Technical Evaluation of Coiled Tubing Applications for Well Stimulation in High-Deviation Wells of the Ude Field, Rivers State, South South Nigeria

Coiled tubing has emerged as a versatile well intervention tool for stimulation operations in high-deviation wells where conventional jointed pipe cannot be effectively deployed due to friction limitations. The Ude Field in Rivers State, South South Nigeria, contains multiple high-deviation production wells with restricted access for conventional stimulation interventions. This study evaluates the technical feasibility and operational requirements of coiled tubing-conveyed stimulation treatments in the high-deviation wells of the Ude Field. Well trajectory data, inclination surveys, and bottomhole temperature and pressure profiles from twelve candidate wells were used to determine coiled tubing reach capabilities and weight transfer limitations as a function of coiled tubing size and borehole geometry. Helical lockup calculations confirmed that 2.375-inch outer diameter coiled tubing can achieve reliable reach to total depth in all candidate wells with inclinations up to 68 degrees, while larger 2.625-inch coiled tubing is limited to wells with maximum inclination below 55 degrees. Stimulation treatment designs including matrix acidising and nitrogen foam acid diversion were developed for the specific reservoir conditions of the Ude Field, with friction pressure calculations for coiled tubing conveyance incorporated into the hydraulic design. The study recommends 2.375-inch coiled tubing with real-time downhole weight indication for all stimulation candidates and estimates an average productivity index improvement of 35 percent based on analogous treatments in offset fields. Keywords: coiled tubing, well stimulation, high-deviation wells, Ude Field, Rivers State.