Alternative Initial Responses to Kicks Taken During Managed-Pressure Drilling

Abstract

This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper SPE 128424, ’Evaluation of Alternative Initial Responses to Kicks Taken During Managed-Pressure Drilling,’ by Majid Davoudi, SPE; John Rogers Smith, SPE; Bhavin M. Patel, SPE, and Jose E. Chirinos, SPE, Louisiana State University, prepared for the 2010 IADC/SPE Drilling Conference and Exhibition, New Orleans, 2-4 February. The paper has not been peer reviewed. An industry-supported research project completed its evaluation of alternative initial responses to kicks taken during the constant-bottomhole-pressure (CBHP) method of managed-pressure-drilling (MPD) operations. This first phase was intended to provide a basis for comprehensive, reliable well-control procedures for MPD operations. Three responses were concluded to have general application: increasing casing pressure until flow out (Qout) equals flow in (Qin), shutting in the well, and adapting an MPD pump-shutdown schedule to detect and shut in low-rate kicks. Selection of the most practical response depends on well conditions and the equipment being used. Potential advantages of and constraints on the use of these responses were summarized. Introduction MPD is an evolving technology used to address drilling problems encountered when using conventional, hydrostatically overbalanced drilling methods. MPD is defined by the International Association of Drilling Contractors (IADC) as a “drilling process used to control precisely the annular pressure profile throughout the wellbore.” The definition also points out that an influx of formation fluids (i.e., a kick) “will be safely contained using an appropriate process.” Establishing the basis for identifying an appropriate process or processes was the focus of this study. CBHP Method of MPD. This method keeps the wellbore pressure relatively constant at a selected depth. This constant wellbore pressure is achieved by adjusting the surface pressure on the annulus to offset changes in the wellbore frictional pressure losses as the pump speed is varied or stopped, such as when making connections. The ability to adjust the surface pressure on the annulus is provided by a rotating control device (RCD), such as a rotating control head, by closing the annulus and directing flow through an adjustable drilling choke. Therefore, the CBHP method of MPD avoids the wellbore-pressure fluctuations that occur when starting and stopping pumps in conventional operations. Consequently, it allows drilling within a narrower “window” between fracture and pore pressures than is safe or practical with conventional methods.