Volume Balance Approach Research Articles

Continuum scale modelling of salt precipitation in the context of CO2 storage in saline aquifers with MRST compositional

Carbon capture and storage (CCS) would contribute considerably towards climate change mitigation, if it would be implemented on a very large scale; at many storage sites with substantial injection rates. Achieving high injection rates in deep saline aquifers requires a detailed assessment of injectivity performance and evaluation of the processes that alter the permeability of the near-well region. One of the most common forms of the injectivity loss in the context of CO2 storage in saline aquifers is salt precipitation driven by the evaporation of brine into the relatively dry injected CO2 stream. We present a novel compositional transport formulation based on overall-composition variables which models salt as a separate solid phase which could potentially form through two essentially different ways, i.e., kinetic or equilibrium. To model formation drying-out and subsequent halite-precipitation, an accurate and reliable fluid model ePC-SAFT, which can effectively account for ionic effects, is applied. In addition, a volume balance approach (i.e., depending on how far the salt saturation is from the solubility limit) is implemented to estimate solid saturation in a simulation cell. The resulting simulator is benchmarked against several well-known examples, with analytical solutions demonstrating the ability of the code to cover a variety of physical mechanisms. Finally, injection of dry CO2 into a brine-saturated core-scale domain is simulated and sensitivity analyses over various parameters are performed. We show that the new model is capable to quantitatively represent the physics of salt precipitation (for example salt self-enhancing) under different reservoir conditions.

METHODS OF INFILTRATION ESTIMATION FOR FURROW IRRIGATION†

AbstractInfiltration is an important evaluation parameter for furrow irrigation. In this study, most common methods for estimation of furrow irrigation infiltration, their weaknesses and strengths, have been reviewed and discussed to select the best method based on field conditions. Intake families, based on soil characteristic data, could be used as a starting point for analysing surface irrigation infiltration. Since furrow irrigation infiltration is affected by parameters such as soil characteristics and furrow irrigation hydraulic behaviour, the methods of estimating this parameter should reflect field irrigation conditions. In other words, the methods based only on advance time, such as the two‐point method, which is a small part of an irrigation event, could not have considered the soil infiltration during irrigation time. Infiltration is simulated more precisely using methods based on advance time and runoff data such as the multi‐level calibration method and volume balance approach. The execution times and iteration through the simulation algorithms were less for the volume balance approach when compared to the multi‐level calibration method. The variance techniques (based on average infiltration and considering infiltration variation) simulated infiltration almost the same as field measurements using a neutron probe. © 2019 John Wiley & Sons, Ltd.

Water in the forest: rain-vegetation interaction to estimate canopy interception in a tropical borneo rainforest

Canopy interception has an important role in the hydrological cycle. This research was conducted in virgin forest area and Intensive Forest Management System (IFMS) with selective cutting and line planting technique in IUPHHK-HA PT. Sari Bumi Kusuma. This study aims to determine: 1) the value of canopy interception in the virgin forest area and IFMS with selective cutting and line planting technique 2) the relationship between gross rainfall and canopy interception in virgin forest area and IFMS with selective cutting and line planting technique. The value of gross rainfall, stemflow, throughfall, and vegetation canopy cover were used to determine the canopy interception. Canopy interception was calculated by volume balance approach’s method. The relationship between gross rainfall and canopy interception was analyzed using SPSS software and SigmaPlot. The results of this research show that the average value of interception in the Virgin Forest is 30,44%, while the average value of interception in Selective Cutting and Line Planting Silvicultural System (TPTJ) is 15,68%. This result shows that there is a strong and positive relationship between gross rainfall and canopy interception, which is expressed in the equation Ic Ha = 0,0001 (P) 2,9972 dan Ic TPTJ = 0,0004 (P) 2,5795

Managed Aquifer Recharge in fractured crystalline rock aquifers: Impact of horizontal preferential flow on recharge dynamics

