On-going development of five geochemical monitoring technologies for onshore CCS

A critical aspect of Carbon Capture and Storage (CCS) will be the ability to adequately monitor the injection site, both to ensure public and environmental safety and for “carbon credit auditing”. In the unlikely event of a leakage in the near-surface environment, the study of natural CO2 emanations in volcanic and geothermal environments have shown that the gas will tend to migrate along the path of least resistance and create spatially restricted “hotspot” leaks at the ground surface that can be challenging to find and quantify. For this reason, innovative technologies are required to improve our ability to detect, locate and characterize such features. To address this need our group is developing geochemical monitoring tools that confront the significant challenges associated with spatial, analytical and temporal resolution and sensitivity. Here we describe on-going work focused on increasing the Technology Readiness Level (TRL) of five prototypes and concepts developed by the Tectonics and Fluid Chemistry Lab (TFCL) at Sapienza University of Rome: the GasPro, Mapper, Multipla, Well-Star, and SWiM systems

Mapping and quantifying CO2 leakage using the Ground CO2 Mapper

The standard method for mapping and quantifying CO2 leakage flux from the ground surface to the atmosphere involves performing numerous point flux measurements using the accumulation chamber technique and then applying geostatistical interpolation to infer spatial distribution and estimate total mass transfer. Monte Carlo simulations using the program MCFlux have recently demonstrated, however, that uncertainty in the resultant estimate can be large if the chosen sample spacing is insufficient to capture the spatial complexity and size distribution of the leakage anomalies. In an effort to reduce this uncertainty we have developed a new tool, called the Ground CO2 Mapper, that rapidly measures the concentration of CO2 at the ground surface as a proxy for flux. Recently published results have illustrated the capabilities of the Mapper in terms of sensitivity and spatial resolution, as well as possible influencing parameters such as wind strength. The present work examines the potential of combining Mapper results with point flux measurements (using multivariate geostatistics) to improve data interpretation, with the MCFlux program being used once again to assess uncertainty in the final estimates

Along strike preorogenic thickness variation and onlapping geometries control on thrust wedge evolution: insight from sandbox analogue modelling

Abstract: Thickness variation of sedimentary sequences is largely viewed as a controlling factor on the evolution of orogenic wedges; among the different structural and stratigraphic features generating thickness variation, we focused our analysis on the onlapping geometries, using laboratory sandbox experiments. The aim was trying to describe how a common sedimentary configuration could influence thrusts geometry and mode of accretion. Model results showed that onlapping geometries in pretectonic sediments cause a great complexity, dominated by curvilinear thrusts, back thrust and out-ofsequence thrusts. They also influence mode of accretion, generating diachronous thrusting along strike, reactivation and under-thrusting alternating to simple piggy-back sequence. Our modeling results are compared with natural examples from the Apennines, the southern Pyrenees, the Pindos (Greece) and the West Spitsbergen (Greenland) fold and thrust belts, among many others, where strain localization and diachronic thrusting affecting thrust propagation in correspondence to complex geometries both in the pre-orogenic stratigraphy and in the upper crust

On-going and future research at the Sulcis site in Sardinia, Italy. Characterization and experimentation at a possible future CCS pilot

National Italian funding has recently been allocated for the construction of a 350 MWe coal-fired power plant / CCS demonstration plant in the Sulcis area of SW Sardinia, Italy. In addition, the recently approved EC-funded ENOS project (ENabling Onshore CO2 Storage in Europe) will use the Sulcis site as one of its main field research laboratories. Site characterization is already ongoing, and work has begun to design gas injection experiments at 100-200 m depth in a fault. This article gives an overview of results to date and plans for the future from the Sapienza University of Rome research group

Preliminary results of geological characterization and geochemical monitoring of Sulcis Basin (Sardinia), as a potential CCS site

The Sulcis Basin is an area situated in SW Sardinia (Italy) and is a potential site for the development of CCS in Italy. This paper illustrates the preliminary results of geological characterization of fractured carbonate reservoir (Miliolitico Fm.) and the sealing sequence, composed by clay, marl and volcanic rocks, with a total thickness of more than 900 m. To characterize the reservoircaprock system an extensive structural-geological survey at the outcrop was conducted. It was also performed a study of the geochemical monitoring, to define the baseline conditions, measuring CO2 concentrations and flux in the study site

