Use of wireline logs to estimate strength of cap-rock lithologies

The characterization of rock strength for cap rock, low-permeability and high capillary entry pressure, lithologies is important for modeling their response to increased fluid pressures in CO2 sequestration schemes and other geo-engineering operations such as waste disposal and recovery of fluids from plays with insufficient permeability. We investigate Mesozoic fine-grained sequences to evaluate the nature of sedimentological and structural processes that may control the nature of brittle deformation observed in these sequences. To characterize these fine-grained sequences we use a combination of data obtained from outcrop, including fracture orientation and density, lithologic stacking patterns, grain-size distributions and mineralogy to predict the potential for fluid bypass. In addition we also use publically available wireline log data to estimate the rock strength of these units in the subsurface. Outcrop observations of the mixed silisiclastic carbonate sequence of the Carmel Formation shows vertically continuous fractures crossing lithologic boundaries and analysis of scan-line and fracture orientation data indicate three discontinuity sets. Sets one and two are a conjugate pair of non-mineralized discontinuities which include faults and fractures, with a mean orientations of 323°/78° and 100°/76° respectively and discontinuity spacing ranging between 0.2-0.4 per meter. Set three is a near vertical, mineralized fracture set which is cross-cut by fractures of set one and two, with a mean orientation 31°/80 and a fracture spacing of 0.2 fractures per meter. Use of publically available wireline log data allows us to estimate rock strength over larger scales than those provided by the local outcrops. The wells selected for analysis are located within a 15-km radius from the outcrop location. Gamma ray, sonic, and density logs from 7 wells were digitized from scanned originals. The inverse of the sonic log data was taken to obtain a velocity value (Vp), no dipole sonic logs are available therefore shear velocity was calculated using empirical relationships established by other workers. Having both compression and shear velocity as well as bulk density values we are able to empirically determine Poisson’s Ratio and Young’s Modulus. Poisson’s Ratio values for these wells ranges between 0.18-0.48, and Young’s Modulus results range from 7GPa-50 GPa. Most of the results obtained by this data analysis fall within the published ranges for these rock types, but the data show variability, which must be further evaluated to understand if these are related to geology or artifacts associated with the wireline

Comparison of Mechanical and Fracture Stratigraphy between Failed Seal Analouges

A cap rock, or seal, provides a barrier to the migration of fluid or gas out of intended trap due to its low permeability, high capillary-entry pressure nature. The presence of discontinuities in seal lithologies affects both their mechanical and hydrogeologic properties; migration of fluids or gas through mm- to cm-scale discontinuity networks can lead to the failure of hydrocarbon traps or waste repositories. We examine the mechanical and fracture stratigraphy of Paleozoic and Mesozoic analogues of failed seals exposed in central and south-east Utah to understand the nature and distribution of fluid flow pathways in various sealing lithologies. We use outcrop surveys of stratigraphic changes and discontinuity distributions to identify the relationships between depositional composition, diagenesis and loading history, and to describe fluid-flow pathways across four seal types. Each seal type has experienced a varied depositional and tectonic history and all show evidence for fracture propagation and fluid flow at depth. Characterizing the distribution and morphologies of open mode fractures (mode I/II), with changes in lithology (which include depositional and structural variations), provides data for accurate quantitative subsurface geomechanical and fluid flow models