To overcome water scarcity issues, Managed Aquifer Recharge (MAR) structures are currently developed in many parts of the world, including poorly permeable terrain like weathered crystalline rocks. In such geological context, characterized by relatively limited groundwater storage mainly associated with fractures located at the interface between the upper weathered layer (saprolite) and the fractured bedrock, the efficiency of MAR is poorly known. To address this question and better understand the factors that control recharge dynamics, an artificial recharge basin was implemented at the Experimental Hydrogeological Park in Telangana (South India), a well-equipped and continuously monitored site situated in Archean granitic terrain. The thickness of the saprolite and hydraulic properties are relatively well known all over the site from previous geophysical surveys and hydraulic tests.To characterize recharge dynamics, recharge has been monitored in different boreholes surrounding the infiltration basin. Infiltration rates and water level data are interpreted by both a volume balance approach and different analytical solutions. In addition, a simple numerical model was used to show how the depth of the permeable interface between saprolite and granite controls recharge dynamics and observed water levels variations. Results show that the permeability of the saprolite/bedrock interface is sufficiently large to allow an efficient recharge that propagates laterally throughout the aquifer through this well connected interface. However, the variable depth of this permeable pathway controls the water level response, acting as a semi-impervious boundary, leading to remarkable water level variations. Thus, our findings show how the characteristics of the most permeable pathways control recharge dynamics in weathered crystalline rocks. In addition, we show how the depth variations of the permeable interface between saprolite and granite may be inferred from the monitoring of water level during recharge events.

Pemodelan Hujan Netto Berdasarkan Tutupan Lahan untuk Analisa Debit Aliran Rendah

This research intends to investigate the land cover change and to obtain the canopy interception in the Lesti sub-watershed, and to produce the rainfall-discharge modeling as the function of net rainfall factor. The methodology consisted of identifying the land cover based on the Normalized Difference Vegetation Index (NDVI) classification of digital satellite images Landsat TM 7 and TM 8, carrying out the field study to obtain the canopy interception used a volume balance approach. The interception rate of Lesti sub-watershed are 5 – 7 % in everage of rainfall, the net-rainfall models of Lesti sub-watershed are Pnetto= P - (-1E07P² + 0.059P +0.260) for land clasification II and Pnetto = P – (-1E07P² + 0.199P + 0.16) for land clasification III, it used as the input on the rainfall-discharge modeling of F.J. Mock, the result showed that the use of net-rainfall on the rainfall-discharge modeling of F.J. Mock increased the accuracy of generated discharge which is strongly influenced by the proportional of land classification.

Development of a fully implicit approach with intensive variables for compositional reservoir simulation

Compositional reservoir simulators are important tools for application in enhanced oil recovery processes. These simulators solve partial differential equations arising from modeling fluid flow in permeable media. Various algorithms for the solution of such partial differential equations are available, which their application greatly impacts the computational performance of the simulators. In this work, a new fully implicit approach called PZS (pressure, overall composition, and water saturation) is proposed and implemented. The new formulation considers pressure, water saturation, and overall compositions as primary variables, reducing the number of unknowns by one when compared to other volume balance fully implicit formulations. The new approach is obtained by a variable change and elimination of a well known volume balance approach. The new approach is implemented in the UTOMPRS simulator that has been developed at The University of Texas at Austin for simulation of several multicomponent/multiphase recovery processes. The PZS formulation is compared to the volume balance based and IMPEC (Implicit Pressure Explicit Composition) formulations in UTCOMPRS. We observe that the PZS approach is, in general, faster than the other approaches tested.

Comparison of two volume balance fully implicit approaches in conjunction with unstructured grids for compositional reservoir simulation

In reservoir simulation, compositional modeling is one of the most commonly used approaches for enhanced oil recovery processes. The methods used to solve the equations arising from the modeling of fluid flow in the reservoirs involve the degree of implicitness and the selection of the primary and secondary equations; primary and secondary variables have a great impact on the computational time. In this work, we implement and compare two fully implicit methods based on volume balance approach. The two methods share the same set of primary variables: pressure and total number of moles of each component. The total number of moles of each component is solved with use its material balance equation, whereas the pressure is solved with use of a volume balance equation. The difference between the two methods is in the nature of the volume balance equation. Whereas for one of the formulations the volume balance equation is the volume constraint and hence the only terms that appear in the Jacobian matrix are those from the volume in which the volume balance is evaluated, the second formulation considers an expanded form of the volume constraint. The main advantage of this expanded equation is that the Jacobian matrix involves information from the volume in which the balance is performed and from all neighboring volumes. The element-based finite-volume method in conjunction with unstructured grids for 2D and 3D reservoirs is used to discretize the material and volume balance equations. For two dimensions, quadrilateral and triangular elements are considered, whereas for three dimensions, hexahedral, prismatic, tetrahedral, and pyramidal elements are considered. The implementations were performed with the UTCOMP simulator developed at the University of Texas at Austin. We compare the performance of the two above-mentioned fully implicit formulations with the implicit pressure explicit composition (IMPEC) formulation of the UTCOMP simulator. The results of several case studies are compared in terms of volumetric oil and gas rates and the total CPU time. The results show good agreement between the production rates and saturation fields for all formulations. Additionally, the performance of the fully implicit methods was superior to that of the IMPEC method as a larger number of grid blocks were used in the simulations.

