Development of marginal/mature fields has become popular because of a significant decline in new field discoveries and high oil prices. In particular, small size fields of this kind are more challenging because of limited options for development. This paper presents a study on the Sinclair field located in Alberta, Canada. The field has 19 wells, six of which are horizontal, and have been in production for more than 20 years. Despite the quality of oil (40 degrees API, 1.5 cp) and rock properties (20% average porosity, water-wet sandstone), the current production is less than 100 bbl/D for the whole field. The field is now undergoing waterflooding. The main challenges are the thin pay zone (similar to 4 m), severe water production and a puzzling recovery factor of approximately 10%. The current study consists of three phases: numerical reservoir modelling and history match to understand the reasons for low oil production and to analyze the hydrodynamic characteristics of the field, characterization of reservoir and interwell connectivity using static and production data and proposing an enhanced oil recovery technique supported by field scale numerical simulation. After modelling and history matching stages, potential reserves locations are estimated for possible dilute surfactant injection. Based on interwell connectivity, different injection schemes that use some producers as injectors are tested. The obtained results are subject to further evaluation and analysis to derive the economic viability of the field.