Interpretation of two-phase relative permeability curves through multiple formulations and Model Quality criteria

We illustrate the way formal model identification criteria can be employed to rank and evaluate a set of alternative models in the context of the interpretation of laboratory scale experiments yielding two-phase relative permeability curves. We consider a set of empirical two-phase relative permeability models (i.e., Corey, Chierici and LET) which are typically employed in industrial applications requiring water/oil relative permeability quantifications. Model uncertainty is quantified through the use of a set of model weights which are rendered by model posterior probabilities conditional on observations. These weights are then employed to (a) rank the models according to their relative skill to interpret the observations and (b) obtain model averaged results which allow accommodating within a unified theoretical framework uncertainties arising from differences amongst model structures. As a test bed for our study, we employ high quality two-phase relative permeability estimates resulting from steady-state imbibition experiments on two diverse porous media, a quartz Sand-pack and a Berea sandstone core, together with additional published datasets. The parameters of each model are estimated within a Maximum Likelihood framework. Our results highlight that in most cases the complexity of the problem appears to justify favoring a model with a high number of uncertain parameters over a simpler model structure. Posterior probabilities reveal that in several cases, most notably for the assessment of oil relative permeabilities, the weights associated with the simplest models is not negligible. This suggests that in these cases uncertainty quantification might benefit from a multi-model analysis, including both low- and high-complexity models. In most of the cases analyzed we find that model averaging leads to interpretations of the available data which are characterized by a higher degree of fidelity than that provided by the most skillful model

Laboratory-scale Investigation of Two-phase Relative Permeability

We present experimental investigations of two-phase (oil and water) relative permeability of laboratory scale rock cores through a joint use of direct X-ray measurement and flow-through investigations. The study is motivated by the observation that appropriate modeling of oil and water displacement in porous media or fractured rocks requires to be firmly grounded on accurate and representative core flood experiments and their appropriate interpretation. Experimental data embed key information relating relative permeability to observables. In this context, direct measurement of in-situ fluid saturation through X-Ray techniques has the unprecedented ability to characterize key processes occurring during the displacement of immiscible fluids through natural permeable materials. Water saturation profiles determined by X-ray scanner can then be linked to relative permeability curves stemming from two-phase flow experiments. We illustrate the benefit of employing direct X-Ray measurements of fluid saturation through a set of laboratory experiments targeted to the estimate of two-phase relative permeabilities of homogeneous samples (sand pack and Berea sandston core). Data are obtained for a range of diverse fractional flow rates and provide information at saturations ranging from irreducible water content to residual oil saturation. Our X-Ray saturation data are consistent with an interpretation of measured relative permeabilities as associated with water-wet rock conditions. The comparison of different preamble samples result high displacement efficiency and recovery factor corresponds to the high permeable and well-connected pores

Evaluation the efficiency of school-based assertiveness program on self-advocacy and self-determination skills in high school students

زمینه و هدف: توجه به خودتصمیم‌گیری و خود‌حمایتی دانش‌آموزان، برای موفقیت در زندگی و آماده‌شدن جهت تصمیم‌گیری، امری ضروری است. مطالعه حاضر با هدف ارزیابی اثربخشی برنامه جرات‌ورزی بر مهارت‌های خودتصمیم‌گیری و خود‌حمایتی دانش‌آموزان دبیرستانی انجام شده است. روش بررسی: در این مطالعه نیمه تجربی140دانش‌آموز دختر (70 نفر آزمون و70 نفر کنترل) از دبیرستان های روزانه اصفهان شرکت داشتند. 8 جلسه برنامه به همراه پرسشنامه‌های اطلاعات دموگرافیک، جرات‌ورزیRichey و Gambrillو مهارت‌های خودتصمیم‌گیری و خودحمایتی به کار گرفته شد. اطلاعات با استفاده از آزمون‌های آماری تی مستقل، آزمون آنالیز واریانس با تکرار مشاهدات و کای اسکوئر تحلیل شدند. یافته‌ها :آزمون کای‌اسکوئر، اختلاف معنی‌داری را در متغیرهای دموگرافیکی بین دو گروه نشان نداد (05/0P)، اما در گروه مورد این اختلاف معنی‌دار بود (002/0P=). همچنین آزمون آنالیز واریانس با تکرار مشاهدات، اختلاف میانگین نمره مهارت‌های خودتصمیم‌گیری و خود‌حمایتی دانش‌آموزان گروه شاهد را معنی دار نشان نداد (05/0P>)، ولی در گروه مورد این نتایج معنی‌دار مشاهده شد (05/0

