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Martin Blunt
Приєднався 12 кві 2011
This channel provides a series of short videos by Prof. Martin Blunt from Imperial College London describing topics related to flow in porous media.
Why ducks don't get wet
Wettability in three-phase flow is presented with an explanation of why surfaces that are non-wetting to water in the presence of oil can also be non-wetting (hydrophobic) in the presence of a gas.
Переглядів: 685
Відео
Spreading in three-phase flow
Переглядів 3846 місяців тому
A presentation of spreading coefficient for three liquid phases.
Relative permeability, wettability and recovery
Переглядів 1,4 тис.6 місяців тому
The relationship between wettability and relative permeability with a discussion of implications for trapping and recovery.
Relative permeability
Переглядів 1,4 тис.6 місяців тому
A presentation of the multiphase Darcy law and the concept of relative permeability as a function of saturation.
Leverett J function
Переглядів 1,3 тис.6 місяців тому
A discussion of permeability, including a derivation of the permeability of a bundle of parallel tubes. This then leads to a brief presentation of the dimensionless form of the capillary pressure - the Leverett J function.
Darcy's law
Переглядів 1,4 тис.6 місяців тому
A presentation of Darcy's law for single-phase flow in porous media.
Navier Stokes equation
Переглядів 9066 місяців тому
A presentation of the Navier-Stokes equation and the laminar steady-state limit for porous media flow.
Capillary pressure saturation relationships
Переглядів 1,8 тис.6 місяців тому
An introduction to capillary pressure as a function of saturation during a displacement process and the effect of wettability and pore structure.
Layers of water and oil
Переглядів 5586 місяців тому
Description of wetting layers of water and oil in porous media.
Percolation and porous media
Переглядів 8136 місяців тому
Percolation theory and how it can be applied to interpret displacements in porous media. The distinction between invasion percolation and ordinary percolation is explained.
Pore filling in imbibition
Переглядів 8836 місяців тому
A description of cooperative pore filling in imbibition.
Snap-off and trapping
Переглядів 8556 місяців тому
A description of wetting layer flow and snap-off in imbibition and how it can lead to trapping of the non-wetting phase.
Primary drainage and capillary pressure
Переглядів 1,3 тис.6 місяців тому
Introduction to displacement in primary drainage and capillary pressure-saturation relationships.
Interfacial tension
Переглядів 2,7 тис.6 місяців тому
A description of interfacial tension as it pertains to flow in porous media.
Motivation: Why study flow in porous media?
Переглядів 2,6 тис.6 місяців тому
Motivation: Why study flow in porous media?
Modelling flow and transport processes
Переглядів 1,4 тис.Рік тому
Modelling flow and transport processes
Solutions to the Buckley Leverett equation
Переглядів 1,8 тис.Рік тому
Solutions to the Buckley Leverett equation
One dimensional advection diffusion equations
Переглядів 2,5 тис.Рік тому
One dimensional advection diffusion equations
Topology, energy balance and contact angle
Переглядів 1,1 тис.3 роки тому
Topology, energy balance and contact angle
Hello, Prof.Martin! I'm impressed by your lectures, but you explain "interfacial tension" matter a bit incorrectly. The key is in intermolecular interaction. The molecules at the interface are pulled into volume so the average distances between molecules at the interface become large than inside the volume. Due to this increase of distance you have additional increase in potential energy for the molecules at the interface. Moreover the increase in distance is the tension! That is why the matter is called surface tension. So energy per unit area, sigma, is the PROPERTY of the fluid at certain temperature. Surface energy Wsurf=sigma*Area. Moreover, once you explain Young's equation you don't use the equilibrium of border line which surrounds the water droplet, i.e. molecules of the interface of each phase pull the border line due to tension and that is why the balance equation is introduced in such simple form. In other words, tension force, F, is proportional to the length of border line, i.e. F=sigma*length. If you consider a small segment of border line then F=sigma*dL. There is no sense to introduce "broken bonds" or similar physics because these are secondary matters. Having say that I'm really expressed by subsequent course where you 've introduced the percolation matter, snap off and trapping. Your triangle example is very helpful in understanding of layering or swelling of layers while imbibition. Sorry for my runglish, i.e. Russian English!
