Posts Tagged ‘fracturing’

Horizontal Drilling to Penetrate More Fractures

The fractures (also known as “joints”) in the Marcellus Shale are vertical. So, a vertical borehole would be expected to intersect very few of them. However, a horizontal well, drilled perpendicular to the most common fracture orientation should intersect a maximum number of fractures.

High yield wells in the Marcellus Shale have been built using the horizontal drilling technique. Some horizontal wells in the Marcellus Shale have initial flows that suggest that they are capable of yielding millions of cubic feet of gas per day, making them some of the most productive gas wells in the eastern United States. Although some experts are very optimistic on the long-term production rates of these wells, it is too early to determine their productive life or long-term yield.

A second method is used to increase the productivity of a well. That is to increase the number of fractures in a well using a technique known as “hydraulic fracturing” or “hydrofracing”. This method uses high-pressure water or a gel to induce fractures in the rock surrounding the well bore.

Hydrofracing is done by sealing off a portion of the well and injecting water or gel under very high pressure into the isolated portion of the hole. The high pressure fractures the rock and pushes the fractures open.

To prevent the fractures from closing when the pressure is reduced several tons of sand or other “propant” is pumped down the well and into the pressurized portion of the hole. When the fracturing occurs millions of sand grains are forced into the fractures. If enough sand grains are trapped in the fracture it will be propped partially open when the pressure is reduced. This provides an improved permeability for the flow of gas to the well.

Copyright: Geology.com

Both vertical and horizontal wells are used in shale gas drilling and completion; however, horizontal wells are the increasing trend due to both environmental concerns and economic efficiency (DOE, 2009). Horizontal drilling allows more exposure within the formation to optimize capture of natural gas as well as reducing the environmental footprint of drilling activity (DOE, 2009). The United States Department of Energy’s recently released document on shale gas development in the United States explains that “a vertical well may be exposed to as little as 50 ft of formation while a horizontal well may have a lateral wellbore extending in length from 2,000 to 6,000 ft within the 50-300 ft thick formation” (DOE, 2009, p.47). As such, surface disturbance and impacts to wildlife and communities are reduced while providing optimal gas recovery; considering 16 vertical wells per 640-acre section of land would disturb 77 acres, the equivalent in horizontal wells (4- horizontal wells) would disturb approximately 7.4 acres (DOE, 2009). In addition to reductions in surface disturbance, horizontal wells allow for development in areas previously considered unavailable, primarily urban and environmentally sensitive or protected areas. Well pads can be located away, or ‘setback’, from residences, roadways, wildlife habitats and other protected areas without hampering access to available gas reserves.

In order to recover the shale gas after drilling a well, current industry practice is to hydraulic fracture the formation to stimulate the near wellbore area and facilitate the release of natural gas trapped within the shale. Hydraulic fracturing is a process whereby a fracturing fluid, primarily water, is pumped into the formation under pressure at a calculated rate to form fractures and cracks within the formation, providing a pathway for the gas to migrate to the wellhead for recovery. Sand or other granular materials are added to the fracturing fluid to help ‘prop’ open the newly created fractures after the fluid has been removed from the formation (ALL, 2008a). Additional chemicals may be added to the fracturing fluid for specific engineering purposes; these additions may include friction-reducing agents, biocides and various stabilizers to prevent corrosion of metal piping in the well (DOE, 2009; ALL, 2008a). Depending on the formation and well characteristics, multiple fracturing procedures may be performed in order to fully develop the well for gas recovery (DOE, 2009). While each well and geologic formation is unique, continuing advances in horizontal drilling and well completion practices provide additional reductions in environmental impacts from oil and gas activities while providing the nation’s critical energy supply.
Copyright: GoMarcellusshale.com

Environmental Resources and Energy hearing Wednesday at Kingston Township building.

By Steve Mocarskysmocarsky@timesleader.com
Staff Writer

KINGSTON TWP. – Several people with concerns about natural gas drilling in Pennsylvania – and especially in the Back Mountain – are scheduled to testify Wednesday at a public hearing before a state House of Representatives committee.

