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Open Access Publications from the University of California

Scholarly Works (21 results)

  • Article
LBL Publications (2006)
A common method used to detect leakage from a natural gas storage reservoir includes measuring fluid pressures and watching for pressure increases in the formation above the reservoir. Here we investigate the sensitivity of these pressure measurements for detecting leakage from underground geological formations used for CO2 storage. Calculations are made regarding the rate and extent of pressure buildup associated with different rates of leakage. The number of observation wells needed to detect specified leakage rates are estimated for a range of hydrogeological parameters. In addition, the magnitude of pressure buildup caused by leakage is compared to common forms of "noise" in the pressure data, namely, pressure fluctuations associated with earth tides, barometric pressure variations, precipitation, and instrument resolution and drift. Based on a comparison between the magnitude of the pressure response and the "noise" in the pressure signal, an assessment of the utility of pressure measurements for monitoring leakage from geological storage projects is provided.
    Cover page: Sensitivity of Pressure Measurements for Detecting Leakage of Carbon Dioxide From Geological Storage Sites
    • Article
    LBL Publications (2004)
      Cover page: Determination of moisture diffusivity for unsaturated fractured rock surfaces
      • Article
      LBL Publications (2003)
      Interpretation of observations of seepage into under-ground openings is often complicated by evaporative potentials created by the necessity to ventilate the openings. Evaporation removes liquid from the seepage face. By doing so, it reduces both the likelihood of seepage onset and the seepage flux, and thus can enhance the perceived effectiveness of the capillary barrier. We modeled liquid-release tests at the proposed high-level waste repository in Yucca Mountain, using an enhanced version of the EOS9 module of iTOUGH2, which incorporates evaporation as Fickian diffusion. The evaporation boundary layer thickness (BLT) over which diffusion occurs was estimated using free-water evaporation experiments conducted at Yucca Mountain under known relative humidity, temperature, and ventilation conditions. The BLT, which represents the thickness of the laminar flow regime, is inversely related to the ambient airflow velocity. At Yucca Mountain, the estimated values of BLT were 5-7 mm for open underground tunnels and 20 mm for closed niches. Compared to previous models that neglected the effect of evaporation, this new approach shows significant improvement in capturing seepage fluctuations into the open tunnels. Increased confidence is gained for the use of the estimated effectiveness of the capillary barrier formed by the tunnel for simulations of future seep-age under differing evaporative potentials.
        Cover page: Evaluating the effectiveness of liquid diversion around an underground opening when evaporation is non-negligible
        • Article
        LBL Publications (2007)
          Cover page: Site Characterization for CO2 Geologic Storage and Vice Versa: The Frio Brine Pilot. Yrcsd. ziDS as a Case Study
          • Article
          LBL Publications (2005)
            Cover page: Comparison of Single and Multiphase Tracer Test Results from the Frio CO2 Pilot Study, Dayton, Texas
            • Article
            • Peer Reviewed
            LBL Publications (2006)

            Sampling of fluids in deep boreholes is challenging because of the necessity to minimize external contamination and maintain sample integrity during recovery. The U-tube sampling methodology was developed to collect large volume, multiphase samples at in situ pressures. As a permanent or semi-permanent installation, the U-tube can be used for rapidly acquiring multiple samples or it may be installed for long-term monitoring applications. The U-tube was first deployed in Liberty County, TX to monitor crosswell CO2 injection as part of the Frio CO2 sequestration experiment. Analysis of gases (dissolved or separate phase) was performed in the field using a quadrupole mass spectrometer, which served as the basis for determining the arrival of the CO2 plume. The presence of oxygen and argon in elevated concentrations, along with reduced methane concentration, indicate sample alteration caused by the introduction of surface fluids during borehole completion. Despite producing the well to eliminate non-native fluids, measurements demonstrate that contamination persists until the immiscible CO2 injection swept formation fluid into the observation wellbore.

