The Impact of Water-Based Drilling Mud Discharges on the Environment: An Overview

The first well drilled in the United States was in the year 1859 in the state of Pennsylvania. Since then about 2.7 million onshore wells have been drilled in the U.S. onshore drilling presently continues at an annual rate exceeding 50,000 wells with total depths ranging from hundreds of feet to greater than 20,000 feet (6,100 metres).