Problems Affecting the Design of Drilling Risers

Abstract

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. Abstract With increasing water depth many of the factors considered in making decisions related to the overall arrangement and operation of floating drilling equipment change significantly in magnitude and, consequently, in relative importance. The paper considers ways of evaluating such factors with sufficient accuracy to enable one to make those decisions which must precede the actual design work. The evaluations also serve to define problem areas which will require attention in the design process. It concludes that increased cost effectiveness is extremely desirable and designs with increased cost effectiveness require a greater amount of cooperation between equipment users and makers than has existed to date. Introduction Drilling risers guide tools into undersea wells and conduct the returning mud flow from the blowout preventer stack to the drilling preventer stack to the drilling vessel. They carry choke, kill, and control lines and provide the usual means for supporting the blowout preventer stack during installation preventer stack during installation and removal. In performing these functions they resist static and dynamic loads which are hard to predict accurately. In turn, they impose loads on both drilling vessels and wells. The magnitude of such loads may actually determine the overall arrangements and procedures of drilling operations. All of the loads mentioned increase as water depth increases and we shall consider depths from one to six thousand feet. Before one can effectively undertake the design of a riser, he must have a procedure for deciding exactly what arrangements and procedures will be most effective. procedures will be most effective. Having decided, one can assume load conditions and design components accordingly.