transcript

"(00:07) so welcome to today's webinar from sca with garrett nutters and leo redheart on wealth stimulation what why and how before we start today's webinar uh we'd like to introduce you to garrett nutters and leo redheart so leo rodhardt has a career in the oil and gas industry spending some 35 years he's worked in a number of areas including stimulation as well as production engineering optimization water management strategic innovation scenario planning and new business development he served a s a dl (00:43) for spe he was also a director on the board and actually became the president of spe in 2009 in addition he served on a number of committees and conferences and forums he's worked for shell international for a number of years and was actually involved as the head well stimulation water management research department and his last position at shell was group game changer focusing on strategic innovation garrett netters has experienced over 40 years in the oil industry also worked at shell and became shell's global wealth (01:22) stimulation coordinator and principal technical expert providing advice to shell activities around the world he's also co-authored many sp papers on this topic he was a dl for spe on well stimulation in 2005. he's also been quite active in spe and contributed to the most recent monograph on acidizing that was issued in 2016. (01:49) so those are our two authors who are going to be speaking today as instructors they have a class that they teach for sca that's called wealth stimulation workshop practical and applied and it's offered two times this year in april it will be in houston and october it will be offered in midland texas so if you're interested in registering for either of those two dates you can schedule your training in either houston or midland or they can come visit you in your location if you'd like to schedule in-house (02:23) training we also are continuing our series of webinars coming up we have uh john lorenz and scott co oper who will be speaking about natural fracture types we have steve sonnenberg who's talking about two of the classes that he teaches an excerpt from each in february uh on med-rock reservoirs and unconventional systems and then we have jennifer ms gimmins uh we'll be talking about fracture conductivity in march as well as raymond woodward who will be talking about geosteering so be sure and look for those opportunities uh to listen in for (03:03) a sample of some of the classes these sca instr uctors teach in addition to training of course sca does provide consulting technical consulting a direct hire services as well as projects and studies so i'd like to remind you today that during our webinar you will be muted as an audience member so you won't be able to pose your questions out loud but you can use the question feature there in your go to webinar dashboard to start asking questions even before the talk concludes and as we do have two presenters today i would ask you if (03:42) po ssible to direct your question to one of them the first half will be presented by garrett netters the second half by leo roadhart and then we'll take questions at the end so it will make it easier if you can address your questions to one of them and before we start our presentation today we're going to do some polling questions just to learn a little bit about our audience and so what is your primary discipline we've opened this poll so you should be able to select your choice quickly it looks l ike we have a good balance (04:18) between petroleum engineers and geoscientists a few petrophysicists in the crowd looks like most of you have voted so i'm going to go ahead and share those results and then our next polling question is how many years of full-time experience do you have in the upstream oil and gas industry so let's see what our audience looks like today it looks like we have a good distribution between all the different uh ranges of experience maybe a third of you have over 30 y ears experience but quite a few in some of the other areas (04:57) and most of you have voted so i'm going to go ahead and close that poll and share the results a pretty good distribution across the ranges of experience and then finally how many years of experience do you have in this topic so in the topic of well stimulation how many years experience do you have so this is interesting we're starting to get quite a few that have less than one year experience and so you're here to to learn someth ing about this topic and quite a few are in the one to ten years experience (05:31) so relative to the demographics of our audience most people are in the one to ten years experience most of you have voted so i'll go ahead and close and share those results so you can see that so again i'll remind you that during today's webinar you will be muted so you're going to ask your questions using the question feature on your dashboard you will receive a link to recording of today's webinar at the end af terwards in evaluation form and additional details about registering for the two classes that we have (06:07) scheduled this year in april in houston and in october and midland and so without further ado i'm going to pass the webinar sharing option to garrett knitters and he can bring up his slides and we will um i'll listen to garrett give the first half of today's presentation garrett it's all yours hello hello can you hear me yes okay good uh let me start about uh the first bit and in fact wh at we're doing we will give you sort of a a peak view of uh of the courses that we do in this year so we're still waiting to see (07:04) your screen garrett should be there okay now we see it thank you okay now i can uh can do it okay let's first start with the uh with the question how you select candidates uh for uh in particular type of treatment for that we we want to show you the the work process that we normally go first of all there's a step zero we usually you start off with step one but we start off with step zero and that actually is to look at existing data and experience of whatever (08:09) treatment evals have been treated before then the next step is to create sometimes a ranking table but the next step is really look at skin analysis and and stuff like that then you continue with the treatment selection for which you can apply certain certain models as well fluid selection is the next step step three step four and step five and let's go together step four is a pumping sch edule you you come to some sort of decision on what type of fluids you want to use what type of different