technique (attribute analysis) resulted in limited conclusions. Faults (structural) and reflection geometries (stratigraphic) were seen on selected attributes particularly on variance, cosine of phase and instantaneous amplitude. In this gas prone region the response of sweetness attribute was not encouraging due to quality of the data not optimized to the required level with regard to processing.