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This paper provides an improved estimate of CO2‐EOR (where CO2 is carbon dioxide and EOR is enhanced oil recovery) and CO2 storage potential for depleted oil fields in Michigan's northern pinnacle reef trend (NPRT). Our methodology is based on capturing data on reservoir performance from reefs currently undergoing CO2‐EOR operations in the NPRT (referred to as 'monitored reefs'), and then applying them to other reefs within the NPRT (referred to as 'catalog reefs'). For each monitored reef, we calculate fractional primary recovery, fractional incremental EOR recovery, net utilization ratio, and storage efficiency factor. The corresponding incremental oil recovery from EOR, storage capacity until end of EOR, and total CO2 injection needs are then estimated for each catalog reef and combined (over all monitored reefs) using a weighted averaging procedure. These weights are related to a statistical similarity measure that is calculated between each monitored reef and each catalog reef based on a number of variables related to production data, formation type, or descriptive geologic attributes. For the entire NPRT catalog of 383 reefs as used in this study, our results indicate 118 million (MM) stock tank barrels (STB) (1.88 × 107 Sm3) of incremental oil from EOR operations, corresponding to 49 MM metric tons (MT) of CO2 storage and 266 MM MT of total CO2 injection. However, approximately one‐third of the reefs provide two‐thirds of the potential for CO2‐EOR and geologic storage, assuming an economic threshold of 0.5 MM STB (80 000 Sm3) of incremental oil from EOR. © 2020 The Authors. Greenhouse Gases: Science and Technology published by Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

• Assessed feasibility of commercial-scale CO 2 storage in Northern Michigan Basin (NMB). • NMB offers stacked storage in saline reservoirs and depleted reef oil fields for EOR. • Analysis shows multiple sites available to store at least 50 million tonnes of CO 2. • Storage resources, CO 2 plume, monitoring options, risks, and economics assessed. • NMB has favorable social, economic, site-access setting for CO 2 storage complex. The Northern Michigan Basin (NMB) Carbon Storage Assurance Facility Enterprise (CarbonSAFE) Integrated Pre-Feasibility Project is part of the U.S. Department of Energy's (DOE) CarbonSAFE initiative. The objective of the NMB CarbonSAFE pre-feasibility project was to assess the feasibility of an integrated, commercial-scale carbon dioxide (CO 2) storage complex in the NMB, which includes one or more deep saline geologic formations with sufficient capacity to permanently store at least 50 million metric tons of CO 2 over a 20- to 30-year period. Subsurface injection of CO 2 into depleted oil reservoirs for enhanced oil recovery (EOR) was also evaluated in the pre-feasibility study as an additional geologic storage mechanism because there are hundreds of depleted pinnacle reef reservoirs in the NMB, along with an established CO 2 -EOR operation, a feature that distinguishes this area from most other locations in the United States. Additionally, these reefs are co-located with the most favorable saline formations in the basin – the St. Peter sandstone and the Bass Islands dolomite – making stacked storage a real possibility. The study demonstrates that there are multiple locations in the northern Michigan study area that could support a commercial-scale storage complex with either saline storage or associated storage via CO 2 -EOR in the depleted pinnacle reefs alone (i.e., each storage mechanism has sufficient capacity alone) or via a combination of the two storage mechanisms. The term stacked storage refers to the concept of using both mechanisms together, in the same area, to achieve the required storage capacity. Key sites were identified in the northern part of the southern Michigan Peninsula that had sufficient geologic storage, nearby CO 2 sources, a favorable social and economic setting, and a strong developed team. [ABSTRACT FROM AUTHOR]

• DTS allows real-time monitoring of subsurface conditions • DTS and warmback analysis can show presence of fluids in formations • Warmback analysis can be useful to detect fluid migration along vertical wellbore • Arrival of CO2 plume can be detected by DTS at monitoring well A Distributed Temperature Sensing (DTS) system, along with a five-level, behind-casing pressure sensing array was installed as part of the Midwest Regional Carbon Sequestration Partnership (MRCSP) large-scale carbon dioxide (CO 2) storage test in a depleted Niagaran pinnacle reef oil reservoir in Northern Michigan. The reef is being monitored during its initial reservoir fill-up period as CO 2 is being injected to raise the reservoir pressure for enhanced oil recovery (EOR). DTS data are analyzed with results from the initial injection of ˜101,000 metric tons of CO 2 , injected between January 2017 and December 2018. This paper discusses the results of real-time DTS combined with multi-level pressure monitoring. The collection, processing, and interpretation of large amounts of data from fiber-optic-based DTS provides an opportunity to obtain high-resolution information on migration of CO 2 in the reservoir. [ABSTRACT FROM AUTHOR]