flushes pump rates stuff and (08:53) stuff like that and then you try with that pumpkin schedule you try to find out before you actually do the treatment is this what i want and then the next step the last step basically is the job execution we are actually going to do it let's first concentrate on the first two steps the this this slide oops this slide shows you a um sort of rules of thumb will tend to produce afterwards more water than oil more water than it did before so i have already fifty percent before you can end up with almost like 100 percent after it so that is not a top-ranking candidate (10:34) the gross recipient height there is no limit on that even if you only have a four or five feet of of resource height you could still do an acid treatment but if you have uh longer intervals then you need some sort of diversion some sort of measure to distribute the asset over th stem is is more or less filled then it's not very useful to do the treatment you will still increase the production of one particular well but you you probably probably cannot handle the increased production so there's no point in doing it uh what we do normally is uh as as a as in the course we present this in more (12:39) very much more detail but what you do normally is you have uh you create some sort of database with a whole bunch of data you can see it here on this graph uh what what kind on afterwards which would give you a gain an unconstrained game and you can actually risk that gain again and you you find out that this in this particular world the key west five there is a potential of an extra production of 28 million cubic meters per day this is um an obviously a non-existing well i'm not aware of anywhere else being present in in key west but that's actually why we chose those names to (14:50) make sure that nobody can actually think it's it's his or her well then you have main drive came actually in the 1980s when there was extensive research done that improved our theoretical understanding and as a result we had new fluid and asset compositions and of late basically this century it was really the start of doing computerized design and execution support of acidizing treatments this is a picture of the very early asset treatment for those that are aware of it it says here already the name dowel which is the pre uh is the company that was set up by dow chemicals u n you can go over the frag pressure and perform an acid-frack treatment and i put in this this (18:48) list as well a mess of hydraulic fracturing treatment those were done a lot of them were done actually in various parts of the world one of the the champions of that is actually a company called mersk in denmark who did offshore jobs where they treated wells with up to about 10 million pounds of propane it was really big jobs and they were successful but they're not done that much anymore forge look like in the lab and you can see why they are called wormholes what is the most important issue for wormhole development you have to have an optimum combination of the reaction rate injection rate and the diffusion rate (21:02) the diffusion rate is the the diffusion of hydrogen ions to travel from the bulk of the fluid to the wall um of the surface of the of the carbonate optimum wormhole formation is when you get very something like 0.01 to 0.001 centimeters per second what does that mean here by the little black particles here in the matrix of the rock the chemistry is that you have i've i forget to tell first that you need a mix of hydrofluoric acid and hydrochloric acid for sensitive acidity um in the old days people started off with 12 hydrochloric acid and with three percent (23:22) i had a flu water guess it and that was called regular medicine uh i think the term mutt acid is is basically a slumbersheet term or in that time a dowel term and if you do a treatment with with d all the silicon would disappear that was strange because we we didn't understand that basically but that's what came out of of the experimental work that was done also analysis of back produced assets from the field and basically what it was that the silicon and sodium and potassium fluoride gates were precipitated so in the solution in this in the in the samples you didn't find anything there (25:37) anymore but there was a lot of fluorosilicate and silicon was actually precipitated inside th ou can have an hdl pre-flush and use that to remove all as much as possible anywhere all carbonates from the about two feet of the formation phase so two feet away from the elbow remove all that and how do we do that just to punt the ahead of the mud asset treatment pump a pre-flush of hydrochloric acid usually it's 15 and that 15 is capable of dissolving um quite a lot of carbonate and here you can see that if you want to have it two feet away if you have something like let's say three percent s that have been proposed and are being used quite a lot (29:37) actually they're still hydrochloric acid uh three percent twelve and three percent hf there's still a regular mod acid it's not used very much anymore it's it's mostly we we are using these days something like thirty and a half one and a half percent or even less especially if you have a lot of feldspars around that's another component of the rock if you have a lot of fails paths around you want to go down to something like nine pe kin during and based on that decide whether you want to stop pumping uh then there are some uh general the core flushing test done and (31:42) there are some design curves which are uh published in the i think one other thing is the old sp monograph but we left them out in the new new monograph that we completed in 2016 and then there's a method based on asset response curves you can do a co-flushing test and find out in a core how much asset you would actually need to resolve whatever your prob i i called it hydraulic fracturing in 20 minutes obviously hydraulic fracturing is a bit more complicated than something we can do in 20 minutes time but i will i will try to give a bit of a summary hydraulic fracturing if you believe the newspapers um hydraulic fracturing is (34:10) one of these um innovations that popped up the last couple of years that allows us to develop shale reservoirs well not true of course like like uh matrix sensitizing hydraulic fracturing is an old technology the fi nnot calculate on the back of an envelope anymore you need you need a computer program and you need to talk to other people key talking to other people it's complicated you need it usually the production engineer who is