Development of Surface Irrigation Systems Design and Evaluation Software (SIDES)

A software for the design and evaluation of surface irrigation systems (furrow, border and basin) along with the design of water conveyance systems (open channel and pipe line) is developed to assist users in educational and research organizations. The software named as ‘SIDES’ is developed using Visual Basic 6 programming language. The developed software for the design of surface irrigation systems is based on the volume balance approach and is tested using the available published datasets. Results obtained using the SIDES matched well with the published datasets for all the designs. Besides the design parameters at maximum application efficiency, SIDES also provides detailed tabular and step wise design results. A comprehensive ‘Help’ menu is incorporated in the SIDES to facilitate a thorough understanding of the theory and methodology adopted for the design.

A SIMPLE ELECTRONIC DEVICE FOR MEASURING ADVANCE TIME AND WATER HEIGHT IN FURROW IRRIGATION SYSTEM

A simple electronic device was designed and created instead of traditional method for measuring advance, recession times and water heights inside and along furrows to be more convenient with an optimization method based on the volume balance approach, originally developed for estimating infiltration parameters for furrow irrigation. Field experiments were conducted at a sugar crops research station- Alexandria, where sugar beet was grown in clay soils to test the accuracy of the developed device work in measurements. The furrow irrigation inflow rates were 1.14, 1.42 and 2.25 (l/s). Measurement parameters included furrow geometry, slope, width, length, advance and recession times, and furrow water heights through irrigation event for each inflow rate. A volume balance method was applied to simulate water flow in the furrow system. The results obtained from the used device were compared with the field collected data by traditional method. The results showed that total advance times (tL) were 56.0, 42.4, and 30.5 min, while, total recession times (tR) were 70.0, 53.4, and 46.0 min, for each inflow rate, respectively. The recession time increased as inflow rate decreased; this revealed to water infiltrated into soil takes more time to disappear. Water infiltrated volume increased when inflow rate was decreased due to slow water movement along the furrow. Maximum calculated values of the infiltrated volumes (Vcal) were 0.515, 0.424, and 0.346 (m3/furrow length) while, minimum values were 0.353, 0.299, and 0.271 (m3/furrow length), by applying 1.14, 1.42 and 2.25 (l/s) inflow rates, respectively. The verification results between measured and calculated data showed that, the data for all the irrigation events with the optimization method using modified Kostiakov equation, fall very close to the 45о line degree with deviate a little. This means, that the used electronic device is expected to be superior for estimating infiltration characteristics and evaluating furrow irrigation system with high accuracy.

Perbandingan Nilai Intersepsi Pohon Mahoni (Swietania mahagoni) dan Pohon Pinus (Casuarina cunninghamia)

Comparation of Interception Loss on Mahoni (Swietania mahagoni) and Pinus (Casuarina cunninghamia)ABSTRACT. Interception of rain is the retention of rainwater on surface vegetation before it evaporates back into the atmosphere. Research relating to the interception is still lacking, so it is necessary to study the interception on some types of plants. Although the interception had a little value, and sometimes overlooked, but in some plants have a considerable effect. The purpose of this study was to determine the magnitude of interception in Mahogany and Pine trees, as well as to determine the relationship between rainfall and interception. In this study, samples taken at the Mahogany and Pine trees by the number of 3 samples of each tree. There were two approaches to measure the amount of interception, the first approach was the Volume Balance Approach and the second approach was the Energy Balance Approach. In this study, the volume balance approach, with measurements of rainfall, throughfall, stemflow and interception for ten days of rainfall. The average amount of interception Mahogany obtained 15.5 mm (7.31%) of the total amount of rainfall and the correlation coefficient (r) was at 0.554. While the average number of interception Pinus acquired 87.23 mm (41.15%) of the total amount of rainfall and the correlation coefficient (r) was at 0.505. The size of the interception was influenced by wind speed, density and canopy shape. The research obtained that the interception for pine trees was higher than Mahogany trees. The results also showed that the higher percentage of rainfall, the smaller interception. This was due to the canopy conditions and climatic factors.