The condition of legacy oil and gas wells is an important issue for geologic CO2 storage projects. Many regions with large CO2 point sources coincide with historical oil and gas fields. This is especially apparent in the Midwestern United States, where over one million oil and gas wells are present dating back to the late 1800s. To investigate wellbore integrity factors in this region, the condition of oil and gas wells in Michigan and Ohio was summarized based on well status, depth, construction, age, and plugging specifications. To better understand the impact of well integrity on a local scale, six test study areas were also analyzed. These hypothetical test study areas were based on subsurface area necessary for an industrial scale CO2 storage application. Detailed records were used to categorize well conditions, and corrective actions necessary to repair the wells were then assigned. The results of the test study area analysis provide a real representation of the level of effort necessary to prepare sites for CO2 storage. Actions may involve relatively low-effort tasks to examine wellheads or more extensive well re-entry and plugging. The analysis indicated that many areas may have hundreds of wells, but no wells penetrating the deeper CO2 storage zones. At sites where many wells require corrective action, it may be challenging to efficiently plug and abandon wells. Options such as testing wellhead pressures, surface monitoring of CO2 leakage, and less extensive plugging requirements may help offset costs associated with remediating a large number of wells. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Research has shown that students' initial attitudes are key to understanding attrition in engineering programs. The College of Engineering at Michigan State University introduced a cornerstone design sequence in fall 2008 that provided an opportunity to study freshman attitudes towards engineering. We tested whether the new design sequence (DS) was more effective than the older traditional sequence (TS) at positively influencing freshman attitudes over the course of one semester. We collected attitude data twice, i.e., in the beginning and towards the end of fall 2008 semester, using the Pittsburgh Freshman Engineering Attitude Survey, and examined changes in attitude in the two groups with repeated analysis of covariance models. In fall 2008, 722 freshmen entered the College of Engineering. The analyses reported here include data from 389 of those students. We found that freshmen join the program with positive or strongly positive attitudes towards engineering. Those strong attitudes are durable and resistant to change. Students in the DS group bad higher A CT scores, enjoyed math and science the most, and did not believe engineering to be an exact science. The DS and TS groups bad similar longitudinal trajectories so there was no evidence for differential influence on student attitudes. Strongly positive initial attitudes coupled with insignificant changes in these attitudes could mean that one semester is insufficient to effect a measureable change. This quantitative study is a subset to the longitudinal study based on explanatory mixed methods design. The qualitative data collected in a follow up study (one-on-one interviews) may shed more light on the numerical results to further investigate the effectiveness of the freshman curriculum. [ABSTRACT FROM AUTHOR]

Abstract: The multiphase flow and solute transport simulator STOMP has been used to assess potential carbon dioxide (CO2) injection rates into saline formations at several sites for the Midwest Regional Carbon Sequestration Partnership (MRCSP). An injection test of approximately 10,000 metric tons into the Bass Islands Dolomite with CO2 injection rates from 250–500 tons per day, was performed in the test well at the MRCSP geologic field test site in Otsego County, Michigan, U.S.A. Reservoir simulations were performed to estimate injection parameters, such as bottomhole pressures and pressure response over time in the storage formation, and compared to measurements taken during the test. [Copyright &y& Elsevier]

The article evaluates the coefficient of thermal expansion (CTE,PCC) test protocol and its impact on jointed concrete pavement performance. A laboratory experiment is conducted using the method of CTE,PCC of concrete paving mixtures made from different sources in Michigan. Coarse aggregates used include limestone, dolomite, gravel and trap rock. Result show that aggregate geology, specimen age, and the number of heating-and-cooling cycles have a significant impact on the magnitude of CTE,PCC.

• Presents modeling study for history-matching oil production and CO 2 injection responses to assess fluid migration in complex depleted reef. • Equivalent simplified conceptualizations of reservoir heterogeneity are effective practical methodology for achieving modeling objectives. • Numerically efficient approach to facilitate improved system understanding and explain reservoir response during MRCSP CO 2 injection phase. The Midwest Regional Carbon Sequestration Partnership has been investigating various reservoir characterization and modeling technologies as part of its commercial-scale implementation of carbon dioxide injection for geologic storage in multiple Silurian carbonate pinnacle reefs in northern Michigan, USA. This paper presents a discussion of the reservoir modeling study that was conducted for history-matching oil production and CO 2 injection responses, forecasting CO 2 plume migration and estimating associated storage to characterize the closed, depleted Dover-33 reef which has undergone extensive primary and secondary production. Dynamic modeling using equivalent simplified descriptions of reservoir heterogeneity were found to be numerically efficient and successfully explained the observed pressure buildup in the reef during the MRCSP CO 2 injection phase. The validated history matched models are extremely useful for potential predictive modeling for considering operational optimization and evaluating subsequent production scenarios relevant to the reef. [ABSTRACT FROM AUTHOR]

