Casing ERD Wells to Target the New Improved Casing Flotation - A New Solution

Abstract

Abstract Getting casing to total depth is one of the most important operation in extended reach drilling (ERD) as increased casing depth increases recovery efficiency hence the need to ensure as much casing as possible is deployed into the wellbore. This paper proposes a new method of casing deployment in ERD wells termed New Improved Casing Flotation (NICF). This method is based on the principle of buoyancy and utilizes multiple fluids to deploy different sections of the casing string into the wellbore. This proposed method is validated using a base case extended reach well and the maximum measured depth attained for the 95/8?? production casing compared against other casing installation techniques. From the result of the simulation, the measured depth attained using the NICF method is 29,400 ft. When compared to partial flotation (23,300 ft), full flotation (12,300 ft) and conventional method (12,300 ft), the measured depth obtained using the proposed NICF method exceed that of partial flotation by 6,100 ft, and that of conventional method and full flotation by 17,100 ft. Introduction The need to get hydrocarbons from ultra deep and complex wells have indeed pushed the limits of well engineering. Critical technologies have led to the advent of rotary steerable systems (RSS) and steerable motors assemblies which have enabled drilling with controlled dog legs thereby minimizing drag as the BHA proceeds through its complex trajectory (Thomas et al 2008). The development and use of low torque drill pipes, specialty equipments like NRDPP, DSTR subs, DPB subs, bi-directional rollers, lubricating beads, spot pills and hard banding of tool joints have all proved to reduce the effect of torque and drag thereby extending the limit of drilling in their different applications (Rae, Williams and Hamilton 2003). It becomes obvious that these successes in drilling have to be complimented by successful casing running to total depth (TD) to enhance optimum production from the reservoir. These have led to great advances in the subject of casing design and running techniques. The onus being to develop casing running techniques that can match up the advances of complex drilling as well as being able to withstand all design loads and operational constraints in the most cost effective way (Jaffe et al 1997).