Thank you for your comment. You are indeed correct in your physical interpretation as to why the interface between two fluids can be considered literally as a tension. Thank you for adding this explanation in the comments. In my video I kept the idea simple as a change in energy following the approach written by a Nobel Prize winner in Physics: 10. Capillary and Wetting Phenomena: Drops, Bubbles, Pearls, Waves, P-G de Gennes, F. Brochard-Wyart and D. Quéré, Springer (2002).
@@BoffyBlunt Thank you, prof.Martin! You actually motivate me to look for the answer. I'm 44 years old, but it sometimes difficult to realise that you missed something in the school and you need to prepare for the lectures for your colleagues. Books on the subject in oil and gas industry are very poor in terms of physics explanation. Wikipedia also gives final result for Young equation without fundamentals in terms of Newton's law, simple sketch with arrows etc. I found thorough explanation in the lectures of school teacher Pavel Victor from Odessa city. He is really genius in explaining the matter with various examples and simple experiments. ua-cam.com/play/PL1Us50cZo25mikFg7yYkpmpNK7tGcub35.html&si=8Ya9_1Wds98tp1zo
i really love the way you teach. u can find many great researcher, but great teacher is really rare
thank you for the amazing video sir! Im currently taking up reservoir engineering class and this reallly helps! <3
I understand everything except that the professor can write backwards.
You make it look easy, thanks!
Are any of these "I" events more common in certain rock types than others? For instance I_1 is more common in sandstone while I_2 and I_3 more common in carbonates?
An excellent question. The relative frequency of these mechanisms is dependent on pore and throat geometry. In general snap-off is most common if throats are much smaller than pores, whereas the different pore-filling processes occur at similar pressures. In more uniform systems, I1 will be much more frequent. It is difficult to say what is the case in general for carbonates and sandstones - it depends on the exact structure of the rock.
Hello Professor, thanks for your video! If it's water-wetting, will the stage of forced water injection happen? For example, raising the water pressure causes some trapped non-wetting phases in the pore body to overcome the capillary resistance of the throat connected to it, then the S1 or Sw further increases.
Hello, Professor. Thanks for your video! Can you explain how to determine the curvature sign? My understanding is that if the curvature center is in the denser phase, then it is positive. Is that right?
I think you have this the wrong way round. We define the capillary pressure as the difference in pressure between the less dense phase and the denser phase, then positive curvature is when the less dense phase bulges out into the less dense phase (think gas and water).
@@BoffyBlunt Thank you sir! I think I've got it.😃
Thank you sir❤
Clear explanation, thank you!
🌹🌹
dear professer blunt , i am also off the "blunt" and just i i was exhaling and then this was reccomended to me So overall 9/10 this is a very good score so enjoy it.
I still don't understand the equation, can someone explain pls
What specifically would you like help with? I can try to clarify points that you are confused with.
@@BoffyBlunt Thank you so much for answering. I just find the 'dv' part in the first equation you presented slightly confusing and the V=4/3(pi)r^3
@@coldchickennoodles5575 The dV comes from work - the work done from basic physics is PdV where P is pressure and dV is the change in volume. The equation V - 4/3(pi)r^3 is the equation for the volume of a sphere in terms of its radius r.
❤️❤️thanks sirr
Yes it is clear now. Thank you so much sir
Very nice explanation Thank you for such quality content
🙏🙏
beautiful
when consider Pc why π(r^2)h is also considered for oil..water has risen till height h not oil
First, we can consider any two fluids 1 and 2, not water and oil specifically. In this term we consider the change in potential energy of phase 1 replacing phase 2.
when consider Pc why π(r^2)h is also considered for oil..water has risen till height h not oil
british man thanks a lot. you are very smart .