• Application of three approaches for analyzing transient pressure and rate data from CCUS projects in depleted reef reservoirs in Michigan, USA. • Methods are: injection-falloff, injectivity/productivity index, and pressure pulse arrival time analysis. • All three methods widely used in oil industry; but latter two hitherto not used for CCS projects. • Theory behind each technique presented and its applicability demonstrated via illustrative examples from multiple wells in different reefs. • Discussion of the relative merits of each interpretive technique, as well as recommendations that could be useful for other field projects. Pressure and rate data are commonly recorded as part of a basic monitoring program in CCS projects. This paper discusses the application of multiple analytical techniques to interpret pressure and rate transient data from CO 2 injection and storage operations. The techniques of interest, i.e., injection-falloff analysis, injectivity/productivity index analysis and pressure pulse arrival time analysis, are commonly used in the oil and gas industry to assess reservoir properties, but not well known in the CCS literature (especially the last two). Injection-falloff analysis involves log-log pressure derivative plotting for the falloff data and history-matching of the entire injection-falloff sequence to determine permeability. In the injectivity/productivity index analysis, rate-normalized pressure buildup is plotted against material balance time or ratio of cumulative injection to injection rate to determine the injectivity index (ratio of injection rate to stabilized pressure buildup) which can be related to the permeability-thickness product. The arrival time analysis identifies the arrival of a pressure disturbance (∼0.1 psi change from ambient) to determine the hydraulic diffusivity from which permeability can be estimated. The applicability of these techniques is demonstrated via illustrative examples from multiple wells in different pinnacle carbonate reefs undergoing CO 2 -EOR in Northern Michigan. The paper ends with a discussion of the relative merits of each interpretive technique, as well as recommendations that could be useful for other field projects. [ABSTRACT FROM AUTHOR]

Geomechanical risks of injection have raised concerns regarding secure CO 2 storage. In this work, a combined monitoring and modeling approach is used to assess the stress changes and surface uplift associated with CO 2 injection into a depleted carbonate reef of the Michigan basin. A site-scale geomechanical model is built by assigning mechanical properties of formations using well-log and experimental data. Gravity load is applied to the model to estimate the vertical component of stress as well as different lateral boundary displacement scenarios to estimate horizontal stresses. We used a poroelastic pressure-dependent model (instead of a linear elastic mechanical earth model) to calibrate initial stresses using hydraulic fracture test data measured at depleted reservoir status. Multi-phase fluid flow-geomechanical simulations are performed to estimate the poroelastic response during (1) primary depletion (2) field-scale CO 2 injection phase (3) a hypothetical forecast scenario in which well bottom hole pressure (BHP) reach 45000 KPa. The predicted surface uplift is less than 1 mm at the end of the field-scale CO 2 injection phase which is in good agreement with Interferometric Synthetic Aperture Radar (InSAR) uplift measurement. Although the InSAR data shows an insignificant uplift, hydromechanical modeling of injection shows that CO 2 injection still causes reservoir deformation emphasizing the role of carbonate overburden and reservoir formation mechanical properties and limited size of reef on diminishing the surface deformation. Modeling indicates poroelastic response of caprock matters to estimate uplift. The lower permeability of the top two layers provides additional barrier to large uplift. Also, history of subsidence due to production should be accounted to predict uplift due to a follow up injection correctly. This study shows the significance of combining a calibrated geomechanical model with field measured stresses and monitoring data to be used as a tool to ensure the safety of CO 2 storage. • Surface uplift was modeled with CO2 injection into a depleted reef of the Michigan basin. • A combined monitoring and geomechanical modeling is used to assess surface uplift. • The modeled surface uplift of less than 1 mm is in agreement with InSAR measurement. • InSAR data shows an insignificant uplift, modeling still shows reservoir deformation. • The lower permeability of the top reservoir layers provides barrier on large uplift. [ABSTRACT FROM AUTHOR]

Development and preservation of carbonate porosity and permeability are critical to characterizing reservoirs. However, secondary porosity, such as vugs and fractures, are difficult to identify and require collection of expensive wireline tools or core sampling. Wireline logs and cores have traditionally been used to identify the presence of secondary porosity but fail to quantify the contribution to total reservoir porosity. Additionally, advanced wireline logs and core are not readily available for most wells. Dual energy CT scans were collected on whole core from the A-1 Carbonate and Brown Niagaran formations drawn from six wells in northern Michigan. 3D analysis techniques were applied to identify and isolate secondary porosity features. A series of machine learning and data analytics techniques were applied to the dataset to predict secondary porosity features on basic wireline logs. The predictive model successfully predicted secondary porosity with high confidence. • Quantification of number and size of secondary porosity features in carbonates. • Secondary prediction model developed with high confidence. • Predicted secondary porosity from basic wireline log data. [ABSTRACT FROM AUTHOR]

