These are industry terms having to do with accidents that can arise from drilling operations. Generally, they are either excluded under the Liability Policy or can be added by endorsement for an additional premium depending upon the judgment of the underwriter.
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Is the uncontrolled eruption of oil, gas, water, or drilling fluid from a well that is being drilled. Cratering is when a well that has already been drilled caves in. Blowouts take place when the pressure of the oil or gas in the reservoir is higher than was anticipated. The result is often a fire fueled by the oil or gas. Cratering often results in the drilling rig falling into the well. Blowout and cratering is excluded in the Commercial General LiabilityA blowoutpolicy but may be added as an endorsement. Operators Extra Expense coverage (also known as Control of Well insurance) may also be purchased. (See Operators Extra Expense).