Chapter 1 - Top Ten Reasons To Refrac An Organic Shale Well

01-00a Introduction (21 min.) Sample Lesson
01-00b - Course Overview (14 min.)
01-01 - Top 10 Reasons To Refrac (9 min.)
01-02 - Top 10 Reasons To Refrac (part 2) (19 min.)
01-03 - Top 10 Reasons To Refrac (Part 3) (19 min.)

Chapter 2 - Where Have Refracs Worked and Are They Economic?

02-01 - Determining who is doing refracs and where they are refraccing (10 min.)
02-02 - Organic Shale Refrac Identification (8 min.)
02-03 to 02-06 - Overall Refrac Market Penetration (17 min.)
02-07 - Refrac Pad Economics (10 min.)
02-08 - Can Refracs Save the World? Expected Daily Production Increase from Refracs (21 min.)
02-09 - Refrac EUR From Cluster Spacing (7 min.)

Chapter 3 - Why Refracs Work In Organic Shales

03-01 - Organic Shale Drainage (23 min.)
03-02 - Role of Well Spacing (13 min.)

Chapter 4 - Why Refracs Work In Matrix Permeability Reservoirs

04-01 - Conventional Matrix Reservoir Horizontal Well Issues (12 min.)
04-02 - Refrac Candidate Selection in Matrix Reservoirs (29 min.)
04-03 - Why Do Multiple Zone Completions Leave Gas Behind? (20 min.)
04-04 - Gas Well Damage from Inter-Stage Flowback and Killing (5 min.)

Chapter 5 - Refrac Candidate Selection In Organic Shales

05-01 - Four Methods Available For Estimating The Recoverable Oil And Gas From Refracs (22 min.)
05-02 - Selection Process Methods 1 to 4 (19 min.)
05-03 - Discussion Of The Merits And Limitations Of Each Technique (16 min.)
05-04- Recovery Factor Concept Background (13 min.)
05-05 - Recovery Factor Calculation (6 min.)
05-06 - Recovery Factor Drainage Height Assumptions (16 min.)
05-07 - Flow Barriers Vs Frac Barriers (17 min.)
05-08 - Unpropped Height Issues (24 min.)
05-09 - EUR Estimation (15 min.)
05-10 - OIP To Decline Curve Conversion (25 min.)

Chapter 6 - Refrac Candidate Selection In Matrix Permeability Reservoirs

06-01 - Role Of Permeability In Refrac Candidate Evaluation (15 min.)
06-02 - Permeability From Production History Matching (11 min.)

Chapter 7 - Derisking Wellbore Mechanical Integrity Issues

07-01 - Wellbore Integrity Issue Discussion (19 min.)

Chapter 8 - "Best Practices" For Isolating Existing Perforations

08-01 - Mechanical Isolation vs. Bullhead Diverter Isolation (16 min.)
08-02 - Mechanical Isolation Options (8 min.)
08-03 - Diverter Options In Horizontal Wells (19 min.)
08-04 - Hybrid Liner And Diverter System Discussion (19 min.)

Chapter 9 - “Best Practices” To Maximize Recovery Factors

09-01a - Extreme Limited Entry (Part 1) (13 min.)
09-01b - Extreme Limited Entry (Part 2) (16 min.)
09-02 - Evaluating The Effectiveness Of XLE (14 min.)
09-03 - Delta-P vs. Perforation Diameter And Rate (17 min.)
09-04a - Comprehensive Cluster Efficiency Study With 4500 Step Down Tests (Part 1) (17 min.)
09-04b - Comprehensive Cluster Efficiency Study With 4500 Step Down Tests (Part 2) (17 min.)
09-05 & 09-06 - Treatment Rate Per Stage Vs Number Of Perforations Per Cluster (17 min.)
09-07 - Perforation Charge Issues (10 min.)
09-08 & 09-09 - Dual String Entry Hole Issues (10 min.)
09-10 & 09-11 - Cluster Efficiency Estimation Overview (7 min.)
09-12 - Step Down Test Analysis (8 min.)
09-13 to 09-16 - Radioactive Tracers/Neutron Logs/Fiber Optics/XLE Implementation (9 min.)
09-17 - Friction Pressure Drop Calculation (9 min.)
09-18 - XLE And Expandable Liners (14 min.)
09-19 to 09-22 - Cluster Spacing, Refrac Orientation and Near Wellbore Friction (18 min.)
09-23 to 09-26 - XLE And FDI's / Refrac Orientation / 7.4% Rf's / Reorientation Proofs (18 min.)