Background: Although mechanical thrombectomy for acute ischemic stroke from a large vessel occlusion is now the standard of care, little is known about cost variations in stroke patients following thrombectomy and factors that influence these variations., Methods: We evaluated claims data for 2016 to 2018 for thrombectomy-performing hospitals within Michigan through a registry that includes detailed episode payment information for both Medicare and privately insured patients. We aimed to analyze price-standardized and risk-adjusted 90-day episode payments in patients who underwent thrombectomy. Hospitals were grouped into three payment terciles for comparison. Statistical analysis was carried out using unpaired t -test, Chi-square, and ANOVA tests., Results: 1076 thrombectomy cases treated at 16 centers were analyzed. The average 90-day episode payment by hospital ranged from $53 046 to $81,767, with a mean of $65 357. A $20 467 difference (35.1%) existed between the high and low payment hospital terciles (P<0.0001), highlighting a significant payment variation across hospital terciles. The primary drivers of payment variation were related to post-discharge care which accounted for 38% of the payment variation (P=0.0058, inter-tercile range $11,977-$19,703) and readmissions accounting for 26% (P=0.016, inter-tercile range $3,315-$7,992). This was followed by professional payments representing 20% of the variation (P<0.0001, inter-tercile range $7525-$9,922), while index hospitalization payment was responsible for only 16% of the 90-day episode payment variation (P=0.10, inter-tercile range $35,432-$41,099)., Conclusions: There is a wide variation in 90-day episode payments for patients undergoing mechanical thrombectomy across centers. The main drivers of payment variation are related to differences in post-discharge care and readmissions., Competing Interests: Competing interests: MLY and JDS receive salary support from Blue Cross Blue Shield of Michigan for their work with the Michigan Value Collaborative., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose: To determine the prevalence of proximal deep venous thrombosis (DVT) in a general hospital., Background: In spite of the importance of proximal DVT, its prevalence in hospitalized patients has been only sparsely studied., Methods: Patients hospitalized with DVT between July 1998 and June 2000 were identified by a computer search of discharge diagnoses. The discharge diagnosis was confirmed by a review of the records for positive findings on compression ultrasound or venogram of the lower extremities. In addition, records of all compression ultrasound examinations and venograms during that period were examined., Results: The prevalence of proximal DVT in adults > or = 20 years old was 271 of 34,567 patients (0.78%). DVT was associated with pulmonary embolism in 57 of 271 patients (21.0%). The prevalence of DVT in adult men was 117 of 13,722 patients (0.85%), and in adult women was 154 of 20,845 patients (0.74%) [not significant]. The prevalence of DVT among men aged 20 to 49 years was higher than in women the same age: 19 of 3,982 patients (0.48%) vs 22 of 9,442 patients (0.23%), respectively (p < 0.02). The prevalence of DVT, however, was comparable among men and women > or = 50 years old. The prevalence of DVT was also comparable in black adults (30 of 4,344 patients; 0.69%) and in white adults (240 of 28,615 patients; 0.84%) [not significant]., Conclusion: Proximal DVT continues to be a frequent illness among hospitalized patients.

Purpose: This study attempts to determine the incidence of established acute pulmonary embolism (PE) in a community/teaching general hospital., Background: The reported incidence of objectively diagnosed acute PE among hospitalized adults in a large urban hospital or major university hospital ranges from 0.27 to 0.40%. Whether the incidence of PE in other categories of hospitals fits within this narrow range is unknown., Methods: Patients with acute PE diagnosed by ventilation/perfusion lung scan, pulmonary angiography, compression ultrasound in a patient with suspected PE, autopsy, or (by coincidence) lung biopsy were identified among patients hospitalized during a 2-year period from 1998 to 2000. The incidence of PE was also determined according to age, sex, and race., Results: Among adult patients (> or = 20 years old), the incidence of established acute PE was 95 of 34,567 patients (0.27%; 95% confidence interval [CI], 0.22 to 0.34%). No PE was diagnosed in patients < 20 years old. The incidence of PE in men was 36 of 13,722 patients (0.26%; 95% CI, 0.18 to 0.36%); in women, it was 59 of 20,845 patients (0.2%; 95% CI, 0.22 to 0.36%; not significant [NS]). The incidence in African-Americans adults was 10 of 4,344 patients (0.23%; 95% CI, 0.11 to 0.42%); in white adults, it was 84 of 28,615 patients (0.29%; 95% CI, 0.23 to 0.36%; NS)., Conclusion: The incidence of PE in a community/teaching general hospital was comparable to the incidence in a large urban-care center and in a major university hospital.