Pore-scale Analysis of Residual Oil in Sandstones and its Dependence on Waterflood Salinity, Analysed by Tomography and Microscopy

Understanding of the pore scale phenomena in porous media is a crucial step towards designing a more efficient enhanced oil recovery techniques in large scale oil reservoirs. Three dimensional (3D) x-ray micro CT imaging and recent advanced in 3D image analysis are primary tools that provide unprecedented level of detailed pore scale information of complex rock structures. Combining this technology with laboratory EOR experiments provides valuable insights into the mechanisms behind the oil recovery process. Low salinity water flooding is a relatively convenient and efficient tertiary recovery method which is applicable to the most of the reservoir types. However, its performance prediction is uncertain because this technique is not fully understood. Fundamental understanding of underlying mechanisms of low salinity water flooding, at the pore-scale, by direct visualization and image analysis is the aim of this thesis. In this thesis a technique to quantify fluids and rocks using series of images is developed and applied to 3D images of mini-plugs that underwent Spontaneous imbibition of high and low salinity brine or flooded by high or low salinity brine. Further, oil/rock and oil//brine interfacial areas, oil/brine interfacial mean curvature and oil saturation configuration in each pore was determined for each mini-plug. The image analysis and data interpretation demonstrate that small incremental oil recovery by low salinity brine corresponded to a slight shift towards water-wet in clay-rich outcrop sandstones. Further, the influence of oil composition in the low salinity brine flooding of reservoir sandstones was investigated. Two crude oil which are mainly distinctive in their total acid number (TAN) were used in spontaneous imbibition experiments. All mini-plugs shows strongly oil wet state after spontaneous imbibition of high and low salinity brine. The low salinity effect was observed in mini plug with high TAN oil while the mini-plugs with low TAN oil exhibited much less tertiary recovery. The analysis of mini-plug with high TAN oil shows that the salinity-induced wettability shift was sufficient to displace oil from locations that were already more water-wet in the state after spontaneous imbibition of high salinity brine, but was insufficient to cause oil movement from more oil-wet locations. Pore scale study of core flooded mini-plug shows that the low salinity brine redistributed oil blobs by displacing them from smaller to the larger pores and disconnecting oil. Microscopy studies of mini-plugs after spontaneous imbibition or core flooding provided further insight to the low salinity oil recovery mechanism at local minerals or wettability of pore walls

Systematic pore-scale study of low salinity recovery from Berea sandstone analyzed by micro-CT

The low salinity effect in clay-rich outcrop sandstones is probed by micro-CT imaging and analysis. A set of eight Berea sandstone mini-plugs underwent primary drainage and aging in crude oil to a mixed-wet state, followed by spontaneous imbibition of high and low salinity brines and imaging of this sequence of prepared starting and endpoint states. Tomogram registration and analysis were used to determine the salinity-induced changes in oil volume, oil/rock and oil/brine interfacial areas, and oil/brine interfacial mean curvature. Pore-scale statistics were extracted to explore any local correlation between the low salinity effect and pore geometry/topology. The qualitative observations and quantitative analyses demonstrated that the small oil recovery by the low salinity effect corresponded to a slight shift towards water-wet.Financial support from the member companies of the Digital Core Consortium Wettability Satellite and Statoil are acknowledged

Comparison of Blood Transfusion Plus Chelation Therapy and Bone Marrow Transplantation in Patients with β-Thalassemia : Application of SF-36, EQ-5D, and Visual Analogue Scale Measures

Date of Acceptance: 08/06/2015 © 2015 by Kerman University of Medical Sciences. Acknowledgments The present article was extracted from the thesis written by Hassan Karami and was financially supported by Shiraz University of Medical Sciences, Shiraz, Iran (grant No. 6292). The authors would like to thank all participants in the study IJHPM supports the Open Access initiative. Abstracts and full texts (PDF format) of all articles published by IJHPM are freely accessible to everyone immediately upon publication. IJHPM also does not charge any submission or publication fees.Peer reviewedPublisher PD

Digital Rock Segmentation for Petrophysical Analysis With Reduced User Bias Using Convolutional Neural Networks

