Mechanics of Static and Dynamic Filtration In the Borehole

1963 ◽  
Vol 3 (03) ◽  
pp. 236-244 ◽  
Author(s):  
H.D. Outmans
Keyword(s):  
Porous Medium ◽  
Filtration Rate ◽  
Filter Cake ◽  
Fluid Pressure ◽  
Rate Of Change ◽  
Filtration Theory ◽  
Dynamic Conditions ◽  
Dynamic Filtration ◽  
Static Conditions ◽  
Filter Cakes

Abstract The mechanics of filtration are described by a theoretical-empirical nonlinear diffusion equation which, under certain circumstances, may be linearized and then solved explicitly.For filtration under static conditions linearization leads to a boundary value problem analogous to a heat flow problem with a known explicit solution. The corresponding solution for static filtration is compared with published experimental data.Under dynamic conditions filtration takes place in three successive stages. During each of these the rate of filtration and/or the thickness of the filter cake are different functions of the filtration time. The proposed mechanism explains the observed high resistance of dynamically deposited filter cakes against erosion and also the connection between filtration rate and viscosity of the drilling fluidSeveral of the quantities governing dynamic filtration have no counterpart in the static filtration mechanism. The static filtration rate is, therefore, not a reliable measure for the dynamic rate and vice versa. Introduction Filtration under simulated borehole conditions, i.e., either from a static suspension or from a suspension flowing parallel to the filter cake (dynamic filtration), has been the subject of several laboratory studies. This experimental and theoretical work showed that many aspects of the filtration mechanism cannot be explained by an elementary filtration theory based on the assumption that the filter cake is incompressible. For a more satisfactory theory compressibility should be taken into account. This has been done, at least to some extent, in the filtration theory developed for the chemical industry. Surveying the literature (see Ref. 8 for a bibliography) it becomes apparent that, although several properties of filter cakes deposited from many different suspensions have been measured, including compressibility, the filtration equations are essentially empirical in nature. No attempt has been made, for instance, to develop filtration theory along the lines of consolidation theory. This theory, upon which a highly successful development in soil mechanics rests, would appear to be an excellent starting point for a filtration theory since the compressibility concept is an essential part of it. As we will use this theory in the following development it is well to state the four assumptions on which it is based:The fluid flow through a compressible porous medium is governed by Darcy's law.The rate of change in fluid content of an element of the porous medium is proportional to the rate of change of solid pressure between the particles.The solid particles are incompressible within the range of pressures considered.The total pressure on a surface normal to the line of flow is equal to the sum of the fluid pressure and the pressure between the particles (solid pressure) at that surface. To calculate the rate of filtration and other quantities of interest it is necessary to know the filter cake compressibility and the permeability as a function of the solid pressure. It has not been possible to calculate these functions from theoretical considerations and they will therefore be introduced in this paper as empirical expressions. Both are determined in a compression cell where the cake is subjected to a mechanical load. Permeability and compressibility are measured after the solid pressure has stabilized, i.e., after the excess fluid pressure has been dissipated and the uniform pressure is transmitted entirely by the solids.The permeability and compressibility thus determined are not the same as during filtration in the borehole, under either static or dynamic conditions, because then, due to frictional drag, the solid pressure and hence also the permeability and compressibility vary along a line normal to the direction of the mean flow and can only be defined locally. DERIVATION OF THE FILTRATION EQUATION FOR COMPRESSIBLE FILTER CAKES As the filter cake in the borehole is thin compared to the radius of the hole the filtration may be considered as linear. Taking the x-axis normal to the wall, with its origin at the formation, we have, according to Darcy's law, ...........................(1) SPEJ P. 236^

Filter Cake Properties of Water-Based Drilling Fluids Under Static and Dynamic Conditions Using Computed Tomography Scan

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Salaheldin Elkatatny ◽  
Mohamed Mahmoud ◽  
Hisham A. Nasr-El-Din
Keyword(s):  
Computed Tomography ◽  
Filter Cake ◽  
Drilling Fluid ◽  
Filter Press ◽  
Filter Medium ◽  
Drilling Fluids ◽  
Dynamic Conditions ◽  
Water Based ◽  
Porosity And Permeability ◽  
Static Conditions

Previous studies considered the water-based drilling fluid filter cake as homogenous, containing one layer with an average porosity and permeability. The filter cake was recently proved to be heterogeneous, containing two layers with different properties (thickness, porosity and permeability). Heterogeneity of the filter cake plays a key role in the design of chemical treatments needed to remove the filter cake. The objectives of this study are to describe filter cake buildup under static and dynamic conditions, determine change in the filter medium properties, and obtain the local filtration properties for each layer in the filter cake. A high pressure high temperature (HPHT) filter press was used to perform the filtration process at 225 °F and 300 psi. A CT (computed tomography) scanner was used to measure the thickness and porosity of the filter cake. The results obtained from the CT scan showed that under static conditions, the formation of filter cake changed from compression to buildup; while under dynamic conditions, the filter cake was formed under continuous buildup. The CT results explained the changes in the thickness and porosity of each layer of the filter cake with time. The CT scans showed the change in the properties of the ceramic disk, such as porosity and permeability, which affect the calculation of the filter cake permeability. The change of the properties of the filter medium was ignored in previous studies.