Fracture behavior across interfaces in seal lithologies

Faults and fracture networks at depth are important fluid pathways, especially in fine-grained, low permeability seal lithologies. Discontinues in sealing lithologies can create seal bypass systems, leading to the failure of CO2 geosequestration sites or hydrocarbon traps. We characterize the occurrence of and changes in discontinuity patterns and the associated changes in elastic moduli across sedimentologic interfaces to document the importance of these discontinuities for fluid management in the subsurface and potential for re-activation in high-pressure injection scenarios. We evaluate well-exposed, fine-grained, low-permeability Mesozoic and Paleozoic units that are seals of potential CO2 repositories on the Colorado Plateau and show evidence for open fractures and fluid flow in the subsurface. Field observations document changes in fracture distributions across lithologic boundaries allowing us to identify mechano-stratigraphic units and focus on the effect of lithologic interfaces on fracture distribution. An interface marks the boundary between facies in a seal and in this study the fractures are shown to deflect or arrest at the interface. In outcrop fracture intensity varies in from 1 to 18 fractures per meter and fracture apertures range from mm to cm. The mineralized fractures often have associated alteration halos along their boundaries; their general orientation follows that of discontinuities within the underlying reservoir facies or adjacent faults. The recognition of these changes in fracture distribution is important for forward modeling of fluid flow and risk management. Studying the occurrence of and changes in fracture patterns from outcrops and scaling it up for use in modeling at a field scale is difficult due to the lack of direct correlation between outcrop observations and subsurface data. Due to the size and amount of data needed to model fluid flow at the field scale the meso-scale (cm to m) variability of rock properties is often neglected. We evaluate this meso-scale variability in elastic moduli, where possible. We combine mechano-stratigraphic outcrop observations with elastic moduli calculated from publically available wire line log data to evaluate the variability in rock strength within the heterolithic top seal. Relationships between changes in Young’s modulus to resulting fracture distribution can then be observed. The outcome of this analysis can be used for modeling the effectiveness of seal for storage of CO2 in the underlying reservoirs. Digitized publically available wire line well log data were used to calculate Poisson’s ratio and Young’s modulus over the Carmel Formation and upper most 3 m of the underlying Navajo Sandstone. Our calculations show that Young’s Modulus can range between 15 to 34 GPa across 60 cm of the intra-seal interfaces, and an average difference of 5 GPa across the reservoir seal interface. These variations will affect fracture distributions and fluid behavior in the subsurface. These data provide a means to closely tie outcrop observations to derived estimates of subsurface rock strength. The characterization of rock strength variability is especially important for modeling the response of seals to increased pressure, due to CO2 injection, and will allow for better site screening and fluid management once injection projects are underway

Use of wire line logs for estimation of strength variability in cap-­‐rock lithologies

The characterization of cap-rock, low permeability and high capillary entry pressure lithologies is important for modeling the response of cap-rocks to increased pressures due to CO2 injection. We evaluate the use of publically available wireline log data to provide empirical estimate of rock strength in order to determine the strength of top seal over a range of scales. This method is being used to characterize cap-rock lithologies in systems proposed for CO2 geosequestration, these data will be combined with outcrop fracture density observations, petrology, lithologic stacking patterns and mineralogy to predict the potential for bypass. Analysis to date includes wells with monopole and dipole sonic logs for comparison of the relationships established empirically by other workers and used in this study to estimate the dynamic values for Poisson’s Ratio and Young’s Modulus from publically available vintage well log data in Utah. This study focuses specifically on the Jurassic Carmel Formation, which is a cap-rock to the underlying proposed CO2 injection reservoir, the Navajo Sandstone. This study compliments the well data with outcrop characterization of the Carmel Formation, which we split into 3 mechanical units based on lithologic stacking patterns, fracture density, and relationships observed between the percent shale and fracture spacing ratio. Results obtained from the well log analysis fall within the published ranges for these rock types, however the data show a variability which is being evaluated further to understand if these observations are related to geology or artifacts associated with the wireline data. In future the use of these empirical estimates will provide a lower estimate for subsurface rock strength, as well as provide a means to closely tie outcrop observations to those made from subsurface data

Localization of deformed wing virus (DWV) in the brains of the honeybee, Apis mellifera Linnaeus

<p>Abstract</p> <p>Background</p> <p>Deformed wing virus (DWV) is a positive-strand RNA virus that infects European honeybees (<it>Apis mellifera </it>L.) and has been isolated from the brains of aggressive bees in Japan. DWV is known to be transmitted both vertically and horizontally between bees in a colony and can lead to both symptomatic and asymptomatic infections in bees. In environmentally stressful conditions, DWV can contribute to the demise of a honeybee colony. The purpose of the current study is to identify regions within the brains of honeybees where DWV replicates using <it>in-situ </it>hybridization.</p> <p>Results</p> <p><it>In-situ </it>hybridizations were conducted with both sense and antisense probes on the brains of honeybees that were positive for DWV as measured by real-time RT-PCR. The visual neuropils demonstrated detectable levels of the DWV positive-strand genome. The mushroom bodies and antenna lobe neuropils also showed the presence of the viral genome. Weaker staining with the sense probe in the same regions demonstrates that the antigenome is also present and that the virus is actively replicating in these regions of the brain.</p> <p>Conclusion</p> <p>These results demonstrate that in bees infected with DWV the virus is replicating in critical regions of the brain, including the neuropils responsible for vision and olfaction. Therefore DWV infection of the brain could adversely affect critical sensory functions and alter normal bee behavior.</p

