Chapter 1 - Well Integrity with Workover Focus

1.01 Well Integrity with Workover Focus - Part 1 (21 min.) Sample Lesson
1.02 Well Integrity with Workover Focus - Part 2 (13 min.)
1.03 Well Integrity with Workover Focus - Part 3 (18 min.)
1.04 Well Integrity with Workover Focus - Part 4 (25 min.)
1.05 Well Integrity with Workover Focus - Part 5 (18 min.) Quiz: 1.05 Well Integrity with Workover Focus - Part 5

Chapter 2 - Casing Damage Associated with Fracturing: Types, Causes, Prevention

2.01 Casing Damage Associated with Fracturing - Part 1 (20 min.)
2.02 Casing Damage Associated with Fracturing - Part 2 (26 min.)
2.03 Casing Damage Associated with Fracturing - Part 3 (23 min.)
2.04 Casing Damage Associated with Fracturing - Part 4 (18 min.)

Chapter 3 - Corrosion, Erosion and Abrasion

3.01 Corrosion, Erosion and Abrasion - Part 1 (18 min.)
3.02 Corrosion, Erosion and Abrasion - Part 2 (21 min.)
3.03 Corrosion, Erosion and Abrasion - Part 3 (20 min.)
3.04 Corrosion, Erosion and Abrasion - Part 4 (19 min.)

Chapter 4 - Exterior Casing Corrosion Causes and Mitigation

4.01 Exterior Casing Corrosion Causes and Mitigation (15 min.)

Chapter 5 - Annular Pressure Causes and Repair

5.01 Annular Pressure Causes and Repair - Part 1 (20 min.)
5.02 Annular Pressure Causes and Repair - Part 2 (13 min.)
5.03 Annular Pressure Causes and Repair - Part 3 (17 min.) Quiz: 5.03 Annular Pressure Causes and Repair - Part 3

Chapter 6 - Failure Causes in Tubulars and Couplings

6.01 Failure Causes in Tubulars and Couplings - Part 1 (19 min.)
6.02 Failure Causes in Tubulars and Couplings - Part 2 (21 min.)
6.03 Failure Causes in Tubulars and Couplings - Part 3 (21 min.)

Chapter 7 - Packer and Liner Hanger Failures

7.01 Packer and Liner Hanger Failures - Part 1 (28 min.)
7.02 Packer and Liner Hanger Failures - Part 2 (22 min.) Quiz: 7.02 Packer and Liner Hanger Failures - Part 2

Chapter 8 - Leak Detection & Repair

8.01 Leak Detection & Repair - Part 1 (18 min.)
8.02 Leak Detection & Repair - Part 2 (16 min.)

Chapter 9 - Tracers in Workovers

9.01 Tracers in Workovers - Part 1 (14 min.)
9.02 Tracers in Workovers - Part 2 (13 min.)

Chapter 10 - Cement Evaluation and Repair

10.01 Cement Evaluation and Repair - Part 1 (23 min.)
10.02 Cement Evaluation and Repair - Part 2 (18 min.)

Chapter 11 - Dual Completion Challenges

11.01 Dual Completion Challenges - Part 1 (16 min.)
11.02 Dual Completion Challenges - Part 2 (12 min.) Quiz: 11.02 Dual Completion Challenges - Part 2

Well Integrity / Chapter 1 - Well Integrity with Workover Focus

Lesson 1.01 Well Integrity with Workover Focus - Part 1

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Transcript

01. Lesson 1.01: Well Integrity with Workover Focus - Part 1 02. Well Barrier Failure vs. Well Integrity Failure 03. Objectives 04. Failures in Age and Era 05. The Element of Time. When does the warranty run out…..?06. But are all operators the same?07. Era of Construction – Technology in Practice 08. Workover Well Integrity Concerns 09. Initial Steps 10. The Potential For Pollution is Reduced by Application of Technology 11. Example Failures in an Era - Casing 12. Barrier and Integrity Failures Study 13. Well Study Review >650,000 wells 14. General Well & Integrity Failure Causes & Estimated Qualitative Failure Frequency by Well Types 15. Leaks are NOT Always From Wells 16. So – What are some more common groundwater pollutants?17. 2000-2011 Pollution Reports in Texas 18. 2000-2011 Pollution Reports in Texas 19. What is a Culture of Maintenance?