scholarly journals The Effect of Various Hydroxide and Salt Additives on the Reduction of Fluoride Ion Mobility in Industrial Waste

2021 ◽  
Vol 13 (3) ◽  
pp. 1554
Author(s):  
Tadas Dambrauskas ◽  
Kestutis Baltakys ◽  
Agne Grineviciene ◽  
Valdas Rudelis
Keyword(s):  
Liquid Medium ◽  
Silica Gel ◽  
Ion Mobility ◽  
Fluoride Removal ◽  
Dynamic Conditions ◽  
Treatment Conditions ◽  
Medium Flow ◽  
Silica Gel Waste ◽  
Fluorine Ions ◽  
Static Conditions

In this work, the influence of various hydroxide and salt additives on the removal of F− ions from silica gel waste, which is obtained during the production of AlF3, was examined. The leaching of the mentioned ions from silica gel waste to the liquid medium was achieved by the application of different techniques: (1) leaching under static conditions; (2) leaching under dynamic conditions by the use of continuous liquid medium flow; and (3) leaching in cycles under dynamic conditions. It was determined that the efficiency of the fluoride removal from this waste depends on the w/s ratio, the leaching conditions, and the additives used. It was proven that it is possible to reduce the concentration of fluorine ions from 10% to <5% by changing the treatment conditions and by adding alkaline compounds. The silica gel obtained after the leaching is a promising silicon dioxide source.

A New Technical Standard Procedure to Measure Stimulation and Gravel-pack Fluid Leak-off under Dynamic Conditions

2015 ◽  
Author(s):  
Mahmoud Asadi ◽  
Brain Ainley ◽  
David Archacki ◽  
Eric Aubry ◽  
Harold Brannon ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Standard Procedure ◽  
Oil And Gas Industry ◽  
Testing Procedure ◽  
Technical Standard ◽  
Gas Wells ◽  
Dynamic Conditions ◽  
Oil And Gas Wells ◽  
Static Conditions ◽  
Gravel Pack

Abstract Historically, leak-off analyses of stimulation fluids have been performed using in-house laboratory procedures. The lack of industry standard procedures to perform leak-off and wall building coefficient analyses of stimulation fluids has introduced inconsistency in both results and reporting for many years. A technical standard adopted in 2006 by both API and ISO for static conditions has provided the oil and gas industry with the first standardized procedure to measure and report leak-off1. However, the more complex testing under dynamic conditions was not addressed. As a result, a group of industry experts have compiled their years of experiences in developing a new technical standard to measure the leak-off characteristics of stimulation and gravel-pack fluids under dynamic flow conditions. Stimulation and gravel-pack fluids are defined, for the purpose of this technical standard, as fluids used to enhance production from oil and gas wells by fracturing and fluids used to place filtration media to control formation sand production from oil and gas wells. Leak-off is the amount of fluid lost to porous media during these operations. The leak-off procedure was developed through the colaberation of several industry companies by evaluating numerous in-house laboratory techniques and conducting round robin testing to ensure that any modifications to these procedures were reliable and repeatable. The new standard provides a step-by-step procedure that includes fluid preparation, experimental equipment design, testing procedure and data analyses for fluids exhibiting viscosity controlled leak-off or wall building characteristics. Example calculations are reviewed within this paper.

scholarly journals Static and Dynamic Performance of Vector Control on Induction Motor with PID Controller: An Investigation on LabVIEW

2021 ◽  
Vol 4 (2) ◽  
pp. 83-96
Author(s):  
Abdillah Aziz Muntashir ◽  
Era Purwanto ◽  
Bambang Sumantri ◽  
Hanif Hasyier FAkhruddin ◽  
Raden Akbar Nur Apriyanto
Keyword(s):  
Vector Control ◽  
Induction Motor ◽  
Pid Controller ◽  
High Reliability ◽  
Load Torque ◽  
Set Point ◽  
Dynamic Conditions ◽  
Low Speed ◽  
Three Phase ◽  
Static Conditions