Key takeaways: 1) Primary drainage or primary migration is the movement of oil (non wetting) inside the reservoir rocks moving the initially present water into smaller pores or corner of the pores. After a while, oil due to its contact with the rock becomes wetting in these regions. 2) Injection of water is in piston like manner, where it fills middle of the pore leading to layer of oil formed between middle water and water at corners. This layer becomes smaller and smaller as more water is injected. 3) Mixed wettability involves both snap off (smaller pores) and percolation (larger pores) processes.
Many thanks for this summary. Point 1 is correct, with the caveat that the wettability change depends on the oil, rock and brine as well as the temperature and pressure: in some cases the rock becomes oil-wet, in others not. Moreover, we can see a mix of water-wet and oil-wet pores in a single sample - this is mixed-wettability. Point 2 is correct in oil-wet pores. Point 3 requires some clarification. In a mixed-wet medium, the water-wet pores and throats fill first (the throats by snap-off) in a percolation-like process. Then oil-wet pores are filled from the already water-occupied regions of the pore space. This is no longer invasion percolation as the water need not be connected through the centre of the pore space to the inlet. Overall displacement in a mixed-wet medium is best thought of as a percolation (not invasion percolation) process.
another amazing vid. thank god i found this channel.
this was great
Prof. Martin, Greetings of the day. Thankyou for the great explanation, however I am unable to imagine that can such a situation arise where both phase 1 & phase 2 has equal tension w.r.to solid I.e., theta = 90.
This can happen when neither phase has a preference for the solid surface.
Thank you uncle Martin. 🖤
Dear professor can we utilize capillary and bond numbers to know which force is dominant (advection,gravity ,capillarity ) in the flow equation you drive
Yes this can be done but with care on definition. You should compare the ratio of advection, capillarity and gravity over a relevant length scale, which is the reservoir scale. The conventional capillary number does not have a length scale and represents a balance of viscous to capillary forces at the pore scale.
@@BoffyBlunt Thank you, Professor. Could you please create a video clarifying the complexities surrounding scales in porous media? Specifically, I'd appreciate insights on how to relate each principle to its respective scale and how we can bridge the pore scale to the reservoir scale. Because here If the capillary number represents all pores in the reservoir, then it essentially represents the reservoir as a whole.
EVANS ASANTE has come to watch this video
Thank you !! I had a question, I need to analyze the interfacial tension in an oil spill that has occurred near the city I live in, how exactly should I use those measurements to calculate the interfacial tension. The oil that was spilt covered approximately 20 square kilometers.
If you had a sample of the oil you could measure interfacial tension using, for instance, the pendant drop technique. This does however require specialist equipment. You can also analyze the spreading of an oil spill on water - when the layer of oil is thin, its movement is controlled by interfacial forces.
from Gita Wirjawan subs.
Professor, I have prepared a PowerPoint presentation based on your explanation, illustrating pore filling, capillary pressure curve, and pressure differences between phases. I would like to share it with you if you are interested.
Sure - email it to me at m.blunt@imperial.ac.uk
Proffesor why the wetting phase goes to the small pores first , i know Wettability impose this , but why wettability didn’t imbibe the wetting phase into the big pore first ,still there is rock and IFT
This is because imbibition into small pores happens at a higher capillary pressure - it is more energetically favourable for the wetting phase to reside close to the solid. The non-wetting phase preferentially minimizes its contact with the solid by residing in the larger pores.
Is it valid to say that if the adhesive force greater than the cohesive force (wetting phase), the fluid tends to maximize its surface area to volume ratio, achievable within small pores? Conversely, if the adhesive force is weaker than the cohesive force (nonwetting phase), the fluid tends to minimize its surface area to volume ratio, achievable within larger pores and by adopting a spherical shape?
@@hamzaalyaseri6047 Yes, this is a way of thinking about it.
Dear proffessore , is it true that : at conditions above the capillary pressure at Swi, capillary forces are entirely dominant, whereas outside the capillary pressure at 100% wetting-phase saturation, the conditions are analogous to the complete dominance of gravity forces, and within these two Pc-Sw endpoints, both gravity and capillary forces can be considered as being active.