01. Lesson 1.01: Well Integrity with Workover Focus - Part 1

One of the factors that you must be concerned about as you deal with any workover or recompletion is the well integrity of the well you are working with. And we have some special application problems in workovers so I'm going to keep this on a focus on the workoverwell integrity itself.

02. Well Barrier Failure vs. Well Integrity Failure

Now, first thing we need to do is to look at what are the barriers in the well. In this case, we have a well barrier failure vs.well integrity failure. Well, wells are made with multiple barriers where if one fails, the one behind it should be able to pick up the entire load, if you will, of stresses and pressure and to be able to keep operations going smoothly. So, well integrity failures now are where all of the barriers break down and you have either emissions to the outside, maybe an underground blowout, even cross-flow in the well. We're trying to prevent those to prevent more serious incidences down the road. Now, if you look at the number of barriers that we would have in a well, it generally should be 2 or more above the pay zone. And that's what we're going to look at. Some of these are steel, some of them cement, some of these can be just the fluid density of a full column. But nonetheless, we have to look at it and individually at every barrier as we go through.

03. Objectives

Objectives here. What are the most likely well integrity failures that you would see? What are the causes of those? And do you expect to see them in the well work arena? Now, if you have barriers in this situation, obviously all of these need to be working and up to the job of minimizing anything that comes into there from getting to the outside. So what well, fluid and operational actions increase the risk of a well failure? And this is where I'll put a little red flag in there and say that there are a number of things that will happen and we'll look at those as we work our way through that you will be able to see as you get close to failure. And if you know what to look for, you can often shut a job down or do it in another manner and avoid a problem entirely. So we're going to be looking at that, the economic and effective monitoring methods and then the common prevention and some remediation methods.

04. Failures in Age and Era

Failures are often associated with either age of the well or era that the well was built in and I tend to look at era first and the age second. The target of the exploration is another factor. What are you trying to do here and what type of a well is it? Obviously, the high temperature, high pressure wells are going to have more of a risk that something might fail. But even when you're down to a low pressure well, you can still get into problems if you're not following the right procedures. So the technology that's been used in that era, if it was used in these wells that you're dealing with right now, look quickly at what's being done there, what was popular in that day and that might give you a hint as to what to look for later on.

05. The Element of Time. When does the warranty run out…..?

Now, when we look at failures, let's just take automobiles for an example. You go back, you look at the start up failures, and those are what that we have a lemon law to protect. Now, over the useful period of life of a car or really any device, the manufacturers know about how long that's going to last under routine operation and that's what they'll generally warranty. They also know when it's going to wear out due to old age, due to erosion, corrosion, any of those factors in there, they've got a pretty good handle on it. So just keep in mind here that as wells do get older, they do have a higher risk, but also look at the era of construction.

06. But are all operators the same?

Now also, all operators are not the same. The generalized failure rate for a specific well population is what I've got on this slide. And it looks at yes, that useful life period could be shortened. If it's abused, if it has poor maintenance, those will fail early and you will not get out to the point of normal wear and read the fine print on things you buy and generally it will mention those things as it goes along.

07. Era of Construction – Technology in Practice

Now, on the era of construction, I want you to think about 2 vehicles here that are shown. On one side is a 1905 Cadillac, 9 hp, top speed of 25 mph, and every practical safety device known to man in 1905. Obviously, that's not much. The car on the other side, 2015, a couple of years ago, but it's one I know a little bit about. Look at the horsepower, 640 hp, getting close to 200 mph if somebody had the talent to drive at that fast and a place to do that, and every practical safety device known to man. Well, by then they had invented seatbelts, of course, shoulder harnesses, they had braking systems that wouldn't lock up. There's a lot of different things, including the crash resistance of the car. What I'm saying here is as eras go through, things should get better. If they don't, then something is wrong with either the maintenance, the abuse, or the way those were applied in the first place. So we're going to look at that one and we're going to carry it on a little bit. Now, let's go back to a well.

