The Value of Well Diagnostics for Drilling Contractors
How do well diagnostics work and what should drillers know about the process? Mike Miller, president and co-founder of Geo Cam Inc., based in San Antonio, is an expert in the service. Miller and his father Edward, a geologist, launched Geo Cam in the late ’90s. His father initially needed well diagnostic services himself, which sparked the idea to create a business out of it that would cater to smaller businesses and help them compete with larger companies.
Geo Cam offers well logging and downhole camera services across the state of Texas mostly. They’ve also completed projects in Louisiana, New Mexico, Florida and Georgia. Miller says the Texas Ground Water Association (TGWA) has played a big part in acquainting him with groundwater professionals, particularly water well drillers, who stand to benefit from his expertise. For nearly a decade now, Geo Cam has continued fine-tuning the tools and tactics that help drilling industry professionals more thoroughly assess wells and boreholes new and old. To gain a better sense of what exactly well diagnostics involves and what value it brings to drilling contractors, National Driller interviewed Miller after meeting him at the 2017 TGWA conference and expo.
This interview has been edited for space and clarity.
Q. GEO Cam specializes in water well and borehole diagnostics. What kind of data are you providing and who is your typical client?
A. Generally speaking, it’s the water well drillers. In that, we typically have a geologist and/or an engineer who is requesting the information, but we really built this business on working with the drillers and their immediate needs on all types of projects where they need information or are having difficulties seeing what’s down there. It’s kind of hard to look down a hole and know what’s going on 200, 300, 1,000, 2,000 feet down. So our specialty is getting down to the problem, trying to identify it better so that they can make their decisions. I’ve learned a lot from those guys because they deal with this day in, day out.
When I started, I had the opportunity to do a lot of field work and run a camera. You really learn a lot about what’s going on downhole when you have that ability, when you have another individual in that truck that maybe hasn’t seen it, but he knows what it is. So now that conversation starts and he’s excited to see something he’s never — he’s maybe drilled on or tried to remove from the hole, or tried to repair. Now he can visually see it. He’s excited to be learning something. So those individuals — the geologists who have decades of experience that I’ve had the opportunity to work with — that’s really where, when you get those two individuals in the back of the truck, you can learn a lot. Typically, our clients are project managers; drillers first, then it goes into project managers who can be engineers or geologists.
Ultimately, what we’re geared up for is public supply. So that’s what we specialize in and [where we] want to be because we know that even though larger companies can do that, their focus may not be on it necessarily. We prepare and make sure our results are driven for the production of water first and foremost. So we do work for municipalities, but we don’t have as much communication with them because ultimately the engineers, geologists and/or drillers are communicating with them. We’re providing the data. Then if they have questions concerning that data, we can certainly discuss it. But that data is there for them to make a decision ultimately.
Q. Aside from water wells, what other sorts of boreholes do you work with?
A. In this industry, there are a lot of different fields you can go into on the mining side, oil and gas, monitor wells. So geophysics has a broad spectrum where it’s utilized. We have been in virtually all of it when it makes sense. So if there’s something we can do or we have an existing client who’s getting into something, we want to be there to support them. So we’ve done everything from uranium logging in south Texas to shallow oil, and in the future we’ll be involved in oil and gas for sure, with some new tools and equipment that we’re utilizing. We’ve done a lot of monitor well work; we call them multi-well packages and that for us is important because we’re very efficient in that regard. We can collect a lot of data in a very short amount of time. In these older fields and monitor well scenarios, we can give them a good heads up on, perhaps, information they weren’t privy to or the economics weren’t there initially for them to gather that information. Now we have a bunch of holes in the ground 100-120 feet deep and we can go in there and get a lot of good data out of them.
But for the most part, water is what we’re interested in in every facet. We do a lot of residential work, of course. The drillers have appreciated the extra knowledge that geophysics brings to the table and we’ve priced it to where it can be affordable for them to get that information. In hard rock drilling that’s important; when you lose circulation you don’t have your cuttings back, you’re not seeing pressure changes, so now the geophysics cleans all that up and we can help them figure out where they ended up drilling to.