Influence of hanger system on structural behaviour of suspension footbridges under pedestrian dynamic loads

none2noFaridani, Hadi Moghadasi; Moghadasi, LeiliFaridani, Hadi Moghadasi; Moghadasi, Leil

Petrophysical Well Log Analysis through Intelligent Methods

Objectives/Scope: Estimating reservoir petrophysical parameters such as porosity, permeability is vital to an in-situ hydrocarbon reserve evaluation. However, conventional laboratory measurements of core samples are extensively costly and time consuming. This work particularly concerns about applicability of different intelligent methods in reproducing horizontal porosity and permeability as main petrophysical parameters of reservoirs. Methods, Procedures, Process: To do so, information in terms of log depth, caliper, conductivity, sonic, natural gamma, density and neutron, water saturation, percent of shale volume, type of lithology as well as horizontal porosity and permeability are collected from well logging (from a total number of 19 exploratory wells) in an oil field in middle-east. Such preliminary design of input-output variables validates later through results from implementing neural networks to come up with selection of optimum number of input variables. Statistical preprocessing also carried out in order to understand the variational correlation of the collected dataset. Four different intelligent techniques of: (i) conventional artificial neural networks, (ii) artificial neural networks based on PCA transformation, (iii) statistical (bootstrapping) neural networks, and (iv) combined neural and fuzzy logic (neurofuzzy inference) networks trained, validated and tested in reproducing available measurements. Results, Observations, Conclusions: Results from implementing mentioned comparative techniques show higher capability of statistical neural network based on bootstrapping approach for our case study. Such network with 11 input parameters provided reliable performances of 93% and 77% respectively through training and validation phases of estimating permeability as desired output. For estimating porosity, results from a trained network with 9 input parameters made 75% and 71.5% correlation fit to the observation values in training and validation phases, respectively. Novel/Additive Information: Results from this study are expected to be applicable in: (i) dealing with incomplete well log dataset, (ii) estimating required petrophysical properties of reservoirs and (iii) decision making about measurements design

Characterization of two- and three-phase relative permeability of water-wet porous media through X-Ray saturation measurements

We present experimental investigations of multi-phase (two-phase (oil/water, oil/gas) and three-phase (oil/ water/ gas)) relative permeabilities performed on laboratory scale rock cores. Two- and three-phase relative permeabilities data were obtained on two core samples (a Sand-pack and a Berea sandstone) by way of a Steady-State (SS) technique. Spatial and temporal dynamics of in-situ saturations along core samples were directly measured through an X-Ray absorption technology. The latter rendered detailed distributions of (section-averaged) fluid flow phases through the medium, which can then be employed for the characterization of relative permeabilities. The technique also enabled us to clearly identify the occurrence of end-effects during the experiments and to quantify the reliability of corrective strategies. For the oil/water settings we considered low and high viscose oil, our findings supporting the observation that relative permeability to oil and water was sensitive to oil viscosity. Three-phase experiments were performed by following an IDI (Imbibition-Drainage-Imbibition) saturation path. The complete experimental data-base is here illustrated and juxtaposed to results obtained by the implementation of simple and commonly employed three-phase relative permeability models. In the three-phase setting, water and gas relative permeabilities display an approximately linear dependence on the logarithm of their own saturation. Consistent with the observation that oil behaves as an intermediate phase in our system, three-phase oil relative permeabilities lie in between those of their two-phase counterparts. Our data-set stands as a reliable reference for further model development and testing, as only a limited quantity of three-phase data are currently available

The effect of family-centered empowerment model on quality of life and self efficacy of multiple sclerosis patients family care givers

