Saju Menacherry

PhD student - Geo

Biography

Saju Menacherry was awarded a Master of Science in geology from Kerala University, Kerala, India in 1991. He joined ABN Minerals Ltd., as an Exploration Geologist and worked for 8 years. In 2000 he has joined Penrice Soda Products Ltd., Adelaide as a Geochemist and in 2002 was employed to Mobil Oil Australia Pty Ltd., as a Chemist. He enrolled in a Ph.D program at the Australian School of Petroleum (ASP) in 2003. His current research topic is ÒSource to SinkÓ Sedimentation and Petrology of a Modern Dryland Fluvial Reservoir Analogue, Western Lake Eyre, Central Australia. Saju is a member of the AAPG, EMD, SEPM and PESA.

PhD research project

Source to Sink" Sedimentation and Petrology of a Modern Dryland Fluvial Reservoir Analogue, Western Lake Eyre, Central Australia.

Supervisors: Tobi Payenberg, Simon Lang (Woodside), William Heins (ExxonMobil)

Scholarship support: ExxonMobil

Project support: ExxonMobil

Project Description

A considerable volume of the world's hydrocarbon reserves resides in reservoirs attributed to dryland systems. The uncertainty surrounding the spatial and temporal variations in sand distribution, reservoir quality and likely geometry can all be reduced or quantified through the study of sand generation and evolution. The focus of the thesis will be on the impact of the provenance and sediment transport history on potential reservoir quality for a variety of depositional facies in an ephemeral river system. These analogue data can be used in a qualitative and quantitative manner when modelling porosity, permeability, depositional processes and diagenesis.

For the "Source to Sink" sedimentation and petrology study of a modern dryland fluvial depositional settings analogue, a small river network, Umbum Creek, western Lake Eyre Basin, Central Australia was selected. The Lake Eyre basin is a wide, shallow, low gradient, intracratonic basin that records a complex history of alluvial, lacustrine and aeolian sedimentation, reflecting several tens of million years of environmental change.

The first part of this thesis is focused on the different basin evolution in the study area to define the processes that control the evolution of sediment composition regionally, and the extent to which cratonic blocks and their sedimentary mantles may be viewed as a dynamically coupled evolutionary system. A basin evolution study through petrography and isopach thickness maps provides the palaeogeographical reconstructions and inference of sediment source routing from past to the present day basins.

The second part of this thesis is focused on the analysis of modern sediment mineralogy, provenance and fluvio-aeolian interaction in a dryland fluvial setting. The main examination and evaluation in modern sediment mineralogy analysis is to answer the question how and what are the major control on sediment composition dominated by complete closed-system sediment reworking, non-reworking sediment (i.e., continuous sediment yielding from the metamorphic and igneous source rocks) and the mixing effect of fluvio-aeolian sand grains. Provenance exerts a significant influence on reservoir quality by controlling the composition of sediments, which in turn impacts both mechanical properties and chemical diagenetic processes that decrease, preserve or increase porosity and permeability.

The third part of this thesis reviews and discusses early diagenetic processes and how they affect reservoir characteristics in the sub-surface. A fundamental challenge in clastic reservoir characterization is predicting the spatial distribution of early diagenesis, which is often a critical control on porosity and permeability heterogeneity. Understanding the processes and products of diagenesis is thus a critical component in the analysis of the evolution of sedimentary basins, and has practical implications for subsurface porosity destruction, preservation and generation. Thus, the study outcome of early diagenesis of modern sediments can be correlated with subsurface reservoir qualities. This in turn is of great relevance for the forward predictions of subsurface reservoir qualities to the petroleum industry.

The significance of the three parts in this thesis is to examine and evaluate reservoir quality aspects based on basin evolution, sediment mineralogy and early diagenetic processes. The study of the modern sediment characteristics and its evolutionary history enables a better understanding of the different types of sediment flux into the modern day sedimentary basin. Reservoir quality of modern sediment can be identified and defined from its mineralogy. In order to integrate the above approaches better, the thesis concentrated not only on establishing the generation of sediment from its provenance, but also focused on when, where and how sediments form, because all these are linked with source to sink sedimentation and, ultimately, with reservoir quality.

Saju is part of the research group RARG (Reservoir Analogues Research Group)