- Drilling and Hydraulic Fracturing in other Parts of Virginia
- The Marcellus Shale in Virginia
- The Taylorsville Basin
- The Virginia DMME FAQ publication: Gas Well Development & Hydraulic Fracturing Frequently Asked Questions
- Horizontal Drilling: A Technological Marvel Ignored
- Current (as of 2015)
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A review of the history of hydraulic fracturing in Virginia reveals some gaps in our knowledge. While the process has been in use in Virginia for more than 50 years, that process has changed significantly. In particular, there has been the move to horizontal rather than vertical fracturing and the inclusion of a broad range of chemical into the process. While horizontal drilling became popular in the 1990’s, it was only through time that it was discovered that the most economical approach is to have multiple wells running in multiple directions from the same drill rig areas. The types of chemical used in the process water are still evolving as more economically efficient methods are constantly sought by companies.
“As of 2014, fracking has been utilized in approximately 2,100 wells producing from shale, sandstone and limestone formations in Southwest Virginia since the early to mid-1950s. In addition, more than 6,000 coalbed methane wells are producing from coal seams that have become fractured by post-mining subsidence or that have been fraced using water, chemicals and nitrogen with sand as the fracture proppant. This type of fracturing is known as a “foam frac.” Due to the physical properties of the rock formations and the fairly low reservoir pressures in Southwest Virginia, large volumes of water are seldom used in the fracing process because water may hinder or block the flow of gas. Recent innovations have developed a 100% nitrogren frac with no liquid added, commonly called a “dry” frac. Development of Southwest Virginia’s natural gas resources continues, with new wells being drilled and hydraulically fractured every year.” https://www.dmme.virginia.gov/dgo/HydraulicFracturing.shtml
Drilling and Hydraulic Fracturing in other Parts of Virginia
“As of early 2014, the only producing gas and oil wells in Virginia are in the southwestern part of the Commonwealth. Exploratory wells were drilled in other parts of the state during the 20th century but all were plugged due to the absence of commercial quantities of hydrocarbons. The advent of horizontal drilling along with existing hydraulic fracturing technology renewed interest in some of these areas, including areas underlain by the Marcellus Shale in the western mountains and valleys, and the Mesozoic basins of eastern Virginia.”
The Marcellus Shale in Virginia
“The Marcellus is an organic-rich shale of Devonian age that is present beneath some of the mountains and valleys of western Virginia. The Marcellus is the primary target for recent horizontal drilling and hydraulic fracturing in Pennsylvania and West Virginia, where it is thick and buried deeply beneath layers of younger sedimentary rock. In Virginia, the Marcellus is present in relatively shallow belts of folded and faulted rock. Due to this tectonic disturbance, much of the natural gas once present in the Marcellus has probably escaped. A recent study by the U.S. Geological Survey indicates that the Marcellus in that part of Virginia is thermally overmature, meaning that the shale was most likely heated to too high a temperature in the past to preserve economic quantities of gas or oil.”
The Taylorsville Basin
“The Taylorsville Basin is a Mesozoic-age sedimentary basin mostly concealed beneath younger sediments of Virginia’s Coastal Plain. The part of the basin beneath the Northern Neck and Middle Peninsula was the subject of oil and gas exploration in the 20th century, with a dozen wells drilled between 1917 and 1992. All of the wells were plugged shortly after they were drilled, but a few showed indications of the presence of small quantities of natural gas and oil. One well that showed an indication of natural gas was hydraulically fractured in 1968, but the stimulation did not result in a commercially viable flow of gas so it was subsequently plugged.
DEQ and the Department of Mines, Minerals and Energy have signed an agreement on the coordinated review of the environmental impacts of potential permits for oil or gas drilling in the Coastal Plain that includes the Taylorsville Basin. The agencies have committed to ensuring a transparent process that includes a thorough environmental impact review and addresses all public comments. The agreement will help the agencies and the public focus on the distinctiveness and complexity of the Coastal Plain aquifer system, including the Potomac Aquifer, which supplies water for about half of Virginia’s population for drinking, agricultural use and industrial use. Read the Memorandum of Agreement.”
The Virginia DMME FAQ publication: Gas Well Development & Hydraulic Fracturing Frequently Asked Questions
This publication is a bit older than the website noted above, but much of the information is still valid and is a useful resource on the history of Fracing in Virginia. At the end of the first paragraph is it noted: “Virginia’s geology is different than that of other states where the Marcellus shale exists. The U.S. Geological Survey (USGS) has indicated a Marcellus play for Virginia is on the outer periphery of the major structural body of the shale. As a result, the concerns regarding conditions in other states are less likely to exist in the Commonwealth.” This makes it clear that Virginia needs to look very careful at the process of “fracing”.