Abstract: (33494 Views) Introduction: Family is primary source for caring of patients. The caregivers make patients in family with economical, affective and health care support. The needs for caregiver’s family increased with hospital - central care to community - center care. Community center care makes increase of knowledge of the care givers on the patients in house. This study with objective of family - center empowerment model was done on the quality of life and self efficacy of the care - givers of multiple sclerosis patients. Methods: This study is clinical trial with 70 multiple sclerosis patients that enrolled in the multiple sclerosis society of Iran classified in two groups based on random allocation (35 patients care givers case and 35 patients care givers in control group). The eight sessions of educational program based on educational needs of caregivers done for three months and matured with checklist of self reported for applied of programs. After three months of program done measured quality of life and self efficacy with questionnaire in case and control groups. Data analyzed with deductional satisfaction tests. Results: Results showed no significant difference on the quality of life and self efficacy in two groups of the case and control before intervention based on independent t-test (P≥0.05) whereas t-test showed significant difference in two groups of case and control after intervention (P=0.001). Pairs t-test showed significant difference in increased of the quality of life and self efficacy in care givers of case group after three mounths of intervention (P=0.001) where as t-test showed no significant difference in all above factors in care-givers of control group after three mounts (P≥0.05). Conclusion: The care - givers of chronic patients considered high risk tendency for covered disease that tolerates high tension. The interaction such as empowerment based on educational needs for them improves attitudes on the sign of disease changed, behavioral signs and also intervention in low - economic safe and affective method for care - givers of multiple sclerosis patients helps them to manage stress and spiritual tensions and increases quality of life

Implementation of Three-Phase Black-Oil Reservoir Models Assisted by Micro-Scale Analyses

Objective/Scopes: We aim at developing a viable workflow for the characterization of reservoir responses under Water Alternating Gas (WAG) conditions for enhanced oil recovery. We do so through a numerical Monte Carlo (MC) framework and by relying on (i) a classical approach, which is grounded on employing results from laboratory-scale core-flooding experiments or (ii) an approach based on relative permeability curves inferred from pore-scale numerical simulations. In these settings we investigate (i) the way uncertainties associated with the parameters of a reservoir model estimated through these approaches propagate to target modeling goals and (ii) assess (through Global Sensitivity Analyses) the relative importance of the uncertain quantities controlling the reservoir behavior via given model outcomes. Methods/Procedures: We consider uncertainty in (a) porosity and absolute permeability as well as (b) parameters of relative permeability models. Three scenarios are assessed, accounting for spatial distribution of porosity and absolute permeability with differing degrees of complexity and corresponding to (i) homogeneous; (ii) randomly heterogeneous; and (iii) well-connected randomly heterogeneous fields. Spatial realizations of the heterogeneous fields are generated considering Gaussian random fields with a Gaussian kernel variance driving the degree of spatial correlation. The two modeling approaches considered take advantage of two-phase relative permeability curves, which are interpreted via commonly used models with uncertain parameters. Three-phase relative permeabilities are then characterized through a previously developed and tested sigmoid-based oil relative permeability model by taking into account hysteretic behavior of gas relative permeability. All field-scale simulations are performed on a simple reservoir model and are set within the MRST suite. Results/Conclusions: In the case of a homogeneous reservoir, we note that reservoir simulation responses are strongly sensitive to the degree of convexity of the two-phase relative permeability curves. In the case of heterogeneous reservoir settings, results are almost similarly sensitive to porosity, characteristics of the relative permeability model, and the degree of heterogeneity of the reservoir. In the case of well-connected (randomly) heterogeneous fields, the importance of the porosity is stronger than in the heterogeneous setting lacking well connected regions. Novel/Additive Information: Characterization of reservoir model attributes relying on pore-scale simulation approaches in the presence of uncertainty can provide a robust term of comparison which can be integrated within a classical reservoir simulation approach relying on relative permeability data stemming from core-flooding experiments. Our results document that uncertainties in the evaluation of (i) reservoir model petrophysical attributes (porosity/permeability) and (ii) relative permeability model parameters can differently influence field-scale simulation outputs, depending on the degree of spatial heterogeneity of the reservoir