08. Workover Well Integrity Concerns

These are the integrity concerns: adequate cement barriers. Well, cement is a very long lasting barrier if you get it in right and if it is treated right and if you don't have materials from the outside like sulfates coming in, that can degrade the cement. That's part of the corrosion and it could be on the outside and/or on the inside. So corrosion, erosion, internal, external and then previous stimulations. Most of these wells that we're going to be considering because we're going to be looking at recompletions and refracturing is these things have been fractured once, at least once. And sometimes if it's a horizontal, it's been multiple fractured. And if you count up the number of stages and then figure in the clusters that we're going into in some of these fracs, it can easily go over 200 fractures going into that wellbore. So that's going to have an effect as this pressure goes up and comes back, it's going to be cyclic pressuring of the casing and the cement. Now, where this all comes down to is look at the barrier failure monitoring and repair. You're looking for leaks, you're looking for pressure increases, you're looking for changes in the produced water, indicating if you have more chrome or iron, then you've got some active corrosion going on downhole. If it's an older well and you've had a lot of CO₂, a lot of water, get a TV camera in there, a video camera or another sonic instrument and look for wall loss on the inside on the low side of the well. And they can have a low side, even if it has 1/10 of a degree of deviation, it will have a channel that that water is going to flow through. Not all wells will have it, but it's common enough to where this is something you should look for. Then the culture of maintenance kicks in, have you been doing the corrosion inhibitor flushes of these wells, the scale inhibitor treatments? Look at all of these things to see what shape is this well in. If there's any doubt, you better do some checking, maybe even pull tubing and figure out can it be done safely? Because we want to find out if a well will break before we actually get to the point of overpressuring and breaking it.

09. Initial Steps

Now, initial steps identify the risks, corrosion, erosion, I've already mentioned, and then review the failures to see what was happening before that failure that would have warned you that that failure was coming. That's the red flag I'm talking about. The monitoring methods, they're going to be different for different types of operations. But it's the when, the how, and the what that is happening. And also look at reliability of a group of wells, not necessarily just one, and look for early failures or failures under different conditions. That's one of the ones you would like to see. And while you're doing that, look at the records to see how those wells were repaired and how well those repairs went.

10. The Potential For Pollution is Reduced by Application of Technology

Now, in the oil industry we've been drilling gas wells in the United States since 1823 and oil wells since 1859. During that time from 1830 up to about 1916, the cable tool drilling, very little cement if anything, actually, the first well that had cement was, I think, 1903. And if the wells were leaking, they were just vented to the atmosphere. Yes, you're going to get some pollution there. Man, that was an era of high pollution risk. As it's gone through, we've got into cementing now, we're using rotary drilling to replace cable tools, no more of the big gushers going over the wooden derricks that were out in the field. One of the biggest things that has helped us minimize the environmental risk is fracturing, something that's actually gotten a bad name but it's let us get more out of one well without drilling a number of wells. So these are the things to remember as you go along and the time since that we have a lot better monitoring methods, we have well integrity assessment procedures. So those are the things we need to look at as we go along.

11. Example Failures in an Era - Casing

Let me give you a small example here of era and that is casing collapses. And if you look in this particular figure, we're seeing a time period here vs. connection, collapses, wear, brittle, and unknown failures. Well, we look at this and it should step down nicely and it does in most cases. But notice that between the 1980s and the 1990s, collapses were over 5 times more frequent in the 90s than they were in the 80s. And just looking at that, considering all wells equal, you might think something was wrong there. But when you really look at the time period, 1990s is when we started doing deep water operations and that's when the potential for collapse failure was much higher.

12. Barrier and Integrity Failures Study

I've looked at over, I have studies that cover over 600,000 fails in wells, about 330,000 studied in the United States and with a lot of documentation around it. And the older wells do fail more than the newer wells. But there are several places where the older wells and the newer wells are reasonably close together and it really depends on the operator and their sense of safety, etc., and of course on the regulations that they operate under.

13. Well Study Review >650,000 wells

Now, the well study also came up with some of the other factors, 2 things here. First is that in a completed and producing well, the most frequent failure, and we've seen this on several studies, is the connection leaks, either the tubing or the casing. And the reason for that is most of the tubing and casing was an 8-round or another type of thread that depended on pipe dope to be able to seal it. Well, pipe dope only has a limited lifespan depending on the conditions of the well and what's produced. But nonetheless, look at that and see what has gone on there, because we've got 100 year old wells that still produce and don't leak, but we've got newer wells that we have problems with. So we've got to identify those activities that really gave us a problem. The other factor in that is on the side under Figure 6 and this is the range of failures by well type. And I've gone back and really looked at the temperature of the well, what it was flowing, if it had a subsidence factor in it and if it had been frac'ed or multiple frac'ed. And basically when you do that, you'll see a lot more failures where you have, for instance, fire flood or cyclic steam or high pressure, high temperature and a lot less when you get down on modern wells, particularly those completed in the last maybe 10 years or so that really were of the era where we had learned how to get good cement jobs and get good isolation and to design the casing to stand all the forces. So the era of construction is something we need to pay attention to.