Pore‐scale digital images are usually obtained from microcomputed tomography data that has been segmented into void and grain space. Image segmentation is a crucial step in the process of digital rock analysis that can influence pore‐scale characterization studies and/or the numerical simulation of petrophysical properties. This is concerning since all segmentation methods have user‐selected parameters that result in biases. Convolutional neural networks (CNNs) provide a way forward since once trained, CNN can provide consistent and reliable image segmentation with no user‐defined inputs. In this paper, a CNN is used to segment digital sandstone data, and various ground truth data sets are tested. The ground truth images are created based on high‐resolution microcomputed tomography data and corresponding scanning electron microscope data. The results are evaluated in terms of porosity, permeability, and pore size distribution computed from the segmented data. We find that watershed‐based segmentation provides a wide range of possible petrophysical values depending on user‐selected thresholds, whereas CNN provides a smaller variance when trained on scanning electron microscope data. It can be concluded that CNN offers a reliable and consistent way to segment digital sandstone data for petrophysical analyse

Comparison of Blood Transfusion Plus Chelation Therapy and Bone Marrow Transplantation in Patients with β-Thalassemia: Application of SF-36, EQ-5D, and Visual Analogue Scale Measures

Background: β-Thalassemia is a prevalent genetic disease in Mediterranean countries. The most common treatments for this disease are blood transfusion plus iron chelation (BTIC) therapy and bone marrow transplantation (BMT). Patients using these procedures experience different health-related quality of life (HRQoL). The purpose of the present study was to measure HRQoL in these patients using 2 different multiattribute quality of life (QoL) scales. Methods: In this cross-sectional study, data were gathered using 3 instruments: a socio-demographic questionnaire, EQ-5D, and SF-36. A total of 196 patients with β-thalassemia were randomly selected from 2 hospitals in Shiraz (Southern Iran). Data were analyzed using logistic regression and multiple regression models to identify factors that affect the patients’ HRQoL. Results: The average EQ-5D index and EQ visual analog scale (VAS) scores were 0.86 (95% CI: 0.83–0.89) and 71.85 (95% CI: 69.13–74.58), respectively. Patients with BMT reported significantly higher EQ VAS scores (83.27 vs 68.55, respectively). The results showed that patients who lived in rural area and patients with BMT reported higher EQ VAS scores (rural; β = 10.25, P = .006 and BMT; β = 11.88, P = .000). As well, SF-36 between 2 groups of patients were statistically significant in physical component scale (PCS). Conclusion: Patients in the BMT group experienced higher HRQoL in both physical and mental aspects compared to those in the BTIC group. More studies are needed to assess the relative cost-effectiveness of these methods in developing countrie

Influence of Clay Wettability Alteration on Relative Permeability

Understanding the wettability of porous materials is important to model fluid flow in the subsurface. One of the critical factors that influences wetting in real reservoirs is the composition of geologic materials. The wetting properties for clay minerals can have a particularly strong impact on flow and transport. In this work, we analyze the chemical composition of a Mt. Simon sandstone core to resolve the microscopic structure of clay regions and assess how alterations to the local wetting properties influence multiphase transport based on core flooding experiments and relative permeability simulations. We show that whichever fluid has greater affinity toward clay minerals will tend to accumulate within these high surface area regions, leading to dramatic shifts in the relative permeability. This work establishes the essential importance of the mineral composition and associated wetting properties in the modeling of flow and transport in reservoir‐scale systems.The authors are thankful to the financial support provided by the University Coalition for Fossil Energy Research (UCFER) Program under the U.S. Department of Energy (DOE)'s National Energy Technology Laboratory (NETL) through the Award Number DE‐FE0026825 and Subaward Number S000038‐USDOE, as well as the support from NETL's Research Participation Program sponsored by the U.S. DOE and administered by the Oak Ridge Institute for Science and Education (ORISE). An award of computer time was provided by the Department of Energy INCITE program and the Summit Early Science Program. This research also used resources of the Oak Ridge Leadership Computing Facility, which is a DOE Office of Science User Facility supported under Contract DE‐AC05‐ 00OR22725

Estimation and prediction of avoidable health care costs of cardiovascular diseases and type 2 diabetes through adequate dairy food consumption: a systematic review and micro simulation modeling study

