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Injection of anthropogenic CO2 into a subsurface reservoir will significantly impact the geochemistry, porosity, and permeability of the reservoir. If a fault or fracture penetrates the reservoir, CO2-enriched brine may migrate into that fault, eventually sealing it via precipitation or opening it up via dissolution. The goal of this study was to identify and quantify such conditions of fault self-sealing or self-enhancing. We found the Damköhler number (Da) provides a meaningful framework for characterizing the propensity of (fault) systems to seal or open up. We tailored a spatiotemporally varying Da framework and applied it to simplified fault models with eight conditions derived from four geologic compositions and two reservoir conditions. The four geologic compositions were chosen such that three of them were representative of distinct geologic end-members (sandstone, mudstone, and dolomitic limestone) and one was a mixed composition based on an average of three end-member compositions. The two sets of P-T conditions chosen included one for CO2 in a gaseous phase ("shallow conditions") and the other for supercritical phase CO2 ("deep conditions"). Simulation results suggest that fault sealing via carbonate precipitation was a possibility for shallow conditions within limestone and mixed composition settings. The concentration of cations in the water was found to be an important control on the carbonate precipitation. A key conclusion suggested by the results of this study is that carbonate precipitation in the near-surface (top 50-100 m) depths of a fault is the most likely mechanism of "self-sealing" for most geological settings. [ABSTRACT FROM AUTHOR]

Injecting anthropogenic CO2 into the subsurface is suggested for climate change mitigation. However, leakage of CO2 from its target storage formation is a concern. In the event of leakage, permeability in leakage pathways such as faults may get altered due to mineral reactions induced by CO2-enriched water, thus influencing the migration and fate of the CO2. An example of such fault permeability alteration is found in the Little Grand Wash Fault zone (LGWF), where the fault outcrops show fractures filled with calcium carbonate. To test the nature, extent, and time-frame of such fault 'self-sealing', we developed reactive flow simulations based on hydrogeological conditions of the LGWF. We measured LGWF water chemistry and conducted an x-ray powder diffraction (XRD) analysis of the fault-rock to constrain the model geochemistry. We hypothesized that the choice of parameters for relative permeability, capillary pressure, and reaction kinetics will have a huge impact on the fault sealing predictions. Simulation results showed that precipitation of calcite in the top portion of the fault led to a decrease in porosity of the damage zone from a value of 40% to [ABSTRACT FROM AUTHOR]

We present a 71-year-old female with human herpes virus 8 (HHV8)-unrelated primary effusion lymphoma (PEL)-like lymphoma. Dyspnea and pericardial effusion led to pericardiocentesis, diagnosing diffuse large B-cell lymphoma. She underwent positron emission tomography/computed tomography (PET/CT), which demonstrated hypermetabolic pericardial, pleural, and ascites fluid without lymphadenopathy elsewhere. Malignant fluid in the absence of lymphadenopathy is a hallmark of PEL. PEL is associated with immunodeficiency states such as acquired immunodeficiency syndrome (AIDS) and infectious agents such as HHV8. Our patient had no such history and had not received immunosuppressive chemotherapy. We present the PET/CT findings of this rare case of HHV8-unrelated PEL-like lymphoma. [ABSTRACT FROM AUTHOR]

Objective: The objective of this article is to provide a practical illustrated review of PET/CT in the imaging evaluation of transitional cell carcinoma., Conclusion: Local evaluation of the primary tumor in patients with transitional cell carcinoma on PET is often limited by the obscuring effect of excreted FDG, but assessment of metabolic activity may still be possible through close correlation with CT images. PET/CT may also be helpful in the detection of disease outside the bladder at nodal or more distant sites and in the assessment of recurrent disease.