Study on open-hole extended-reach limit in horizontal drilling with wavy wellbore trajectory

Drilling a series of sinuous wellbore trajectories has emerged as a promising operation, offering significant advantages in enhancing reservoir contact. Based on various development cases (Zili and colleagues), it has been observed that horizontal wells with wavy wellbore trajectories tend to exhibit higher production rates. However, extending the length of these wavy trajectories requires careful consideration in terms of safe drilling practices, as the pressure management associated with these intricate trajectories has been seldom explored. In this study, we establish a modified model for annular pressure to predict and assess the open-hole extend-reach limit of horizontal wells with wavy wellbore trajectories. The introduced model incorporates dry friction force and annular geometry influenced by cuttings bed, making it more accurate than traditional models based on experimental observations. The wavy wellbore trajectory comprises three types: the up-dip wellbore, the down-dip wellbore, and the complex wellbore. Overall, the horizontal interval limits for the down-dip wellbore and up-dip wellbore are smaller than those of the corresponding smooth wellbores under varying factors. Notably, the complex wellbore trajectory offers advantages in navigating formations with narrow pressure windows compared to conventionally horizontal wellbores (smooth wellbores), thanks to its longer extended-reach limit. Drilling a series of wavy wellbore trajectories has emerged as a promising operation, offering significant advantages in enhancing reservoir contact. Extending the length of these wavy trajectories requires careful consideration in terms of safe drilling practices, as the pressure management associated with these intricate trajectories has been seldom explored. image