Channel Characterization in Sandstone Formation Using Pressure Transient Analysis - A Practical Overview to Define Geological Attributes

Abstract

Understanding reservoir systems is of significant importance in optimal exploitation, development plans and management strategies. Sandstone reservoirs consisting of stacked channel deposits are known for their heterogeneity and varying depositional facies adding to their complexity. This paper will focus on the characterization of sandstone reservoirs in channel environments using pressure transient analysis coupled with seismic attributes and stratigraphic features. Proper channel mapping and precise predications of the spatial distribution of sand bodies is a challenging process. Pressure transient analysis can identify the existence of channel features, reservoir properties, extent of formation properties, and boundary conditions. However, linear flow identified in well tests does not predict the direction of these channels. The proposal integrates both static and dynamic reservoir data along with regional geological interpretation which plays a vital role in the proper characterization and modeling of these channel systems. The findings of this study enrich a deeper reservoir understanding of the structural features’ extent, continuity and connection. Different pressure regimes were observed in both vertical and lateral directions showing the complex heterogeneity in between layers and irregular channel distribution patterns. This response is similarly exhibited in the reservoir flow capacity which resulted in abrupt shifts in reservoir characteristics as evident in the acquired pressure transient data. It is proposed to revise seismic attributes and the use of stratigraphic core data to validate the conceptual connections between this complex channel system. In addition, findings are used to re-distribute formation properties in order to improve future reservoir models. The combined use of dynamic and static data improves the regional interpretation of challenging sandstone systems. Adequate understanding of the spatial distribution of the sand facies and reservoir properties ensures effective well placement and development strategies.