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Underground gas storage (UGS) and CO 2 sequestration (CCS) are strategic practices to address the growing demand of energy and reduction of greenhouse gas emission. There is an interest from the energetic, economic, and environmental viewpoint to store as much gas as possible consistent with the requirement of a safe disposal. A transversely isotropic geomechanical model is developed and calibrated using the vertical and horizontal displacements measured by SAR-based interferometry over an exhausted gas field located in Northern Italy where UGS is active since 1986. The predictions show that a maximum storage pressure up to 140% p i , p i being the virgin fluid pore pressure, may yield a 400% increase of the gas stored relative to p i provided that an accurate assessment of the parameters defining the yield surface, i.e. friction angle and cohesion in the Mohr–Coulomb criterion, is performed for the reservoir formation. No appreciable risk for the integrity of the sealing layer is ever expected, along with a negligible impact on the ground structures. Land motion does not exceed few centimeters with the differential displacements safely below the bound required by structural safety.

[1] Underground gas storage (UGS) in depleted hydrocarbon reservoirs is a strategic practice to cope with the growing energy demand and occurs in many places in Europe and North America. In response to summer gas injection and winter gas withdrawal the reservoir expands and contracts essentially elastically as a major consequence of the fluid (gas and water) pore pressure fluctuations. Depending on a number of factors, including the reservoir burial depth, the difference between the largest and the smallest gas pore pressure, and the geomechanical properties of the injected formation and the overburden, the porous medium overlying the reservoir is subject to three-dimensional deformation with the related cyclic motion of the land surface being both vertical and horizontal. We present a methodology to evaluate the environmental impact of underground gas storage and sequestration from the geomechanical perspective, particularly in relation to the ground surface displacements. Long-term records of injected and removed gas volume and fluid pore pressure in the “Lombardia” gas field, northern Italy, are available together with multiyear detection of vertical and horizontal west-east displacement of the land surface above the reservoir by an advanced permanent scatterer interferometric synthetic aperture radar (PSInSAR) analysis. These data have been used to calibrate a 3-D fluid-dynamic model and develop a 3-D transversally isotropic geomechanical model. The latter has been successfully implemented and used to reproduce the vertical and horizontal cyclic displacements, on the range of 8–10 mm and 6–8 mm, respectively, measured between 2003 and 2007 above the reservoir where a UGS program has been underway by Stogit-Eni S.p.A. since 1986 following a 5 year field production life. Because of the great economical interest to increase the working gas volume as much as possible, the model addresses two UGS scenarios where the gas pore overpressure is pushed from the current 103%pi, where pi is the gas pore pressure prior to the field development, to 107%pi and 120%pi. Results of both scenarios show that there is a negligible impact on the ground surface, with deformation gradients that remain well below the most restrictive admissible limits for the civil structures and infrastructures.

Recent improvements in instrumentation and surveying techniques have made time-lapse gravity and gravity gradient surveys a cost-effective and useful method for gas and hydrocarbon monitoring. The objective of this study was to investigate if time-varying gravity measurements can be correlated to the gas storage activities or not.

A03 HQ & FULL FIDELITY 3D LAND SEISMIC DATA ACQUISITION – EXPERIENCES AND APPROACHES IN HIGH INHABITED AREAS Introduction 1 The necessity of high resolution 3D seismic data is of paramount importance. Today thanks to the very dramatic development of electronics in the last few years the single sensor/single channel acquisition seems to be the optimal tool. Unfortunately the effective drawbacks discouraging the actual use of this technology are the operative constraints and high costs mainly due to the large recording channel number and the huge amount of data to be managed. This is particularly true in highly inhabited areas

The Cavone Field is an Agip-operated oil field located in the Po Valley of ltaly. lt produces from a Mesozoic carbonate reservoir Iying at a moderate depth of approximately 2900m. Field recovery rates are relatively low, and significant quantities of mobile oil could remain in place after primary and secondary recovery operations if trapping and production rnechanisms in the reservoir are poorly understood.