The “systolic volume balance” method for the noninvasive estimation of cardiac output based on pressure wave analysis

Cardiac output (CO) monitoring is essential for the optimal management of critically ill patients. Several mathematical methods have been proposed for CO estimation based on pressure waveform analysis. Most of them depend on invasive recording of blood pressure and require repeated calibrations, and they suffer from decreased accuracy under specific conditions. A new systolic volume balance (SVB) method, including a simpler empirical form (eSVB), was derived from basic physical principles that govern blood flow and, in particular, a volume balance approach for the conservation of mass ejected into and flowed out of the arterial system during systole. The formulas were validated by a one-dimensional model of the systemic arterial tree. Comparisons of CO estimates between the proposed and previous methods were performed in terms of agreement and accuracy using "real" CO values of the model as a reference. Five hundred and seven different hemodynamic cases were simulated by altering cardiac period, arterial compliance, and resistance. CO could be accurately estimated by the SVB method as follows: CO = C × PP(ao)/(T - P(sm) × T(s)/P(m)) and by the eSVB method as follows: CO = k × C × PP(ao)/T, where C is arterial compliance, PP(ao) is aortic pulse pressure, T is cardiac period, P(sm) is mean systolic pressure, T(s) is systolic duration, P(m) is mean pressure, and k is an empirical coefficient. SVB applied on aortic pressure waves did not require calibration or empirical correction for CO estimation. An empirical coefficient was necessary for brachial pressure wave analysis. The difference of SVB-derived CO from model CO (for brachial waves) was 0.042 ± 0.341 l/min, and the limits of agreement were -0.7 to 0.6 l/min, indicating high accuracy. The intraclass correlation coefficient and root mean square error between estimated and "real" CO were 0.861 and 0.041 l/min, respectively, indicating very good accuracy. eSVB also provided accurate estimation of CO. An in vivo validation study of the proposed methods remains to be conducted.

Comparison of Multilevel Calibration and Volume Balance Method for Estimating Furrow Infiltration

Furrow irrigation is one of the oldest methods of irrigation in which the soil surface is used to convey and infiltrate water. The most important problem in the path of improving furrow irrigation performance is the difficulty of estimating the infiltration function. In this study, the multilevel calibration method and the volume balance approach were used for estimating the Kostiakov-Lewis infiltration equation parameters and roughness coefficient for the constant and cutback inflow hydrograph shapes for furrow irrigation using field data. The multilevel calibration method predicts the total volume of runoff and infiltration with less relative error than the volume balance approach. The results of this study indicate that the simple volume balance approach and the multilevel calibration method predicted infiltration equation parameters and roughness coefficient with nearly the same accuracy, but the volume balance approach involved shorter execution times and required less iteration through the simulation algorithms than the multilevel calibration method.

Generalized Darcy's Law by Control Volume Analysis Including Capillary and Orifice Effects

Abstract The equation of motion for single-phase fluid flow through porous media is derived by rigorous analysis of forces acting upon fluid based on a control volume momentum balance approach. Resistive forces associated with pore surface and pore throat are characterized by the capillary-orifice model of porous media. This analysis reveals deficiencies of previous efforts in deriving the generalized momentum equation. The present approach provides resolution to several issues, including porous media averaging of the pressure and shear-stress terms, effect of porous media heterogeneity and anisotropy, and threshold pressure gradient that must be overcome for fluid to flow through porous media. Introduction Derivation of generalized equation of momentum for fluids flowing through porous media has occupied many researchers and is not by any means a trivial task. Since its inception, the fundamental law of flow through porous media given by Darcy(1) has been scrutinized greatly and been the subject for many modifications to take into account the effect of other factors which are not considered by this law. In spite of an exhausting amount of effort, and prolonged occupation and obsession with derivation of an improved formulation, a satisfactory generalized equation of fluid motion in porous media still does not exist. In an effort to shed some light into the adequate treatment of the control volume balance approach, this paper attempts to revisit, modify and improve the generalized formulation presented by Das(2). Many researchers attempted to improve Darcy's law by various approaches to take into account other conditions of practical importance. The outstanding approaches have been developed primarily on the bases of dimensional analysis(3), control volume balance(1, 2) and porous media averaging(4–12). There are some discrepancies, however, between the results presented by various researchers. As pointed out by Civan(13), porous media averaging does not only require extremely complicated and intricate algebraic manipulation procedures, but also has been implemented inadequately in many studies. Consequently, debate about proper handling of various issues dealing with porous media averaging is still continuing, judging by the high number of papers being published. The results presented by various studies do not agree whether the porous media averaged pressure gradient term should include the porosity. The same concern can be raised about shear-stress. Liu and Masliyah(12) emphasize that averaging of pressure and viscosity terms in the microscopic equation of motion should be treated differently than the other terms. Also, the mathematical definition of partial derivatives assumes a limit as control volume approaches zero, i.e., collapses to a point of zero volume. By and large, discussion of differences introduced by the application of such a condition in deriving porous media equations of mass, momentum and energy conservation have been omitted, whereas, representative elementary bulk volume is a finite quantity in definition of volume averaged quantities used for deriving the porous media (macroscopic) equation of motion.