Q. When and why do clients call you? Is it after well problems arise, or before?
A. It’s really probably two different areas. You have well rehabilitation, and then you have new well construction and design. The well rehabilitation portion of it, there’s typically an issue or a problem. Some of them are very basic, and they just need to identify and confirm that is in fact what’s going on. Some of them are straight up we’re pulling this well every five to 10 years and we’re going to run a camera on it and see what condition it’s in so we can run a rehabilitation program for it. We also provide sonar jet services, which is a well cleaning technique using a light detonation and gas charge to pressure jet the screen. That is a portion of what we do on the rehab side.
A cased hole is fun because you have several different reasons for evaluating the existing well. You can be profiling water moving from one screen to another, you could be evaluating the most productive zone within a multi-stage completion or looking for a constituent giving you a problem across another zone. All of these things, with geophysics, you can determine. They may desire the data, to help them design the next phase of wells because once you have that in the ground, you can test it and profile it and make a better design in the future. Once you have that historical data, that’s the best time to really gather it so you can make better decisions in the future. In rehab, there are a lot of different aspects and elements involved in it. Those are fun.
On new well construction or design, they may be contacting us for a bid proposal. At that point, we kind of know what we’re doing; we know what the aquifer is. This is typically what’s done and what works, so we’re just providing those services on new construction. So they drill the well down, remove the drill pipe and we’re going in with the geophysics. That log helps them ultimately with the final construction of the well. In that portion of it, you have the subset. So there’s the pilot hole log; then when they ream the well they want to evaluate the diameter, make sure it’s what they intended it to be, that they don’t have any major washouts or any tight spots that will prevent them from being able to put their casing in the well and get a good cement job. That’s one aspect after the pilot hole log. From there they’ll do deviation surveys. That’s another aspect of geophysics, where they may do a gyroscopic survey or a deviation survey to make sure the well is plumb and straight to accept a large diameter pump. So those are all in new construction. You might even be doing a cement bond log on the well to make sure the cement job went well and that they’re not going to have problems down the road with saltwater intrusion. So that’s all new well construction type aspects. Then at the end of that, when they have this beautiful well completed and ready to go, they will do a final camera survey to make sure everything is where they wanted to put it and that it’s been cleaned up from the process of drilling and is ready for production.
Q. What size boreholes do you work with, as far as depth and diameter?
A. You can have a 2-inch PVC monitor well 20 feet deep. We’ve had 20-plus-inch casings, 2,000 feet deep. Some of the larger wells — they completed one that had 18-Inch casing to 2,900 feet and they under-reamed a 24-inch hole to 3,300 feet, so these are massive constructions. So we’ve profiled 30- to 33-inch holes once they’re opened up. I think the deepest we’ve gone now is 6,100 feet for water. We have a wide range and utilize different size equipment for specific jobs.
Q. What does logging involve? What techniques are implemented and what kind of tools and technology are used?
A. When you start the project, the geologists, engineers and drillers together decide what would be the best geophysical logging program for the environment. They may contact us and get our input as well. Once that’s determined, typically the water well suite will have a natural gamma ray, which is evaluating the different strata and is measuring the natural radioactivity emitted from the formations. So that’s probably the most important tool starting in a test well. Then you typically have some type of electrical properties that you’re evaluating, either with resistivity or induction tools. This is beginning to let us understand where our water bearing zones are and what type of water is in those zones.
Then, typically, you’ll ad a caliper. That helps with knowing what your borehole diameter is. Even though they may cut it with a 7⅞-inch bit, some areas will wash out, some areas are fractured, you have bedding planes obviously in karst environments. So that caliper allows you to understand the log response better because, if you have a change in diameter, it’s going to affect most of the log responses. We want to monitor that and know if we see an anomaly, is it associated with just a change in diameter.
