Fracking – Perilous pathways – how drilling near an abandoned well produced a methane geyser

Posted in: Fracking, Ground Water News, Health effects, Water Contamination, Water Education
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Article courtesy of Scott Detrow|October 9, 2012| stateimpact.npr.org | Shared as educational material only

10/09/2012 All week, StateIm­pact Penn­syl­va­nia will explore the issue of Pennsylvania’s aban­doned oil and gas wells. They’ll explain how shale drilling and frack­ing oper­a­tions can push nat­ural gas through these decades-old con­duits, how dif­fi­cult it is to locate and plug the hun­dreds of thou­sands of wells, and what, if any, legal oblig­a­tions shale drillers are under to find and fill them.
…recommended reading >>

Previous related fracking news: Methane migration probed in Tioga County June 22, 2012 Laura Olson / Post-Gazette Harrisburg Bureau
Part 1: Why aban­doned wells are a problem

In Feb­ru­ary 1932, the United States was in the midst of the Great Depres­sion. Franklin Roo­sevelt was plot­ting a run for the White House. And in Union Town­ship, Tioga County, the Mor­ris Run Coal com­pany had just fin­ished drilling a gas well on a farm owned by Mr. W.J. Butters.

The But­ters well was 5,385 feet deep, and lined with four lay­ers of metal cas­ing. Mor­ris Run Coal had a bit of trou­ble drilling it, though. Two dif­fer­ent times, accord­ing to the company’s drilling log, work­ers hit pock­ets of gas that “blew tools up [the well’s] hole.”

Eighty years and four months later, the But­ters well was tied to another inci­dent — even though it had been inac­tive for gen­er­a­tions. It played a key role in a methane gas leak that led to a 30-foot geyser of gas and water spray­ing out of the ground for more than a week.

The geyser wasn’t the only way the methane leak man­i­fested itself. At the Ral­ston Hunt­ing Club, a water well inside a cabin over­flowed, flood­ing the build­ing. Methane bub­bled out from a nearby creek, as well. Shell asked the hand­ful of nearby landown­ers to tem­porar­ily evac­u­ate their homes while the com­pany worked with well con­trol spe­cial­ists, a fire depart­ment and state envi­ron­men­tal reg­u­la­tors to bring the leak under control.

Methane is an odor­less, col­or­less gas that exists nat­u­rally below the sur­face. It isn’t poi­so­nous, but it’s dan­ger­ous. When enough methane gath­ers in an enclosed space — a base­ment or a water well, for instance — it can trig­ger an explosion.

The gas didn’t come from the But­ters well, nor did it orig­i­nate from the Mar­cel­lus Shale for­ma­tion that a nearby Shell well had recently tapped into. What most likely hap­pened to cause the geyser in June, Shell and state reg­u­la­tors say, was some­thing of a chain reac­tion. As Shell was drilling and then hydrauli­cally frac­tur­ing its nearby well, the activ­ity dis­placed shal­low pock­ets of nat­ural gas — pos­si­bly some of the same pock­ets the Mor­ris Run Coal com­pany ran into in 1932. The gas dis­trubed by Shell’s drilling moved under­ground until it found its way to the But­ters well, and then shot up to the surface.

Com­pa­nies have been extract­ing oil and gas from Pennsylvania’s sub­sur­face since 1859, when Edwin Drake drilled the world’s first com­mer­cial oil well. Over that 150-year times­pan, as many as 300,000 wells have been drilled, an unknown num­ber of them left behind as hid­den holes in the ground. Nobody knows how many because most of those wells were drilled long before Penn­syl­va­nia required per­mits, record-keeping or any kind of regulation.

It’s rare for a mod­ern drilling oper­a­tion to inter­sect — the tech­ni­cal term is “com­mu­ni­cate” — with an aban­doned well. But inci­dents like Shell’s Tioga County geyser are a reminder of the dan­gers these many unplot­ted holes in the ground can cause when Mar­cel­lus or Utica Shale wells are drilled nearby. And while state reg­u­la­tors are con­sid­er­ing requir­ing energy com­pa­nies to sur­vey aban­doned wells within a 1,000-foot radius of new drilling oper­a­tions, the loca­tion of nearby wells is cur­rently miss­ing from the per­mit­ting process.

That’s the case in nearly every state where nat­ural gas drillers are set­ting up hydraulic frac­tur­ing oper­a­tions in regions with long drilling his­to­ries. Reg­u­la­tors don’t require drillers to search for aban­doned wells and plug them because, the think­ing goes, this is some­thing drillers are doing anyway.

All week, StateIm­pact Penn­syl­va­nia will explore the issue of Pennsylvania’s aban­doned oil and gas wells. We’ll explain how shale drilling and frack­ing oper­a­tions can push nat­ural gas through these decades-old con­duits, how dif­fi­cult it is to locate and plug the hun­dreds of thou­sands of wells, and what, if any, legal oblig­a­tions shale drillers are under to find and fill them.

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Fred Bal­das­sare worked at Pennsylvania’s Depart­ment of Envi­ron­men­tal Pro­tec­tion for 25 years. He spent more than half his career inves­ti­gat­ing cases of methane migra­tion, where gas from wells, coal mines, land­fills or other sources broke loose and made its way to the surface.

Bal­das­sare inves­ti­gated more than 200 dif­fer­ent episodes. Only a hand­ful of them, he says — per­haps five or six — involved an active drilling site com­mu­ni­cat­ing with an aban­doned oil or gas well. But when the new and old oper­a­tions did inter­sect, Bal­das­sare says, the results were often “dramatic.”

