transcript

"(00:01) hello everyone welcome to the third week the first weapon off this is me ahmed el garaje and today I will be your moderator for this session let me introduce my friend dr. Ahmed Gama Ahmed is currently a fracturing fluid engineer for you know unconventional reservoirs in BP United States Ahmed previously worked as petroleum engineer for Saudi Aramco for one year also Ahmed work as research scientist for Baker Hughes for more than five years Ahmed his major is you know including hydraulic fracturing fluid acid (00:47) stimulation fluid diversion and engineering treatment design in general he holds a Bachelor degree and master's degree from Cairo University in Egypt and also a PhD from Texas A&M University in the United States oil and petroleum engineering Ahmed published 10 granted patents US patents and 15 patent applications 15 zone and publications and 70 conference papers Ahmed we are happy to have you today please you know we we are waiting for your presentation you can sto onists just Oh heart it is like unsteady type (02:11) of injection so it's not this state is actually on a steady state it's mom either settlement so actually temperature will change as you are injecting your fluid at the fluid is reacting and also is a 3d type of float it's not linear flow is not to be beautiful oh actually it's almost like if you have a perforation who are talking about spherical flow so we have a flow in the say D button and as the or does it mean we have a chemical so we are reduces the strain factor by removing or bypassing any near wall bore damage so that's like a quick definition about the simulation however the main (04:00) question that you should ask yourself like when best treatment is needed like is my existing world need to have a nicer treatment or not a lot of people will ask themself this one and a lot of people need to know exactly when the applied acid for their walls I said we don't bumpit just don't carry the product empty no I said only bump it wh not really high and that's happened in the cases like when you have a calcium carbonate scale and this can be a very building slow news time and the client that you'll have in the oil and gas production will be slowly style and fat and one can be (05:54) really rubbery it can happen suddenly and that's happened when you are blogging your formation blogging informational bragging you're perforation or actually plugging your tubing this can happen very quick and very extensively a second one whole edge where this water coming from and what is the source of the damage that can water happening to us so what type of acid simulation we are talking about mainly we have two type of s estimation that a lot of people when we mentioned estimation they talk about it's a matrix is writing or fracturing as arising and that the main key factor is how we're actually bombing (07:43) your job in case of matrix is dicing you are injecting at the rate and the pressure usually less than the fraction gradien frack and the acid wouldn't actually react with the surface of the friend little v divorced there is definitely somebody cook that method were acting divorce but the main job here is the asset to react with the surface of the frack trying to edging the surface of the frack and create what we called hedonic heterogeneous surface a cheek that's what helped after the how can I say the closure this heterogeneity will not make it completely sealed when the fracas closed of that treatment and (09:26) ent that been in the industry can dissolve in the sandstone (10:49) except HF therefore any sandstone treatment must have somehow away that contain a chief then we have another asset based on the chemistry origin which is organic acids which came from organic component like acetic forming citric acids and other engineer who are really good at blending will let a lot of balance we like to blend different acid to get a better results and to get a more optimized system so you can have a blend of HC amily for this one however we just use them very narrow usage but under special condition moment so let's cover the mean acid that we usually pump in in oil field industry (12:54) the first one and the most popular one is the HCL it has a lot of advantage and we like this acid a lot first the concentration you can have a wide range of concentration from 3% up to 28% so you have that you have like how can I save a word or type of design of consultations that you can use HCl being delivered to the eact with a calcium carbonate or calcium or dolomite which is calcium magnesium carbonate all the reaction product is water soluble as (14:59) you can see here the reaction product so I have here the reaction rate between HCL and calcium carbonate and the reaction product will be Hudson chloride which is salt and that can be dissolved quickly co2 which is gas and h2o which is water so we don't have anything that can use any damaging or precipitation again monitor Actos dolomite which is calcium e that it nothing can be accusing any precipitation or anything however it is a tricky to design with HCl because a lot of things first order corrosion rate itself also can eat your pipes especially at really high temperature so you need to have (17:00) additional additives with HCl to reduce any corrosion for the wives that you are injecting with second faster activity HDL react in seconds very high activity so sometimes if you like to have some time to be able to inject your HDL deeper in but ur clay like if you have iron hydroxide that's one of the concern that you'll have was iron and the Saltine will kill the sludge and close some some damage that HCL will not remove the only two movie tools installment so in this case we need to have also additional additives like iron control agent to be (18:59) able to to overcome any concerns we have from the compatibility issue and as you can see like additives is that is like HCl system usually we bump it with alternatives so the acid itself r it is develop a lot of reaction product insoluble reaction product but actually is not good and can significantly reduce your cost and permeability and can significantly how can I say it make the job but you are trying to improve your production give you the opposite direction therefore when you are talking about Sanderson as bad you need to be really careful about how you design in a job what's the post flash of reflux that (21:11) you're bumping and how you're bumping your job and definitely point to seven point two one seven pounds of sand