An Analysis Of Well Kicks On Off Shore Floating Drilling Vessels

Abstract

This paper was presented at the 47th Annual Fall Meeting of the Society of Petroleum Engineers of AIME, held in San, Antonio, Tex., October 8–11, 1972 and is considered the property of the Society of Petroleum Engineers. permission to publish is hereby restricted to an Petroleum Engineers. permission to publish is hereby restricted to an abstract of not more than 300 words, with no illustrations, unless the paper is specifically released to the press by the Editor of the Journal of paper is specifically released to the press by the Editor of the Journal of Petroleum Technology or the Executive Secretary. Such abstract should Petroleum Technology or the Executive Secretary. Such abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in Journal of Petroleum presented. Publication elsewhere after publication in Journal of Petroleum Technology or Society of Petroleum Engineers Journal is granted on request, providing proper credit is given that publication and the original providing proper credit is given that publication and the original presentation of the paper. presentation of the paper. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of petroleum Engineers office. Such discussion may be considered with the paper for publication in one of the two SPE magazines Abstract Well control for land or offshore bottom supported drilling rigs has been published in the literature in sufficient detail. A floating vessel has inherent motions which are transferred to the drilling rig and the well control techniques become more challenging. In February 1972 it was estimated that 41 floating drilling vessels were under construction. This new construction represents an investment of $850 million and a 70% increase in the number of floating drilling vessels. The paper attempts to offer a review of well control problems while drilling from a floating drilling vessel. The motions of a floating drilling unit and the configuration of the available well control equipment are reviewed. Available data which presented interesting aspects of the well control problem was analyzed. Solutions which were found to these problems are presented for the use of all operators of floating units to assist personnel transfering from bottom supported to floating drilling operations. Well control is possible from floating drilling vessels with the proper configuration of well control equipment, development of operating procedures and constant training of personnel. Specific areas have been suggested for further research and development by individuals or organizations interested in refining the well control operations. THE MOTIONS AND FORCES ACTING ON A FLOATING RIG An accepted definition of a blowout has been an uncontrolled flow of fluids from the wellbore. A kick precedes a blowout and occurs when a formation that has a pore pressure which exceeds the hydrostatic pressure of the mud column is drilled into. Personnel assigned to floating drilling operations should command a working knowledge of kick control techniques and pore pressure prediction methods. prediction methods. A simplified analysis of the motions of a floating drilling unit is useful in order to appreciate the differences between well control on a floating drilling vessel and map control on land. A vehicle in space has three motions parallel to a theoretical x, y, z axis; surge, heave and sway; and three rotating motions about these axis; roll, yaw and pitch. Roll and pitch limit the ability to handle pipe on the rig floor and hence, may be considered to hamper well control operations. Heave, which is the motion parallel to the vertical y axis is of most concern in well control operations since it is transferred to the drill string in the region of the subsea blowout preventors.