The U-tube sampling methodology and real-time analysis of geofluids

The U-tube geochemical sampling methodology, an extension of the porous cup technique proposed by Wood [1973], provides minimally contaminated aliquots of multiphase fluids from deep reservoirs and allows for accurate determination of dissolved gas composition. The initial deployment of the U-tube during the Frio Brine Pilot CO{sub 2} storage experiment, Liberty County, Texas, obtained representative samples of brine and supercritical CO{sub 2} from a depth of 1.5 km. A quadrupole mass spectrometer provided real-time analysis of dissolved gas composition. Since the initial demonstration, the U-tube has been deployed for (1) sampling of fluids down gradient of the proposed Yucca Mountain High-Level Waste Repository, Armagosa Valley, Nevada (2) acquiring fluid samples beneath permafrost in Nunuvut Territory, Canada, and (3) at a CO{sub 2} storage demonstration project within a depleted gas reservoir, Otway Basin, Victoria, Australia. The addition of in-line high-pressure pH and EC sensors allows for continuous monitoring of fluid during sample collection. Difficulties have arisen during U-tube sampling, such as blockage of sample lines from naturally occurring waxes or from freezing conditions; however, workarounds such as solvent flushing or heating have been used to address these problems. The U-tube methodology has proven to be robust, and with careful consideration of the constraints and limitations, can provide high quality geochemical samples

Advanced Monitoring Technology Report For an Integrated Risk Management and Decision-Support System (IRMDSS) for Assuring the Integrity of Underground Natural Gas Storage Infrastructure in California

Previous studies have shown that underground natural gas storage (UGS) in California has served a critical role in meeting energy demands in California, and there is no immediate alternative. Therefore, it is important to ensure the safety of UGS infrastructure, especially considering that many of the UGS sites are using a combination of new and old wells, some of which were installed decades ago and re-purposed for UGS. The purpose of this project is to develop an integrated risk management and decision support system (IRMDSS) to manage risks associated with this heterogeneous subsurface infrastructure. The approach of the IRMDSS is to take advantage of the predictive capability of mechanistic models, with support from data acquired from advanced monitoring technologies, for evaluation and analysis of various incident scenarios or potential threats. In this project, we have demonstrated data collection by four advanced monitoring technologies. These include two downhole monitoring technologies, distributed temperature sensing (DTS), distributed acoustic sensing (DAS), and two surface monitoring technologies, Interferometric Synthetic Aperture Radar (InSAR), and unmanned aerial vehicle (UAV). DTS and DAS data are collected continuously, providing information related to individual wells. InSAR data are collected frequently (~every 24 days), and UAV data can be collected as frequently as is practical depending on need. Together, these subsurface and surface monitoring technologies provide near real-time information useful for risk management of UGS facilities

Laboratory measurements on core-scale sediment/hydrate samples topredice reservoir behavior

Measurements on hydrate-bearing laboratory and field samplesare necessary in order to provide realistic bounds on parameters used innumerically modeling the production of natural gas from hydrate-bearingreservoirs. The needed parameters include thermal conductivity,permeability, relative permeability-saturation(s) relationships, andcapillary pressure-saturation(s) relationships. We have developed atechnique to make hydrate-bearing samples ranging in scale from coreplug-size to core-size in the laboratory to facilitate making thesemeasurements. In addition to pressure and temperature measurements, weuse x-ray computed tomography scanning to provide high-resolution dataproviding insights on processes occurring in our samples. Several methodsare available to make gas hydrates in the laboratory, and we expect thatthe method used to make the hydrate will impact the behavior of thehydrate sample, and the parameters measured

Stepping into the Same River Twice: Field Evidence for the Repeatability of a CO2 Injection Test

A single well characterisation test was conducted at the CO2CRC Otway storage site in Victoria, Australia, in 2011 and repeated in 2014. The near-well permeability was found to have declined nearly 60% since the 2011 test, while the residual saturation inferred from a variety of techniques was lower in 2014. There was a significant change in water chemistry, suggesting an alteration of near-well reservoir properties. Possible reasons for these changes are explored, and the implications for other field tests are discussed

Using oxygen isotopes to quantitatively assess residual CO2 saturation during the CO2CRC Otway Stage 2B Extension residual saturation test

Residual CO2 trapping is a key mechanism of secure CO2 storage, an essential component of the Carbon Capture and Storage technology. Estimating the amount of CO2 that will be residually trapped in a saline aquifer formation remains a significant challenge. Here, we present the first oxygen isotope ratio (δ18O) measurements from a single-well experiment, the CO2CRC Otway 2B Extension, used to estimate levels of residual trapping of CO2. Following the initiation of the drive to residual saturation in the reservoir, reservoir water δ18O decreased, as predicted from the baseline isotope ratios of water and CO2, over a time span of only a few days. The isotope shift in the near-wellbore reservoir water is the result of isotope equilibrium exchange between residual CO2 and water. For the region further away from the well, the isotopic shift in the reservoir water can also be explained by isotopic exchange with mobile CO2 from ahead of the region driven to residual, or continuous isotopic exchange between water and residual CO2 during its back-production, complicating the interpretation of the change in reservoir water δ18O in terms of residual saturation. A small isotopic distinction of the baseline water and CO2 δ18O, together with issues encountered during the field experiment procedure, further prevents the estimation of residual CO2 saturation levels from oxygen isotope changes without significant uncertainty. The similarity of oxygen isotope-based near-wellbore saturation levels and independent estimates based on pulsed neutron logging indicates the potential of using oxygen isotope as an effective inherent tracer for determining residual saturation on a field scale within a few days