Chapter 10 - “Best Practices” To Protect Infill Wells From Asymmetric Fracs

10-01 to 10-03 - Parent Well Pressure Sinks And Asymmetric Fractures (16 min.)
10-04 to 10-07 - Level Of Depletion Needed For Asymmetric Fracture Generation (15 min.)
10-08 to 10-10 - Haynesville New Well Recovery Factor Comparison With Protective Refracs (8 min.)

Chapter 11 - Booking Behind Pipe Reserves For Refrac Candidates

11-01 to 11-06 - Recompletions Vs Refracs (15 min.)

Chapter 12 - Case Studies In Organic Shale And Conventional Reservoirs

12-01 to 12-06 - Case Studies & Field Examples (22 min.)

Best Practices for New Well Fracs and Legacy Well Refracs / Chapter 1 - Top Ten Reasons To Refrac An Organic Shale Well

Lesson 01-00a Introduction

Access All SAGA Wisdom Training content Subscribe

Already a member? Sign in

Access All SAGA Wisdom Training content Subscribe

Already a member? Sign in

Transcript

01. Lesson 1.00a: Introduction 02. Give me six hours...03. Course Background 04. Course Background (2)05. Course Instructor 06. Course Instructor (2)07. Refrac Papers and Articles 1 08. Refrac Papers and Articles 2 09. Patent Pending Super Bullhead Refrac 10. Conventional vs Organic Shales

01. Lesson 1.00a: Introduction

Good morning! Whatever time of day it is where we are at. Bob Barba, and you got a good course today: Best Practices for New Well Fracs and Legacy Well Refracs. I've been doing this course since 2009; back in the vertical well days, and got some background coming up on that. You'll see some references to Subsurface Consultants & Associates. That's a company I work through in Houston. We've got a joint venture with them in SAGA Wisdom, this course is being presented through. So, we've been working on this for a while to get an agreement where we all are happy, but I teach to them. And they are a full-service consultancy company. They have a geologist, geophysicist, reservoir engineers, pretty much. They can sign off/on reserves. They do detailed field studies, a pretty neat little group there. And I've been training through them for the last 5 or 6 years.
It's the official title here. And kind of based in Houston, Texas. Here's my email if you're interested.

02. Give me six hours...

Some thoughts to start off on is one of my favorite quotes. "Give me six hours to chop down a tree and I will spend the first four sharpening the axe." Well, this is an axe-sharpening exercise. And a lot of completions. Basically, you go out and do what other people do all the time. It used to have a joke when I taught these courses back in the day, where the ideal team to do an optimized frac or refrac is a geologist, engineer, a reservoir guy, completion guy, petrophysicist, the whole 9 yards. But normally, what happens is you've got a service company engineer and a reproduction engineer where they pretty much xerox the procedures.
So, hopefully, some of the stuff we're doing here will make you think a little bit, because a lot of the things we present in here are not mainstream. We present a lot of ideas that have been proven to be solid science and proven to show good results, but they're not done in any number of things in this class or that way. So, you're going to hear stuff that we're recommending and say, We don't do that. And then, you'll find out—I think hopefully by the end of the course—that the reason you don't do that is just because you don't do that. I mean, we've got a lot of good reasons behind all this. We don't recommend anything that hasn't been tried before, and we don't recommend anything that hasn't been tried successfully to try and basically get the lowest cost completions to deliver the best possible results. And there's a lot of twists and turns to it. So that's where the 4-hour sharpening is important on that.