Those are the three types of logs we generally start out with. After that, the specialty tools come in where you’re looking at either a full waveform sonic, neutron porosity, or gamma density. These tools begin to evaluate the type of formation you’re in, the different densities involved, which allow you to derive porosity data to tell you exactly how successful you’re going to be to some degree in having available water to produce. Those are typical options when you go into the test hole portion of it. Then in production we have the larger XY calipers, which will help evaluate when they ream these wells out to 20-plus inches, what’s going on with the borehole. Then you have deviation tools that help ensure that the borehole is straight.
Q. How are findings provided to customers? What form does a report take?
A. At that point it is a geophysical log. That’s printed on continuous feed paper and it provides all the logs that we ran for that borehole. That’s pretty much the report for everyone to evaluate and begin to make decisions off of. This is the part where I preface that it is really only one part to the puzzle. Geophysics can only do so much, but the drilling process is very important as far as what the driller is writing down in his log. So drill rates, hardness, those things matter as far as cleaning up your geophysical log and understanding exactly the rest of the story, if you will. The drill cuttings have come out and those being sampled correctly, then we can actually see what does the cutting show across that section. You get your sieve analysis from that, which is really important.
The geologist in the field is then evaluating those cuttings, so he has that information and the driller has his drilling information. The geophysicist has his information. The geologist who has done his background on that specific area knows where in the formation he is starting out on surface, and has some idea of the different layers we should encounter. All of those three pieces allow you to have a picture of what you have down hole. So the geophysical log is not the end all, be all; it is complementary to the background work that’s done ahead of time and the work that’s done during the drilling process. The hardest part for us is if those other pieces are missing or that wasn’t part of the scope on a well. It can be difficult to know fully what’s going on down hole. In areas where you have a lot of control and a lot of experience, it’s easier, but you really want to have those other pieces of information.
Q. How has logging technology evolved since your time in the business and what advancements would you still like to see made to it?
A. At the end of the day, it’s physics. Nothing’s changed, but everything’s changed. It’s really the acquisition of the data. The principles are the same; the way of deriving that information may change. There is an analog versus digital scenario, if you will, and digital has done very well in bringing advancements to logging and enabling us to get more information with single-pass runs and utilizing single-conductor cable. Probably the neatest change is processing software. There are so many different programs out there that allow you to dress up this data very simplistically, whereas before there was a lot of programming that went into a geophysical log and everything had to be right the first time on the run. Now you can adjust calibration settings and replay logs.
At the end of the day, it’s acquisition and software for post processing. Even printers, the color printers you can get for out in the field. They’re still expensive, but it’s amazing what kind of product you can produce. I [also] think tool string size. We’ve had digital logging tools that are compact and allow us to work very efficiently and are single-man lifts. Now we have 4-inch tools where it’s a two- to three-man lift. That is going back to decades old of proven technology that’s been in the field that works really well. We’re utilizing that on deeper wells. We’re actually utilizing new and old technology now.
Q. What key challenges do you face with respect to logging?
A. Of course it’s logistics. We’re part of a construction process, so when they need you, they need you. You are beholden to the rig, if you will. There’s rig time and it’s the most expensive piece of equipment in the field along with the skilled labor that has to operate that piece of equipment. We really need to be there when they need us. There’s also that hole condition and when the borehole is prepped and ready, you really can’t let that sit. So the challenge for us is being a part of that communication process, and we’ve excelled at that. To make sure that we keep that rig moving, we keep the schedule on track, we do a lot of things behind the scenes to accommodate those schedules and be there when they really need us.
Q. Are there any misconceptions about well logging that you’d like to set straight?
A. If anything, they joke because what we do — we’re not out there with them 10-12 hours a day, five to seven days a week, so getting to that location and getting that well down is a very involved process. We’re there for a very short period of time and we work very efficient because we have to be. So we have kind of a lot of down time and a lot of travel time, but when we are asked to perform, we have to perform pretty much flawlessly for a certain amount of time. So they see it as, “Y’all have got it kind of easy,” but the reality is that we’re very well trained, we’re very good at what we do and we do a lot of preparation so we don’t have down time issues in the field related to repairs and breakdowns. It’s kind of like a race car mentality where your pit crew is more important than anything else. You’re prepping so that you can go out there and perform flawlessly and get them that information, and sometimes they might take that for granted, if you will.