Photoelectrochemical Hydrogen Evolution Using Si Microwire Arrays

Arrays of B-doped p-Si microwires, diffusion-doped with P to form a radial n+ emitter and subsequently coated with a 1.5-nm-thick discontinuous film of evaporated Pt, were used as photocathodes for H_2 evolution from water. These electrodes yielded thermodynamically based energy-conversion efficiencies >5% under 1 sun solar simulation, despite absorbing less than 50% of the above-band-gap incident photons. Analogous p-Si wire-array electrodes yielded efficiencies <0.2%, largely limited by the low photovoltage generated at the p-Si/H_2O junction

Newspaper media framing of obesity during pregnancy in the UK: A review and framework synthesis

Two thirds of women report experiencing weight stigma during pregnancy. Newspaper media is powerful in framing health issues. This review synthesized UK newspaper media portrayal of maternal obesity. NexisUni was searched to identify newspaper articles, published January 2010 to May 2021, reporting content on obesity during pregnancy. Framework synthesis integrated quantitative and qualitative analysis of the content of articles. There were 442 articles included (59% tabloids and 41% broadsheets). Three overarching themes with interacting sub-themes were as follows: (1) Women were blamed for their weight, risks, and NHS impact. (2) Women were solely responsible for solving obesity, gendered from school age. (3) Women with obesity were a burden on individuals (e.g., themselves, their children, and health professionals), to society, and the NHS. Catastrophizing language framed the “problem,” “scale,” and “public health concern” of maternal obesity, emphasizing risk, and danger and was alarmist, aggressive, and violent as to elicit fear or devalue women. Articles platformed ‘expert’ voices rather than women's lived experiences. This review identified that UK newspaper media negatively frames and oversimplifies the topic of maternal obesity. Exposure to blaming and alarmist messaging could increase women's guilt, stigma, and internalized weight bias. The newspaper media should be harnessed to de-stigmatize maternal obesity and promote maternal well-being

Differences in access to Emergency Paediatric Intensive Care and care during Transport (DEPICT): study protocol for a mixed methods study.

INTRODUCTION: Following centralisation of UK paediatric intensive care, specialist retrieval teams were established who travel to general hospitals to stabilise and transport sick children to regional paediatric intensive care units (PICUs). There is national variation among these PICU retrieval teams (PICRTs) in terms of how quickly they reach the patient's bedside and in the care provided during transport. The impact of these variations on clinical outcomes and the experience of stakeholders (patients, families and healthcare staff) is however unknown. The primary objective of this study is to address this evidence gap. METHODS AND ANALYSIS: This mixed-methods project involves the following: (1) retrospective analysis of linked data from routine clinical audits (2014-2016) to assess the impact of service variations on 30-day mortality and other secondary clinical outcomes; (2) a prospective questionnaire study conducted at 24 PICUs and 9 associated PICRTs in England and Wales over a 12-month period in 2018 to collect experience data from parents of transported children as well as qualitative analysis of in-depth interviews with a purposive sample of patients, parents and staff to assess the impact of service variations on patient/family experience; (3) health economic evaluation analysing transport service costs (and other associated costs) against lives saved and longer term measurements of quality of life at 12 months in transported children and (4) mathematical modelling evaluating the costs and potential impact of different service configurations. A final work stream involves a series of stakeholder workshops to synthesise study findings and generate recommendations. ETHICS AND DISSEMINATION: The study has been reviewed and approved by the Health Research Authority, ref: 2 18 569. Study results will be actively disseminated through peer-reviewed journals, conference presentations, social media, print and broadcast media, the internet and stakeholder workshops

Assessing the Necessity of Stopping Antithrombotic Agents Before Wide-Awake Hand Surgery

This review of 304 carpal tunnel release procedures examines the necessity of stopping antithrombotic medications prior to carpal tunnel release surgery