Work-Flow for Selecting the best seismic Attributes for effective Basin Analysis

Abstract

In an effective basin analysis, one crucial step is how to delineate the geometry of source, reservoir and seal rocks and understand their physical properties in an efficient way. Since well and seismic data is normally limited, then the challenge is how to select the best, most applicable seismic attributes which suit the unique geological conditions of the studied basin. The problem is that there are abundant seismic attributes available and not every attribute is applicable for all geological conditions. Thus the selection of the best applicable attributes is often a very time consuming effort with unclear final results. This paper discusses a workflow for intelligent and efficient selection of the best seismic exploration techniques for an effective basin analysis. The work-flow is developed based on the criteria of target characterization objectives (geometry delineation and/or physical properties description), the nature of the seismic data, the mathematical-physical basis of each attribute and their geological meaning. Cases studies from three major producing basins in Indonesia: Central Sumatra, South Sumatra and Northwest Java basins are discussed to show the efficient applicability of the work-flow. In the Central Sumatra basin the challenge is to map fluvio-deltaic sand deposits which are undetectable using normal seismic. In the Northwest Java basin, the objective is to map sand channels controlled by growth faults as well as carbonates where the porosity is controlled by sealevel changes. In the South Sumatra basin, the primary focus is to map the net-pay and porosity of sands which onlap granitic basement and form a combination of structural and stratigraphic traps. The study concludes that to find the best attributes, understanding the relationship between the targeted reservoir properties and the nature of elastic properties is very important. Key-words: seismic attributes, basin analysis, field exploration *Institute of Technology Bandung INTRODUCTION Effective basin analysis is important for successful petroleum basin exploration. The prime objective in basin analysis is generally to map the geometry of targeted layers and understand the physical properties in an efficient way. On the other hand, the common problem faced during exploration is that the availability of well and seismic data is limited. Therefore the challenge is how to select the best, most applicable seismic techniques which suit the objective and unique geological conditions of the studied basin. Nowadays there are abundant seismic attributes available but not every attribute is applicable for all geological conditions. The selection of the best applicable attribute is often a very time consuming effort with unclear final results. This paper discusses a work-flow for intelligent and efficient selection of the best seismic exploration techniques for effective basin analysis. The workflow is developed based on the criteria of target characterization objectives (geometry delineation and/or physical properties description), the nature of the seismic data, the mathematical-physical basis of each attribute, and their geological meaning. Case studies from three major producing basins in Indonesia: Central Sumatra, South Sumatra and Northwest Java basins are discussed to show the efficient applicability of the work-flow.