14. General Well & Integrity Failure Causes & Estimated Qualitative Failure Frequency by Well Types

I put a chart in here on general well and integrity failure causes and some of the estimated qualitative failure frequency. And I'm not going to go through all that but you can look at this and you'd see from fire floods down to producing wells, some of the failures, the common causes, the failure rank expected, whether it's extremely high, medium, low, and then how do you stop it? How do you prevent it from happening? And sometimes how do you repair it? A lot of times you need to know what that red flag means that you're seeing there. And it won't be colored red, but it will be a change in the data that says, Hey, something's going on here that's changing the way this well is going to be able to operate.

15. Leaks are NOT Always From Wells

Now, the leaks from a well are infrequent. Not many wells leak. It's a 0.002% of the wells, but there's over 4.3 million wells out there. So you look at the older ones, you look at the era of construction, and that's where a lot of your problems are going to be coming from. Also, when you're seeing methane around a well, you can't assume that it's coming from that well, even if you can tell the difference between biogenic from the cows and thermogenic from the wells, because the pay zones down here are continually pushing the methane up toward the surface and that comes through as a natural seep. And you can see the pattern of the natural seep and then you can overlay the number of wells, frequency of wells in the United States and in some parts of Canada on that, and you see a direct correlation with those.

16. LIDAR Bare-earth Elevation Map

Also, when you see methane in the water, you have a water well. If there's a lot of cases of that, in fact, the most polluting form of any kind of a pollutant in water is methane. And a lot of it is biogenic but some of that is this thermogenic that has come up through the soil. So a lot of these things, there are some wells here that there's no fracturing anywhere around them yet they have methane in them.

17. So – What are some more common groundwater pollutants?

Now, what's in the water? Well, if you're seeing hydrocarbons and looked like it came out of the well, look to see is it gasoline or diesel? Those are the two biggest contaminants that are down there and most of that comes from underground storage tanks of the 40s, 50s, 60s that were leaking and have had to been repaired and that is getting lower all the time. The rest of this right down to almost the very end there is agriculture, it is the way that people have built septic systems, and there's a lot of dumping into the subsurface that's very illegal. So when you have a lot of pollution in an area, check it for what it is and then track it back to its source.

18. 2000-2011 Pollution Reports in Texas

Now, this is just a little piece I put together. I had some information from 2000 - 2011. And this was pollution reports for the state of Texas, the top 20 listed. And if you look down through there, you're still seeing the gasoline, the chlorinated hydrocarbons from dry cleaning and from other blending type operations. But look at the 2000 level, the 2006 and the 2011. And you can see in most cases, this leaking underground storage tanks have been repaired and are getting steadily less frequent in the groundwater itself. This is just a little aside to get over the fear that all the pollution comes from a well.

19. What is a Culture of Maintenance?

Now, I've mentioned culture of maintenance before and maintenance is the set of actions that minimize deterioration of an asset. I don't care what asset it is, it will have some maintenance on it. And if we're willing to get everybody involved in this, you'll protect against corrosion, erosion, abrasion and other forms of deterioration of that well. But it does take monitoring and then it takes an action to either minimalize it or stop it completely.
King, George E., and Daniel E. King. "Environmental risk arising from well-construction failure—differences between barrier and well failure, and estimates of failure frequency across common well types, locations, and well age."Etiope, Giuseppe, and Ronald W. Klusman. "Geologic emissions of methane to the atmosphere." Chemosphere 49, no. 8 (2002): 777-789.Molofsky, Lisa J., John A. Connor, Albert S. Wylie, Tom Wagner, and Shahla K. Farhat. "Evaluation of methane sources in groundwater in northeastern Pennsylvania." Groundwater 51, no. 3 (2013): 333-349.