A three-phase induction motor is often used in everyday life because of its high reliability. However, it is associated with some disadvantages, including difficulties in maintaining constant speed during load changes and speed regulation due to the decoupled system. Therefore, this study aims to adjust the three-phase induction motor control to become a separate amplifier DC motor by setting the vector control using the IFOC method, which changes the coupled to the decoupled system. The speed settings are equipped with a PID controller where its parameters, which are obtained using Ziegler Nichols, produce speed output with fast research time and small steady-state errors. This research was conducted to observe and analyze the performance of a controller based on the IFOC approach with a PID controller at speed differences, with static and dynamic conditions in the entire speed working area. In the first stage of the research, simulation is carried out with static conditions, namely changes in speed variations throughout the work area (low speed to high speed), the next stage is a simulation with dynamic conditions, which is to provide changes in the value of the load torque when the system is operating. The simulation result carried out with LabVIEW shows a response time of 1.13 ms, a settling time of 9.9 ms, and a steady error of 0.4% at the 500 Rpm set point. It also indicated dynamic characteristics with a recovery time of 4.9 ms at the 300 Rpm set point. When operated at low speed, IFOC with PID controller has a stable response. But In dynamic conditions, the use of a PID controller is considered unsuitable. This is because the PID controller is less fast and less robust in responding to the system when conditions change in the value of the load torque.

scholarly journals On some pre-Cambrian metadolerites from the central Ivigtut region SW Greenland

1965 ◽  
Vol 52 ◽  
pp. 1-42
Author(s):  
E Bondesen ◽  
N Henriksen
Keyword(s):  
Shear Zones ◽  
Metamorphic Grade ◽  
Amphibolite Facies ◽  
Dynamic Conditions ◽  
Static Conditions

After their consolidation, the Ketilidian gneisses were transversed by several generations of tensional, doleritic dykes-the Kuánitic dykes. During a later episode (the Sánerutian) these dykes were metamorphosed to varying degrees of alteration which increase in the described area from west to east. Along a specific metadolerite, which can be traced approx. 40 km, the metamorphic grade changes from greenschist to amphibolite facies. In the western parts static conditions and in the eastern parts dynamic conditions, prevailed during the alteration. Sánerutian shear zones in the eastern parts depict the dynamic conditions found here.

scholarly journals Using natural aluminosilicate (vermiculite) sorbent for purifying waste water from antibiotics

2022 ◽  
Vol 6 (4) ◽  
pp. 387-394
Author(s):  
D. S. Galchenko ◽  
M. G. Smirnova ◽  
L. I. Sokolova
Keyword(s):  
Waste Water ◽  
Total Concentration ◽  
Total Content ◽  
Fish Farming ◽  
Model System ◽  
Fish Processing ◽  
Dynamic Conditions ◽  
Natural Aluminosilicate ◽  
Antibiotics Detection ◽  
Static Conditions

The problem of wastewater treatment from residual antibiotics is of particular relevance, since these drugs are used in many agricultural sectors. Antibiotics get into water, animal and human bodies, where they can accumulate negatively affecting health. The aim of this article is to study the possibility of using natural aluminosilicate vermiculite sorbent from the Koksharovskoye field (Primorsky Region) for purifying fish processing and fish farming enterprises’ waste water from antibiotics (chloramphenicol, tetracycline, cefazolin, cefuroxime, ceftriaxone, cefepime and and ciprofloxacin) under static and dynamic conditions. The study was carried out on a model wastewater system with injected antibiotics. The purification ability of the model system using the method of spectrophotometric antibiotics detection is analyzed. Under static conditions, the total content of antibiotics varied from 0.25 mg to 1.00 mg per 1 g of sorbent. Under dynamic conditions, the antibiotic content was 0.025 mg per 1 g of sorbent. High values of absorption for all studied antibiotics, except for chloramphenicol, were achieved both in static and dynamic modes. For chloramphenicol, when examined under static conditions, the maximum absorption rate was 45% with the minimum total concentration of antibiotics. With an increase in the load on the sorbent, the degree of absorption decreased to 3%. Thus, vermiculite modified with 7% hydrochloric acid is a promising sorbent for cleaning water bodies from residual antibiotics.

Development of Novel Test Methodology to Understand the Mechanisms of Halite Inhibition and Environmentally Acceptable Halite Scale Inhibitors for High Temperature Application

2014 ◽  
Author(s):  
Kimberley Ho ◽  
Tao Chen ◽  
Ping Chen ◽  
Thomas Hagen ◽  
Harry Montgomerie ◽  
...  
Keyword(s):  
High Temperature ◽  
Test Procedure ◽  
Dynamic Test ◽  
Operation Time ◽  
Field Conditions ◽  
Dynamic Conditions ◽  
Test Methodology ◽  
Static Conditions ◽  
Batch Treatment ◽  
Nucleation Growth

