Hydraulic fracturing activities implemented in Sirikit onshore oilfield of Thailand over a decade. Before 2018, the variation in post-fracturing production performance resulted in about 50% stimulation success rate. This outcome posted a big challenge to maintain project momentum. Hence, the candidate selection methodology was developed in-house which recommends "suitable" reservoirs. Using selection criteria, the multi-layered, low permeability reservoirs were selected for the 2018-19 Hydraulic Fracturing Campaign. Production analysis was conducted using the information gathered from past hydraulic fracturing campaigns. Reservoir Index (RI) was invented to distinguish the subsurface quality by formation permeability, thickness, pressure, and fluid properties. Together with the Fold of Increase (FOI) owing to hydraulic fracturing, a performance-based relationship was created which can categorize suitable reservoirs based on their RI ranges. This method has been applied to newly drilled wells during 2018. In the end, there were 13 wells selected to perform 28 hydraulic fracturing stages. The 2018-2019 Hydraulic Fracturing Campaign at Sirikit Oilfield was planned and executed. Post-fracturing production tests showing significant improvement. Some wells resulted in excellent oil production rate naturally, while some maintained high rate by artificial lift. According to post-campaign analysis, hydraulic fractures were proved to connect multiple layers of satisfactory flow capacity. In addition, well angle and stress direction accommodated the placement and orientation of multiple hydraulic fractures. As a result, the number of hydraulic fracturing stages that achieved economic production tests improved to 75% success rate. Hydraulic fracturing results from the past were fully utilized in order to achieve sustainable production improvement, thus driving continuous stimulation activities in the future. The candidate selection methodology has shaped up a candidate selection workflow that pointed out success criteria and avoided those that may lead to failure, which proved to be successful in one of the most complex fields in Thailand.