Deepwater Open Water Work Drilling Optimization

Abstract The use of motorized rotary steerable system (RSS) and advanced measurement-while-drilling (MWD) tools optimized the open-water work (OWW) scope of deepwater drilling operations in Guyana. The objective was to improve drilling efficiency, reduce slide mode drilling, and enhance directional control. While similar BHAs had been used in vertical wells in the Gulf of Mexico, their application in the challenging OWW scope in Guyana was a novel endeavor. To overcome the limitations of the standard bottomhole assembly (BHA), a novel approach was adopted, incorporating a 26-in. rotary steerable system, straight mud motor, and advanced MWD for dynamic surveying. Detailed planning and tool selection, including RSS and motor tendencies analysis, were crucial for establishing initial motorized RSS BHA design. Ten out of fourteen planned wells used motorized RSS BHA, while the remaining four employed a motor and gyro due to anticollision concerns. The study involved optimizing BHA configuration, drilling parameters, and survey acquisition processes to enhance performance. The implementation of the motorized RSS along with advanced MWD tools led to significant improvements in deepwater drilling operations in Guyana. A 75% improvement in drilling efficiency was achieved compared to previous conventional drilling assemblies. The use of the motorized RSS BHA design resulted in the elimination of slide mode drilling, enabling directional objectives to be met more effectively. The average 26-in. section drilling time was reduced by 18 to 28 hours per well. This method allowed for better control and reduced borehole tortuosity, ultimately improving well performance. The success of this approach has now become the standard for future OWW campaigns in the region. Apart from the enhancement in drilling efficiency, this case study has not only pinpointed solutions to overcome directional challenges but has also paved the way for the industry to attain higher inclinations in top hole. This achievement, in turn, addresses challenges encountered in intermediate and production sections by facilitating the creation of smoother catenary curves and delivering less tortuous boreholes. The implications extend to the realm of production and completion, providing a foundation for more streamlined processes and improved precision in the installation of production and completion components.