This article reports that “Due to the structure of geologic formations in Virginia, large volumes of water are not used in fracing because it may hinder or block the flow of gas within the formation.” Unfortunately, this cannot be taken as a blanket statement as they are looking only at the geologic formation where fracking is occurring, in Southwest Virginia. The geologic formations in the Central and Eastern parts of the state differ quite significantly, and the underground reservoirs are in those areas are much shallower. Care must be used when interpreting older data on hydraulic fracturing to be aware of the geologic differences as well as the technological changes in the process.
While noting that “fracing” wells have been established in Southwest Virginia since the mid-1950’s, it is not noted that the majority of these wells have been vertical rather than horizontal wells. The techniques of horizontal drilling did not become cost effective for commercial application until the 1980’s according to “Drilling Sideways — A Review of Horizontal Well Technology and Its Domestic Appliction, April 1993 (http://www.eia.gov/pub/oil_gas/natural_gas/analysis_publications/drilling_sideways_well_technology/pdf/tr0565.pdf). This article also gives what may be some of the driving forces behind the rapid growth of hydraulic fracturing and the incorporation of more chemicals in the process:
“Desired Compensating Benefits
Even when drilling technique has been optimized for a target, the expected financial benefits of horizontal drilling must at least offset the increased well costs before such a project will be undertaken. In successful horizontal drilling applications, the “offset or better” happens due to the occurrence of one or more of a number of factors.
First, operators often are able to develop a reservoir with a sufficiently smaller number of horizontal wells, since each well can drain a larger rock volume about its bore than a vertical well could. When this is the case, per well proved reserves are higher than for a vertical well. An added advantage relative to the environmental costs or land use problems that may pertain in some situations is that the aggregate surface “footprint” of an oil or gas recovery operation can be reduced by use of horizontal wells.
Second, a horizontal well may produce at rates several times greater than a vertical well, due to the increased wellbore surface area within the producing interval. For example, in the Austin Chalk reservoir of Texas’ Giddings Field, under equal pressure conditions, horizontal completions of 500 to 2,200 foot HD produce at initial rates 2½ to 7 times higher than vertical completions. Chairman Robert Hauptfuhrer of Oryx Energy Co. noted that “Our costs in the [Austin] chalk now are 50 percent more than a vertical well, but we have three to five or more times the daily production and reserves than a vertical well.” A faster producing rate translates financially to a higher rate of return on the horizontal project than would be achieved by a vertical project.
Third, use of a horizontal well may preclude or significantly delay the onset of production problems
(interferences) that engender low production rates, low recovery efficiencies, and/or premature well
abandonment, reducing or even eliminating, as a result of their occurrence, return on investment and total return.”
Horizontal Drilling: A Technological Marvel Ignored
Although not specific to Virginia, this article does help to explain the evolution of hydraulic fracturing in Virginia and elsewhere. The term hydraulic fracturing (fracking, fracing) in its current usage actually refers to two different processes: horizontal drilling and hydraulic fracturing. Horizontal drilling was once a “standalone” process that was perceived as being positive for the environment. It was when hydraulic fracturing began being used in conjunction with horizontal drilling that concerns arose.
Current (as of 2015)
According to FracTracker Alliance (https://www.fractracker.org/2015/08/1-7-million-wells/), Virginia currently has 11,850 wells using hydraulic fracturing. Of these, 113 are horizontal wells that are actively producing. 35 horizontal well permits have expired and 41 permits have been issued. The remainder of the 210 horizontal wells are in various states of development. All of the rest of the 11,850 fracking wells are vertical wells.
Gas and Oil Extraction
Virginia Gas and Oil Act – (PDF)
Code of Virginia – Title 45.1 – Chapter 22.1
Virginia Geothermal Energy Resources Conservation Act – (PDF)
Code of Virginia – Title 45.1 – Chapter 15.1
Chesapeake Bay; drilling for oil or gas prohibited. – (PDF)
Code of Virginia – Title 62.1 – Chapter 20 (includes rules specific to drilling in Tidewater Virginia)
Coalbed Methane Gas: Release of Funds Held in Escrow or Suspense – (PDF)
Code of Virginia – Title 45.1-361.22:2 – Chapter 396
Virginia Gas and Oil Regulations – (PDF)
Virginia Administrative Code – Title 4 – Agency 25 – Chapter 150
Virginia Gas and Oil Board Regulations – (PDF)
Virginia Administrative Code – Title 4 – Agency 25 – Chapter 160
Geothermal Energy Regulations – (PDF)
Virginia Administrative Code – Title 4 – Agency 25 – Chapter 170