Analytical Investigation of Wellbore Heat Loss and Fluid Temperature Profiles in Steam Injection Wells in the Eriemu Field, Delta State

Wellbore heat loss during steam injection is a critical factor determining the steam quality and enthalpy delivered to the formation, and accurate temperature profile modelling is essential for optimising steam injection well design and evaluating thermal recovery project performance in heavy oil fields. This study analytically investigates wellbore heat loss mechanisms and constructs fluid temperature profiles for steam injection wells in the Eriemu Field, Delta State, South South Nigeria, where shallow heavy oil reservoirs are targets for pilot thermal recovery. The Ramey wellbore heat loss model and its modifications for two-phase steam-water flow were applied to compute steam quality and temperature distributions along the injection wellbore using measured surface injection parameters as boundary conditions. Temperature profiles from distributed temperature sensing measurements in one pilot injection well were used to validate the model predictions, with a mean absolute deviation between measured and calculated temperatures of 4.2 degrees Celsius. Sensitivity analysis demonstrates that wellbore insulation using vacuum-insulated tubing reduces heat loss per unit depth by 73 percent compared to uninsulated production tubing, with the projected benefit most significant in the first 400 metres of depth where thermal gradient losses are greatest. A thermal well completion design optimisation for future injection wells in the Eriemu Field is presented, specifying vacuum-insulated tubing in the upper casing section and conventional insulated tubing below the point of crossover temperature to ambient formation temperature. Keywords: wellbore heat loss, steam injection, thermal recovery, Eriemu Field, Delta State.