37. If the material below the sandstone of problem 26 is a shale with E=31.2 x 109 N/m, Poisson\'s Ratio 0.3, and a density of 2650 kg/m3, what is the reflection coefficient of the interface between the shale and sandstone?? a. 0.078 b. -0.225 c. -0.311 d. 0.179 e. None of the above 38. What is the most common well type used to produce natural gas from the Barnett Shale at DFW Airport? a. Vertical wells b. Disposal wells c. Individual horizontal wells d. Multiple horizontal wells from a single drilling pad e. None of the above 39. Why is fracking necessary to produce natural gas from the Barnett Shale in the DFW area? a. b. c. d. e. Fracturing breaks the Barnett Shale seal providing access to sandstone reservoir Fracturing reduces the permeability of the Barnett Shale Fracturing increases the permeability of the Barnett Shale Fracturing permits the natural gas to be absorbed in the fracking fluids None of the above 40. What is the source rock in the East Texas Oil Field? a. b. c. d. e. Barnett Shale Morrison Formation Eagle Ford Shale Woodbine Sandstone None of the above 41. Which of the following describes processes that formed Guadalupe Peak in West Texas? a. b. c. d. Formed by deposition of sediments rich in calcite Tectonic activity has been minimal in the area during the past 20 my The limestone was precipitated from sea water by marine organisms None of the above Solution 40.EAGLE FORD SHALE: The Eagle Ford is a geological formation directly beneath the Austin Chalk. It is considered to be the \"source rock\", or the original source of hydrocarbons that are contained in the Austin Chalk above it. The formation was penetrated many times as operators targeted the Edwards Limestone formation along the Edwards Reef Trend. The formation is best known for producing variable amounts of dry gas, wet gas, NGLs, condensate and oil. The most active area lies above the Edwards Reef Trend where the formation yields a gas-condensate production stream. Unlike many other shale plays, it does not exhibit natural fracturing within the formation. 41.d The Permian period of geologic time occurred from 251 to 299 million years ago. The earth had already seen life diversify from simple, primitive forms such as algae and fungi to amphibians, fishes, and insects. The earth\'s surface had also been evolving and shifting. Thin plates of crust moved constantly over the softer material below, steadily changing the position of the continents. Through much of the early and middle Permian all of the continents were joined together, forming the supercontinent of Pangea. Much of modern-day New Mexico and Texas occupied the western edge of this enormous landmass near the equator. A vast ocean surrounded Pangea, but a narrow inlet, the Hovey Channel, connected the ocean with the Permian Basin, an inland sea which covered parts of what is now northern Mexico and the southwestern United States. The Permian Basin had three arms: the Marfa, Delaware, and Midland Basins. The .

1. 37. If the material below the sandstone of problem 26 is a shale with E=31.2 x 109 N/m,
Poisson's Ratio 0.3, and a density of 2650 kg/m3, what is the reflection coefficient of the
interface between the shale and sandstone?? a. 0.078 b. -0.225 c. -0.311 d. 0.179 e. None of the
above 38. What is the most common well type used to produce natural gas from the Barnett
Shale at DFW Airport? a. Vertical wells b. Disposal wells c. Individual horizontal wells d.
Multiple horizontal wells from a single drilling pad e. None of the above 39. Why is fracking
necessary to produce natural gas from the Barnett Shale in the DFW area? a. b. c. d. e. Fracturing
breaks the Barnett Shale seal providing access to sandstone reservoir Fracturing reduces the
permeability of the Barnett Shale Fracturing increases the permeability of the Barnett Shale
Fracturing permits the natural gas to be absorbed in the fracking fluids None of the above 40.
What is the source rock in the East Texas Oil Field? a. b. c. d. e. Barnett Shale Morrison
Formation Eagle Ford Shale Woodbine Sandstone None of the above 41. Which of the following
describes processes that formed Guadalupe Peak in West Texas? a. b. c. d. Formed by deposition
of sediments rich in calcite Tectonic activity has been minimal in the area during the past 20 my
The limestone was precipitated from sea water by marine organisms None of the above
Solution
40.EAGLE FORD SHALE:
The Eagle Ford is a geological formation directly beneath the Austin Chalk. It is considered to be
the "source rock", or the original source of hydrocarbons that are contained in the Austin Chalk
above it. The formation was penetrated many times as operators targeted the Edwards Limestone
formation along the Edwards Reef Trend.
The formation is best known for producing variable amounts of dry gas, wet gas, NGLs,
condensate and oil. The most active area lies above the Edwards Reef Trend where the formation
yields a gas-condensate production stream. Unlike many other shale plays, it does not exhibit
natural fracturing within the formation.
41.d
The Permian period of geologic time occurred from 251 to 299 million years ago. The earth had
already seen life diversify from simple, primitive forms such as algae and fungi to amphibians,
fishes, and insects. The earth's surface had also been evolving and shifting. Thin plates of crust
moved constantly over the softer material below, steadily changing the position of the continents.
Through much of the early and middle Permian all of the continents were joined together,
forming the supercontinent of Pangea. Much of modern-day New Mexico and Texas occupied
the western edge of this enormous landmass near the equator. A vast ocean surrounded Pangea,
but a narrow inlet, the Hovey Channel, connected the ocean with the Permian Basin, an inland

2. sea which covered parts of what is now northern Mexico and the southwestern United States.
The Permian Basin had three arms: the Marfa, Delaware, and Midland Basins. The middle arm
(the Delaware Basin) contained the Delaware Sea which covered and area 150 miles long and 75
miles wide over what is now Western Texas and Southeastern New Mexico.
39.Hydraulic Fracturing, or fracking, is a process by which natural gas is extracted from shale
rock. It is a well-stimulation technique where fluid is injected into deep rock formations to
fracture it. The fracking fluid contains a mixture of chemical components with different
purposes. Proppants like sand are used in the fluid to hold fractures in the rock open once the
hydraulic pressure is removed. Fracking fluid also contains biocides, surfactants, friction
reducers, buffers, and corrosion inhibitors.1 Many different chemicals can be used to achieve
particular effects. Companies change the chemical blend depending on the exact conditions
found at the well. When the pressure is reduced, the gas is free to be pumped back to the surface
for use. Fracking is a key method in extraction unconventional oil and gas reserves. According to
the international Energy Agency, there are an estimates 208 trillion cubic meters of shale gas
alone.2 Hydraulic fracturing can be used to access shale gas, tight gas, tight oil, and coal seam
gas.3 This large production of previously inaccessible fuel has made fracking a fast-growing and
profitable industry. However, fracking remains controversial due to potential environmental
fallout such as ground and surface water contamination or Earthquakes along previously
unknown faults
38.c
Horizontal drilling has increased the potential of the Barnett Shale as a major source of natural
gas. Horizontal drilling has changed the way oil and gas drilling is done by allowing producers
access to reservoirs which were otherwise too thin to be economically viable through vertical
drilling. Much of the gas in the Barnett Shale is beneath the City of Fort Worth. The new
technology has attracted a number of gas-production companies.
In addition to extended reach, horizontal drilling drastically increases production. In "tight"
rock (low permeability) like the Barnett Shale, the gas uses fractures to move out of the rock and
into the wellbore. The fractures may be natural or induced (see below). A horizontal well
exposes more rock (and therefore more fractures) to the wellbore because it is usually designed
with the horizontal portion of the well in the productive formation.