When energy com­pa­nies drill down to the Mar­cel­lus Shale, deep below the sur­face, their wells pass through sev­eral smaller, shal­low gas for­ma­tions. Drillers go to great lengths to seal off their gas wells, and Penn­syl­va­nia reg­u­la­tions require com­pa­nies to bond their mul­ti­ple lay­ers of steel cas­ing with top-grade cement. Shell’s Guin­don well, located a few thou­sand feet from the old But­ters well, was lined with more than 1,200 sacks of cement, along with four lay­ers of cas­ing rang­ing from 13 3/8 inches to 4 1/2 inches in diameter.

Most of the time, this cas­ing pre­vents the shal­low gas from mov­ing to the sur­face. (That’s not always the case – just see StateIm­pact Pennsylvania’s report­ing on a methane leak in Brad­ford County.)

But if an old, unplugged gas well has been drilled into the same for­ma­tion already, the new activ­ity can dis­place pock­ets of gas, through pres­sure changes and phys­i­cal inter­ac­tion. Bal­dasarre explains, “that gas can move to the old well, because [the well] rep­re­sents a low pres­sure zone and a nat­ural migra­tion highway.

“Gas always wants to go from high pres­sure to low pres­sure,” Bal­das­sare con­tin­ues. “That old well rep­re­sents a low-pressure zone. Much like water wants to move down­hill, gas wants to move to low-pressure zones.” The low­est pres­sure is near the sur­face, so once the gas reaches an old well, it will shoot straight up.

And a new well doesn’t need to be present to trig­ger this migra­tion. Gas can migrate to the sur­face through these path­ways on its own. The state has inves­ti­gated dozens of cases where unknown wells have led to gas pool­ing in base­ments, water wells, or other locations.

Depend­ing on how old the aban­doned well is, the cas­ing can be leaky, rot­ten, or nonex­is­tent. Methane can eas­ily move into nat­ural faults and cracks, fol­low­ing a path toward the sur­face that can travel through aquifers. That’s likely how gas ended up bub­bling into a creek, out of a water well and up into the 30-foot geyser in Union Township.

“Every­one worked together to avoid catastrophe.”

The dam­age caused by Shell’s methane leak was rel­a­tively min­i­mal, due largely to the fact the gas bub­bled to the sur­face in a sparsely pop­u­lated, extremely rural area. That wasn’t the case in Day­ton, Arm­strong County, when a 2008 gas leak led to the evac­u­a­tion of an ele­men­tary school and two houses.

Then, an active, ver­ti­cal gas rig — not a shale oper­a­tion — hit a pocket of gas linked to an undoc­u­mented aban­doned well. The dis­placed gas moved quickly, rac­ing straight to the sur­face. It shot straight through 90 feet of gravel, dirt and other fill mate­r­ial, push­ing the mate­r­ial to the sur­face when it spewed out of the ground. “There was a small com­mu­nity lit­er­ally a few hun­dred yards away at most,” recalls Bal­das­sare. “The gas was mov­ing toward that community.”

Depart­ment of Envi­ron­men­tal Pro­tec­tion offi­cials worked with the gas oper­a­tor to vent off nearby wells in order to lower under­ground gas pres­sure. They also installed vents on the homes, to keep methane from gath­er­ing in a con­cen­trated place. The efforts brought the well under con­trol, but just barely. “[The gas] got close — eight feet [from one of the houses],” says Bal­das­sare. “Every­one worked together to avoid catastrophe.”

Plugged Up

The best way to ensure an aban­doned well won’t cre­ate a gas leak is to make sure it’s plugged. When wells are cemented shut, they’re much less likely to cre­ate a methane path­way to the sur­face. The cement seals off the con­duit to the sur­face, keep­ing methane below the ground.

In Union Town­ship, Shell knew about the old But­ters well before it began drilling nearby. “As part of our well loca­tion screen­ing process, we did map that aban­doned well, which we under­stood had been prop­erly plugged and aban­doned,” Shell spokes­woman Kelly op de Weegh tells StateIm­pact Penn­syl­va­nia. “It was deter­mined, due to that, that the old well would not pose any addi­tional risk.”

The But­ters well is marked on Shell maps that StateIm­pact Penn­syl­va­nia obtained through a Right-To-Know Request filed with the Depart­ment of Envi­ron­men­tal Pro­tec­tion. (We asked for all DEP emails and accom­pa­ny­ing attach­ments related to the Shell Tioga spill.)

The pres­ence of the But­ters well is bet­ter doc­u­mented than most aban­doned wells. The Depart­ment had an old drilling log on file, which StateIm­pact Penn­syl­va­nia also received in its open records request.

But even know­ing that the old But­ters well was there was not enough to stop what hap­pened in June. In the days after the methane geyser erupted, DEP staffers emailed to Shell all the infor­ma­tion they could find about nearby aban­doned wells. There were three files on record.

Two were for wells drilled after Penn­syl­va­nia stan­dard­ized its oil and gas laws in 1984. Those records included detailed reports on when the wells were ini­tially drilled, how deep they went, and cer­tifi­cates show­ing that the wells had been plugged accord­ing to state standards.

The third was for the But­ters well. It was easy to see that Mor­ris Run Coal had drilled the well back in 1932. But there was no infor­ma­tion at all about if, or when, the com­pany plugged it once the well had played out and Mor­ris Run Coal had moved on.

How many aban­doned wells are out there, and what is Penn­syl­va­nia doing to plug them?

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