Explorational Rock Physics and Seismic Reservoir Prediction

Course Description

The field of rock physics represents the link between qualitative geologic parameters and quantitative geophysical measurements. Increasingly over the last decade, rock physics stands out as a key technology in petroleum geophysics, as it has become an integral part of quantitative seismic interpretation. Ultimately, the application of rock physics tools can reduce exploration risk and improve reservoir forecasting in the petroleum industry.

This course covers fundamentals of rock physics, ranging from basic laboratory and theoretical results to practical recipes that can be immediately applied in the field, presenting qualitative and quantitative tools for understanding and predicting the effects of lithology, pore fluid types and saturation, stress and pore pressure, fractures and temperature on seismic velocity and attenuation.

The importance and benefit of linking rock physics to geologic processes, including depositional and compactional trends as well as tectonic uplift and unloading, are key to this course, which demonstrates in detail how to build so-called rock physics templates that can be used to interpret both well log and seismic inversion data in terms of geological trends and reservoir properties. It is important in exploration and appraisal to extrapolate away from existing wells, taking into account how the depositional environment changes as well as burial depth trends. In this way rock physics can better constrain the geophysical inversion and classification problem in underexplored marginal fields, surrounding satellite areas, or in new frontiers.

In particular, we focus on how rock physics properties, fluid sensitivities and associated seismic signatures change as we go from soft sediments in the shallow subsurface to well consolidated rocks that have undergone more severe mechanical and chemical compaction, and even uplift and brittle deformation. Likewise, we show how seismic amplitudes can change drastically as we go from one depositional environment to another, for instance in a channel-levee complex as we go from central axis to the levee and overbank area.

The course includes practical examples and case studies, as well as suggested workflows, where rock physics models are combined with well log and prestack seismic data, sedimentologic information, inputs from basin modeling and statistical techniques to predict reservoir geology and fluids from seismic amplitudes.

Course Objectives

Upon completion of the course participants will understand:

• The link between geologic processes and rock physics properties;
• Pore fluid / rock interactions during wave propagation;
• Upscaling and heterogeneous reservoirs;
• How to build their own rock physics template.

The ultimate goal is to improve the understanding of seismic amplitudes and predict geologic and reservoir parameters from seismic inversion data and at the same time create awareness about limitations and pitfalls.

Course Outline

• Basic rock physics theory and relations; 
• Fluid and lithology substitution for reservoir rocks;
• Pore fluid — rock interactions during wave propagation;
• How to build a Rock Physics template;
• Upscaling and seismic signatures of heterogeneous reservoirs;
• Introduction to shale and carbonate rock physics.

Participants’ Profile

The course is intended for geophysicists, geologists and petrophysicists who wish to be involved in quantitative seismic interpretation. The course will focus on how rock physics can be used in exploration but many aspects will also be relevant for production and 4D geophysics.

Prerequisites

Fundamental understanding of physics and mathematics. Educational background and/or practical experience in geology, geophysics and/or petrophysics.

About the Instructors

Per Avseth is a geophysical advisor at Tullow Oil in Oslo, Norway, and adjunct professor in geophysics at the Norwegian University of Science and Technology (NTNU) in Trondheim, Norway. Per received his M.Sc. in Applied Petroleum Geosciences from NTNU in 1994, and his Ph.D. in Geophysics from Stanford University, California, in 2000. Per worked as a research geophysicist at Norsk Hydro in Bergen, 2001-2006. Per’s research interests include applied rock physics and AVO analysis, for quantitative seismic exploration and reservoir characterization.

Tor Arne Johansen is a full professor in Reservoir Geophysics at the Department of Earth Science, University of Bergen, and a scientific advisor for NORSAR. He received his PhD in Geophysics in 1990 from Bergen University. His research interests cover remote sensing techniques, rock physics, seismic modelling and processing.