The number of US unconventional oil and natural gas wells drilled in 2011 totaled 10,173 with an expenditure of $65.5 billion, estimated API’s 2011 Joint Association Survey on Drilling Costs report.
Shale drilling expenditures increased by 87.6% from 2010 and the number of estimated shale wells drilled in 2011 was 43.8% more than 2010, API said.
The number of estimated shale wells has risen from 5,531 in 2009 to 7,077 in 2010 to 10,173 in 2011. Among the shale wells, shale oil wells in 2011 were 6,759 vs. 3,414 shale gas wells.
The report also showed expenditures on shale drilling accounted for more than half of total well drilling expenditures in 2011, up from barely more than one fourth in 2009.
“The rising numbers illustrate the growing importance of shale drilling in US oil and natural gas development,” said API Statistics Director Hazem Arafa. “Shale drilling drove most of the overall increase in drilling and now accounts for an estimated 23 percent of all wells drilled in the United States.”
Reflecting at least in part of the drilling moratorium by the administration following the deepwater Macondo well blowout and resulting Deepwater Horizon semisubmersible incident, estimated expenditures for offshore drilling slumped from $24.9 billion in 2009 to $4 billion in 2010. Expenditures increased to an estimated $8.1 billion in 2011.