B-Virus (Cercopithecine herpesvirus 1) Infection in Humans and Macaques: Potential for Zoonotic Disease

Nonhuman primates are widely used in biomedical research because of their genetic, anatomic, and physiologic similarities to humans. In this setting, human contact directly with macaques or with their tissues and fluids sometimes occurs. Cercopithecine herpesvirus 1 (B virus), an alphaherpesvirus endemic in Asian macaques, is closely related to herpes simplex virus (HSV). Most macaques carry B virus without overt signs of disease. However, zoonotic infection with B virus in humans usually results in fatal encephalomyelitis or severe neurologic impairment. Although the incidence of human infection with B virus is low, a death rate of >70% before the availability of antiviral therapy makes this virus a serious zoonotic threat. Knowledge of the clinical signs and risk factors for human B-virus disease allows early initiation of antiviral therapy and prevents severe disease or death

Heletz experimental site overview, characterization and data analysis for CO2 injection and geological storage

International audienceThis paper provides an overview of the site characterization work at the Heletz site, in preparation to scientifically motivated CO2 injection experiments. The outcomes are geological and hydrogeological models with associated medium properties and baseline conditions. The work has consisted on first re-analyzing the existing data base from ∼40 wells from the previous oil exploration studies, based on which a 3-dimensional structural model was constructed along with first estimates of the properties. The CO2 injection site is located on the saline edges of the Heletz depleted oil field. Two new deep (>1600 m) wells were drilled within the injection site and from these wells a detailed characterization program was carried out, including coring, core analyses, fluid sampling, geophysical logging, seismic survey, in situ hydraulic testing and measurement of the baseline pressure and temperature. The results are presented and discussed in terms of characteristics of the reservoir and cap-rock, the mineralogy, water composition and other baseline conditions, porosity, permeability, capillary pressure and relative permeability. Special emphasis is given to petrophysical properties of the reservoir and the seal, such as comparing the estimates determined by different methods, looking at their geostatistical distributions as well as changes in them when exposed to CO2

Lessons learned : the first in-situ laboratory fault injection test

The CSIRO In-Situ Laboratory has been a world first injection of CO2 into a large faulted zone at depth. A total of 38 tonnes of CO2 was injected into the F10 fault zone at approximately 330 m depth and the process monitored in detail. The site uses a well, Harvey-2, in SW Western Australia (the South West Hub CCS Project area). The top 400 m section of Harvey-2 was available for injection and instrumentation. An observation well, ISL OB-1 (400 m depth) was drilled 7 m to the north east of Harvey-2. ISL OB-1 well was cased with fibreglass to provide greater monitoring options. The CSIRO In-Situ Laboratory was designed to integrate existing facilities and infrastructure from the South West Hub CCS Project managed by the West Australian Department of Mines, Industry Regulation and Safety. While new equipment was deployed for this specific project, the site facilities were complemented by a range of mobile deployable equipment from the National Geosequestration Laboratory (NGL). The geology of the area investigated poses interesting challenges: a large fault (F10) is estimated to have up to 1000 m throw overall, the presence of packages of paleosols rather than a contiguous mudstone seal, and a 1500 m vertical thickness of Triassic sandstone as the potential commercial storage interval. This unique site provides abundant opportunities for testing more challenging geological environments for carbon storage than at other sites. While details of this first project are described elsewhere, lessons were learned during the development and execution of the project. A rigorous risk register was developed to manage project risk, but not all events encountered were foreseen. This paper describes some of the challenges encountered and the team's response. Relocation of the project site due to changes in landholder ownership) and other sensitivities resulted in the need for rapid replanning of activities at short notice resulting in the development of the site at Harvey-2. The relocation allowed other research questions to be addressed through new activities, such as the ability to consider a shallow/controlled release experiment in an extensive fault zone, but this replanning did cause some timing stress. The first test at the In-Situ Laboratory was reconfigured to address some of those knowledge gaps that shallow/controlled release experiments had yet to address. Novel approaches to drilling and completing the monitoring well also threw up unanticipated difficulties. Loss of containment from the wellbore also posed significant challenges, and the team's response to this unintended release of gas and water from the monitoring well at the conclusion of the field experiment will be discussed. Other challenges that we encountered, their impacts, and our response are also catalogued here (Table 1 and below) to enable broad knowledge exchange