Geostock (United States)

Abstract The subsurface data acquisition during drilling, mud logging, coring, core analysis, rock mechanical tests, and well logging was meticulously executed to identify the optimal salt interval for cavern hosting. This involved comprehensive salt composition analysis, potential salt interval identification, lateral salt extent analysis, fracture and fault network analysis, in situ stress and salt stability analysis, and porosity and permeability assessment. This thorough approach ensured precise characterization of salt, paving the way for optimal cavern development. A comprehensive subsurface data acquisition was conducted from drilling, mud logging, coring, and advanced geophysical well logging. Techniques like XRD, XRF, DE CT, elemental logs, and spectral gamma were used to analyze salt composition. Core description and multivariant logs identified potential salt and insoluble intervals. 3D borehole electromagnetic logs and VSP tested lateral salt extent. Fracture and fault networks were assessed using core CT scans, image logs, and seismic data. In situ stress and salt stability were analyzed through mini-frac, rock mechanical tests, creep test, dissolution and thermal expansion tests. This thorough data acquisition ensured accurate characterization for cavern design. The study provided significant insights by integrating multidisciplinary data and utilizing a robust approach to derisk subsurface parameters. Salt and insoluble facies were characterized by integrating core measurements such as sedimentology, dual energy CT, XRD, XRF, thin section, and SEM studies, and correlating them with various logs. Salt facies classification considered factors like salt type and percentage, crystal size and shape, color, impurities, and bedding effects, while insoluble facies were based on lithologies, size, color, distribution, and porosity types. A wide variety of wireline logs, both basic and advanced, were used for multimineral analysis, calibrated with core descriptions, XRD, and XRF, to ensure accurate determination of salt and insoluble content, porosity, and permeability. New technologies like 3D borehole electromagnetic logs and VSP confirmed the vertical and lateral extent of salt. Stress and mechanical behavior were assessed through mini-frac tests, core rock mechanical tests, and dipole shear imager. Various mechanical tests, including unconfined compressive tests, triaxial tests, Brazilian tests, long-term creep tests, dissolution tests, and thermal expansion tests, were conducted to ensure salt stability. Integration of all data qualified salt intervals for leaching design and operation, developing the desired underground storage volume.

Abstract The Newark Basin is one of the major Mesozoic rift basins along the U.S. Atlantic coast evaluated for carbon dioxide (CO2) storage potential. Its geologic setting offers an opportunity to assess both the traditional reservoir targets, e.g., fluvial sandstones, and less traditional options for CO2 storage, e.g., mafic intrusions and lavas. Select samples from the basal, predominantly fluvial, Stockton Formation are characterized by relatively high porosity (8%–18%) and air permeability (0.1–50 mD), but borehole hydraulic tests suggest negligible transmissivity even in the high-porosity intervals, emphasizing the importance of scale in evaluating reservoir properties of heterogeneous formations. A stratigraphic hole drilled by TriCarb Consortium for Carbon Sequestration in the northern basin also intersected numerous sandstone layers in the predominantly lacustrine Passaic Formation, characterized by core porosity and permeability up to 18% and 2000 mD. However, those layers are shallow (predominantly above 1 km in this part of the basin) and lack prominent caprock layers above. The mudstones in all three of the major sedimentary formations (Stockton, Lockatong, and Passaic) are characterized by a high CO2 sealing capacity — evaluated critical CO2 column heights exceed several kilometers. The igneous options are represented by basalt lavas, with porous flow tops and massive flow interiors, and a crystalline but often densely fractured Palisade Sill. The Newark Basin basalts may be too shallow for sequestration over most of the basin's area, but many other basalt flows exist in similar rift basins. Abundant fractures in sedimentary and igneous rocks are predominantly closed and/or sealed by mineralization, but stress indicators suggest high horizontal compressional stresses and strong potential for reactivation. Overall, the basin potential for CO2 storage appears low, but select formation properties are promising and could be investigated in the Newark Basin or other Mesozoic rift basins with similar fill but a different structural architecture.