Gas migration along fault systems and through the vadose zone in the Latera caldera (central Italy): Implications for CO2 geological storage

A clear and detailed understanding of gas migration mechanisms from depth to ground surface is fundamental to choose the best locations for C02 geological storage sites, to engineer them so that they do not leak, and to select the most appropriate monitoring strategy and tools to guarantee public safety. Natural test sites (or "natural analogues") provide the best opportunity to study migration mechanisms, as they incorporate such issues as scale, long-time system evolution, and interacting variables that cannot be adequately addressed with laboratory studies or computer models. To this end the present work examines the migration to surface of deep, naturally produced C02 along various buried and exposed faults in the Latera caldera (central Italy) by integrating structural geology and near-surface gas geochemistry surveys. Results show how gas migration is channelled along discrete, high -permeability pathways within the faults, with release typically occurring from spatially restricted gas vents. Size, distribution, and strength of these vents appear to be controlled by the evolution and deformation style of the fault, which is in turn linked to the rheology of the lithological units cut by the fault. As such gas migration can change drastically along strike. Gas migration in the vadose zone around these vents is also discussed, focussing on how the physical-chemical characteristics of various species (C02, CH4, and He) control their spatial distribution and eventual release to the atmosphere. (c) 2008 Elsevier Ltd. All rights reserved

Making the Communication of CCS more "human"

CCS communication has proven a tough challenge, particularly for the difficulty in raising interest for the technology, which is still unknown to the majority of the population, and for the complexity of conveying information about its potential for reducing emissions. In this paper we present a research based effort for bringing CCS nearer to people, through visual material developed taking into account emotional needs related to the technology. The production of a short introductory film on CCS is illustrated and its testing with a sample of 700 high school students

Static modelling of geological structures for carbon sequestration purposes in the Lorestan area of Iran

One of the most important methods aimed at climate mitigation technology is carbon geological sequestration. During the process of site selection and characterization required for evaluation of capacity storage potential of a given region, geological static modelling plays an essential role by providing a better understanding of the structure in terms of petrophysical and geological characteristics. This work presents the 3D geological model of several anticlines in the Lorestan area (northwestern Zagros), to evaluate their carbon storage capacity potential. The 3D geological model is based on seismic data and well-log data from 2 wells drilled in the area, kindly provided by the National Iranian Oil company (NIOC). Preliminary well logs analysis allowed to identify potential target formations by considering pivotal criteria of CO2 storage such as depth, porosity, and other petrophysical characteristics. The 3D model will be followed by the construction of a geocellular model that will be populated by petrophysical data obtained from well logs. The reconstructed volume will be then used for injection simulations to obtain an evaluation of the volume available for storage. The dynamic simulation will also provide and support the evaluation of other important aspects such as the injection strategies and efficiency coefficient, comparing the observed theoretical and effective capacity

Cap rock efficiency of geothermal systems in fold-and-thrust belts:evidence from paleo-thermal and structural analyses in Rosario de La Frontera geothermal area (NW Argentina)

Cap rock characterization of geothermal systems is often neglected despite fracturing may reduce its efficiency and favours fluid migration. We investigated the siliciclastic cap rock of Rosario de La Frontera geothermal system (NW Argentina) in order to assess its quality as a function of fracture patterns and related thermal alteration. Paleothermal investigations (XRD on fine-grained fraction of sediments, organic matter optical analysis and fluid inclusions on veins) and 1D thermal modelling allowed us to distinguish the thermal fingerprint associated to sedimentary burial from that related to fluid migration. The geothermal system is hosted in a Neogene N-S anticline dissected by high angle NNW- and ENE-striking faults. Its cap rock can be grouped into two quality categories: ● rocks acting as good insulators deformed by NNW–SSE and E–W shear fractures, NNE-SSW gypsum- and N-S striking calcite-filled veins formed during the initial stage of anticline growth. Maximum paleo-temperatures (<60°C) were experienced during deposition to folding phases. ● rocks acting as bad insulators deformed by NNW-SSE fault planes and NNW- and WNW-striking sets of fractures associated to late transpressive kinematics. Maximum paleo-temperatures higher than about 115°C are linked to fluid migration from the reservoir to surface (with a reservoir top at maximum depths of 2.5 km) along fault damage zones. This multi-method approach turn out to be particularly useful to trace the main pathways of hot fluids and can be applied in blind geothermal systems where either subsurface data are scarce or surface thermal anomalies are lacking