Accelerated Design of Sidetrack and Deepening Well Trajectories

Abstract

Summary Sidetrack and deepening wells play a pivotal role in enhancing oil and gas recovery while simultaneously reducing drilling costs, particularly in cluster well scenarios. These wells leverage existing wellbores effectively, resulting in substantial reductions in development expenses. Deepening wells maximize cost savings by utilizing the entire length of preexisting wellbores. These wells strategically access low-permeability layers, thin pay zones, wedge zones, and marginal reserves while also serving as rapid response solutions during emergencies to expedite risk mitigation in accidents. There is a pressing need for expedient, safer, and cost-effective well designs to achieve economic efficiency, which necessitates the development of advanced design methodologies. However, designing optimized 3D sidetrack and deepening well trajectories for oil and gas reservoir access while mitigating collision risks is a complex and time-consuming task that demands meticulous planning and exhaustive well path analysis, often involving multiple iterations to ensure cost-effective solutions meeting drillability and safety constraints. In this study, we develop an integrated framework for the accelerated design of sidetrack and deepening well trajectories, complemented by a trajectory optimization algorithm to generate safer and cost-effective well trajectories. The developed framework is rigorously tested in a live Nigerian oil and gas field. The case study involves the design of a sidetrack and a deepening well trajectory in a crowded brownfield consisting of 21 legacy wells. The results of the case study exhibit the significance of the established framework on streamlining the well design process, leading to expedited creation of efficient and safe sidetrack and deepening well trajectories.