This is not really correct - there is simply an equilibrium between gravitational and capillary forces. At the pore scale capillary forces dominate for the whole saturation range.
Dear proffessor , in labrotary how can we consider the pump pressure is equal to the capillary pressure , its confusing me because i think pump pressure is the displacing fluid pressure and we have to apply capillary pressure formula (Pnw-Pw) to find it. thank you in advance
You are correct - the capillary pressure is the difference between the pressures in the phases. So this could be, for instance, the pressure in an injection pump of phase 2 minus the outlet pressure in phase 1.
@@BoffyBlunt thank you very much
Dear professor can i say snap off is capillary dominated flow where the front is not flat while cooperative pore filling is advection dominated flow where there is a shock (flat front )or this is irrelevant.
No, this is not correct. Both processes are capillary dominated. It is simply that cooperative pore filling alone does lead to frontal advance and little trapping.
Dear proffessor Will there be residual non-wetting fluid in the throat due to snap-off phenomena, or is it only traped in the pore? or its depend on the radius of the throught. thank you in advance
No - if there is snap-off in a throat, the throat is completely filled with the wetting phase, and the residual saturation will be found in adjacent pores.
Dear Professor, i might have misconception In terms of pressure, any fluid will flow directly towards the lowest pressure, which in this case is the wider thoughts. In another context, fluids tend to follow the path of least resistance. I understand that there are preferences and wetting properties that influence fluid flow through smaller throughts, but I'm struggling to grasp how these two principles work together. Is the high cohesive force in the small thoughts attracting the water, and because this high cohisive force we need a high pressure to overcome this attraction force and displace oil ? Thank you for your guidance.
The capillary pressure is determined by wettability - the cohesive force, as you say, for the fluid to the solid. In this case the water pressure is lowest in the small throats, as here the capillary pressure is highest.
Please how did the " 2 " in the capillary pressure equation disappear in the J- function equation ?
This is accounted for in the J-function. The function J is a dimensionless form of the capillary pressure.
@@BoffyBlunt okay, thanks 👍
Great
I enjoyed the lecture and your animated speech and hand gestures 😊
Excellent class. I am interested in knowing how one can use j function modeling to calculate the thickness of transition zone. In other words what are the criteria to use transition zone thickness to come up with j function modeling .???
You can use the J-function to estimate the saturation as a function of height in the transition zone. The capillary pressure is the density difference between water and oil times the acceleration due to gravity times height above the free water level. You find the saturation whose capillary pressure gives this value - the J-function allows you to account for variations in local porosity and permeability.
Hey, I found you through an amazon review for a wacom tablet. You're stuff is great man, keep it up <33 If you have a donation link, I'd love to donate some
Many thanks for your kind words. No need for donations - the videos were made by Imperial College London.
How low residuel saturation of the oil is in?? the case of oil wet
In careful coreflooding experiments, typical residual saturations of less than 10% are possible. Of course, these saturations are never reached overall in the field, as thousands of pore volumes of water need to be injected.
Such an easy-to-follow up explanation! I was a physicist student until last year, when I decided that I wanted to do more practical things and moved to an electronic engineering degree. Also, I am a barista and I'm utterly amazed by the mathematical modeling of many coffee systems, a branch which is not deeply explored yet, which makes it more interesting. Also, I am keen on modeling the flow of cars in cities to further improve congestion in cities, so this knowledge comes in handy. What books can I read? What mathematical areas do I have to handle? Thanks again for the video, Francisco from Argentina
A good, short introduction to the theory is "Introduction to Percolation Theory" by Dietrich Stauffer and Amnon Aharony, Taylor and Francis (2nd edition, 1992).
@@BoffyBlunt Thanks!
Dear Sir, thank you very much for your a clear lecture.
Thầy đúng là professional, cảm ơn Thầy <3
good presentation
Thank you so much for uploading these videos. They R of great help.
I like the Wilhelmy Plate Method - with the advancing and receding contact angles.
Got it the moment just when I needed it