03. Course Background

A little bit on the background. But we did a lot of work back in the 90s and early aughts, where we were doing a lot of integrated reservoir studies. I'm a petrophysicist by training. I worked for Schlumberger for a number of years—10 years. And then, done a lot of these integrated reservoir studies, where we basically identified what the oil and gas in place was. And basically, what's left over? What's there? And what I found during these studies is there's a lot of stuff. There's a lot of meat being left on the bone out there. And I say, What's going on here? And then, I had a background in completions, which we'll talk about in a minute as well. And start realizing that, wait a minute, we really need to start educating people on what fracs do and what fracs can't do because there's a lot of misconceptions out there.
And so, basically, we saw lots of stranded reserves in the ground. And so, there had to be a way to get it out.
And so, basically, once we put everything together, we found out, like I say, there's a lot of stuff left behind out there. And the question comes up: What do you do? I mean, you got the wellbore there already. You've got that proration unit already drilled. Well, then that's when refracs come in. The major problem we've had with a lot of people in the past, and it really continues today, is that people assume that fracs do things they don't do.
And it's almost like once you start putting it all together, it looks like the engineers who designed the frac assumed they were reserve-seeking missiles, and they would find the pay. And as most of you know, I'm sure that the fracs are going to follow the path of least resistance, whether it's a multiple zone scenario, or you've got depleted zones, or if it's in a parent-child relationship where you've got a depleted region, offsetting a brand new child well. And you got to basically start that frac; it's going to seek the path of least resistance. It's not going to seek the reserves. You're not going to get a symmetricalfracture on both sides of that wellbore. And that's today. We have people today now going out and refracing or fracing child wells with parent wells within 1,000 ft, which seems to be about magic number, may be actually higher than that, but it's no less than 1,000 ft, all right. Basically, you're going to have problems out of that because it's really just a lower energy. If that frac sees that depleted zone, it's going to take off in that direction and stop growing in the other direction. And that's where this comes in.
We're basically looking at with the completion itself; there you got gas fields with 10% recovery factors, and should be 65 or 75. 65 on organic shale, 75 up in conventional. A lot of oil reservoirs with single-digit recoveries, where you should be getting 14 with horizontal organic shales and 15 with horizontal matrix reservoirs. But there's a lot of stuff left out there. We got some numbers on that coming up, which should open your eyes as far as what the potential is.

04. Course Background (2)

We started publishing papers on this in 2009. And again, the emphasis was on doing what we normally do with these, where we are doing the field studies, where we do the hydrocarbons in place, and then just see what's remaining there. And then, how do you get it out is the next question.
And we did a paper. It was kind of fortuitous. El Paso hired me back in 2003 to actually come up with reservoir pressures in their zones in the field. They had this stack pays, sometimes 6 or 7 different pays in south Texas, Wilcox. And they saw I was getting reservoir pressure from the frac data, and I said, Well, let's get reservoir pressure where we don't have reservoir pressure data. And we start going through the data and realize, well, we got logs, we got perm, we got all kinds of stuff. So, we were able to come up with a fairly comprehensive deal there where we could show what was working and what wasn't working. A lot of the theories we had, like, single interval completions vs. try to put multiple clusters in a vertical well, things like that. And a lot of things. We'll talk about that coming up. But basically, we shifted our course. We had a course until that point on basically developing inputs for hydraulic fracturing models to be able to come up with FracPro,stress profiles, and rock properties profiles, and frac, and the like. But then, once we published this paper back in 2003 and 2004, we shifted gears to well performance-based type stuff because it was actually a little easier way to do it. And then, also, the service companies by that time had pretty much developed their own in-house thing. We probably had 400 or 500 service company engineers through our classes during the 1990s. So, I think pretty much everybody is already trained on that anyway. So, it was time to shift gears.
So, we recommended mechanical isolation back then, just based on basic physics. I mean, it was all the stuff we talked about pathways resistance. And it's amazing when you look at some of these completions—what people think that fracs do, and they clearly don't. That's the old 4 hour sharpening the axe business. Sometimes, when you go out to complete a well and you're not really familiar, you don't understand the physics, you don't have the information to work with, the safest path there if you want to keep your job is to do what your boss says to do or also do what the other guy did. If Fred didn't get run off for doing this procedure, then you're probably OK. Now Bob comes in and says you should be doing this. Well, Fred didn't do it that way. And most of the time, Fred wins, and I'm running into that right now with stuff like expandable liners. I'm still having a real hard time getting people run expandable liners, even though you'll see at the end of this course that clearly that's really the only way to do it. But why are'nt people running them? Because they're not running them. It's not really related to the physics as well. It was not related to what's right and what's wrong. It's related to what's being done. There's a lot of inertia out there that's really hard to overcome in this business. We're probably one of the least responsive businesses to change of all the industries out there. I think I saw a deal a while back that showed that electronics industry, or in semiconductors, you've got like 6 months or a year before 50% of the population accepts it as a good practice. Medical is like 2 or 3 years. Some other engineering stuff is 4 or 5 years. And oil and gas is something like 10 years. You'd think that, in the business that small, in the wildcats of old, the people would be rolling the dice and taking risks. But it's almost like these companies are run by accountants now. And nobody wants to take risks. Nobody wants trust of the new. And the ones that do are getting rewarded quite nicely.

