Reading Comprehension

PT116 · S1 · P1 · Q2 Oil Drilling Contamination

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The accumulation of scientific knowledge regarding the environmental impact of oil well drilling in North America has tended to lag behind the actual drilling of oil wells.

Topic

The environmental impact of oil well drilling on groundwater and the ongoing challenges in regulating and preventing contamination.

Framework

Problem / Solution

Main Point

Efforts to prevent groundwater contamination from oil drilling have often been reactive rather than proactive, and recent disasters show that regulatory and technological solutions are still limited by incomplete scientific knowledge. *The most valuable sentence appears at the end of the first paragraph:*

P1: Overview of the Regulatory Lag

Scientific understanding and regulation of environmental impacts from oil drilling often come only after problems are noticed—especially with groundwater contamination.

P2: Early Focus of Regulation and Emerging Problems

At first, regulations protected oil from being contaminated by water, but no one thought about protecting groundwater from oil until people started finding oil in their drinking water wells.

P3: How Contamination Happens and Industry Responses

Drilling can connect different underground layers, letting oil or salty water leak into groundwater; attempts to seal off fresh water have evolved from using hollow trees to modern metal casings with cement.

2.

The passage states which one of the following about underground oil reservoirs?

  1. They are usually located in

    Too Strong: usually

    All we know about oil (petroleum) reservoirs is that they are in porous and permeable geologic formations, at greater depths than groundwater. We don't know if more than 50% of the areas they're located in have poorly understood subsurface geology. We only know in the final paragraph that there was one well on the west coast of North America that was located in an area with a poor understanding of subsurface geology.

    4% picked this

  2. They are generally less common

    Unknown Comparison: less common

    All we know about oil (petroleum) reservoirs is that they are in porous and permeable geologic formations, at greater depths than groundwater. We don't know if they're less likely to be found in coastal vs. inland regions.

    0% picked this

  3. They are usually located in

    Too Strong: usually

    All we know about oil (petroleum) reservoirs is that they are in porous and permeable geologic formations, at greater depths than groundwater. We don't know if more than 50% of them are located in formations where gas is found.

    4% picked this

  4. They are often contaminated by

    Implied, Not Stated

    The 2nd paragraph does talk about the risk of oil wells being contaminated by fresh water. (It never talks about them being contaminated by saline water.) But the passage never says that underground oil reservoirs often are contaminated by fresh water. Meanwhile, with the correct answer, the passage actually states that oil reservoirs are deeper than groundwater reservoirs.

    9% picked this

  5. Correct

    They are generally found at

    Why this is right

    This restates what we were told in the first sentence of the 3rd paragraph. S U R F A C E then, groundwater reservoirs then, oil reservoirs

    Skill tested: Locate Detail · how this choice captures the passage's function is the move to repeat next time.

    83% picked this

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