[Note: a true story from the oil fields. You may have burned some of the associated gasoline.]
I am no longer in the directional drilling business due to the industry downturn. Since many of us will not be returning to the oil fields, those who have this experience will be fewer in number, and the demands on their time will be great.
My work with horizontal drilling began in 1995 in the Williston Basin. Previously I had been a “mudlogger” in the Gulf of Mexico and onshore Gulf Coast, working primarily vertical wells, then directional wells from fixed platforms. Eventually I became a lead well-site geological consultant.
In the Williston, we worked the Cedar Hills Anticline in Bowman County, North Dakota. An anticline is a gentle uplifting structure that provides the classic oil trap in geological textbooks. This anticline was the training ground for many who would later use their skills in the famous Bakken Shale play. Our target zone was “Red River B” formation--a 10-foot-thick, oil-bearing layer 9000 feet underground; only the top three feet was the “sweet spot”--the best producer. This layer consisted of a fine micro-crystalline, dark brown dolomite that looks like brown sugar. “Sucrosic” describes how it appears under a microscope. As we drilled wells south along the anticline, problems always popped up, hence the nickname “Aggravation Acres.”
Some wells are memorable. One for the books was the “Eagon”, named after the rancher on whose land it was drilled. The area around the Cedar Hills Anticline is known for the Badlands that were created when the area uplifted. The Hell Creek formation outcrops in this area; it is famous for the Triceratops, T-Rex and other dinosaur fossils found in the area. During the Indian Wars, a U.S. General quipped that the area was “like hell with the fires put out”.
I arrived in early April after a 10-hour drive from Colorado, looking for a derrick among the panoramic buttes. The few cottonwood trees along the coulées were still bare, as spring comes late to North Dakota. I found Rig 52, drove on site and checked in at the “Company Man's” trailer. The first sensation on a rig is the sound and vibration of the multiple engines that power it. The generators and power plants are loud and starkly contrast to the peaceful surroundings.
The Eagon was a re-entry well, meaning that it had been drilled previously and we were going to try to correct what had been done before. I reviewed the log history. After some 9000 vertical feet of cased well, the first horizontal leg had been drilled and they were in “search” mode within the pay zone, with the wellbore drifting up and down, when they hit a problem. They pulled back to near the end of the well casing and drilled a new wellbore. They used the first lateral as a “roadmap.” About 2500 feet into the second horizontal leg, they lost the formation again and decided to drill down. At that point they had a failure, and in an attempt to pull out of the hole they got stuck, accidently twisted off and then abandoned the Bottom Hole Assembly (= expensive equipment). In a word, let me assure you that this well had trouble written all over it.
We drilled the cement plug that had capped the old well. At first things went pretty well. My logging equipment allowed me to see the amounts and types of hydrocarbons encountered. The tools allowed me to describe rock cuttings that were flushed to the surface by the drilling fluid. We calculated the “lag time” from when the bit cut the rock until it would reach the surface; that told us the depth from which those cuttings were coming up. In the case of the Eagon, at the start it took about 45 minutes. We were getting good “shows” of oil.
So how do you know where you are, in a well bore, relative to the thickness of the pay zone layer? After a couple hundred feet out horizontally, we steer the Bottom Hole Assembly (with drill bit) slightly upwards. The Measurement-While-Drilling surveys indicates the wellbore’s angle is at 91 degrees from the vertical. The anhydrite “roof” of the target zone is encountered, and a slowdown is noted. At this point, the bit is tilted a bit down, dropping lower into the zone. The survey should note that you now are at 89 degrees, or less than 90 degrees (90 = horizontal). Keep in mind that this is not the angle at the bit but typically 45 feet or so behind the bit; it is kind of like driving a car forward while looking in the rear view mirror. This maneuver should produce a “top strike” that can be seen in the rock cuttings or gamma log. A few hundred feet further out we do this again, producing another top strike. Using geometry and knowing the True Vertical Depth (TVD) of the two top strikes, a dip angle of the formation can be calculated. In a perfect world, the formation could be projected the mile or so out that the lateral would be drilled. But the earth’s formations are complex; they may be up-dip for a distance, then “roll over” and down-dip, then go up-dip again.
While we kept drilling, it started raining Friday evening, April 4, 1997. Soon the temperature dropped and rain turned to snow, falling about 2 inches per hour. Then the Dakotas wind kicked up to about 60 miles an hour; by 10:00 p.m., we were in a full-fledged blizzard. Come morning, snow had drifted over the pipe racks and packed against the trailers, completely covering the Company Man's trailer. He called over the handheld radio, “Guys, the roads are all closed and drifted over. No one can get in or out of here. There’s no relief crew until roads are cleared, and I have no idea how long that will be. The wind is blowing too hard to send the derrick man up to trip out [pull the pipe out of the well], so we can either come off bottom and circulate [fluids only, no rock] or we can try to drill ahead as long as we can.” There was a pause as the crew chewed it over in the “doghouse.” Finally, the driller called back. “We’ll drill ahead.”
Had the Toolpusher (rig supervisor) been on location, there may have been a different decision, but. he had gone to town on Friday night and was missing in action. The risk was that by drilling ahead, should anyone get hurt, there was zero chance of getting an ambulance to the rig. The crew had already worked their 12-hour shift and were now facing an indefinite schedule. They came from the local area and had only brought enough food for the one shift. The Company Man came back on the radio, “All right, we will drill as long as we can. Let’s gather up whatever food we have on location and start splitting it up. We may be here a while.”
