Reelwell drilling method - installation and cementation of 10 ¾’’ casing and 7" liner - method and case example

Abstract

Current technology gives an opportunity to drill Extended Reach Drilling (ERD) wells with a tremendous length of horizontal departure. The Reelwell Drilling Method (RDM) is a drilling technology particularly suited for such long reach wells. This technology gives an opportunity to limit the impact on the environment and reduce the costs. However, to drill ERD wells effectively requires significant improvements in drilling fluids, pressure management, cuttings transport, and mechanical performance of the drillstring. This thesis presents a simulation study the challenges regarding mechanical loads and pressure management for installation and cementation of 10 ¾ casing 7”. For the study, a 15,800 m Measured Depth (MD) ERD well which is planned to be drilled by the RDM was considered. The main objective of the study is to provide an advice for the feasibility of the RDM technology, which is under research and development phase. The study was performed with Landmark WELLPLANTM commercial simulator and literature based theory implemented in MATLAB. The results of the study summarize as follows: o For installation: - The simulation result shows that the drag forces under tripping in or tripping out can be kept within the buckling and tensile limit. This is done by controlling friction coefficient and the operation parameters such as RPM and running speed. o For cementing: - By the use of standard cementing fluids (cement slurry, spacer, and mud), the simulation results show well integrity problems. Even at very low rates the formation will fracture. - The cementing operation can safely be done by controlling the Equivalent Circulating Density (ECD). This can be controlled by reducing the fluid flow rate, reduce the length of the cemented section, and by the use of low density and/or low viscosity cementing fluids. The lower density and viscosity cementing fluids can even be circulated at very high flow rates without well integrity problem.