State Rep. Phyllis Mundy requested and is hosting a hearing of the House Environmental Resources and Energy Committee at the Kingston Township Municipal Building from 1 to 3 p.m.

Mundy, D-Kingston, said she has “grave concerns” that there are inadequate protections in place to protect the environment from drilling associated with the Marcellus Shale formation.

“I don’t think we’re going to be able to stop Marcellus Shale drilling, but we need to make sure it doesn’t leave a legacy like that of coal. An ounce of prevention is worth a pound of cure,” Mundy said on Monday.

She said she believes a proposed drilling site in Lehman Township is “much too close” to the Huntsville and Ceasetown reservoirs, which provide drinking water to many of her constituents.

Committee Majority Chairman Camille “Bud” George notes in a press release that the state Department of Environmental Protection issued more than 1,300 drilling permits in 2009 and more are expected in coming years, yet no study exists on the environmental or human health impacts of gas development in Pennsylvania.

Testimony will be presented about mitigating environmental risks and House Bill 2213 – the Land and Water protection Act introduced by George, D-Clearfield County.

The bill would:

• Require state inspections of wells during each drilling phase.

• Extend to 2,500 feet the presumed liability of a well polluting a water supply; the current radius is 1,000 feet.

• Require full disclosure of chemicals used in the hydraulic fracturing of the gas.

• Update bonding requirements to cover the costs of decommissioning a well. Current regulations call for a $2,500 bond, but the cost to cap a well could range from $12,000 to $150,000 for a deep well, according to George.

Scheduled to testify are Dr. Thomas Jiunta, a local podiatric physician active in environmental causes; Dr. Gere Reisinger, a physician whose 200-acre farm in Wyoming County has been affected by drilling; Victoria Switzer, whose water at her home in Dimock, Susquehanna County, was contaminated after nearby drilling; Brady Russell, eastern Pennsylvania director, Clean Water Action; and Jeff Schmidt, senior director, Sierra Club, Pennsylvania Chapter.

Copyright: Times Leader

Throughout most of its extent, the Marcellus is nearly a mile or more below the surface. These great depths make the Marcellus Formation a very expensive target. Successful wells must yield large volumes of gas to pay for the drilling costs that can easily exceed a million dollars for a traditional vertical well and much more for a horizontal well with hydraulic fracturing.

And rock units are not homogeneous. The gas in the Marcellus Shale is a result of its contained organic content. Logic therefore suggests that the more organic material there is contained in the rock the greater its ability to yield gas. John Harper of the Pennsylvania Geological Survey suggests that the areas with the greatest production potential might be where the net thickness of organic-rich shale within the Marcellus Formation is greatest.

Copyright: Geology.com

As recently as 2002 the United States Geological Survey in its Assessment of Undiscovered Oil and Gas Resources of the Appalachian Basin Province, calculated that the Marcellus Shale contained an estimated undiscovered resource of about 1.9 trillion cubic feet of gas.  That’s a lot of gas but spread over the enormous geographic extent of the Marcellus it was not that much per acre.

In early 2008, Terry Englander, a geoscience professor at Pennsylvania State University, and Gary Lash, a geology professor at the State University of New York at Fredonia, surprised everyone with estimates that the Marcellus might contain more than 500 trillion cubic feet of natural gas. Using some of the same horizontal drilling and hydraulic fracturing methods that had previously been applied in the Barnett Shale of Texas, perhaps 10% of that gas (50 trillion cubic feet) might be recoverable. That volume of natural gas would be enough to supply the entire United States for about two years and have a wellhead value of about one trillion dollars!
Copyright: Geology.com


Natural gas captured from organic shale formations is not new to the oil and gas industry; shale gas has been produced since the early 1800s (DOE, 2009).  Most shale gas formations have historically been deemed economically impractical to drill due to the available technology and relative abundance of domestic conventional natural gas sources.  However, recent technological advances in horizontal drilling and hydraulic fracturing along with increasing demand for natural gas and recent price trends for natural gas, have allowed previously inaccessible reserves to become technologically feasible and economically efficient to recover (DOE, 2009).