05. Course Instructor

A little about my background and qualifications to be here. I started out as an openhole wireline engineer in 1981, field engineer, sales engineer,rock properties log champion for USA, and got into the software business with Schlumberger as well. We had the first PC-based log analysis package. And basically, I was running complete analysis. They had this computing center product that they were running. It took like 2 or 3 days to get cranked out. And between QLA and between some of the other rock properties work that I did. And with Bruce Myers Mfrac program, I was able to basically do everything that Schlumberger could do, only better and faster.
So, I decided to leave in 1991. And what I did before I left was I went to Schlumberger management and said, Let's build a team that integrates wireline logs with completion and reservoir engineering, basically tying it all together, because we were having tremendous success on that. I mean, actually, we did some work with ExxonMobil in Midland, where the stuff we did, I mean, this may have been just coincidence, and we may be patting ourselves on the back inappropriately. But the day we found out that when we started integrating logs with the geology and where the perfs go was a completion engineering, we doubled production in the field. And the management just took notice of that. And within about 6 months, they had gone. They shifted completely in that office from basically a silo-based system where the reservoir engineers report to the reservoir management guy and all that to an asset team deal where you had two different things. You had a chain of command for the technical, and then you had a chain of command for the operational. And there were two different bosses, and they adopted that. Now, where we responsible for that? I mean, I'd like to think that it's basically that's what we were doing. So, I assume that they were following that. But it's quite possible that they were also solving that in parallel. So, I really can't take credit for that. But Schlumberger didn't see the benefit for some reason, even though I was recognized several times for the work we did out there. We went to the International Paper deal in Richfield twice for the work we did, and they knew it was good because the clients were paying for it, and we had incredible results.
But basically, they told me... I wouldn't repeat what they said because I'm sure this is not politically correct. What they told me exactly is that says, you should be working for (some adjectives in there), Dowell. And I was working for Wireline; fracture something the Dowell does. We don't get involved in fracs in Wireline. So, I knew that wasn't right.
So basically, I left in 1992, and the rest of the world that I already kind of recognized it was good, and the SPE recognized it. In 1995, they got me on the DL tour.
And then, it's kind of an ironic year after that Schlumberger got on board just pretty soon after that and bought Holditch. And basically, it's the same process he does is what I recommended back in 1991. And basically, Steve was one of, I say he's my mentor. I mean, we weren't really good friends. So, we didn't really knew each other, talk to each other. But he was a key influence on me. And when I took his course in 1983, we were just getting started with this wireline integration with fracs. And he was the first guy, a credible guy, who said, We need this stuff; we need this log information; we've got to have it. And nobody else was saying that at the time. So, I took that and ran. And it kept turn out to be a pretty good move.

06. Course Instructor (2)

Again, basically after that I took his course, I went on to become the rock properties champion for the FracHite log and involved in basically go and give them talks all over the place and working with operators on that.
And since then, not taught schools on it. Chief Petrophysicist at BG which was a really rewarding job because I got to see how the petrophysics tied into the integrated reservoir studies, where you get your gas in place, where you get your oil in place. The integrated reservoir studies work is really what drives this whole refrac thing. Without the integrated reservoir studies, the refrac concept might not have ever got on the radar. But we're seeing the results of the completions people were doing day in, day out. And it's just not cutting it. They are not getting what they need to be getting out of the rock. And it's been pretty successful.
I mean, SPE got the Southwestern North American Region Formation Evaluation Award because what we're actually doing in the shales is predicting production ahead of time. We can basically give you EURs ahead of the bid. And that was something new. That's one of the reasons they gave me that award. And I was also nominated for the DL program this year. Unfortunately, something like 75 - 80% of the SPE is in areas that don't have organic shales. So that was kind of a no-brainer that I wasn't gonna make it to the next cut for 30. But anyway, at least I was honored to be nominated for it. And SPE is becoming truly an international organization now.

