Geology topics

A. Raef

Publications and source records attributed to A. Raef.

3 recordsLinked to original sources

USGS2011

Rock formation characterization for CO2-EOR and carbon geosequestration; 3D seismic amplitude and coherency anomalies, Wellington Field, Kansas, USA

In this paper, we present a workflow for a Mississipian carbonates characterization case-study integrating post-stack seismic attributes, well-logs porosities, and seismic modeling to explore relating changes in small-scale "lithofacies" properties and/or sub-seismic resolution faulting to key amplitude and coherency 3D seismic attributes. The main objective of this study is to put emphasis on reservoir characterization that is both optimized for and subsequently benefiting from pilot tertiary CO2-EOR in preparation for future carbon geosequestration in a depleting reservoir and a deep saline aquifer. The extracted 3D seismic coherency attribute indicated anomalous features that can be interpreted as a lithofacies change or a sub-seismic resolution faulting. A 2D finite difference modeling has been undertaken to understand and potentially build discriminant attributes to map structural and/or lithofacies anomalies of interest especially when embarking upon CO2-EOR and/or carbon sequestration monitoring and management projects. ?? 2011 Society of Exploration Geophysicists.

SEG Technical Program Expanded Abstracts↗

USGS2009

Land 3D-seismic data: Preprocessing quality control utilizing survey design specifications, noise properties, normal moveout, first breaks, and offset

The recent proliferation of the 3D reflection seismic method into the near-surface area of geophysical applications, especially in response to the emergence of the need to comprehensively characterize and monitor near-surface carbon dioxide sequestration in shallow saline aquifers around the world, justifies the emphasis on cost-effective and robust quality control and assurance (QC/QA) workflow of 3D seismic data preprocessing that is suitable for near-surface applications. The main purpose of our seismic data preprocessing QC is to enable the use of appropriate header information, data that are free of noise-dominated traces, and/or flawed vertical stacking in subsequent processing steps. In this article, I provide an account of utilizing survey design specifications, noise properties, first breaks, and normal moveout for rapid and thorough graphical QC/QA diagnostics, which are easy to apply and efficient in the diagnosis of inconsistencies. A correlated vibroseis time-lapse 3D-seismic data set from a CO 2 -flood monitoring survey is used for demonstrating QC diagnostics. An important by-product of the QC workflow is establishing the number of layers for a refraction statics model in a data-driven graphical manner that capitalizes on the spatial coverage of the 3D seismic data. ?? China University of Geosciences (Wuhan) and Springer-Verlag GmbH 2009.

Conference Paper↗

USGS2005

4D seismic to image a thin carbonate reservoir during a miscible CO2 flood: Hall-Gurney Field, Kansas, USA

Time-lapse (TL) seismic monitoring has proven a valuable tool for reservoir management. If available in a timely and cost-effective manner, it can be incorporated into a dynamic reservoir management approach, spec-ifically in terms of assessing sweep efficiency through constraining reservoir simulations, quantifying compartmentalization, and enhancing the placement of infill wells. Thus, cost-effectiveness, rapid turnaround time, and sensitivity of the seismic response to subtle changes in reservoir properties evident in production data are critical assets of a robust and economic TL application. Successful applications of TL monitoring have been predominantly offshore—Gulf of Mexico and North Sea—in thick clastic reservoirs characterized as low technical risk. Changes in TL seismic images as a direct result of enhanced oil recovery operations in low compressibility, “stiff” carbonate reservoirs are so small that distinguishing reservoir fluid changes from background noise on seismic attribute maps is challenging at best and many times impossible. Consequently, reservoirs predicted to produce weak TL anomalies associated with enhanced oil recovery (EOR) operations are classified as high-risk cases and languish in what has been designated the “stretch portfolio” of time-lapse application in reservoir management.

Kansas↗