Q. You also offer downhole camera services. Under what circumstances should camera technology be utilized for water wells and boreholes, and what information does it provide?
A. If you simplistically say a picture’s worth 1,000 words, if you can get the shot with the image giving the borehole conditions, you can really simplify what’s going on to a myriad of people. Especially in a municipal situation or public situation where you want to convey something, if they can see that, it’s much more helpful to them than if you give them a piece of paper with a bunch of geophysical squiggly lines on it. That piece of technology is undervalued sometimes because if you get the right shot, [it’s] the end all be all. It doesn’t have a place in every scenario. It’s a great tool for evaluating a well’s life.
Q. How big are the cameras you use and how does the process of investigating boreholes with them work?
They vary depending on the size of the borehole you need to video. So there are some factors there as far as your light source. You can be 4-inch, 3-inch or a little under 2-inch on cameras. We utilize all of them so we have the best opportunity to image anything.
The cameras are lighter typically than most geophysical logging strings, but they’re deployed the same way and it’s real time. You’re in the truck with the client looking at what’s going on down hole, and you’re recording that.
Q. What advice do you have for getting the most out of a downhole camera?
A. It’s preparation to some degree, letting the well settle. A lot of times you’re removing the pump. People flush water down them sometimes to try and remove debris; they’ll use a flocculent to grab the floating particulates and drop them to the bottom. For the most part, if we can have a little bit of time on the well, it’ll settle out and we have an opportunity. But just by the mere necessity of running a video, sometimes you don’t have really good conditions because you have something going on with the well. So there are different qualities or grades of camera surveys. On a new well that’s been pumped and developed and cleaned and ready to go, those can be some of the prettiest camera surveys in the world.
When you get into rehab phase, you’re going to have buildup incrustation from different chemistries of water, from the movement of the fluid, from the deterioration of the casing due to — this casing is utilized to literally keep back bad areas that we don’t want inside the well so we can get to good areas and produce them. So this casing has cement behind it, and this is all in an effort to keep [out] contaminants of any kind — usually saltwater, water that has a little bit degraded quality or … fluoride at elevated levels, arsenic, those types of things, uranium. So that water is sitting there eating away at that cement. It’s heating up the cement and the casing, it’s allowing bacteria to grow on the inside of the casing and it’s … trying to deteriorate that cement and casing so it can get through it and create problems. So that casing is changing over time and with a camera survey you can go in and look at it and say, “OK. It’s holding up well,” or “We need to brush it again,” because the bacteria is beginning to eat at the casing. So if you know every five to seven years how that well is degrading or functioning, you can start to look at its life expectancy.
Q. Is downhole camera technology all that you want and need it to be? If not, what limitations would you like to see addressed?
A. If you asked me a couple years ago, I’d say probably not too happy, but they’re making some good advancements on the next round of cameras. So, really, they’re utilizing some of the better technology out there. So that’s come a long way. But there are other options out there now with geophysics, and a lot of different tool manufacturers have ways of evaluating casing and the deterioration of casing. So there are different technologies out there, now there are some available to the groundwater industry that we also provide. I think that is one area that really needs to take off and try and provide more information to the municipalities so they can better evaluate, from year to year, their assets.
Q. If nothing else, what would you like the drilling community to know about well diagnostics?
A. We enjoy being a part of it. At the end of the day, we feel we provide value and we enjoy that process. We’re here ultimately to help. … When you provide services like this, you’re on several different projects within a month, so we get to see a lot of different scenarios in a short amount of time. So a lot of times, we can aid [drillers] in something where we say, “We were on this project and did this and it was really successful,” or vice versa. So we hope that because we do this day in and day out, that we will see something or notice something that typically someone might not notice. At the end of the day, that’s our job, so we hope we provide that.
Q. What are your hopes and expectations for the future of well diagnostics?
A. More and more, I think on the geophysical side. We make sure we protect, at the end of the day, our groundwater resources. We implement measures to ensure well construction and design are going to prevent groundwater contamination. That sounds very simplistic to some degree, but that’s my hope, is that we as professionals protect our resource.