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Water: Hydraulic Fracturing

Hydraulic Fracturing Information Requests

List of the 9 oil and gas companies that received EPA's request

Oil and gas companies that received the request:

Clayton Williams Energy
Conoco Phillips
EQT Production
Hogback Exploration
Laramie Energy II
MDS Energy
Noble Energy
Sand Ridge Operating
Williams Production


Explanation of method used to randomly select wells for this request

In response to EPA’s September 2010 request to nine hydraulic fracturing service companies, we received a list of approximately 25,000 oil and gas production wells that were hydraulically fractured between 2009 and 2010 and the names of the oil and gas operator for each well.

To identify the wells for this request, we first sorted the list of operators by those with the most wells to those with the fewest wells. We defined operators to be “large” if their combined number of wells accounted for the top 50% of wells on the list, “medium” if their combined number of wells accounted for the next 25% of wells on the list and “small” if their number of wells were among the last 25% of wells on the list.  To minimize potential burden on the smallest operators, we removed all operators with 9 wells or less from consideration for selection.

Then, using a map from the U.S. Energy Information Administration showing all shale gas plays, EPA classified four different areas of the nation: East, South, Rocky Mountain (including California) and Other.  To choose the nine companies that received the request, EPA randomly selected one “large” operator from each geographic area, for a total of four “large” operators, and then randomly, and without geographic consideration, selected two “medium” and three “small” operators.

Once the 9 companies were identified, we used a computer algorithm that balanced geographic diversity and random selection within an operator’s list to select 350 wells.

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