Offshore drilling of large diameter holes in rock formations
Patent 4470468 Issued on September 11, 1984. Estimated Expiration Date: 
July 6, 2003. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
July 6, 2003. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesInventorAssigneeApplicationNo. 06/511504 filed on 07/06/1983US Classes:175/7Boring from floating support with submerged independent anchored guide baseExaminersPrimary: Purser, Ernest R.Assistant: Bui, Thuy M. Attorney, Agent or FirmInternational ClassesE21B 41/00 (20060101)E21B 41/10 (20060101) E21B 17/00 (20060101) E21B 17/01 (20060101) E21B 7/136 (20060101) E21B 7/12 (20060101) E21B 33/13 (20060101) E21B 33/134 (20060101) E21B 33/14 (20060101) AbstractA drilling rig comprises a platform (10) supported above a sea surface (14) by legs which extends to the sea bottom (16). A drill guide (30) of rigid open framework construction extends down from the platform to the sea bottom. The drill guide is only minimally affected by turbulent sea conditions because of its open framework construction. A hardenable substance such as concrete (54) is poured into a flexible bag (50) at the lower end of the drill guide to form a solid structure conforming to the uneven sea bottom and having a substantially flat upper surface. Drilling takes place through the hardenable substance and into the underlying sea bottom.Other References
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