just remember like it's 15 percent HCL can dissolve 1.7 bound of calcium carbonate but that's another type of formation but just to highlight how this material is and you are talking here about three percent of xef to dissolve 0. (23:08) 217 so why should I haven't good dissolving power for this type of material this is some chemical reactions about the chief and how we are bumping it the first one I would like to highlight look like when betch b s react was clay like for example I went on bentonite it produces the same as it the fluoric acid emboss then this acid will react with a sodium and what assume is that exists in the clay or actually exists in your formation water using some sodium flow circuit or potassium flow circuit and this is the material actually that will precipitate so in H if you have like what we called secondary reaction or secondary action reaction precipitation (25:10) because the reaction happen in two step and so near water area it will happen far away (26:38) from your world bore area and this case negative effect you will have from this precipitation would be very minimized and overall you will get a good success from bashing HF treatment also what if your sandstone formation have a slight amount of carbonate not really high but you still having some amount of carbonate in this case you cannot start with HDL HF just over lied when you have a blend of acids the strongest acid is the one that will first n of HCl it do what what what HCl can do so this one also can dissolve carbonate only but does not have any ability to dissolve silica so actually dissolve carbonate or (28:54) any carbonate or dolomite calcium magnesium parent it has a much better than the H field series it has a lower rate so does not help your tube as much as HCL and that's why we like it at high temperature especially we can inhibit it at high temperature pretty easy so we can bump it at high temperature with a less concern om dialogue from your case one of the things like iron also can proceeded and can significantly reduce can significant accuse your damage the formation and the embeddable talk of your treatment so having an organic acid or reduce the precipitation happened from my own one (31:04) of the things that i would like to highlight like we said like HCl we start from pH of 0 and at the end of the treatment let me actually before however organic acids like formic acid for example you start from pH of 2 b have for whatever company you have the main difference between these companies is actually what additives they can provide to you HDL HF Formica setting citric acid all these acids as Thunder acids so there is no much difference between them however the main difference between the difference FS company it what as it atoms each company can provide and how effective each additives is good so when (33:14) you are doing the design you are selecting between different companies based on actually the a s corrosion have to work for film there's corrosion helps to work for organic acid and there's except encouragin have to work HF so it's not one corrosion having to work for everything and the solute the best way to select the corrosion inhibitor is doing a corrosion test for example you are expecting to bump six-hour job and your static reservoir temperature is 250 from height so what you usually do you need to provide the surface company with the tubes that you are bumping to it (34:58) it's c llimeter of your tube so both of five pound per square feet is the sickness that I'm the sequence of the children that would be dissolved then for this mode sickness point all three one millimeter of the choping and that is acceptable surface more than this one is not acceptable by by the designing engineers and one of the things you left overshoot there is no betting pitting is like you you have like a hole or a small area the bassett (36:39) is focusing in the vibe and attack attacking signifi are adding this one because (37:58) usually intense fire minute at higher temperature certain additives what we call iron plating agent as we say they're only like iron is one of the mineral that exists in your formation it can use a lot of a sheen mainly precipitation especially at high pH pH when the beach ball to above tune so you need some chemical to clip this iron to remove it and keep so applies as much as we possible so we we have like what we called some people call it iron patrolling maybe any organic component that's can actually that work as a barrier between HCl and the calcium carbonate or the material (39:57) that would let goes forth so that's why it came we need to have a solvent and a lot of time we'll bump solve and confront HCl especially in a black oil wells or the oil that has a lot of organic deposition just to be sure that were cleaning the surface of the rock so allowing the HCL to be react and brisket so that's one of the main as it tips you have it when you ve a different type of treatment that we typically use acids the first one called pickling treatment soaking or scale remover treatment as it breakdown job matrix as diving which is a boss like one for sandstone one who (42:01) carbonate and finally acid fracturing treatment so I'll go for each one and what why we need it and how we can do it the first liquid is called break link treatment and here we are trying to clean the tubing we're not trying to to do anything in the formation who are main at we do before bumping the acids inside the formation back link we are talking about a weak acid so usually from three to five percent HCl and as additives usually you are having to only additives corrosion inhibitor and iron control agent that is the two items that you have there is no need for access for the agent or solvent (43:59) or any other other items because you are not expecting to go inside the formation we are only expecting to clean the wellbore so that's why you are only having to it inside the formation we are just like as a maximum or the maximum location is just the formation this because we have scale we have a calcium carbonate acid concentration when we go higher so typically you are using four case around 15 what percentage do that's how our typical acid concentration that we typically use from this type of treatment again we have will always have a corrosion inhibitor and as we're (45:57) talking about scare removal and we are not expecting to have a lot of violen s one of your main additives you still having some formation compatibility and somewhat with all diverting agent