Abstract Halite deposition is most commonly observed in gas/gas condensate fields with low water cut, high TDS produced brines and high temperature. Halite is notoriously difficult to inhibit and there are limited studies focused on halite due to it being incredibly challenging to have an effective test methodology under laboratory conditions that reflect the field conditions. The mechanisms of halite inhibition are unclear. In the published literature, static jar testing is primarily used to evaluate the performance of halite inhibitors. It is not representative of dynamic field conditions and provides limited information of halite inhibition. A new methanol driven dynamic test methodology has been developed alongside a novel jar test procedure, which together provides an effective methodology to evaluate halite inhibition under both static and dynamic conditions and provides an insight into the understanding of the mechanisms of halite inhibition. Using these novel test methodologies, four short-listed inhibitor chemistries including environmentally acceptable inhibitors were assessed and categorised into two types based on the understanding of the mechanism. ➤ Nucleation/growth inhibitors. Inhibitors reduce the nucleation/growth of halite crystals and give good performance under both static and dynamic test conditions.➤ Dispersion inhibitors. Inhibitor doesn't stop the nucleation/growth of halite crystals and gives poor performance under static conditions, but good performance under dynamic conditions due to dispersion effect. Both types of halite inhibitors have been successfully deployed in the fields through continuous injection or batch treatment. Coreflood tests were carried out to confirm the potential risk of formation damage during downhole batch treatment. Other deployment methods have been discussed such as through methanol injection line as both inhibitors are fully methanol compatible. This paper will give a comprehensive study of halite inhibition for challenged wells, including prediction, novel methodology, program of laboratory qualification, mechanism understanding and field deployment, coupled to the development of a chemical technology toolbox to design field halite applications. The value that a fuller understanding of halite control gives the industry is the ability to reduce/eliminate water wash application to control halite formation and so improve well operation time. If halite inhibition is considered at the capex phase of field development, provisions can be made for chemical injection facilities to maintain uninterrupted production.

Silicon Dissolution from Microporous Silicon Substituted Hydroxyapatite and its Effect on Osteoblast Behaviour

2006 ◽  
Vol 309-311 ◽  
pp. 117-120 ◽  
Author(s):  
Katharina Guth ◽  
Tom Buckland ◽  
Karen A. Hing
Keyword(s):  
Significant Variation ◽  
Direct Contact ◽  
Culture Medium ◽  
Initial Level ◽  
Culture Conditions ◽  
Dynamic Conditions ◽  
Medium Change ◽  
Static Conditions ◽  
Silicon Dissolution ◽  
Apatite Lattice

In this study silicon release from SiHA into tissue culture medium was investigated under static and semi-dynamic conditions. The effect of silicon release under semi-dynamic conditions on alkaline phosphatase activity (ALP) and collagen I (CICP) expression by osteoblast like cells (HOS TE85) was also examined. Under static conditions a low level of silicon was released within 24 hours, this initial level dropped over 3-7 days but subsequently increased again by 10-14 days. Under semi-dynamic conditions silicon was released within 24 hours and was subsequently reduced with each medium change until equilibrating at close to 0 after 10 days. ALP and CICP showed significant variation in expression between culture conditions. In direct contact with SiHA ALP peaked at day 10 and CICP was constantly elevated. Cells grown in the presence of but not on SiHA expressed progressively decreasing levels of ALP from 7-14 days, with CICP peaking at day 10. On thermanox (TMX) ALP constantly increased and CICP peaked at day 10. The results indicate that silicon leaches out of the lattice of the SiHA crystal structure but may also be reprecipitated onto the substrate. We have also demonstrated that Si influences osteoblast metabolism and differentiation whether it is available as free silicon or 'bound' in the apatite lattice.

Study of the fouling of a mineral microfiltration membrane using scanning electron microscopy and physicochemical analyses in the processing of milk

1988 ◽  
Vol 55 (3) ◽  
pp. 381-400 ◽  
Author(s):  
Claudine Vetier ◽  
Michel Bennasar ◽  
Blas Tarodo de la Fuente
Keyword(s):  
Milk Proteins ◽  
Casein Micelles ◽  
Microfiltration Membrane ◽  
Dynamic Conditions ◽  
Milk Processing ◽  
Fat Globules ◽  
Velocity Effect ◽  
Dynamic Filter ◽  
Static Conditions ◽  
Matter Transfer

SummarySoluble proteins and Ca and P salts in the fouling deposit on a mineral microfiltration membrane obtained in static conditions were analysed and compared with those found using dynamic filter conditions in a laboratory pilot installation for milk processing. The serum milk proteins were retained by the porous micellar deposit under both static and dynamic conditions, resulting in progressive fouling of the dynamic micellar membrane, enabling milk to be processed with a mineral microfiltration membrane. Ca and P salts increased fouling probably by allowing better adsorption of casein micelles on the alumina and by acting as intermicellar bonds in the deposit. Fat globules modified porosity, permeability and resistance to matter transfer of the deposit. The dynamic conditions gave a deposit of the same type and structure as with the static conditions although made thinner by the velocity effect.

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