07. Refrac Papers and Articles 1

On the refrac side, out of the total of 57 publications I've had since the early 1990s, 11 SPE presentations, 4 Hart Energy DUG conferences, and then 4 major magazine articles on refracturing. I won't go into each one, but they're in the slides for reference.
And there's the first page here. I won't really go into that. There's the first one, back in '09.

08. Refrac Papers and Articles 2

And then the most recent one—we just had one come out this week in Oil and Gas Journal. Just an aside, I should have mentioned this earlier, but by accident, I went ahead and started putting a manual together. Kind of funny. I mean, John Thompson here at SAGA said, Look at Dave Anderson's talk and look at Cam talk on the petrophysics and try to pattern your school after that. I was like, OK, great. And I pulled up their talks, and it's got riding off to the right. And I go, OK, well, I guess we have to have a manual there. So, I started this manual. About 2 weeks later, I watched Cam's again. I go, oho! And they're just transcribing what I'm saying. I didn't really need a manual, but it turned out that doing the manual was a really neat exercise because it forced you to kind of coalesce your ideas and be more concise and be more organized, and you make it a lot better. And everybody that takes this course is going to be provided with a copy of that manual. We won't have it in the presentation here, because pretty much everything that's in the manual is in the slides, but it's presented you with the table of contents and all kinds of stuff in there. So, it's little more formal as a good reference if you want to find something that you jump that comes up, like, well, what about parent-child or what about expandable liners or whatever. You just look at the table of contents. This where it is, and this is out in the pages it's on, and all that. So, it should be pretty good. And we're going to mail that out to all our former attendees. We've had about 50 people in the classes over the last few years, and everybody's going to get a copy of that as well.

09. Patent Pending Super Bullhead Refrac

Some of the stuff we're working on. I've got a patent pending on called Super Bullhead. Still trying to find operators to team up with on it. What we're trying to do is kind of combine the liner technology with the bullhead technology. Because one of the problems with bullhead is if you're going into phase perforations, you don't ball out a cluster with one ball or one pod. You basically have it. It's a real messy inefficient operation. You typically pump for a day. You don't usually go more than a day. So, there's only so much volume you can pump in there, and you waste a ton of that volume going into these other clusters. You're going in the same cluster several times, sometimes 4 or 5 times. Because if you got 5 spf or 6 spf, or some of these Haynesville wells are 12 shots per 2 ft. One of the case studies we have in the back of the class is Lucas Marzano, who was consultant at Houston, did a Ball out on a Marcellus well, and it took 4 days to ball out 720 perfs. And it was all phase perforations. So, it was one of the things that kind of triggered my thoughts on this.
But the benefits of it is you can basically do it long stages: 1,000 ft there, 800 ft. I mean, that's something we need to test out when they have some velocity issues. I mean, it's something trial and error, but we can certainly do a lot more than the traditional 200 ft, 250 ft stages that people are using now. Maybe it's going to end up being double that, but anyway. But it's going to drop the cost quite a bit. And the main reason for it is to try and have a lower-cost option for parent-child protection. And it's going to improve production as well. Are we going to get 95%, 97%, or whatever the current tap rock paper cluster efficiency is? Maybe not, but you're going to get more than 29. And 29 is what you get now with the conventional bullhead. So that's the hope. And so, we're still waiting on an operator to team up with on that, hopefully. And also, the patent is also Tim Leschyshyn here in Calgary, and he's trying to work it from this end up as well. I brought him on board on this because he's got several patents under his belt. So, he's another resource for this particular technique.