While the storm raged, we were 9,000 feet deep and 2000 feet horizontal. During slight letups in the blizzard, I staggered from the logging shack to the shale shaker to grab rock cuttings for analysis. As we drilled, I drew a “graphical log” showing our progress. We were about 2 feet beneath the top of the formation. At about 2500 horizontal feet the penetration rate slowed; that normally indicated another top strike into the “roof” above the pay zone. I radioed the Company Man: “I think we better [steer the bit] down here. I may be wrong but this is where they screwed up the first time.” At the time, and on most horizontal drilling operations today, decisions are made at the well-site. Several companies have tried drilling from the office or by committee and have met with limited success. Maybe someday, but it wasn't practical then.
An hour later, the cuttings arrived at the surface (lag time increases as you drill further) from the earlier slowdown in penetration rate. Pure limestone. No sucrosic dolomite visible whatsoever. We had drilled through a fault, and were either in the upper or lower limestone. Now we were again, as the others before us, searching for the pay zone…with an exhausted crew.
By Saturday afternoon, the rig crew had been working 24 hours straight—double the normal shift. They were catching naps as best they could, with the driller and derrick man changing out on the brake handle from time to time. The Company Man was also acting as directional driller and was trapped in his trailer under 10 foot snowdrifts, but sat in a lounge chair with a radio call waking him up about every hour to make a decision, after getting data, on where to steer.
I trudged from the logging unit over to our living trailer, which we shared with the MWD hand, Steve, who had set up his equipment there. Steve had terminal cancer, though we didn’t know it at the time. In hindsight, that explained some of his strange behavior. He constantly watched religious programming and made comments like, “These are the End Times.” As the wind sounded like it was going to shred the shack, Steve sat staring at the satellite TV that was down. Snow blew in cracks around windows as he stared on, mumbling something about “the wrath of God”. I ate my sandwich and shook my head. Then we heard the radio crackle, “Hey – anybody got any drinking water? We're out.” Steve and I looked around the shack and found about a half gallon--barely enough to make one pot of coffee. Coffee was the juice these guys were running on. We began melting snow, but it took hours to make enough for just a few pots.
We continued to drill down through the Red River Limestone when, once again, the penetration rate slowed. I radioed the Company Man, “I think we need to pick up and circulate out for samples to find out what this is.” “Not a problem,” he responded, “Maybe the boys can get an hour nap.” At that point--Saturday evening--they had been working about 36 hours. The driller began working the pipe up and down, taking steps to prevent anything getting stuck in the well. A little over an hour later, I trudged through the snow, grabbed a cutting sample, and scoped it. Fine white particles of anhydrite were visible. We were approaching the “roof” of the Red River B zone. I called the Company Man, “Let's keep going down.” We drilled at a slower rate as we penetrated the thin anhydrite section, then the drilling rate increased from 20 feet to 80 feet per hour. “Zone!” At almost 3000 feet lateral, we had drilled through a fault, turned the bit down and had re-entered our production zone. Now we were trying to recover and level out in the zone without drilling past it. An hour later, we got confirmation that we were still in the pay zone.
By Monday morning, the winds let up and the sun broke through. The snow was about 3 feet deep with drifts up to 10 feet. One of the hands called out on the radio: “Hey there's somebody walking, about a mile over there!” We sent out our skid loader and recovered the mystery man; it was our Toolpusher, Mike, who had gone missing Friday night. He had driven off the road into a coulee, then had left his truck and made it to a nearby rancher's home. Since it was early April and calving season, the rancher brought the newborn calves into the home to try to keep them alive. “Hannah” was one of the most brutal springtime blizzards in modern history, killing over 100,000 head of cattle in the Dakotas. As the snow melted, its runoff flooded the Red River Valley, including Grand Forks. Mike had spent his time helping the rancher keep his calves alive. Later that day, the roads were cleared and our relief crew finally arrived, honking their horns as they drove in. At this point, we had worked 66 hours straight. As darkness fell, the relief crew began tripping out to change the bit that had managed to last through the ordeal, both above and below the surface. These men would, a few years later, become Toolpushers themselves and would become the workforce that would discover and exploit the Bakken Shale. The “Red River B” formation was estimated to contain about 120 million barrels of oil, but after about 10 years of development, it annually supplies less than a week of U.S. oil consumption.
Later that night, my night hand man Dave and I drove two miles west of the rig and stopped. The lights of Rig 52 were behind us. We wanted to see Comet Hale Bopp, then at its closest approach in its orbit. I stood there in the still, cold North Dakota night and saw Hale Bopp brightly visible above the Cretaceous age buttes that held the bones of dinosaurs. For a moment I could sense the passing of time, from when those animals roamed the earth and how we ourselves, and maybe our entire civilization, are here for only an instant. After a moment of reflection, we returned to Rig 52 and would successfully finish the unforgettable Eagon well.
Charlie Brister has spent over three decades working in various arms of the energy sector: oil, utilities, solar, and residential energy. After his layoff, he’s migrating back into the latter realm.