Infiltration parameters from surface irrigation advance and run-off data

A computer model was developed to employ runoff data in the calculation of the infiltration parameters of the modified Kostiakov equation. The model (IPARM) uses a simple volume balance approach to estimate the parameters from commonly collected field data. Several data sets have been used to verify the procedure. Infiltration parameters were calculated using both advance and runoff data combined and advance data alone. Simulations of each example using SIRMOD were compared to the measured data to identify the possible benefits of the procedure. The inclusion of runoff did not compromise the ability to reproduce the advance curve however the simulations are more capable of reproducing the measured runoff rates and volumes and therefore offer better estimations of the total volume applied to the soil (in one case a reduction in error of the total infiltration from 22% to 1%). This procedure will be of most benefit where the infiltration parameters are expected to represent soil hydraulic characteristics for times greater than the completion of the advance phase. Further analysis has shown that the infiltration parameters are more sensitive to runoff than the advance highlighting the requirement for accurate field measurement and a weighting factor between the advance and runoff errors.

Application of the optimization method for estimating infiltration characteristics in furrow irrigation and its comparison with other methods

The infiltration characteristics of a soil vary spatially and temporally, and due to this the available methods for estimating the characteristics in furrow irrigation are either not suitable or have restrictions for their field use. An optimization method based on the volume balance approach, originally developed for estimating infiltration parameters in border irrigation, and using multiple observations of arrival time of the wetting front was modified for furrow irrigation. The method was applied to 13 irrigation events on furrows monitored on a farm in northern New South Wales, Australia. The soil type at the experimental site has a high clay content (up to 67%) and develops cracks when dry. In addition to the optimization method, one-point and two-point methods using observations of arrival time reported in the literature were also used. The accuracy of different methods was evaluated by comparing the calculated total volume of water infiltrated into the furrow with that observed in the field. The optimization method was the most accurate and the one-point and the two-point were the least accurate among three methods considered in the present study. A possible explanation for a poor performance of the one-point and two-point methods might be related to the assumptions made in the derivation of the methods and the unsuitability of the Philip and the Kostiakov infiltration equations used for the field condition in the present study.

Determination of infiltration rate from border irrigation advance and recession trajectories

A volume-balance technique utilizing irrigation advance and recession functions, numerical integration, and an optimization procedure was developed to determine infiltration parameters. The procedure is simple yet rational and accounts for spatial variability of soil characteristics. The required data are flow rate, the coefficients and exponents of the advance and recession functions, and inflow shut-off time. In a field experiment on a clay loam soil (typical of southern Alberta) at the Lethbridge Research Centre, infiltration rates estimated by this technique were similar and in close agreement with those measured with a ring infiltrometer. Except for two border strips, there were no significant mean differences between simulated ( I s) and measured ( I m) infiltration rates. In the two non-conforming border strips, field measured infiltration rates were higher than those simulated with the volume balance approach, most likely due mainly to spatial variability of soil characteristics and partly to lateral flow which occasionally occurs when measuring infiltration with a ring infiltrometer.

Intake Parameters from Advance and Wetting Phases of Surface Irrigation

A volume balance approach to determine the parameters of the Kostiakov or modified Kostiakov infiltration equations in border and furrow irrigation is presented. The approach requires measured data...

A Direct IMPES-type Volume Balance Technique for Adaptive Implicit Steam Models

ABSTRACT In this paper an IMPES-type thermal volume balance technique is presented applying a direct solution of the set of mass and energy conservation equations. The effect of the convective energy transport can be considered m the isothermal pressure (volume balance) equation by a modification of the coefficients. The solution yields the pressure implicitly, component masses and energy explicitly (IMPEME technique) while keeping the mass, and energy balances. The explicit treatment demands timestep limitation. Volume balance errors are used to control timesteps. Compared with the direct isothermal volume balance approach, significant volume balance errors occur only at the front and at well regions. This is the portion of the reservoir in an adaptive implicit method (AIM) where the fully implicit handling is used. The IMPEME method is proposed to be the explicit approximation of a thermal AIM. The method can also be incorporated in black oil or compositional isothermal volume balance models to include thermal effects.

Analytical Model for Border Irrigation

This study develops a simple analytical model, using the volume balance approach, to simulate all phases of border irrigation. The surface and subsurface flow profiles in the advance phase are assu...

An analytical closed border irrigation model I. Theory

This paper, Part I in a series of two, describes an analytical model for the entire irrigation cycle of closed borders, using a volume balance approach. The irrigation cycle is simulated in five phases: advance, storage, vertical recession, horizontal recession, and impounding recession. The model will be verified with experimental data in Part II.