as you can feel like you will have in this case I have a horizontal one with a multi-stage acid icing so you have like after you injecting in a certain way in a certain perforation you need to blood this perforation and allow the acid to go to another one and we will talk about as a blessing placement a later point for matrix we have what we call some dishonest advising in this case w to remove any carbonate then you pump your main acid which is the mixture between HCl HF (49:09) and then the finally over flush with HCL to keep the pH low and bumping your eliminate any proceeded happening in your area make it happen deeper inside the formation there's different concentrations that you can select depending of situation if pure damage is not severe is pretty small in this case we recommend to have what we call diluted mud asset which is HCl will be less than 7% and hydrofluoric bypassing this damage and the way that why we're bypassing it because HCl is the brita aggressive reaction reactor and actually can (51:11) significantly react with the carbonate creating actually holes this holds what we called a wormhole and depending on the injection rate the shape of the oneworld can be happening so if you are actually injecting at a lower rate usually get what were called conical world one world which is a pretty sick tube like imagining like you are actually having the hol eat deeper so if you do a little bit higher rate you'll have what we call conical which is still I said react mainly with the surface of the hole but because of that it is a little bit high some of the acids will go inside and create some of the warm (53:12) water but at the optimum rate you will start seeing a good and nice wormhole pattern as you can see from these two pictures and that's what we called an optimum rate that's why when we are designing for companies who would like to bump as mu d here were injecting the acids to actually to create a frack and and pump a higher pressure sometimes you're actually is a create a new flag or open a pre-existing flag and the idea here is not to create a wooden wall or to move the damage the idea here is trying to itching the fracture surface so when (55:04) it's closed after treatment you will still having an open area this will be conductive and productive so I have here a three scenario that you are actually bumping the assets friend one o benefit of thousands we bomb does it we do it in a silly ways the first way is a bad which is done Maori actively usually cross think it fluent and the idea here we would like just to break the formation and create the Frank so the bad section is to just break down the deformation and create the fact that we would like to have the second we bump the assets which will etch the formation and usually we are (56:51) talking about between 15 to 21 percent HDL if the relative pressure is too high we' id will inject and will go only to the high permeability formation and will keep injecting acid in this one you will not see as it will go in the low permeability section here or here mainly the acid will go to this one so after treatment you will see yourself on the treating one zone so I said only become here and this zone is not treated and this one is not treated and that's what we don't need you always when you're typically doing acid icing would like to have a good coverage of (58:35) the ou set the worker in the zone that you are like to (59:45) treat them treat it they release the butter and go to another section and treated and keep going on section by section for the treatment branch blood is the same concept like usually both the blood treat the zone and they remove it with another plug tree the zone and remove it step by step both zeros is like a bowl and that's actually sit in the perforation so you're injecting veritable Bassett that will go through the high permeability e expensive it's a pretty expensive to use so the cost when we are trying to is a call tubing or bridge of lugs and release and batter lays it on and off (1:01:34) become a pretty expensive technique so you don't want to depend mainly on this one that's why we will like the other part there is a bullshitters which is like again like applied for the perforation part but additional to the mechanical it needs a higher rate what's yours need a higher rate for for to be abundant so you cannot pump wh certain one I will show you how to drum how how to work definitely it controlled the fluid inside that one poor and also inside the formation and actually we we notice that this who are bumping this type of chemical we got a much efficient or (1:03:28) rolling better we have mainly to type what we call volume are based and surfactant base as a gelling agent or at the chemical part for volume are it it called also there's some people call it as a self diverting acid and some people also has a vis swer it thank you very much for the presentation as usual I have many many questions but you know let me select like five questions so someone asking it does acid izing changed when ability and porosity or just play with the conductivity like an as a Dyson does water change the permeability of the horrors of war it only trained the Prima belt in a rural (1:05:29) area so they affect there will not be such that huge and there is a for a scale that's why we said like when we have the damaged part t as it fracturing is a different technique because acid fracturing is changing the way from the word reducing from like if you were poor here you have a like a radial flow but if you have an acid frack you change it to a lower to a linear flow type of behavior and linear flow definitely will have a much higher impact in the world option than just a methods advising so if you are really would like to change you well production type of treatment to get a much higher (1:07:27) amount so you are ta the sandstone Bart why we need (1:08:49) the mixing because as we have the reaction rate HF will do a lot of precipitation the reaction product from HF will precipitate so you need to have the HCL with HF to keep the pH low like around zero to make this bracelet does not happen immediately to lower it a little bit so it can push it away from the window area so you near wellbore area you have a clean zone and this is you can see the best the skin reduction type of performance okay so someone aski d okay so I thank you dr. (1:10:48) Ahmed gonna pose a great presentation and hope to see you in Marietta giving a lecture here and thank you for everybody thank you thank you"