leading it helped by the reservoir engineer because you need to get a deep understanding of the of the of the productivity in that particular reservoir obviously (36:13) the drillers in the well well designed people should be involved rock mechanics is important fluid mechanics i flowing bottom low pressure basically in in in your well it's a drawdown divided by the viscosity obviously a low viscous fluid will give you a higher productivity in a high physics fluid there's a constant here called b b b naught uh it's it's a volume factor basically it means that one barrel of oil down hole is less than one barrel of oil at surface it expands coming to surface no big deal not important it's it's usually 1.1 or (38:09) something like that and there's c for uh for radial coord will connect um particularly laminated or layered reservoir it will connect layers of producing zones that are not in contact with the wellbore because it's not perforated often in a limited perforated interval if you fracture l suddenly you see your kh double or triple which makes quite a difference in your flow and last but definitely not least is the re divided by rw the reservoir radius uh divided by the velvet radius one can show mathematically which i'm not going to do here because it's q to do most of it what you do is in the office (41:35) back in the office months before you do your treatment you basically like her told you you select your candidates so you pick a number of candidate wells that probably benefit from hydraulic fracturing treatment we use the same spreadsheet as henna talked about and i'm not going to go into much detail for that it's a it's a it's an exercise you can do using excel or there is a commercially available software for that available as well which w hat needs to be able to cope with 10 000 psi during head pressure while pumping your treatment not always the case so you might want to order a new well head (43:25) your tubing your whole completion might not be able to handle the cold fluids you pump in at a high pressure uh you need to know whether your completion is anchored or a sliding sleeve all sorts of questions you need to answer back in the office and finally after you've done that you go on site the day before the main fact job you how do you do frag design well there is software basically software you can buy if you have the money the programs are quite expensive 300 000 each you can get a design simulator it's called frac pro (45:17) it's called mfrec herd and i use mfreck we like that better it's called prosper there is slimmer j has his in-house design program it's a numerical simulator that will calculate the length the width the height of hydraulic fracture and the volumes you need to do that in our course we we use is lost to the formation how much is acting really as a fracture generating fluid basically it asks you what is the efficiency of my friction fluid that is a very important parameter efficiency how efficient is your frac fluid and the efficiency and i will come back to that in a minute is defined as (47:17) the volume leaking off by the volume staying back basically oh it's sorry it's the volume leaked off divided by the total volume now there is another parameter that is very important that wi ngth and the height of a fracture with the volume that i pump and the young's modulus e which is basically the the force of the spring of the reservoir the width of the fracture is is a function of the length obviously or the radius and the delta p now if i know the height the length and the width i know the volume of that fracture if i know the volume of the fracture that i (49:15) generate by pumping a certain volume i know the volume of propent that i'm going to use also if i know my efficien ou have to make your sums but that's good enough and i'll show you why because now we're going to optimize we're going to optimize the treatment based on economics based on money now the moment you talk money you start to talk about increases increased production and this is a topic uh due to a lot of discussion what i'm going to tell you now your reservoir engineer might not agree at all but this is a real example it's a real example of an oil well (51:14) that was producing anywhere between 2 y that was my decline (52:38) so maximum would that well have produced 200 000 battles a day by fracking it i took it to if i would have let it go here to a million by refracting it do it again 1.2 million instead of 200 000 barrels i got 1.2 that's a million barrels of oil extra now is that good economics or not problem is your reservoir engineer will not allow you to do that they say no it doesn't work like that if you frack it your decline will be much faster they keep telling me that althoug you do is you calculate the gain the gain in in barrels a day or cubic meters a day whatever (54:38) units you like of that particular well the example i'm here is kw12 glaswell it's doing half a million cubic meters a day and if i would create a fracture of 30 foot that will double the production so my gain is half a million cubic meters a day right um what i typically do is you take different frack length 30 60 100 140 just as an example you might as well take 50 or 100 500 i don't care you ca final design and you analyze the whole thing but that will take too much time can't do that today it will stop here and wait for some questions thank you thank you very much leo we are receiving questions from the audience and the (56:40) first question is for garrett is there a maximum well inclination above which acidizing cannot be performed garrett i think you might still be on mute you're mute we can't hear you garrett now we okay thank you well the simple answer to that question is no ther there's another option to use to use a cold tubing to distribute the asset across a particular zone so the next question is for leo you you showed us an example where a well was refract one time giving a five-fold increase the second time a double increase how can you improve the success of refracting of wells i don't think you can get more out of a (59:08) second and a third fraction because basically the reservoir pressure is going down while depleting it so you can't expect it to go back to eceive a link to a recording of the webinar an evaluation form and a link to the registration details for the class that leo and garrett teach on well stimulation workshop practical and applied that's scheduled for april in houston and october in midland and of course we can bring it to your office in-house thanks for joining us today goodbye"