The Annual Energy Outlook for 2009, recently released by the United States’ Energy Information Administration, projects an increase of 0.5% total primary energy consumption annually through 2030 (EIA, 2009).  The majority of this demand increase will come from the residential sector’s demand for additional electricity (EIA, 2009).  Currently, coal-fired electricity generation dominates the electricity generation sector at approximately 49% of total U.S. domestic generation capacity (EIA, 2009).  However, due to emerging concerns and public policy developments regarding greenhouse gases and renewable portfolio standards for a sustainable energy supply, lower carbon energy sources needed for electricity generation are expected to gain marketplace demand (EIA, 2009).  Unfortunately, conversion from a fossil fuel-dependent energy economy to a low-carbon energy economy will take time and significant capital investment for infrastructure development (DOE, 2009).  A recent Wall Street Journal article cites Carl Pope, executive director of the Sierra Club as viewing natural gas as a “bridge fuel” from carbon-intensive fossil fuels, such as coal and petroleum, to cleaner future fuel sources (Casselman, 2009).

In order to meet the expected increased demand for natural gas without increasing dependence on foreign imports, development of domestic unconventional natural gas sources will need to grow rapidly.  Production from unconventional natural gas sources, namely organic shales, tight sand formations, and coal-bed methane, currently account for approximately 50% of the total domestic natural gas production (DOE, 2009), this total production from unconventional resources was estimated at 8.9 trillion cubic feet (Tcf) per year in 2007 (ALL, 2008c).  Of the 8.9 Tcf of unconventional natural gas produced in the United States in 2007, 1.2 Tcf was from shale formations; however, shale gas production is expected to grow to 4.2 Tcf by 2030, accounting for an estimated 18% of the total U.S. gas production in 2030.  Unconventional sources combined are predicted to grow to nearly 56% of total U.S. domestic natural gas production (EIA, 2009).  To date, four evolving shale gas plays (Haynesville, Marcellus, Fayetteville and Woodford) are estimated to have over 550 Tcf of total recoverable gas resources, these formatiosn are expected to be capable of providing sustainable production of 2-4 Tcf of natural gas annually for decades (DOE, 2009).  Of these four, the Haynesville Shale and Marcellus Shale may have the most significant additions to domestic reserves of natural gas in recent decades.

Copyright: GoMarcellusshale.com

DAVID WETHE Bloomberg News

HOUSTON — Halliburton Co. and Schlumberger Ltd., trying to forestall a regulatory crackdown that would cut natural-gas drilling, are developing ways to eliminate the need for chemicals that may taint water supplies near wells.

At risk is hydraulic fracturing, or fracking, a process that unlocked gas deposits in shale formations and drove gains in U.S. production of the fuel. Proposed regulations might slow drilling and add $3 billion a year in costs, a government study found. As one solution, energy companies are researching ways to kill bacteria in fracturing fluids without using harmful biocides.

“The most dangerous part in the shale frack is the biocide,” said Steve Mueller, chief executive officer at Southwestern Energy Co., the biggest producer in the Fayetteville Shale of Arkansas. “That’s the number-one thing the industry is trying to find a way around.”

House and Senate bills introduced in 2009 would force producers to get permits for each well. That and other proposed environmental measures would cut drilling by as much as half and add compliance costs of $75 billion over 25 years, according to the U.S. Energy Department.

Biocides are employed because the watery fluids used to fracture rocks heat up when they’re pumped into the ground at high speed, causing bacteria and mold to multiply, Mueller said. The bacteria grow, inhibiting the flow of gas.

“You basically get a black slime in your lines,” he said. “It just becomes a black ooze of this bacteria that grew very quickly.”

Halliburton said March 9 that it’s testing a process using ultraviolet light to kill bacteria in fracking fluid.

