First Break - Volume 29, Issue 1, 2011

Jean-Georges Malcor, recently appointed CEO of CGGVeritas, envisages seismic imaging of the subsurface in the next 10 years becoming increasingly important through the full cycle of exploration and production.

Bob Peebler, CEO, ION Geophysical and well known E&P industry commentator, sees compute power as a major driver for change in the next decade.

Eldad Weiss, CEO, Paradigm.

Prof Anton Ziolkowski, PGS professor of petroleum geoscience, Edinburgh University.

Rutt Bridges is a leading geoscientist of his generation, venture capitalist, and a significant figure in the politics of Colorado. In this article he reviews some inconvenient truths about the timely implementation of CCS projects in the US, some of which may resonate in other countries seeking CO2 reduction measures.

Alana Robinson and Thomas L. Davis show how results of seismic monitoring of an EOR project can be applied to seismic monitoring of CO2 sequestration projects to ensure efficient CO2 distribution within the reservoir.

Lingli Wei argues that when estimating the amount of dissolved CO2 during the life cycle of a carbon storage project, it is important to model the processes involved including variability of reservoir/aquifer permeability, salinity, and capillary pressures, with appropriate simulation grid sizes and time steps.

Trevor Richards of Denbury Resources describes an ongoing project involving the injection of CO2 for tertiary oil recovery from the Delhi field in Louisiana. The 4D seismic monitoring experience could potentially provide valuable research data for future CCS projects.

Philip Neri argues that the emerging importance of pre-stack seismic data in interpretation and characterization workflows has created a major requirement for innovative data management solutions.

There are several methods based on seismic reflection data for locating natural fracture systems and predicting their permeability. The only practical way to compare the predictive accuracy of each method is to evaluate the results from different oilfields using data from several wells in each field. We have studied methods based on reflection amplitude, reflection curvature and its derivatives, coherency cube, spectral decomposition, ant tracking technology, azimuthal anisotropy of P-wave velocity, and duplex wave migration (DWM) amplitude cube analysis. Here we report and analyse the results of each method for carbonate fracture plays. The study involved the analysis of several 3D data volumes from two different areas using results from hundreds of wells which have been drilled over the last three decades. We conclude that the DWM technique is the most reliable method for fracture permeability prediction. Lukoil planned a 2010 drilling programme for horizontal wells based on this DWM technology, and the first exploration results show that the locations of fracture systems were predicted with an accuracy of 25 m.

An increasing number of low-enthalpy geothermal power plants are being implemented in the Munich area with holes drilled into the Malm Formation (Upper Jurassic carbonates) to depths greater than 3000 m, where temperatures in excess of 100°C are encountered. Optimal development of geothermal productivity requires exploration of the geological structure, as well as information on the karstification of the Malm. Seismic surveys, including reprocessed older 2D lines from hydrocarbon exploration, new 2D lines filling gaps, and 3D surveys, are increasingly used for geothermal exploration. A geothermal power plant at Unterhaching, near Munich, has been producing heat and electrical power since 2009. A high resolution 3D seismic volume has been acquired over an area of 27 km2 for hydrological modelling purposes at the Gt2 reinjection well, located within the southern suburbs of Munich. First results show preferential hydraulic pathways along reactivated fault zones within the Malm reservoir which were partly active until the Aquitanian (Early Miocene). Additionally, a great number of sinkholes have been identified at the top Malm, located along fault zones which constitute new possible targets for geothermal exploration.

We present new results of the recently introduced approach to surface-multiple attenuation through sparse inversion. This method aims to attenuate surface multiples of all periodicities without the need for an adaptive subtraction or a near offset extrapolation. The aim of our paper is twofold. First, we subject the sparse inversion method to data beyond previously published proof-of-principle models and present results on highly complex 2D synthetics and real data, demonstrating that sparse inversion may, in principle, serve as a powerful tool to attenuate short and long period multiples in complex settings. We illustrate the competitive nature of the sparse inversion predictions by benchmarking the method’s results to standard processing flows. In addition, we demonstrate the correspondence of the estimated primaries to the underlying impedance models. Next, we show results of a 2D sparse inversion approach to real 3D deep-marine data and demonstrate, through a further synthetic study, that the presence of cross-line dip leads to a time shift of the predicted multiples, resulting in reduced multiple attenuation. Our results confirm that future developments of this technique will require a full 3D approach in order for the sparse inversion method to be widely effective in practice.