Background: Recent evidence from prospective cohort studies show a relationship between consumption of dairy foods and cardiovascular diseases (CVDs) and type 2 diabetes mellitus (T2DM). This association highlights the importance of dairy foods consumption in prevention of these diseases and also reduction of associated healthcare costs. The aim of this study was to estimate avoidable healthcare costs of CVD and T2D through adequate dairy foods consumption in Iran. Methods: This was a multistage modelling study. We conducted a systematic literature review in PubMed and EMBASE to identify any association between incidence of CVD and T2DM and dairy foods intake, and also associated relative risks. We obtained age- and sex-specific dairy foods consumption level and healthcare expenditures from national surveys and studies. Patient level simulation Markov models were constructed to predict the disease incidence, patient population size and associated healthcare costs for current and optimal dairy foods consumption at different time horizons (1, 5, 10 and 20 years). All parameters including costs and transition probabilities were defined as statistical distributions in the models, and all analyses were conducted by accounting for first and second order uncertainty. Results: The systematic review results indicated that dairy foods consumption was inversely associated with incidence of T2DM, coronary heart disease (CHD) and stroke. We estimated that the introduction of a diet containing 3 servings of dairy foods per day may produce a $0.43 saving in annual per capita healthcare costs in Iran in the first year due to saving in cost of CVD and T2DM treatment. The estimated savings in per capita healthcare costs were$8.42, $39.97 and$190.25 in 5, 10 and 20-years’ time, respectively. Corresponding total aggregated avoidable costs for the entire Iranian population within the study time horizons were $33.83,$661.31, $3,138.21 and$14,934.63 million, respectively. Conclusion: Our analysis demonstrated that increasing dairy foods consumption to recommended levels would be associated with reductions in healthcare costs. Further randomized trial studies are required to investigate the effect of dairy foods intake on cost of CVD and T2DM in the population

Global, regional, and national burden of traumatic brain injury and spinal cord injury, 1990-2016: a systematic analysis for the Global Burden of Disease Study 2016.

Traumatic brain injury (TBI) and spinal cord injury (SCI) are increasingly recognised as global health priorities in view of the preventability of most injuries and the complex and expensive medical care they necessitate. We aimed to measure the incidence, prevalence, and years of life lived with disability (YLDs) for TBI and SCI from all causes of injury in every country, to describe how these measures have changed between 1990 and 2016, and to estimate the proportion of TBI and SCI cases caused by different types of injury. METHODS: We used results from the Global Burden of Diseases, Injuries, and Risk Factors (GBD) Study 2016 to measure the global, regional, and national burden of TBI and SCI by age and sex. We measured the incidence and prevalence of all causes of injury requiring medical care in inpatient and outpatient records, literature studies, and survey data. By use of clinical record data, we estimated the proportion of each cause of injury that required medical care that would result in TBI or SCI being considered as the nature of injury. We used literature studies to establish standardised mortality ratios and applied differential equations to convert incidence to prevalence of long-term disability. Finally, we applied GBD disability weights to calculate YLDs. We used a Bayesian meta-regression tool for epidemiological modelling, used cause-specific mortality rates for non-fatal estimation, and adjusted our results for disability experienced with comorbid conditions. We also analysed results on the basis of the Socio-demographic Index, a compound measure of income per capita, education, and fertility. FINDINGS: In 2016, there were 27·08 million (95% uncertainty interval [UI] 24·30-30·30 million) new cases of TBI and 0·93 million (0·78-1·16 million) new cases of SCI, with age-standardised incidence rates of 369 (331-412) per 100 000 population for TBI and 13 (11-16) per 100 000 for SCI. In 2016, the number of prevalent cases of TBI was 55·50 million (53·40-57·62 million) and of SCI was 27·04 million (24·98-30·15 million). From 1990 to 2016, the age-standardised prevalence of TBI increased by 8·4% (95% UI 7·7 to 9·2), whereas that of SCI did not change significantly (-0·2% [-2·1 to 2·7]). Age-standardised incidence rates increased by 3·6% (1·8 to 5·5) for TBI, but did not change significantly for SCI (-3·6% [-7·4 to 4·0]). TBI caused 8·1 million (95% UI 6·0-10·4 million) YLDs and SCI caused 9·5 million (6·7-12·4 million) YLDs in 2016, corresponding to age-standardised rates of 111 (82-141) per 100 000 for TBI and 130 (90-170) per 100 000 for SCI. Falls and road injuries were the leading causes of new cases of TBI and SCI in most regions. INTERPRETATION: TBI and SCI constitute a considerable portion of the global injury burden and are caused primarily by falls and road injuries. The increase in incidence of TBI over time might continue in view of increases in population density, population ageing, and increasing use of motor vehicles, motorcycles, and bicycles. The number of individuals living with SCI is expected to increase in view of population growth, which is concerning because of the specialised care that people with SCI can require. Our study was limited by data sparsity in some regions, and it will be important to invest greater resources in collection of data for TBI and SCI to improve the accuracy of future assessments