About 80 percent of gas wells drilled in North America, including virtually all of those in the Marcellus Shale in Pennsylvania, are stimulated or fractured in some way, Tim Probert, corporate development chief at Halliburton, said.

“It’s incumbent on the industry to continue to develop tools and technologies that are compatible with minimizing the environmental impact of the stimulation process,” Probert said.

Copyright: Times Leader

Rail cars of sand to be used in Marcellus Shale natural gas extraction get a home.

By Steve Mocarskysmocarsky@timesleader.com
Staff Writer

DURYEA – Investment spurred by Marcellus Shale natural gas exploration has transformed an antiquated, weed-ridden rail yard just north of Pittston into a state-of-the-art transloading terminal teeming with rail and trucking activity on an almost daily basis.

Over the last year, Reading & Northern Railroad Co. sunk $100,000 into Pittston Yard, laying new track to accommodate 100 new rail cars and constructing a facility to store and hold up to 800 cars of sand to be used in hydraulic fracturing, or “fracking,” operations at Marcellus Shale drill sites throughout Northeastern Pennsylvania, said Reading & Northern President Warren A. Michel.

“The reason for our success is that we are the largest facility in the region capable of handling hundreds of rail cars of sand. We now have 130 (sand) rail cars at the yard and we’ll be expanding substantially over the next six months,” Michel said.

The company rewarded its full-time employees for their work on the project and throughout last year with an extra week of paid vacation this year and a paid trip to their choice of either Disney World; Branson, Mo.; Williamsburg, Va.; London; or a cruise.

“This is our way of saying thank you for a job well done,” company owner and Chief Executive Officer Andrew M. Muller Jr. said in a press release.

Between Reading & Northern and its customers, who are involved in the Marcellus Shale fracking and drilling industries, Michel expects another half-million dollars of investment with the laying of more track, construction of bucket conveyors and four holding silos for the sand, and construction of facilities to handle other aspects of the drilling process, such as pipe delivery and the transportation of brine water from the area.

The upgrade and expansion project began about a year ago after Reading & Northern officials began hearing that drilling companies were challenged with the logistics of transporting and storing significant volumes of sand, pipe, water and other materials, according to a marketing release prepared by Daniel Gilchrist, Reading & Northern vice president of marketing and sales.

After several discussions with Reading & Northern partner Norfolk Southern, company officials believed they could offer substantial benefits to customers, Gilchrist said.

Pittston Yard, formerly Coxton Yard, was built in 1870 by the Lehigh Railroad as a hub to move coal from the region to Eastern markets. And while the yard had had been serving many Reading & Northern customers, it was overgrown with weeds and trees and was underutilized.

Many of the tracks were suitable only to hold empty storage cars, and it was not apparent initially how much track and acreage was actually there and available for use, Gilchrist said.

After showing the site and meeting with several potential customers, Reading & Northern began discussions with D&I Silica and its transload operator, the Myles Group, and developed a plan.

Work began in November with tree removal, clearing of several acres, surfacing of more than 5,200 feet of track and construction of a 600-by-80-foot unloading pad. By Dec. 7, the company had more than 50 loaded rail cars on site ready to be transloaded. The following day, at 3 a.m. in the midst of a snowstorm, the first trucks were loaded with sand for customers.

Because of a number of factors including the Marcellus Shale drilling industry, Reading & Northern has hired 10 new employees over the last two months. The company also recently purchased two new locomotives, 101 rail cars and six miles of short-line track between Monroeton and Towanda, where much of Northeastern Pennsylvania’s Marcellus Shale economic activity is focused, Michel said.

Copyright: Times Leader

DEP probes Cabot Oil & Gas query about “discharge of black water” in Dimock Twp.

By Steve Mocarskysmocarsky@timesleader.com
Staff Writer

DIMOCK TWP. – The state Department of Environmental Protection is investigating a possible leak or spill at a natural gas drilling site in Susquehanna County.

Mark Carmon, DEP spokesman at the Wilkes-Barre office, said the department received a call to its emergency response line from Cabot Oil & Gas Co. on Sunday afternoon informing the department that employees found “a discharge of black water” at the site.