10. Conventional vs Organic Shales

There's always a question on what are the differences between these two and what's the completions strategy between the two. And we get a lot of comments in the class from people that are in organic shales that, well, the conventional stuff wasn't very useful. We should have just talked about shales, and I apologize in advance for that. And there's a lot of cross-pollination between these two. A lot of these multi-stage horizontal fracs now are done in matrix reservoirs, the Montney, for instance, the Bakken, the Jo-Mill, Bone Springs. They were on 40-acre spacing vertical before they went to horizontal. So, they actually drain; you got 1,300 ft cluster spacing, still makes good wells or economic wells, not really great wells.
But there's a lot of opportunities out there. I mean, inventory, inventory, inventory is something all these companies keep going. And sometimes, if you're a small operator and you've got so much to work on, you're having a hard time getting acquisitions. We do a lot of work for companies that are looking to acquire properties that want to know if there's refrac potential. And you'll have 10 companies bidding on a project. And it's a dog-eat-dog world out there; expanding your inventory. Well, people have pretty much ignored the vertical world. I mean, it's been a stepchild ever since the shales came in. And everybody is all enamored with the shales. But there's a ton of gas and oil out there behind pipe on these vertical wells. And if you run out of prospects or your inventory started to shrink, maybe you're down on Tier 2 or Tier 3 shale, look at vertical, I mean, for refracs. I mean, there's a real good opportunity.
And the big thing about refracs, that last sentence there is key. The current PV10 of that well is not tied to the refrac potential. It's tied to what's in the ground. And it's tied to how they did it the completion start with. The 3 things that drive it: cluster spacing, cluster spacing, cluster spacing. So, basically, you could have a well that's got a present value of $50,000.
And one of the examples we're going to show you the PV10 on basically the EUR was 100,000 bbls from a 9-well pad. And when you refrac that, it goes up to 2.5 MMbbls recoverable. Now, we've looked at other ones that have maybe $1 million PV10; maybe a lot higher numbers. But the end result is still the same. It's the oil in place, gas in place, and what's stranded. It drives it. So, you can buy wells for nothing. In fact, there's a lot of wells out there you can pick up for plug-in liability that are really good refrac candidates. It doesn't get any cheaper than that. And sometimes, they'll even pay you to take them away. I mean, there's a lot of opportunities out there. And I think people are just really... We're just scratching the surface on this.
Why haven't they really taken off? The current theme is that, basically, it's fracture mechanics or lack of understanding of fracture mechanics. That reserve seeking missile thing is kind of a joke, but it's really not because we see a lot of that, a lot of completion designs that are basically assume that. And it's not true. We know that's not true. If an operator in West Texas tell me, I'm not worried about it. The frac is going to find the good stuff, yeah, it's going to find the good stuff. It's going to find where the oil gas was really well. Where it is now? Not so much. And we prove that over and over again. We'll show you that, OK.
All right, before we get the first section, it's probably a good time to take a little break here.
Robert E. Barba, "A Novel Approach to Identifying Refracturing Candidates and Executing Refracture Treatments in Multiple Zone Reservoirs", Paper presented at the SPE Annual Technical Conference and Exhibition, NO, Louisiana, October 2009.Barba, Robert E., and Ronald A. Shook. "Post Frac Evaluation of Multiple Zone Fracture Treatments Using the" Completion Efficiency"" Concept."" In SPE Annual Technical Conference and Exhibition, pp. SPE-90483. SPE, 2004.Barba, Robert E. "Liquids Rich Organic Shale Recovery Factor Application." In SPE Annual Technical Conference and Exhibition, p. D031S041R008. SPE, 2015.Barba, R. E. "Evaluating Refrac Potential in the Permian Wolfcamp Formation." 2017.Barba, Robert, and Mark Villareal. "Maximizing refrac treatment recovery factors in organic shales using expandable liners and the extreme limited entry process." In SPE Annual Technical Conference and Exhibition, p. D021S029R006. SPE, 2019.Barba, Robert, John Stroder, and Mark Villarreal. "Evaluating Refrac Economic Potential and Primary-Infill Relative Well Performance in Permian Organic Shales." In SPE/AAPG/SEG URTEC, 2020.Barba, Robert, Justin Allison, and Mark Villarreal. "A comparison of latest generation frac new well and refrac results with evidence of refrac reorientation." In URTeC Conference, 20–22 June 2022, pp. 2034-2040.Barba, Robert E. "The High Cost of Poor Child Protection: Economic Evaluation at the Pad Level with Primary Well Refracs." In SPE Oklahoma City Oil and Gas Symposium/Production and Operations Symposium, p. D031S010R001. SPE, 2023.Barba, Robert, and Mark Villarreal. "The Economics of Refracturing in the Haynesville." In SPE Hydraulic Fracturing Technology Conference and Exhibition, p. D021S005R003. SPE, 2023.Fleming, Mark, and Robert Barba. "Refracturing increases recovery in mature unconventional assets." 2024.