              Cover page: Real-time quadrupole mass spectrometer analysis of gas in borehole fluid samples acquired using the U-Tube sampling methodology
              • Article
              • Peer Reviewed
              LBL Publications (2024)
              Correction to: Transport in Porous Media (2024) 151:55–84https://doi.org/10.1007/s11242-023-02033-0. There are three numbers in Table 2 of the original paper that were incorrect. Specfically, the value of the density of hydrogen (H2) for the DB model and the values of density and viscosity of H2 for the TOUGH2 model listed in Table 2 of the original paper were incorrect. (Table presented.) Properties of the H2-water upconing system for comparison against the DB model. Property DB model Used for TOUGH2 Gas cap thickness, total reservoir thickness, and radial extent (outer radius) of the reservoir Infinite, infinite, infinite 50 m, 100 m (with open boundary at bottom), 100 m (open boundary condition) Porosity (ϕ) 0.10 0.10 Permeability (kH) 1.0 × 10−12 m2 1.0 × 10−12 m2 Permeability (kV) 1.0 × 10−12 m2 1.0 × 10−12 m2 Relative permeability (krel) Not applicable Linear with Slr = 0.99 Distance from well to H2-water interface (d) 10 m 10 m Extraction rate of rate of H2 (Qm) − 5.5 kg s−1 − 5.5 kg s−1 Density of water 996 kg m−3 996 kg m−3 Density of H2 7.32 kg m−3 7.87 kg m−3 Viscosity of water 6.54 × 10−4 Pa s 5.11 × 10−4 Pa s Viscosity of H2 9.31 × 10−6 Pa s 9.53 × 10−6 Pa s A corrected Table 2 is shown below. The erroneous values in Table 2 were not used in any of the modeling and simulation. Accurate values for density and viscosity in the modeling and simulation come from CoolProp for the DB model and from EOS7CH for the TOUGH2 simulations.
                Cover page: Correction: Water Upconing in Underground Hydrogen Storage: Sensitivity Analysis to Inform Design of WithdrawalCreative Commons 'BY-ND' version 4.0 license
                • Article
                • Peer Reviewed
                LBL Publications (2023)
                The gas–water interface in Underground Hydrogen Storage (UHS) reservoirs creates the possibility that water will upcone to the well during hydrogen (H2) withdrawal with detrimental impacts. We study the upconing of water to a hydrogen injection/withdrawal (I/W) well using both an analytical solution and numerical simulation. We carried out sensitivity analyses of the engineered properties (e.g., distance of well bottom to gas–water interface, withdrawal rate) and the intrinsic properties (e.g., reservoir permeability, porosity) of an idealized UHS system. Horizontal permeability is the main parameter controlling the height of upconing. Daily I/W cycles to some degree mitigate upconing because injection pushes down the gas–water interface. Sampling-based global sensitivity analyses show clearly that reservoirs with large horizontal permeability are preferred for avoiding upconing. Minimizing withdrawal rate and maximizing either the distance from well to gas–water interface or the length of the perforated well interval are important engineering controls to minimize upconing.
                  Cover page: Water Upconing in Underground Hydrogen Storage: Sensitivity Analysis to Inform Design of WithdrawalCreative Commons 'BY' version 4.0 license
                  • Article
                  LBL Publications (2004)
                    Cover page: The Frio Brine Pilot CO2 Sequestration Test - Comparison of Field Data and Predicted Results
                    • Article
                    LBL Publications (2006)

                    WESTCARB, one of seven U.S. Department of Energy partnerships, identified (during its Phase I study) over 600 gigatonnes of CO2 storage capacity in geologic formations located in the Western region. The Western region includes the WESTCARB partnership states of Alaska, Arizona, California, Nevada, Oregon and Washington and the Canadian province of British Columbia. The WESTCARB Phase II study is currently under way, featuring three geologic and two terrestrial CO2 pilot projects designed to test promising sequestration technologies at sites broadly representative of the region's largest potential carbon sinks. This paper focuses on two of the geologic pilot studies planned for Phase II -referred to-collectively as the Rosetta-Calpine CO2 Storage Project. The first pilot test will demonstrate injection of CO2 into a saline formation beneath a depleted gas reservoir. The second test will gather data for assessing CO2 enhanced gas recovery (EGR) as well as storage in a depleted gas reservoir. The benefit of enhanced oil recovery (EOR) using injected CO2 to drive or sweep oil from the reservoir toward a production well is well known. EaR involves a similar CO2 injection process, but has received far less attention. Depleted natural gas reservoirs still contain methane; therefore, CO2 injection may enhance methane production by reservoir repressurization or pressure maintenance. CO2 injection into a saline formation, followed by injection into a depleted natural gas reservoir, is currently scheduled to start in October 2006.

                      Cover page: The Rosetta Resources CO2 Storage Project - A WESTCARB Geologic Pilot Test
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