The call was referred to the department’s Gas & Oil Program team, which operates from DEP’s Williamsport office.

Dan Spadoni, DEP spokesman at that office, said the team is investigating “the possibility of a spill or leak at Cabot’s Hibbard drill pad” since Monday, but has not yet determined if there was a spill or leak at the site.

Spadoni said there are two wells on one pad at the site, and no drilling activity is currently taking place. He said the team took samples from a private drinking water well that is currently not being used, from two nearby springs and from the site pit.

The samples are being analyzed at DEP’s lab in Harrisburg.

“We need to see those results to see what our future course of action will be,” Spadoni said.

He expected lab results back in a week or two.

Spadoni said Cabot’s consultant also collected samples and the drill cuttings in the pit for analysis. Site pits, which are lined, are where the residue from the drilling and hydraulic fracturing processes ends up, he said.

There was discussion on an online Susquehanna County gas forum about the possibility of a nearby pond being drained, but Spadoni said he had no information about the pond and no samples were collected from it.

He confirmed Cabot had a vacuum truck on-site “in response to where this dark fluid was observed. It was a voluntary measure on their part,” he said.

Spadoni said he believes there was no recent drilling activity at the site. The site had not been shut down because of the discovery of the liquid, he said.

Ken Komoroski, spokesman for Cabot Oil & Gas, said there was no indication of any environmental contamination or pollution.

“Discolored water was observed over the weekend and Cabot immediately responded to observing water in a ditch. We notified DEP and took the additional measure to have a vacuum truck remove water from ditch,” Komoroski said, adding that employees noticed the water while driving by the site on Route 29.

Cabot also drained the pit to check if it was possible the water was leaking from the drill pit, but the pit liner was “completely intact. All indications are that it was not a result of Cabot activities,” Komoroski said.

Komoroski said the drill site has been in existence “for quite some time, and there doesn’t seem to be any reason” for the discolored water to appear “since it hasn’t been active site. We were not able to identify any potential cause or relationship.”

He said the water was found “in the vicinity of the site, but close enough that we wanted to consider the possibility that it was related to our activities.”

Steve Mocarsky, a Times Leader staff writer, may be reached at 970-7311.

Copyright: Times Leader

Nearly $2 million will be allocated for a look at environmental results.

STEVE GELSI MarketWatch

NEW YORK — The U.S. Environmental Protection Agency said Thursday it will conduct a massive study to investigate any potential adverse impact of hydraulic fracturing to extract natural gas, as the energy industry moves to boost domestic natural gas supplies.

The effort comes as part of a move by government officials and academics to grapple with an expected increase in the decades-old practice of extracting natural gas by injecting water and fracturing rock, a practice known as fracking.

In Northeastern Pennsylvania, drilling is proceeding in the Marcellus Shale, a layer of bedrock containing natural gas.

“There are concerns that hydraulic fracturing may impact ground water and surface water quality in ways that threaten human health and the environment,” the EPA said Thursday.

The agency said it’s reallocating $1.9 million to help pay for a “comprehensive, peer-reviewed” study. Regina Hopper, president of industry group America’s Natural Gas Alliance, said the EPA study will help affirm the safety of fracking.

“Hydraulic fracturing has been refined and improved over the past 60 years and has been used safely on more than one million U.S. wells,” Hopper said in a prepared statement. While hydraulic fracturing usually takes place far underground, well below aquifers for domestic water supplies, it also produces wastewater which must be treated on site or trucked off for disposal.

Last month, the House Energy and Commerce Committee launched an investigation into the potential impact and said it would like to see more information on the chemicals used in fracturing liquid.

“Hydraulic fracturing could help us unlock vast domestic natural gas reserves once thought unattainable, strengthening America’s energy independence and reducing carbon emissions,” said Chairman Henry Waxman, D-Calif. “As we use this technology in more parts of the country on a much larger scale, we must ensure that we are not creating new environmental and public health problems.”

Copyright: Times Leader